Final Design Review Report - Purdue University...2020/08/04 · cause 50 psi, 30 psi, and 15 psi of...

Final Design Review Report

Design of a Particulate Material

Compression Feed Screw for Research and

Data Collection

Submitted to:

Dr. Marcial Gonzalez

Dr. Carl Wassgren

Dr. Charles Jensen

Abhishek Paul

Submitted by:

The Feed Screw Speed Crew:

Marcus Gunyon

Mohammed Matar

Josh Meiners

Evan Selking

Yun-Jui Jeremy Tu

Rachel Wasem

8/4/2020

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Executive Summary:

Our mission was to produce a cost-effective, modular tabletop design of a compression

feed screw for formulation and validation of predictive models of torque, angular speed, and

mass flow. Currently, the project is prepared for fabrication, as all manufacturing and systems

design is complete. The team members’ leads, charter, and schedule can be found in Appendix

A, B and D. The focus of this phase has been finalization of the prototype and validation of met

engineering requirements, summarized in Table 1 below and detailed in Appendix Q:

Table 1: Customer Requirements and Validation of Parameters

Close attention to mitigation of risk (Appendix E) and adherence to the project budget

(Appendix C) resulted in a safe and readily accessible means of data model validation costing

tens of dollars instead of thousands per test. Providing a personal feed screw also allows for

more thorough improvement in the researcher’s models, leading to exponentially larger

improvements and smaller costs of feeding issues in multi-million dollar biorefineries, saving

them up to $1,000,000 per year. The final prototype, as pictured in Figure 1 below, was

mechanically and electronically designed to provide repeatable feeding experiments while

producing useful data for model validation.

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Figure 1: Photo-Realistic Render of Fully Assembled Device

The mechanical model was dimensioned as a scale model (Length: 53 in. Width: 9.5 in.

Height: 10.5 in., Weight: 103 lbs) of a provided basic feed screw. The team innovated this design

to include clamshelled casing, flexible chain coupling, a motor and modular supporting stand,

and a simulating, spring loaded back-pressure plate to resist flow of biomass. The basic model

alone was previously unable to collect or electronically record any operational data, lacked

flange connections, and only included 4 total parts. Perhaps the largest innovation made was the

creation of the pressure plate, made up of a 45 degree cone extruding to block the end of the

plug, forced against fed particulate material by 4 15 lbs/in springs. The springs are pushed by a

1/16 in. A36 Steel plate that butts up against a load cell, which is attached to a supported 9.5 in.

square plate. The 9.5 in. plate’s supports are then screwed into one of 5 potential steel insert

locations. These locations were chosen specifically to provide spring displacements that will

cause 50 psi, 30 psi, and 15 psi of pressure on the fed material. A closer view of the pressure

plate apparatus can be seen below in Figure 2. Appendix G illustrates all the innovations made to

the physical design, while Appendix H validates operability. Products of the design process,

including benchmarks and sketches exist in Appendices N and F respectively.

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Figure 2: Photo-Realistic Render of Pressure Plate Apparatus

The device allows for user control of motor speed, controlled by a potentiometer. Once

running, an Arduino collects readings of shaft speed, motor power, pressure load, torque, and

strain on 12 different bolt connections and records them each second. This data is placed into

visual time graphs, highlighting maximum and minimum values and when variations may occur.

The mass flow is also measured using a simple scale underneath the exit of the feed screw, from

which average mass flow is calculated by dividing mass collected by time of operation. A wiring

diagram, displaying the Arduino based circuit is seen below in Figure 3, while Figure 4 shows

the data table and example graph that the operator would see automatically updating while

running the device. Appendices I, J, and K contain further details, as well as the electronic

schematic, Arduino code, and a flow chart.

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Figure 3: Full Wiring Diagram

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Figure 4: Automatically Updating Example Graph and Data Collection Table

The parts as seen in Figure 1 will be manufactured 1 of 3 ways: Xometry custom

manufacturing, personal manufacturing at Bechtel Innovation Design Center, or pre-

manufactured part orders. Manufacturing drawings for parts produced in BIDC or Xometry can

be found in Appendix L, and links for any needed purchases are found in Appendix R. Further,

Appendices M, O and P outline what was learned from each of the three prototypes produced

during the project, the basic physics model of the device, and a list of standards referenced.

Appendix U was used to confirm the necessary tolerances of these manufactured parts.

Given all this information, the team requests that the researchers fabricate and assemble

the design using steps listed in Appendix S, the manufacturing plan laid out in Appendix T, and

apply all physical validations stated in Appendix Q before operating.

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Contents

Appendix 8

A: Team Members and Organization Structure 8

B: Charter 9

C: Business Case and Project Budget 10

D: Work Breakdown Structure and Project Schedule 13

E: Risk Mitigation 15

F: Sketches 17

G: Mechanical CAD 30

H: Mechanical CAE 36

J: Arduino Code 54

K: Flow Chart of Control/Operation 63

L: Manufacturing Drawings 67

M: What was Learned from the Low, Mid, and High-Fidelity Prototypes 86

N: Benchmark research 88

O: Basic Physics Model (Free Body Diagram) 91

P: Standards Referenced/Used/Applied 96

Q: Testing and Validation 98

R: Links to Purchased Components and Display Videos 100

S: Assembly Instructions 104

T: Manufacturing Plan 112

U: Table of Fits and Tolerances 115

NOTE:

For the Final Design Review (FDR), each Appendix was finalized. The updated

appendices from the Critical Design Review (PDR) exist in appendices A through P. While they

were created for the PDR, they reflect progress made in preparation for the CDR and FDR.

Significant changes from CDR to FDR can be found in Appendices F, G, H, J, L, M, P, Q, R, S

and T. All new appendices created specifically for the CDR exist after Appendix P.

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Appendix

A: Team Members and Organization Structure

The roles and coverage of the six members of the Feed Screw Speed Crew has not

changed since the CDR stage as seen in Table 2.

Table 2: Team Organization structure

Team Member Role Coverage Contact

Information

Rachel Wasem Research and Sketch

Artist

Sketches, WBS, Project

Schedule and Notebook,

Project Vision

[email protected]

Marcus Gunyon CAD Lead Dimensioning, Control of

files, Incorporating

sketches into CAD

[email protected]

Josh Meiners Organizer and Editor Formatting, Drafting,

Project Scoping,

Brainstorming

[email protected]

Mohammed

Matar

Risk Management

and FEA

Budgeting, FEA Analysis,

Manufacturing Research

[email protected]

Yun-Jui

(Jeremy) Tu

Controls and Coding Motor and Sensor Control,

Arduino Coding, Wiring

Flow Charts/ Diagrams

[email protected]

Evan Selking Instrumentation Research and Sensor

Selection, Sensor CAD

File Control

[email protected]

The project clients are shown in Table 3 with their contact information. Each client has

offered ideas, project guidance, and standards to be met by the team. They are available via

email at any time and have scheduled meetings with the team every week on Tuesdays at 9:00

AM.

Table 3: Client Organization structure

Client Contact

Abhishek Paul [email protected]

Dr. Carl Wassgren [email protected]

Dr. Marcial Gonzalez [email protected]

mailto:[email protected]









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B: Charter

Appendix B includes the project charter, shown below in Figure 5, which reflects the

final vision statement of the team and a basic overview of the project in the current FDR stage.

The project charter was last updated to include more risks and clarify some resources required

(such as machining and assembling).

Figure 5: Team charter stating a basic overview of the project

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C: Business Case and Project Budget

Appendix C provides the justification and financial planning of the project. Updated

business model benefits for the FDR have been appended to the end of this section.

The project budget was finalized for fabrication and is shown in Figure 6. The total cost

of the device is estimated to be $4,649.05 (92.98% of budget), with the addition of generous

estimates of $1,000 for shipping costs and $500 for the motor that still has yet to deliver a quote,

leaving $350.95 left in the $5,000 budget. The bulk of this cost ($1603.02) comes from the

manufacturing costs of the specialized casing and screw needed for this project. This

manufacturing will be done with Xometry, an on-demand industrial manufacturer of custom-

made parts. Having an outside manufacturer was chosen rather than writing machining

instructions for the clients for a few reasons. Firstly, as the clients are research professors at

Purdue University, the clients indicated they would rather receive completed parts and only have

to spend time doing minimal assembly. Secondly, the $5,000 budget leaves the team with this

option, and having professionals manufacture it will minimize risks that arise from having the

Feed Screw Speed Crew relay instructions to another team. Other parts that are simple shapes

and made out of either Aluminum 6061 or A36 Steel can be left for the researchers to assign to

an undergraduate for manufacturing utilizing the provided drawings in the Bechtel Innovation

and Design Center. Finally, profit is not the motivation for this project, and minimizing risks is

worth this added cost.

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Figure 6: Project Budget List

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The device will save researchers both time and money. The current arrangement requires

them to spend $10,000 for every test, while having to wait months for results from the industrial

model. A personal tabletop device therefore shortens the wait time for results to days or weeks,

allowing much more data to be gathered and more tests to be run in the same timespan. By

having a robust system, it allows them to have more confidence in their models and ensure their

robustness. On a larger scale, the estimation is that it will save industrial plants anywhere from

$100,000 to $1,000,000 per year. It will also allow them to collect data that the industrial plant

cannot provide.

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D: Work Breakdown Structure and Project Schedule

Appendix D contains documents that allow the team to plan and manage the project.

A work breakdown structure is seen below in Figure 7 that indicates the different tasks

that were completed throughout the different phases of the project. The chart was updated to

include the more detailed tasks done for the FDR, such as the Assembly Instructions and Testing

and Validation. These tasks have been put into a schedule seen in Figure 8. Specific tasks were

divided among the team members based upon their role assignments as seen in Table 1 and are

shown in the resources column.

Figure 7: Work Breakdown Structure highlighting the different tasks needed for the project

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Figure 8: Project schedule showing the timeline of the project

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E: Risk Mitigation

Appendix E includes the risk mitigation spreadsheet that was compiled by the team. It has been

updated to reflect the risks identified throughout the entirety of the project.

The team’s risk mitigation spreadsheet is seen in Table 3. The risk mitigation spreadsheet

was updated to reflect the risk mitigation strategies developed since the beginning of the project,

such as the installation of a specially designed mesh, allowing for only the particulate material

and the non-handle end of a stoking rod to enter the hopper. Damage to the device caused by

excessive torque due to blockages will be prevented by a torque limiter that will shut down the

device if a certain torque output is surpassed. There will also be a manual emergency stop button

unforeseen contingencies. Some new risks were identified, such as the risks arising from using a

custom manufacturer, Xometry, for the parts.

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Table 3: Risk Mitigation Spreadsheet

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F: Sketches

Appendix F contains the various sketches compiled over the course of the design process.

Additions to the sketches during preparation for the FDR can be found after Figure 16.

Figure 9 shows the different support methods explored by the team to hold the modular

barrels in place. The left design uses simple supports, the middle uses clamps, and the right uses

rotating arms. The clamp and arms were considered for their superior ability to adapt to

differently sized barrels, however the simplicity of the simple support coupled with a decreased

need for full adjustability rendered the simple support the best design choice. Therefore, Team

down selection led to the selection of the static support structure, as seen in Appendix G.

Figure 9: Sketch of potential support methods

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The decision matrix in Figure 10 was utilized to compare the three main group ideas for

how to support the device and its modular capabilities. Originally, the rotating pads was the

leading idea when it was incorrectly believed to have a need for vast variation in dimension.

Once it was clarified that the supports only needed to hoist similar parts with 2 differing inside

diameters, the normalization caused the simple supports to be the final chosen support frame

design.

Figure 10: Decision Matrix for Down Selection of Support Frame

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Figure 11 illustrates the location and usage of the RPM Hall Effect Sensor. A gear

attached to the rotating drive shaft will have teeth passing over the inducting sensor, registering a

readable angular velocity, that when wired to the Arduino will output the RPM of the driveshaft

and contribute to torque calculation. This gear and sensor combination can be placed anywhere

along the driveshaft in between the hopper and motor.

Figure 11: Sketch of RPM Hall Effect Sensor Location

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Figure 12 shows how the different sections will be attached using flanges in both a front

view and a side view to highlight the connections between the top and bottom halves of the

barrel as well as the connections between barrel sections. The strain gauges posted at the flanges

of the clamshell design will serve to measure load on the outer caging of the feed screw.

Figure 12: Sketch of assembled screw casing, front view and side view

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Figure 13 illustrates the mass flow system, within which biomass will flow out of the

plug and into a collection bin to be weighed. Alternative methods for mass flow measurement

were considered, but in Down Selection this was by far the least complicated and most cost-

efficient option. It is important to realize that the back pressure plate posted at the end of the plug

is representative of the pressure from what would be a chemical reactor. The plate is designed to

apply various amounts of pressure for testing of multiple different reactor needs.

Figure 13: Sketch of Back Pressure Plate and Mass Flow Sensor or Scale

Figure 14 illustrates the concepts created while exploring how to generate a controllable

and measurable back pressure. The first utilizes a load cell to measure the force applied by a

linear actuator. Fluctuations in the measured load during testing due to the forces applied by the

material exiting can be tracked. The middle concept utilizes springs to calculate the force exerted

when a linear actuator moves the plates closer together. Again, variations measured by the force-

sensitive plate can be tracked during experiments. However, this design could unevenly apply

back pressure as the material exiting will disproportionately compress the bottom springs. This is

improved on in the final design, which allows the plate to slide along rigid rods like the first

design to limit the possible rotation of the plate.

Figure 14: Sketches of Back Pressure Plate Concepts

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The decision matrix in Figure 15 was utilized to compare the three main ideas for the

pressure plate design. The deciding factors were the cost and ability to limit rotation to ensure

accurate force readings.

Figure 15: Decision Matrix for Back Pressure Plate

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Figure 16 shows different designs that were considered for the clamshell sections of the

tapered zone and the plug. The first would reduce the number of moving parts by connecting the

bolts to the casing by a pin, which would allow the bolts to be loosened and removed without

having as many pieces to keep track of. The hinge design would allow the two sections of the

flange to rotate and open without having to remove any parts, however it might not be able to

withstand the pressures inside

Figure 16: Alternative designs for clamshell

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Figure 17 represents a schematic drawing for the creation of the CAD model displaying

the coupling of the feed screw shaft to the motor’s drive shaft. Exiting the hopper, the screw

shaft encounters a large bearing that supports the shaft and allows free rotation. A 1 inch gap, the

shaft runs through the first of 3 bored sprockets. The first sprocket runs its teeth just above the

Hall-Effect sensor, incrementing each time a tooth passes by to measure the actual RPM of the

rotating screw. The middle sprocket is then coupled with the motor-side sprocket with a double

chain. The screw shaft ends inside the chained section, and the motor shaft begins. The Motor

shaft enters the motor-side sprocket, where it is attached to the motor just outside. This coupling

is a flexible coupling, meaning that up to 1 degree of misalignment between the motor shaft and

screw shaft will not affect the driving of the feed screw.

Figure 17: Screw/Motor Shaft Coupling Schematic

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Figure 18 displays a schematic drawing for the creation of the CAD model displaying the

back-pressure plate. The 45 degree conical steel plug is inserted into the end of the feed screw,

plugging both the 1.5 in. or 1.25 in inner diameter modular parts. A flange attached at the end of

the casing supports 4 0.25 in. diameter rods that act as rails for the following plates to slide upon,

and supports for the springs. The conical plug is part of a square A36 steel plate that sits on the

rails. Between this plate and the one to follow, 4 springs with a k value of 15 lbs/in apply axial

force to the conical plug plate along the rails. This pushes the plug into the casing to block

feeding material and apply a specific pressure to simulate chemical reactor back-pressure. The

A36 steel plate on the opposite side of the springs will be a simple 1/16 in. plate that will

experience the equal and opposite force from the springs, and push onto a load sensor attached to

the plate just to the right of it. The A36 steel plate containing the load cell, is then supported by

90 degree shelf supports. The location of these shelf supports will depend on the desired

pressure, compressing the springs a specific amount to apply a specific force to the specific area

of the feed exit, producing a predetermined pressure to the fed material.

Figure 18: Pressure Plate Schematic

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Figure 19 and 20 include a drawing and list to communicate the necessary location of the

shelf supports. The customer requirements state that pressures of 50 psi, 30 psi, and 15 psi need

to be able to be applied to both the 1.5 in. and 1.25 in. inner diameter parts. Since the areas will

differ, there are 6 locations for the shelf supports to sit in order to apply the listed pressures. The

supports will be bolted into the bottom plate in three locations, marked with press-fit inserts

supporting ¼ in. bolts. After calculation, it was found that 2 of the 6 cases only differed by 0.01

inches, meaning that only 5 total sets of holes were needed. Cases A through C in Figure 20

represent locations for the 1.5 in. diameter hole and apply 50 psi, 30 psi, and 15 psi respectively.

Cases D through F do the same, but for the 1.25 in. diameter case. These locations were

determined based on spring compression calculated from the excel sheet in Appendix H.

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Figure 19: Shelf Support Bolt Locational Schematic

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Figure 20: Horizontal Shelf Support Bolt Locations

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Figure 21 a schematic drawing for the creation of the CAD model displaying shelf

support bolt location in the vertical A36 steel plate holding the load cell. Each set of holes is

displaced by ½ in. to account for the separation of the bolt holes on the bottom plate.

Figure 21: Horizontal Shelf Support Bolt Locations

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G: Mechanical CAD

Appendix G demonstrates the final FDR design. It offers explanations regarding its concept and

the relationships between parts.

As seen below in Figures 22 and 23, a lot of progress has been made from the low-

fidelity prototype to the high-fidelity prototype. Many additions to the original provided CAD

file have been made, since this file only included a rough representation of the hopper, throat,

plug and screw. The additions include the clam-shelled designs of the throat and plug for access

in instances of blockage. A protective grate was added to the top of the hopper for limb safety.

All sensors, their locations, software, and circuit were created so that the operator is able to

produce data and store it for analysis. The motor was selected by the team, and configured to

couple with the feed screw shaft, while being electronically controlled by a RPM Potentiometer.

The team also designed the pressure plate at the exit of the feed screw, to provide multiple

different reactor-simulating back-pressures, including the use of steel plates, load cells to display

the exact force, and carefully placed mounts to achieve correct spring displacement. To present

the Mechanical CAD model, Figure 24 through Figure 32 display zoomed in views, and are

labeled with the portion of the design they emphasize.

Figure 22: Low-Fidelity Prototype

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Figure 23: High-Fidelity Prototype

Figure 24: Electronic Components Laid out and Wired

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Figure 25: Hopper Zoom with view of Feed Screw Within

Figure 26: Shaft Coupling Zoom with visible Hall-Effect Sensor Location

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Figure 27: Motor Support System and Control Panel

Figure 28: Backside view of Control Panel

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Figure 29: View of Main Body of Feed Screw Casing

Figure 30: Zoom of Spring Loaded Pressure Plate Apparatus

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Figure 31: View of Mass Flow System with Base Plate Mounted Load Cells

Figure 32: View of Pressure Plate’s Supporting Brackets, Mounted into the Base Plate

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H: Mechanical CAE

To analyze the material and thickness of the design, finite element analyses studies were

carried out in Solidworks. For preprocessing, a mesh was created using parabolic tetrahedral

elements with global element size of 9 mm was used as seen in Figure 33. 110827 nodes were

created (corresponding to 66714 elements). This fine mesh was used to avoid interference errors,

particularly in the hopper mesh section.

Figure 33: Visible Mesh for FEA

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To analyze the case, a pressure load was applied on the screw and plug sections as seen in

Figures 34 and 35 to simulate the pressure from the back reactor, leaving the base plate fixed.

The pressure is assumed to parabolically grow from 350 Pa at the beginning of the screw section

to a peak of 15 MPa at the screw-plug junction, with the pressure values being specified by the

clients. The pressure value then exponentially decays to a value equal to the back pressure

simulated (in this study a pressure of 0.3447 MPa, which amounts to 50 psi). Figures 36 and 37

show a graphical representation of the applied pressure function.

Figure 34: Pressure Loading Exponentially Increasing Along Junction

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Figure 35: Pressure Loading Exponentially Decreasing Along Screw

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Figure 36: Pressure Representation Along Screw, with 0 Distance at the Screw-Plug Intersection

Figure 37: Pressure Representation Along Junction, with 0 Distance at the Screw-Plug

Intersection

After applying the pressure load, the material of the case was selected to be 6061-T6

aluminum. With a maximum yield strength of 275 MPa and at a cost of $4.54/lb (See Budget in

Appendix C), the material was selected as a good balance between strength and affordability.

Due to the peak pressure value being applied at the screw-plug junction, the thickness of the

junction was also analyzed and chosen to ensure structural integrity of this critical point. With a

thickness of 0.25 inches, the displacement plot and the Von-Mises stress plot were generated.

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The displacement plot seen in Figure 38 determined a maximum displacement of

4.339*10-3 mm at the junction, indicating no major deformation overall.

Figure 38: Displacement Distribution on Casing (mm)

The Von Mises stress plot in Figure 39 indicated a maximum stress of 23.1 MPa at the

junction. With a maximum yield strength of 275 MPa, the casing is not expected to fail under the

applied pressure load and has a factor of safety of 11.9.

Figure 39: Von Mises Stress Distribution on Casing (N/mm2)

The results of the analyses show that with a material of 6061-T6 aluminum and a screw-

plug junction thickness of 0.25 inches, the case is able to handle the pressure load.

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Next, the shaft was also analyzed in Solidworks. For preprocessing, a similar mesh with a

size of 10mm (10714 elements) was used as seen in Figure 40. The base of the screw connected

to the motor was modeled to be fixed. To analyze the shaft, a constant torque of 300 Nm was

applied on the screw as seen in Figure 40 to simulate the motor acting on the shaft. The material

of the shaft was chosen to be AISI 4130 steel to handle the additional stress the screw may

experience. With a shaft outer diameter of 1 inch, the displacement plot and the Von-Mises stress

plot were generated.

Figure 40: Mesh and Torque Loading on Screw

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The displacement plot seen in Figure 41 determined a maximum displacement of 0.122

mm at the free end of the screw, indicating no major deformation overall.

Figure 41: Displacement Distribution on Screw (mm)

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The Von Mises stress plot in Figure 42 indicated a maximum stress of 38.5 MPa at the

connection with the motor. With a maximum yield strength of 460 MPa, the casing is not

expected to statically fail under the torque.

Figure 42: Von Mises Stress Distribution on Screw

A fatigue study was also performed to study the longevity of the screw. Due to the

alternating stresses of the model being below the minimum S-N curve values of AISI 4130 steel,

there is no expected damage from fatigue.

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The mass properties of the final assembly were analyzed and given in Figure 43. The

final mass of the assembly is estimated to be 103 pounds. Because the part is a tabletop design

and largely stationary, the principal axes, moments of inertia, and centers of mass are not of

primary concern.

Figure 43: Assembly Mass Properties

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Figure 44 is a picture of the excel document utilized to calculate the spring displacement

needed in order to apply a specific force in lbs to the end of the screw casing, so that when

material is fed through the exit hole, it experiences a pressure of 50 psi, 30 psi, or 15 psi based

on the exit area. For this application, the team used 15 lbs/in springs at a free length of 2.5

inches.

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Figure 44: Spring Displacement Calculation

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I: Electronic Schematics

Appendix I includes information, images, and relationships between the various sensors

and electrical components used in the system. Figure 49 was updated to show the new load cell

being considered for use in the force-sensitive plate, and Figure 52 was updated to show the new

motor to be used to drive the screw.

A Hall Effect sensor like the one in Figure 45 will be used to record motor position and

motor speed. This data will be used to help calculate the torque put on the screw. A Hall Effect

sensor measures the magnetic field around the sensor and uses that to determine speed and

position. This sensor will be installed near the shaft of the motor to read the rotation position of

the shaft and convert that over time to rpm of the shaft. This, along with the known power

supplied to the motor, will allow torque to be calculated.

Figure 45: Hall Effect Sensor to record motor position/speed

Strain Gauges, seen in Figure 46, will be inserted into the bolts to measure axial force,

strain, and vibration. These sensors will give insight into what is going on regarding the forces

experienced by the bolts. This will be essential data for the researchers. The strain gauges will be

installed on the clamshell bolts as well as the bolts fastening the shell to the base. The installation

of the gauges is as simple as inserting them into the bolt holes and sealing them in the holes with

adhesive. For the FDR, the strain gauges will be upgraded from the LB11 model to the TB21

model. This allows for compatibility with the arduino, allows for higher strain readings, and is

operational in a larger temperature range. The TB21 is a more durable, industrial sensor with

very little added cost.

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Figure 46: TB21 Strain Gauges for Measurements in Screws and Bolts

Figure 47 visualizes how the force within the barrel translates to the forces exerted on the

bolts. As can be seen, the horizontal forces offset each other, leaving only the vertical forces to

affect the bolts. The sensors in the bolts are bonded with a special adhesive to their insides so

that they experience the same forces as the bolts.

Figure 47: Force Diagrams of Pressure in the Screw Barrel and Force Exerted on the Bolts

An Emergency Stop button, in Figure 48, will need to be included in the design for safety

reasons. The E-Stop button will allow the user to shut the motor off should anything go wrong

while operating. A representation of the E-Stop button is seen below in Figure 48. The

emergency stop button will be installed on the base of the feed screw, near the hopper. This is the

most dangerous area for users so it is important to have the E-stop nearby. For the FDR, a

smaller, more inexpensive model of E-stop was chosen to reduce cost and fit more appropriately

on the model.

Figure 48: E-Stop button

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Since the CDR, a decision was made to move from one load cell to four smaller load

cells, one for each spring. This allows larger forces to be measured because each sensor will

ideally experience ¼ of the total load. This allowed the team to use a smaller sensor that was

capable of reading the expected load. The expected load was calculated by using the applied

back pressure from the springs and the plug area. These smaller sensors can give more precise

readings than one large sensor, are less bulky, and cheaper. The new sensor can be seen in Figure

49. The Degraw 50 kg load cell combo kit will be used on the high fidelity prototype. The kit

comes with 4 load cells and amplifiers to make them compatible with the arduino.

Figure 49: Degraw load cell that will be used to measure force on springs

Degraw 50 kg Load Cell with HX711 Amplifier are chosen because it is straightforward

and versatile. Each Degraw load cell shown in Figure 49 can measure up to 50kg. The HX711

amplifier sensor module can be used with 1 or 2 or 4 load cells and measure 50 ~ 100 ~ 200 kg.

Each strain gauge will need one HX711 amplifier and there are 12 strain gauges in total. A set of

4 load cells and 1 HX711 amplifier will be used for the measurement of mass flow while another

set of 1 load cell and 1 HX711 amplifier will be used for the pressure plate load. When using the

load cell, the load cell will need to be mounted on a surface with screws and bolts, so that the

weights/loads/forces exerted on the surface can be measured by the load cell.

The HX711 amplifier module shown in Figure 50 amplifies the voltage difference from

the Degraw load cell and then outputs the value. This value is not necessarily in gram, so it needs

to be calibrated using another Arduino calibration algorithm. Then the calibration value is then

put into the main Arduino code. The HX711 amplifier can receive values from 1 or 2 or 4 load

cells with different circuit wirings, where each load cell can measure up to 50 kg. Therefore, we

use only 1 load cell for the pressure plate measurement to save rooms needed and the measure

limit of 50 kg fits our requirements. On the other hand, we use 4 load cells for the mass flow

measurement to measure up to 200 kg. The HX711 is also used for the TB21 strain gauge sensor

to measure the strain inside of a certain screw. Each strain gauge connects to 1 HX711 amplifier

and 12 strain gauges are in use. Overall, 14 HX711 amplifier modules are used for the pressure

plates, mass flow and strain gauge measurements. Different calibration factors are needed for

different uses and will need to be input by the user to the main code.

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Figure 50: Degraw 50 kg Load Cell with HX711 Amplifier

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Figure 51: HiLetgo ACS712 30A Current Sensor Module 30A Range ACS712 Module

The voltage of the motor power supply shown in Figure 52 is 24 V fixed, which should

be provided from the wall outlet through a transformer. In order to calculate the power

consumption of the motor, the team needs either the current or the resistance of the motor and the

resistance is hard to measure. Therefore, an ACS712 current sensor will be used in series with

the motor to measure the current through the motor and the power can be calculated. The

ACS712 current sensor shown in Figure 26 can measure between positive and negative 20

Amperes, which covers the possible range of the current through motor, being lower than 1.5

Ampere based on the specification sheet. After the power consumption is calculated, a hall effect

sensor is used to measure the rotational speed of the motor in rpm. The current sensor and the

hall effect sensor are selected for easy use with Arduino.

Figure 52: MM 504-11 Low rpm High Torque DC Planetary Reduction Gear Motor 300w 24v

jensen23

Sticky Note

you figure # are not correct, in appendix I

of 115

The team selected the BMM504-4 Low rpm High Torque DC Planetary Reduction Gear

Motor 300w 24v reducer motor, seen in Figure 52. The motor provides 4 rpm motor speed and

543.4 N-m torque because at least 500 N-m is required for this motor. This motor provides a

large torque value at the expense of speed, for which the team has little use for. The

potentiometer shown in Figure 54 has 360-degree ticks so the user can adjust the input desired

motor speed very accurately. This motor was updated from the previous design due to the

previous design not meeting the torque and speed requirements set by the researchers. Also a

knob is a better choice because it is more user friendly.

Finally, the L298 H-bridge DC motor driver shown in Figure 53 is used to control the

motor with PWM signal. The two input pins of the motor driver receive digital signals for the

rotational direction of the motor. If either pin is 1 and the other is 0, then the motor will rotate in

one direction. On the other hand, if the pins are flipped, the motor will rotate in other direction.

In addition, the Arduino will input an PWM signal to the enable pin on the motor driver and

easily control the rotational speed of the motor can be easily and effectively controlled. If the

enable pin receives no PWM signal, then the motor will stop abruptly.

Figure 53: L298 Dual H Bridge DC Motor Driver Speed Controller

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Figure 54: Cylewet CYT1100 360 Degree Rotary Encoder Code Switch Digital Potentiometer with Push

Button 5 Pins and Knob Cap for Arduino

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J: Arduino Code

Appendix J includes the Arduino code. This code defines all variables however does not

yet utilize the real values that will be used in the program. Through it, the shape of the final

program and its functions can be seen.

Figure 55 lays out the full extent of the code, defining variables and functions and

including comments to indicate the purpose of each line. If a certain value needs testing and

calibration by the user before running the main code, the certain values are shown in the default

number of 9999. On the other hand, the connection pin numbers of wires are also expressed with

9999, because they are subject to change and the user can change them easily. For detailed

wiring procedures, please refer to the schematic wiring diagram.

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#include "HX711.h"

#define Kp 9999 // experiment to determine this, start by something small

#define Kd 9999 // experiment to determine this, slowly increase the speeds and adjust this value. ( Note: Kp <

Kd)

#define Maxspeed 9999 // the max speed for the motor before it become dangerous, should be slightly higher

than the rpm_max

#define calibration_factor 9999 //This value is obtained using the SparkFun_HX711_Calibration sketch for the

Strain Gauges

#define calibration_factor_PPloadcell 9999 //This value is obtained using the SparkFun_HX711_Calibration

sketch for the Pressure Plate load cell

#define calibration_factor_MFloadcell 9999 //This value is obtained using the SparkFun_HX711_Calibration

sketch for the Mass Flow load cell

#define DOUT01 9999 // The digital data pin number for the strain gauge 01

#define CLK01 9999 // The digital clock pin number for strain gauge 01



















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#define DOUT_PPloadcell 9999 // The digital data pin number for the Pressure Plate load cell

#define CLK_PPloadcell 9999 // The digital clock pin number for the Pressure Plate load cell

#define DOUT_MFloadcell 9999 // The digital data pin number for the Mass Flow load cell

#define CLK_MFloadcell 9999 // The digital clock pin number for the Mass Flow load cell

HX711 straingauge01;












HX711 PPloadcell;

HX711 MFloadcell;

// Constant pin numbers on the Arduino which are connected to the electronic devices

const int Motorpin1 = 9999;

const int Motorpin2 = 9999;

const int ENA = 9999;

const int rpmpin = 9999;

const int currentpin = 9999;

const int EStoppin = 9999; // the pin number of the Emergency Stop button pin

const int potentiometer_pin = 9999; // the pin number of the potentiometer knob

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// Constant values for safety measures and the supply voltage of the motor

const int power_limit = 9999;

const int torque_limit = 9999;

const int voltage = 9999; // Fixed value from the power source and motor itself

const int rpm_max = 9999; // Fixed value from the motor itself

// Initialization

int EStopState = 0; // variable for reading the EStoppin status

int rpm_desired = 0;

int rpm = 0;

int current = 0;

int potentiometer_val = 0;

int power = 0;

int torque = 0;

int lastError = 0;

int error = 0;

int motorSpeedCorrection = 0;

int Motorspeed = 0;

// Data arrangement variables for data streaming to excel

const byte kNumberOfChannelsFromExcel = 6;

const char kDelimiter = ',';

const int kSerialInterval = 50;

unsigned long serialPreviousTime;

char* arr[kNumberOfChannelsFromExcel];

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void setup() {

Serial.begin(115200);

Serial.println("Basic Encoder Test:");

pinMode(rpmpin, INPUT);

pinMode(currentpin, INPUT);

pinMode(Motorpin1, OUTPUT);

pinMode(Motorpin2, OUTPUT);

pinMode(ENA, OUTPUT);

pinMode(EStoppin, INPUT);

straingauge01.begin(DOUT01, CLK01);












PPloadcell.begin(DOUT_PPloadcell, CLK_PPloadcell);

MFloadcell.begin(DOUT_MFloadcell, CLK_MFloadcell);

straingauge01.set_scale(calibration_factor); //This value is obtained by using the

SparkFun_HX711_Calibration sketch for the Strain Gauges

















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PPloadcell.set_scale(calibration_factor_PPloadcell); //This value is obtained by using the

SparkFun_HX711_Calibration sketch for the Pressure Plate load cell

MFloadcell.set_scale(calibration_factor_MFloadcell); //This value is obtained by using the

SparkFun_HX711_Calibration sketch for the Mass Flow load cell

straingauge01.tare(); //Assuming there is no weight on the scale at start up, reset the scale to 0












PPloadcell.tare(); //Assuming there is no weight on the scale at start up, reset the scale to 0

MFloadcell.tare(); //Assuming there is no weight on the scale at start up, reset the scale to 0

delay(5000);

}

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void loop() {

EStopState = digitalRead(EStoppin);

rpm = analogRead(rpmpin); // Get the motor speed (rpm) from the hall effect sensor

current = analogRead(currentpin); // Get current through the motor from the current sensor

potentiometer_val = analogRead(potentiometer_pin); // reads the value of the potentiometer (value

between 0 and 1023)

rpm_desired = map(potentiometer_val, 0, 1023, 0, rpm_max); // scale it to use it as the desired rpm (value

between 0 and rpm_max)

power = current * voltage; // With the provided Voltage and Current of the motor, P = IV

torque = power / rpm;

lastError = 0;

error = rpm_desired - rpm;

motorSpeedCorrection = Kp * error + Kd * (error - lastError);

Motorspeed = rpm_desired + motorSpeedCorrection;

if(power > power_limit || torque > torque_limit){

Motor_Brake();

printf("Power or Torque value exceeds the limit value!!!\n");

}else if(EStopState == HIGH){

Motor_Brake();

printf("The Emergency Stop is pressed!!!\n");

}else{

Motor_Forward(Motorspeed);

}

if(Motorspeed > Maxspeed){

Motorspeed = Maxspeed; // prevent the motor from going beyond max speed

}

processIncomingSerial(); // Read Excel variables from serial port (Data Streamer)

processOutgoingSerial(); // Process and send data to Excel via serial port (Data Streamer)

lastError = error;

}

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void Motor_Forward(int MotorSpeed)

{

digitalWrite(Motorpin1, HIGH);

digitalWrite(Motorpin2, LOW);

analogWrite(ENA, MotorSpeed / rpm_max); // the PWM signal output to the Enable pin on L298 should be a

percentage

}

// Brake the motor

void Motor_Brake()

{



}

// OUTGOING SERIAL DATA PROCESSING CODE----------------------------------------

void processOutgoingSerial()

{

// Enter into this only when serial interval has elapsed

if((millis() - serialPreviousTime) > kSerialInterval)

{

// Reset serial interval timestamp

serialPreviousTime = millis();

Serial.print(EStopState);

Serial.print(kDelimiter);

Serial.print(rpm_desired);


Serial.print(rpm);


Serial.print(Motorspeed);


Serial.print(current);


Serial.print(power);


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Figure 55: Code to control Arduino

// INCOMING SERIAL DATA PROCESSING CODE----------------------------------------

void processIncomingSerial()

{

if(Serial.available()){

parseData(GetSerialData());

}

}

// Gathers bytes from serial port to build inputString

char* GetSerialData()

{

static char inputString[64]; // Create a char array to store incoming data

memset(inputString, 0, sizeof(inputString)); // Clear the memory from a pervious reading

while (Serial.available()){

Serial.readBytesUntil('\n', inputString, 64); //Read every byte in Serial buffer until line end or 64 bytes

}

return inputString;

}

// Seperate the data at each delimeter

void parseData(char data[])

{

char *token = strtok(data, ","); // Find the first delimeter and return the token before it

int index = 0; // Index to track storage in the array

while (token != NULL){ // Char* strings terminate w/ a Null character. We'll keep running the command until

we hit it

arr[index] = token; // Assign the token to an array

token = strtok(NULL, ","); // Conintue to the next delimeter

index++; // incremenet index to store next value

}

}

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K: Flow Chart of Control/Operation

Appendix K includes diagrams of the code in block format to see the relationship

between processes as well as the diagrams of the electrical connections.

As can be seen in the flowchart of Figure 56, the team will take input from the user for

the desired motor rotational speed in rpm. The error will be calculated by subtracting the actual

rotational speed measured by the hall effect sensor from the input desired speed. The error and a

PD controller are then used to adjust the PWM signal to keep the actual rotational speed as close

as possible to the desired speed.

Figure 56: Flowchart of Control for the motor control device

Figure 57 shows the final schematic wiring diagram corresponding to the Arduino code

and the flowchart. Wires such as ground and power are color-coded black and red respectively in

accordance with general wiring diagram practices. All pin numbers in a certain type are all

exchangeable. Only do not mix up the digital pins, analog pins and PWM pins with each other.

of 115

Figure 57: Final schematic wiring diagram for the motor control device

As shown in Figure 57, the enable pin of the L298 motor controller is connected to the

PWM pin of the Arduino. On the other hand, the two input pins controlling the direction of the

motor of the L298 motor controller as well as the input of the emergency push button are

connected to the digital pins of the Arduino. A digital pin on Arduino will keep tracking the

emergency stop button, which is 1 if pressed and 0 if not pressed. Once the emergency button is

pressed, Arduino will send OFF value to the 2 digital pins on the motor driver and set the motor

speed to zero. Finally the power pins of the L298 motor driver will be connected to an external

12V power supply and a transformer might be needed depending on different situations.

The ACS712 current sensor will measure the current value through the motor and

Arduino can calculate the power consumption of the motor with the current value and the voltage

value of the motor. Next, the torque provided by the motor is calculated by the motor power in

watts and the motor speed in rpm. In addition to the emergency stop button, once the power or

the torque exceeds their corresponding limit values, the motor will be shut down with the same

method as well.

An analog pin on Arduino will keep taking the desired motor speed value from the user

through the potentiometer with a knob. Then the hall effect sensor will measure the actual motor

speed in rpm and send the value back to Arduino through an analog pin. The error, which is the

desired value subtracted by the actual value, will be used for a PD controller. The PD controller

will transmit a certain percentage of PWM signal to the L298 motor driver Enable pin to control

the motor speed and keep it as close to the desired speed. Therefore, the user should be able to

easily control the motor speed with the potentiometer knob outside of the machine without

changing and re-running the Arduino code.

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HX711 will measure and sum up all reading values from all load cells and use 2 digital

pins (DOUT and CLK) on Arduino. If the HX711 amplifier uses 4 load cells, measurement of

the mass flow rate for example, the 4 load cells will form a Wheatstone bridge. The Wheatstone

bridge circuit has 2 compression and tension resistors pairs. Once any of the 4 sensors are

pressed, the compression and tension resistor will change their resistance value in opposite

directions. Then the voltage readings at the two points will be slightly different, the voltage

difference is very small but can be measured, amplified and calibrated by the HX711 sensor

amplifier module to the weight or load for our purpose. Arduino will receive a value and convert

this value to our sensor value with its corresponding calibration factor, which would be acquired

before running the main code.

First, the user needs to input the HX711 library into Arduino. The library file “HX711-

master.zip” has been included in our submission and can also be found in the github link

provided in the Appendix of Purchase links. Then the user needs to run the Arduino code

“HX711_Calibration” to determine the calibration factor needed for each use of the HX711

modifier, which means the HX711 modules used with strain gauges, pressure plate and mass

flow need different calibration factors, based on their various units and approaches. When using

the calibration code, the user needs to put certain known weight on the sensor, and check if the

sensor reading is the same as the real known weight. The user can also adjust the calibration

factor by pressing “+” or “-” to increase or decrease the calibration factor. The adjusted final

calibration factors for different uses of HX711 are then substituted into the main code,

respectively.

If the HX711 only uses one load cell, then two 1000 Ohm resistors are required to form a

Wheatstone bridge circuit similar to the case of 4 load cells. For example, the measurement of

the pressure plate load only needs one load cell because the maximum reading of one load cell

(50kg) fits our requirements and saves some room for us. Also, each TB21 strain gauge needs

one HX711 amplifier, so 12 TB21 strain gauges need 12 HX711 amplifiers, with the same

structure of circuits. Therefore, as shown in the schematics on the top left, only one set of 1

TB21 strain gauge and 1 HX711 amplifier is shown within the blue dash line, in order to keep

the schematic organized and avoid redundancy.

The Arduino will collect all the sensor reading, including all calculated values and the

output motor speed to an Excel data sheet, instead of outputting to its serial monitor. Each

channel corresponds to a value output from the Arduino, separated by a delimiter (comma).

Totally 21 data values are to be exported from Arduino to the excel file, so there will be 21

channels. The line graphs of corresponding values are shown to the right of the data tables. An

instructional video for the feature of Arduino data streaming to Excel has been provided. The

data streaming feature in Excel is an add-in for full versions only and it needs to be enabled

through File > Options > Add-ins > Manage: Com Add-ins > Microsoft Data Streamer for Excel.

The Office 365 version provided by Purdue University has this add-in while free versions might

not have this add-in. The user will have to upload the code to Arduino Mega again after plugging

it in and then collect the data with Excel directly, without turning on the serial monitor in

of 115

Arduino. The duration of the data history shown in the excel and the sampling frequency can be

changed in the Settings tab in the Excel file.

of 115

L: Manufacturing Drawings

Appendix L contains the manufacturing drawings produced over the course of the

project, including assembly drawings, general part drawings, and purchased and modified part

drawings. The manufacturing drawings span pages 67 to 84.

The parts can be found in the following order:

1. Assembly …………………………………………………………………………..68

2. Frame components ……...…………………………………………………….……..70

3. Screw Casing …………………………………………………………….………….....79

4. Screw ……………………………………………………………..……….…………...82

5. Pressure Plate ……………………………………………………………….………….83

6. Purchased and Modified Parts ……………………………………….………….85

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7.11

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A A

B B

4

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MATERIAL

DIMENSIONS ARE IN INCHES

TOLERANCES:

X.XXX±0.005

PROPRIETARY AND CONFIDENTIAL

THE INFORMATION CONTAINED IN THIS

DRAWING IS THE SOLE PROPERTY OF

THE FEED SCREW SPEED CREW. ANY

REPRODUCTION IN PART OR AS A WHOLE

WITHOUT THE WRITTEN PERMISSION OF

THE FEED SCREW SPEED CREW IS

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7.110

R1.575

0.500 6.610

0.131

4.073

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4.000

0.250

0.500

3.305

3.555

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6.495

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2.055

2.555

4.555

5.055

4.100

0.100

5.100

0.250 x2

3.247

3.555

0.250

0.500

0.750


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.10

4.10

R1.78

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3.25

3.56

.250 x2

.25 .50

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3.35

.75

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R1.76

3.56

.25

3.25

.25 x2

.50 View is symmetrical about centerline

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R.13 x2

R1.00

3.22

4.10

.10

3.25

3.56

.50 .25

.25 x2

.88

3.25

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jensen23

Sticky Note

you do not have a 2 place tolerance only a 3 place tolerance.

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.50

2.00

2.00

1.79

2.22

.50

.50

.50

.13

.19

.44

.87

.86

6.29

9.79

1.79

2.22

.24 x30

16.31 11.61 1.25 12.87 9.41

1.06 5.30 .70 4.31 .70 3.40 1.06 3.50 5.25 1.01

52.01

3.28

3.31

3.30 3.25

3.31

4.75 3.56

2.70

.25 x20

1. Unless otherwise specified, dimensions are symmetric across the centerlines in both views

NOTES:

2. Every grouping of five holes in the enlarged view maintains the same relative location to each other. The leftmost and bottommost holes have been located in each group to apply the relative locations. This view is an enlarged section (1:1 scale) of the top view

A A

B B

C C

D D

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2.50

3.16

.50 x2

.72

A A

B B

C C

D D

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1.25

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2.75

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3.90

4.00

1.50

1.25

2.00

2.50

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R.988

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.250 x2

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R1.735

4.760

2.853°

47.853°

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3.910

.550

1.992

1.989

.986

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.250 x4

2.000

2.000

2.489

.100

1.000

4.010

4.910

5.010

R1.500

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R2.000 R1.500

R.625

2.498

0°

45° 135°

R1.749 R1.249

.250 x4 45° .125

1.500

1.250

1.497

1.998

.100

1.000

5.000

5.900

6.000

.077

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.999 .848

8.740

14.500

20.125

.75°

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.380

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1.50

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44.82° 134.82°

224.82° 314.82°

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60°

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.250 x4

9.500

9.500 .063

A A

B B

4

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A36 Steel



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.079 .453

Note: Bolt purchased from McMaster Carr

A A

B B

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YELLOW CHROMATE-PLATED ZINC



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M: What was Learned from the Low, Mid, and High-Fidelity Prototypes

Appendix M includes the insights gained from the design process of each stage as labeled

below. Lessons learned from the CDR have been included towards the bottom of this section.

Low-Fidelity Prototype:

From the low fidelity prototype the team learned that it must ensure modularity of parts,

proper sensor placement, and simple supports. While designing the modularity of the barrel, the

team learned it had to either maintain a constant outside diameter across all modular parts or

ensure the base structure was able to adjust to components of varying diameters.

Further insights gathered from the low-fidelity prototype were possible locations for

sensor placement. This forced each section to be considered separately in the design process.

For example, the motor and its connection were isolated and determined to be the best fit for a

hall effect sensor that will track the rotation of the shaft. Flanges were added to allow the barrel

to open and to provide locations for strain gauges to measure the stresses of the structure. A scale

was added to capture fed material to determine mass flow rate out, and the back pressure plate

was designed to incorporate a pressure sensor to allow the simulated pressure to be measured and

adjusted.

The final insights were in relation to the support structure. There were several designs

considered, but ultimately, the team learned it was simplest from a manufacturing and design

perspective to create a set of simple supports to elevate the screw system and connect it to the

baseplate.

Mid-fidelity Prototype:

The mid-fidelity prototype allowed the thicknesses of parts and tolerances in connection

areas to be validated. For example, the shaft was determined to be an R4 fit due to the pressures

experienced by that section of the shaft. For the bolts, an LC3 fit was determined to be proper

due to the tighter tolerances. This will prevent the internal casing from shifting and interfering

with the screw. The mid-fidelity prototype also required a deeper analysis of sensor locations.

The E-stop was placed on a panel for easy reach. The force plate and scale had to be designed to

not interfere with each other as they occupy a similar space. The force plate required a thicker,

reinforced section of the stand in order to provide support for the desired pressures.

FEA analysis was performed on the inside of the casing and was able to verify the

thickness was correct. The shaft was analyzed using a simple mathematical model and the

material properties and factors of safety were found to be much higher than desired. This allowed

a smaller design to be considered, however the current system was still viable within the

specified design parameters, so the design was not changed.

High-Fidelity Prototype:

When completing the high-fidelity prototype, the team updated and improved the back

pressure plate. A concern was raised about the springs being compressed by the material exiting

the plug and not falling into the collection bin. To combat this, the back pressure plate was

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changed to a conical shape without the tip. The center of the plate would be a flat circle the same

size as the screw. The angled sides interacting with the material will push the material radially

outwards, forcing it to fall into the bin. This will decrease the fluctuation of back pressure by

reducing the length fluctuation of the spring.

Another lesson learned regarding the back pressure plate was the need for additional

support to the wall supporting the springs (pushing the plate into the plug of the screw). To

overcome this, 2 L-brackets were added to the back of the plate. These L-brackets also make it

easier to move the support plate forward and backward to adjust the back pressure.

To create a prototype that is easier to work with, the inner diameter was scaled down

from 2” to 1.5” and 1.25” (2 test cases). This will allow testing to be done on a table top and

keep the device from getting too heavy. It will also cut costs. Since this device will only be used

for testing purposes, rather than full-scale production, a size-reduction made sense in every

aspect.

After discussing pros and cons of balancing rpm and torque in a motor, the team decided

it was best to sacrifice some speed for extra torque. This is because when testing, it will be more

important that the motor is able to push the material out when up against the back pressure, than

how fast the motor is able to turn. It was impossible to find a motor that fit the size requirement,

5+ rpm, and 500+ Nm torque. The team decided on a 24V DC Motor Low Rpm High Torque DC

Planetary Reduction Gear Motor that could spin at 4 rpm and had 543.4 Nm torque. This motor

has slightly under 5 rpm and is able to exceed the 500 Nm torque requirement. The team was

much more comfortable sacrificing speed for torque to reduce jamming of the material inside the

casing in a case where the motor would not be strong enough to push the material out, one of the

researchers’ main concerns.

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N: Benchmark research

Appendix N contains information relating to similar designs to the desired feed screw

that already exist. This includes multiple Figures that highlight different aspects of the

benchmarks.

The Screw and Barrel System by Dynisco

The price of this benchmark is not provided on their website. This design seems to

be very comprehensive and expensive, which goes against the requirement of keeping the

table-top feed screw inexpensive. Because our design only uses milled or pelleted biomass

into chemical reactor vessels, the feed screw can be simplified and focused to keep costs

low.

One of the existing benchmark solutions is The Screw and Barrel System by

Dynisco. Figure 58 shows the components of this screw and barrel system design. The

screw consists of three different sections: the feed zone, transition zone and metering zone.

The compression ratio, which is the ratio of the volume of the flight in the feed zone to the

volume of the flight in the metering zone, is 3:1 for their design. This design also provides

a variety of different screw types according to each material or process, such as the

extrusion screw shown in Figure 59. They also provide multiple methods to achieve screw

mixing in order to deliver the material at a constant and controllable rate. Figure 60 and

Figure 61 show the dispersive mixing and distributive mixing, respectively. The static

mixer in Figure 62 is the device to perform the mixing methods. The screen packs, with the

support of breaker plates, build up pressure in a machine to uniformly heat, melt, and mix

the material, as shown in Figure 63. Both AC and DC motors could be used in their design.

The price of this benchmark is not provided on their website. This design seems to

be very comprehensive and expensive, which goes against the requirement of keeping the

table-top feed screw inexpensive. Because our design only uses milled or pelleted biomass

into chemical reactor vessels, the feed screw can be simplified and focused to keep costs

low.

Figure 58: The Basic Extrusion Screw Design

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Figure 59: Elements of an Extrusion Screw

Figure 60: Dispersive Mixing

Figure 61: Distributive Mixing

Figure 62: Static Mixer

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Figure 63: Breaker Plate and Screen Pack

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O: Basic Physics Model (Free Body Diagram)

Appendix O contains free body diagrams and force analysis of different aspects of the

screw. Additional analysis from the FDR has been appended to the end.

The main forces concerning this project will be torque applied by the motor, pressure

from the back-pressure plate, and normal force by the tapered walls. The torque can be

calculated, utilizing a volt sensor attached to the motor, and an RPM sensor we plan to have

attached to the driveshaft. The back-plate pressure will be measured utilizing the force sensing

plate itself. Finally, the normal force on the tapered walls can be found using strain gauges

attached to the flanges holding the tapered, clamshell section together. These forces are shown

below in Figure 64.

Figure 64: Force Identification upon Powdered Microcrystalline Cellulose

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In Figure 65, to estimate the bending moment, the end of the shaft connected to the motor

was simulated as being fixed to the wall, disallowing rotation. The weight of the shaft was

calculated using the density of Aluminum 6061 (2.7 g/cm^3) and the volume of the shaft. This

then showed the shear forces and bending moment the shaft would experience at any point in its

operation due to the force of gravity. This estimation was used in the subsequent calculations as

the bending moment experienced by the shaft.

Figure 65: Force diagram of shaft

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Figure 66 calculates the factor of safety of the shaft in operation. Using the maximum

specified torque and the bending moment found in Figure 65 above, the factor of safety was

found to be 9.14 for normal operation and 8.184 for the possibility of a static failure in the first

load. The first factor of safety was calculated using the Goodman criteria because it is an

extremely conservative estimate. This should ensure a safe design. Both factors of safety are well

above the minimum factor of safety of 2, indicating this is a good design that could theoretically

be adjusted to reduce the factor of safety, thereby reducing space and cost of the system.

Figure 66: Factor of safety during operation of shaft

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Figure 67 calculates the minimum possible diameter for the desired factor of safety of 2

for the operation of the shaft. It uses the Goodman criteria to remain consistent with other

calculations of the factor of safety. Using this, it was found that the minimum acceptable

diameter to retain a factor of safety of 2 was 1.537 inches.

Figure 67: Minimum possible diameter calculations

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Figure 68 estimates the factor of safety in an instance where the material flowing through

the feeder compacts and the motor stalls. In this event, the weight of the shaft is supported on

both ends by the compacted material and the motor, so it experiences pure torsion. It used the

factor of safety of yielding to check for yielding. The factor of safety was found to be 8.203,

comparable to the value found previously for shaft operation. The equation was then rearranged

to solve for the minimum diameter of the shaft, which was found to be 1.829 inches. This

confirms that the current shaft design is within the desired factors of safety and can withstand the

forces experienced when the material plugs the feeder.

Figure 68: Factor of safety and minimum acceptable diameter during stall

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P: Standards Referenced/Used/Applied

Appendix P has been included to show the standards identified and used in the design of

the screw and casing. They are used to determine the tolerances needed for each mating section

of the system shown in Appendix Q.

The first reference used below in Figure 69 is the American National Standard Running

and Sliding Fits ANSI B4.1-1967 (R2004). This table aided in the creation of the table of fits and

tolerances, seen in Appendix Q. The table was located at the following link:

http://www.zpag.net/Usinage/standard_ansiB4_1_1967.htm. This link also contained tables for

LC fittings which were utilized for analysis of bolt hole tolerances.

Figure 69: American National Standard Running and Sliding Fits ANSI B4.1-1967 (R2004)

The following drawing in Figure 70 is a reference provided in class by Dr. Jensen. This

example part drawing helped the team formulate part drawings in preparation for FDR.

http://www.zpag.net/Usinage/standard_ansiB4_1_1967.htm

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Figure 70: Example Part Drawing

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Q: Testing and Validation

Pre-Fabrication Electronic Testing (Completed by Team)

Test 1: Arduino Coding:

To ensure the start button is able to begin operating the feed screw, the Arduino program

should be able to simulate rotating the screw, collecting speed, torque, pressure, mass flow rate,

clamshell and flange bolt strain, and begin accepting speed adjustment input by the RPM Knob.

Since the Hall Effect Sensor, Pressure Sensor, Mass Flow Scale, Current Sensor, and Strain

Gauges will not be providing any readings with this test, they may be temporarily replaced with

constants to be read for validation. This can be tested by:

● Apply constant test values temporarily replacing the readings from:

○ Hall Effect RPM Sensor

○ Load Cell (Pressure Plate)

○ Mass Flow Scale

○ Current Sensor

○ Each Strain Gauge

○ RPM Knob

● Apply “Print” functions to display the following information:

○ Print “The Screw ___(insert is or is not) rotating at ___(insert Hall Effect Sensor

Reading) RPM due to an input of ___(insert RPM Knob Reading) RPM with a

torque of ___(insert calculated Torque value) Nm. The Pressure Plate is exerting

___(insert calculated Pressure value from Load Cell) psi on material exiting the

feed screw at ___(insert calculated Mass Flow Rate) g/s. The Strain Gauges are

reading as follows: 1:___(1) 2:___(2) 3:

● Run the Arduino Code

● Activate the Start Button with a virtual positive

● Test Successful if all input values are reflected in the printed statement and update the

Data IN excel file and associated graphs

Completed? - YES

Test 2: Motion Tests of the Screw Turning and Pressure Plate Moving:

To ensure there are no instances of interference within the device during the turning of

the feed screw or the slight displacement of the pressure plate plug, videos were created

simulating the motion, and can be found within the FDR Presentation provided. The videos show

that in each case, motion causes no interference, and the physical prototype will be able to move

in a similar manner.

Completed? - YES

Test 3: Finite Element Analysis Results:

After putting both the outer casing and feed screw made of Aluminum 6061 and Steel

4130 respectively, through maximum stress analysis, as seen in detail in Appendix H, all factors

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of safety reach far above the team’s goal of 2. This shows that if put together correctly, the

device will not fail under static conditions. Due to the high fatigue strength of each of these

materials, the team can guarantee that the device will last a minimum of 5 years of 40 hour per

week operation.

Completed? - YES

Post-Fabrication Electronic and Mechanical Testing (Completed by Researchers)

Test 4: Service Checks on all means of Operation:

Before feeding material into the fabricated device, the user should attempt to run the

device without any material within. The following operations should work seamlessly before

feeding the microcrystalline cellulose:

● The screw turns when and only when the start button has been activated via the

controlling laptop/computer

● The screw stops turning when and only when the start button has been deactivated OR

the E-Stop has been engaged

● The Hall-Effect Sensor reading correctly reflects the input speed determined by the

position of the 10-click potentiometer

● The Pressure Plate pressure is correctly reflected by the load cell located on the supported

9.5 in. by 9.5 in. plate

○ This load cell should read nothing more than 50 lbs of force, otherwise material

may not be able to be pushed out, causing a blockage

● The protective mesh is in place and prevents any limbs from entering the turning feed

screw

● The strain gauges are able to see small readings from small pushes executed by the

operator

● The collection bin underneath the feed screw exit is in place and on top of the mass flow

reading load cells

Completed? - NO

Conclusions-

Once all of these tests have been successfully completed, the device will be ready to serve its

original purpose, and provide data based validation of existing predictive models to improve

industrial feed screws. It will be very cost effective when compared to the alternative $10,000

per run existing feed screw being used by the clients. The data it provides will also help in the

formation of new models, saving biorefineries up to $1,000,000 per year in feed screw

inefficiencies.

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R: Links to Purchased Components and Display Videos

Appendix R lists all purchased parts with their corresponding links for purchase. It allows the

team to easily relay information to the researchers to continue the project by assembling the

proposed solution.

E-Stop: The E-Stop button is used to stop the motor in the case of an emergency.

Link: https://www.amazon.com/TWTADE-Emergency-Pushbutton-

Switches%EF%BC%88Quality-years%EF%BC%89LA38-

11ZS/dp/B07C4YCYRZ/ref=sr_1_1_sspa?dchild=1&keywords=E-

STOP&qid=1596027474&sr=8-1-

spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyUzFXTFZSUE5PWUZWJmVuY

3J5cHRlZElkPUEwNDUzMDM5MzNJMlVMOEZCQ0pJRCZlbmNyeXB0ZWRBZElkPUEwN

jQxOTYyMVBBWU1VRzZCUjBWVyZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xp

Y2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

Instructional Assembly: https://www.instructables.com/id/Emergency-Stop-Button/

Strain Gauges: The strain gauges will be inserted into the bolts to measure the strain and axial

forces experienced by the bolts.

Link: https://b2bstore.hbm.com/myHBM/app/displayApp/(layout=7.01-

16_153_6_9_70_34_65_73_134&citem=A01D4895C9E81EE895EA843B7658C4CDA01D489

5C9E81ED890E05C562A8991D1&carea=A01D4895C9E81EE895EA843B7658C4CD&xcm=h

bm_b2boccasionalcrm)/.do?rf=y

Instructional Assembly: https://www.hbm.com/en/7452/cylindric-strain-gauges-for-

measurements-in-bolts/

Strain Gauge Adhesive: The strain gauge adhesive will be used to adhere the sensors into the

bolts and make sure they are set in place.

Link: https://b2bstore.hbm.com/myHBM/app/displayApp/(cpgnum=1&layout=7.01-

16_153_6_9_70_34_65_73_134_6&uiarea=6&citem=0E3B0B4E540ACD18E1000000AC1099

34A549494869EF3C62E1000000AC10A039&carea=0E3B0B4E540ACD18E1000000AC10993

4&rdb=0&cpgsize=0)/.do?rf=y

Hall-Effect Sensor: The Hall-Effect sensor will be used to record the rotation of the screw and

be used to calculate angular speed of the screw.

Link: https://www.amazon.com/Effect-Magnetic-Sensor-Arduino-

MXRS/dp/B085KVV82D/ref=sr_1_3?dchild=1&gclid=Cj0KCQjwvIT5BRCqARIsAAwwD-

R3eooa8QBsY9M3pFyHJFGiAM9JoNIE4T_VHETSDFqiOW4jD79X9vcaAvyhEALw_wcB&h

vadid=410019012916&hvdev=c&hvlocphy=9016722&hvnetw=g&hvqmt=b&hvrand=25004802

6171785736&hvtargid=kwd-

300612634942&hydadcr=15827_11428628&keywords=hall+effect+sensor&qid=1596029495&

sr=8-3&tag=googhydr-20

https://www.amazon.com/TWTADE-Emergency-Pushbutton-Switches%EF%BC%88Quality-years%EF%BC%89LA38-11ZS/dp/B07C4YCYRZ/ref=sr_1_1_sspa?dchild=1&keywords=E-STOP&qid=1596027474&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyUzFXTFZSUE5PWUZWJmVuY3J5cHRlZElkPUEwNDUzMDM5MzNJMlVMOEZCQ0pJRCZlbmNyeXB0ZWRBZElkPUEwNjQxOTYyMVBBWU1VRzZCUjBWVyZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=








https://www.instructables.com/id/Emergency-Stop-Button/

https://b2bstore.hbm.com/myHBM/app/displayApp/(layout=7.01-16_153_6_9_70_34_65_73_134&citem=A01D4895C9E81EE895EA843B7658C4CDA01D4895C9E81ED890E05C562A8991D1&carea=A01D4895C9E81EE895EA843B7658C4CD&xcm=hbm_b2boccasionalcrm)/.do?rf=y




https://www.hbm.com/en/7452/cylindric-strain-gauges-for-measurements-in-bolts/

https://www.hbm.com/en/7452/cylindric-strain-gauges-for-measurements-in-bolts/

https://b2bstore.hbm.com/myHBM/app/displayApp/(cpgnum=1&layout=7.01-16_153_6_9_70_34_65_73_134_6&uiarea=6&citem=0E3B0B4E540ACD18E1000000AC109934A549494869EF3C62E1000000AC10A039&carea=0E3B0B4E540ACD18E1000000AC109934&rdb=0&cpgsize=0)/.do?rf=y




https://www.amazon.com/Effect-Magnetic-Sensor-Arduino-MXRS/dp/B085KVV82D/ref=sr_1_3?dchild=1&gclid=Cj0KCQjwvIT5BRCqARIsAAwwD-R3eooa8QBsY9M3pFyHJFGiAM9JoNIE4T_VHETSDFqiOW4jD79X9vcaAvyhEALw_wcB&hvadid=410019012916&hvdev=c&hvlocphy=9016722&hvnetw=g&hvqmt=b&hvrand=250048026171785736&hvtargid=kwd-300612634942&hydadcr=15827_11428628&keywords=hall+effect+sensor&qid=1596029495&sr=8-3&tag=googhydr-20







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ACS712 Current Sensor: The current sensor will be used to measure the current supplied to the

motor to allow the motor power to be calculated.

Link: https://www.amazon.com/SMAKN%C2%AE-ACS712-Current-Detector-

Amperage/dp/B00N2EUPUG/ref=sr_1_1?dchild=1&keywords=ACS712&qid=1596028605&ref

inements=p_76%3A1249158011&rnid=1249156011&rps=1&s=industrial&sr=1-1

L298 DC Motor Driver: The motor driver is used to control the motor speed.

Link: https://www.amazon.com/DROK-Controller-Regulator-Industrial-

Optocoupler/dp/B06XGD5SCB/ref=sr_1_1?dchild=1&keywords=DC+Motor+Driver%2C+DRO

K+L298+Dual+H+Bridge+Motor+Speed+Controller+DC+6.5V-

27V+7A+PWM+Motor+Regulator+Board+12V+24V+Electric+Motor+Control+Module+Indust

rial+160W+with+Optocoupler+ Isolation&qid=1596028696&sr=8-1

Instructional Video: https://www.youtube.com/watch?v=kv-9mxVaVzE

Arduino Mega 2560 REV3 [A000067]: The Arduino is used as an open-sourced electronic

platform for the model.

Link: https://www.amazon.com/ARDUINO-MEGA-2560-REV3-

A000067/dp/B0046AMGW0/ref=sr_1_3?dchild=1&keywords=Arduino+MEGA+2560+REV3+

%5BA000067%5D&qid=1596028730&sr=8-3

4 pcs 50kg Load Cells and HX711 Combo Pack Kit: The four piece load cell and amplifier kit

is used to measure the spring force applied.

Link: https://www.amazon.com/Degraw-amplifier-weight-Arduino-

Bathroom/dp/B075Y5R7T7/

Instructional Video: https://www.youtube.com/watch?v=LIuf2egMioA

Instructional Assembly1: https://circuitjournal.com/50kg-load-cells-with-HX711

Instructional Assembly2: https://www.instructables.com/id/Arduino-Bathroom-Scale-

With-50-Kg-Load-Cells-and-H/

HX711 Library: https://github.com/olkal/HX711_ADC

Potentiometer: The potentiometer dial is used to control the speed of the motor.

Link: https://www.amazon.com/Cylewet-Encoder-Digital-Potentiometer-

Arduino/dp/B07DM2YMT4/ref=sr_1_12_sspa?dchild=1&keywords=arduino+potentiometer&qi

d=1596114814&sr=8-12-

spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyQkZPWUYwRENBNUJYJmVu

Y3J5cHRlZElkPUEwMjEwMjUwMktWN0VFMThEVDI2RSZlbmNyeXB0ZWRBZElkPUEw

NDc2MTEyMzQ2TzdOOERTRVlHRSZ3aWRnZXROYW1lPXNwX210ZiZhY3Rpb249Y2xp

Y2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

BM504-11 Motor: This is the motor chosen to drive the screw.

https://www.amazon.com/SMAKN%C2%AE-ACS712-Current-Detector-Amperage/dp/B00N2EUPUG/ref=sr_1_1?dchild=1&keywords=ACS712&qid=1596028605&refinements=p_76%3A1249158011&rnid=1249156011&rps=1&s=industrial&sr=1-1



https://www.amazon.com/DROK-Controller-Regulator-Industrial-Optocoupler/dp/B06XGD5SCB/ref=sr_1_1?dchild=1&keywords=DC+Motor+Driver%2C+DROK+L298+Dual+H+Bridge+Motor+Speed+Controller+DC+6.5V-27V+7A+PWM+Motor+Regulator+Board+12V+24V+Electric+Motor+Control+Module+Industrial+160W+with+Optocoupler+Isolation&qid=1596028696&sr=8-1





https://www.youtube.com/watch?v=kv-9mxVaVzE

https://www.amazon.com/ARDUINO-MEGA-2560-REV3-A000067/dp/B0046AMGW0/ref=sr_1_3?dchild=1&keywords=Arduino+MEGA+2560+REV3+%5BA000067%5D&qid=1596028730&sr=8-3



https://www.amazon.com/Degraw-amplifier-weight-Arduino-Bathroom/dp/B075Y5R7T7/

https://www.amazon.com/Degraw-amplifier-weight-Arduino-Bathroom/dp/B075Y5R7T7/

https://www.youtube.com/watch?v=LIuf2egMioA

https://circuitjournal.com/50kg-load-cells-with-HX711

https://www.instructables.com/id/Arduino-Bathroom-Scale-With-50-Kg-Load-Cells-and-H/

https://www.instructables.com/id/Arduino-Bathroom-Scale-With-50-Kg-Load-Cells-and-H/

https://github.com/olkal/HX711_ADC

https://www.amazon.com/Cylewet-Encoder-Digital-Potentiometer-Arduino/dp/B07DM2YMT4/ref=sr_1_12_sspa?dchild=1&keywords=arduino+potentiometer&qid=1596114814&sr=8-12-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyQkZPWUYwRENBNUJYJmVuY3J5cHRlZElkPUEwMjEwMjUwMktWN0VFMThEVDI2RSZlbmNyeXB0ZWRBZElkPUEwNDc2MTEyMzQ2TzdOOERTRVlHRSZ3aWRnZXROYW1lPXNwX210ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=







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Link: https://www.mcmaster-electric.com/24V-DC-Motor-Low-Rpm-High-Torque-DC-

Planetary-Reduction-Gear-Motor-MM504-pd20496067.html

Rods: These rods are used to keep the back-pressure plate from rotating when the springs are

being compressed.

Link: https://www.grainger.com/product/NB-Shaft-3FUH7

Springs: The springs are used to apply back pressure to the end of the feed screw casing.

Link: https://www.centuryspring.com/catalog/compression-

regular?page=product&cid=compression-regular&id=12473CS

Inserts: These press fit inserts are used to create a threaded outer diameter for the bolts to secure

into the base plate.

Link: https://www.mcmaster.com/97191A150/

Wires: These are wires used for the connection of electronic components.

Link: https://www.amazon.com/120pcs-Multicolor-Jumper-Arduino-

Raspberry/dp/B01BAXKDN4/ref=asc_df_B01BAXKDN4/?tag=hyprod-

20&linkCode=df0&hvadid=198075247191&hvpos=&hvnetw=g&hvrand=13742451337297765

677&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9016164&hvt

argid=pla-317965496827&psc=1

Resistors: These resistors are used as amplifiers for the strain gauges.

Link: https://www.amazon.com/EDGELEC-Resistor-Tolerance-Multiple-

Resistance/dp/B07QH5QLR1/ref=sr_1_1_sspa?crid=3AITE4Z0LMW49&dchild=1&keywords=

120+ohm+resistor&qid=1596379149&sprefix=120+ohm+%2Caps%2C345&sr=8-1-

spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyRVhFVUlQQ0pDMlgyJmVuY3J

5cHRlZElkPUEwOTk1NzY4MjNKSUJaTjlDVzdRVyZlbmNyeXB0ZWRBZElkPUEwNjIxMT

M3Mk5TNjhOUTFUTlJZMyZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWR

pcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

Motor and Screw Sprockets and Hall-Effect Gear: This is a coupling socket used to be driven

by the motor to drive the screw.

Link (1in): https://www.grainger.com/product/POWER-DRIVE-Chain-Coupling-Sprocket-

6AGR4

Link (⅝ in): https://www.grainger.com/product/POWER-DRIVE-Chain-Coupling-

Sprocket-6AGR7

Connecting Chain: This connecting chain is used to connect the motor to the coupling sprocket.

Link: https://www.grainger.com/product/POWER-DRIVE-Double-Strand-Coupling-

Chain-6AGR2?cm_sp=Product_Details-_-Customers_Also_Purchased-_-AZIDPBR_BRDS-

https://www.mcmaster-electric.com/24V-DC-Motor-Low-Rpm-High-Torque-DC-Planetary-Reduction-Gear-Motor-MM504-pd20496067.html

https://www.mcmaster-electric.com/24V-DC-Motor-Low-Rpm-High-Torque-DC-Planetary-Reduction-Gear-Motor-MM504-pd20496067.html

https://www.grainger.com/product/NB-Shaft-3FUH7

https://www.centuryspring.com/catalog/compression-regular?page=product&cid=compression-regular&id=12473CS

https://www.centuryspring.com/catalog/compression-regular?page=product&cid=compression-regular&id=12473CS

https://www.mcmaster.com/97191A150/

https://www.amazon.com/120pcs-Multicolor-Jumper-Arduino-Raspberry/dp/B01BAXKDN4/ref=asc_df_B01BAXKDN4/?tag=hyprod-20&linkCode=df0&hvadid=198075247191&hvpos=&hvnetw=g&hvrand=13742451337297765677&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9016164&hvtargid=pla-317965496827&psc=1





https://www.amazon.com/EDGELEC-Resistor-Tolerance-Multiple-Resistance/dp/B07QH5QLR1/ref=sr_1_1_sspa?crid=3AITE4Z0LMW49&dchild=1&keywords=120+ohm+resistor&qid=1596379149&sprefix=120+ohm+%2Caps%2C345&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyRVhFVUlQQ0pDMlgyJmVuY3J5cHRlZElkPUEwOTk1NzY4MjNKSUJaTjlDVzdRVyZlbmNyeXB0ZWRBZElkPUEwNjIxMTM3Mk5TNjhOUTFUTlJZMyZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=







https://www.grainger.com/product/POWER-DRIVE-Chain-Coupling-Sprocket-6AGR4




https://www.grainger.com/product/POWER-DRIVE-Double-Strand-Coupling-Chain-6AGR2?cm_sp=Product_Details-_-Customers_Also_Purchased-_-AZIDPBR_BRDS-040120&cm_vc=AZIDPBR_BRDS-040120&req=Customers_Also_Purchased&opr=AZIDPBR_BRDS-040120


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040120&cm_vc=AZIDPBR_BRDS-

040120&req=Customers_Also_Purchased&opr=AZIDPBR_BRDS-040120

Xometry Parts: This is the location of all the custom made parts from xometry.

Link: https://get.xometry.com/quote/25799-15000

Supports: The supports are to support the back pressure assembly and keep it in the correct

location.

Link: https://www.homedepot.com/p/Everbilt-12-in-x-8-in-Black-Heavy-Duty-Shelf-

Bracket-14337/206086895

Aluminum Plates: The aluminum plates are used for construction of the base plate and supports.

Link: https://www.midweststeelsupply.com/store/6061aluminumplate

Bolts: These bolts will be used to connect the clamshells as well as the supports

Link: https://www.mcmaster.com/bolts/head-type~hex/fastener-strength-grade-

class~grade-8/thread-size~10-32/thread-size~1-4-20/thread-size~1-4-32/length~0-75inches/

Nuts: These nuts are used with the bolts to secure the clamshell casing.

Link: https://www.mcmaster.com/nuts/hex-nuts/thread-size~10-32/thread-size~1-4-

20/thread-size~1-4-28/thread-size~1-4-32/medium-strength-steel-hex-nuts-grade-5/

Videos as Seen in PDR Presentation:

Assembly: https://youtu.be/RSZKWf1FJ-c

Throat: https://youtu.be/x8cvvGAOm84

Screw: https://youtu.be/DeaLk9zBOrE

Pressure plate: https://youtu.be/R45zu0PEFkQ



https://get.xometry.com/quote/25799-15000

https://www.homedepot.com/p/Everbilt-12-in-x-8-in-Black-Heavy-Duty-Shelf-Bracket-14337/206086895

https://www.homedepot.com/p/Everbilt-12-in-x-8-in-Black-Heavy-Duty-Shelf-Bracket-14337/206086895

https://www.midweststeelsupply.com/store/6061aluminumplate

https://www.mcmaster.com/bolts/head-type~hex/fastener-strength-grade-class~grade-8/thread-size~10-32/thread-size~1-4-20/thread-size~1-4-32/length~0-75inches/

https://www.mcmaster.com/bolts/head-type~hex/fastener-strength-grade-class~grade-8/thread-size~10-32/thread-size~1-4-20/thread-size~1-4-32/length~0-75inches/

https://www.mcmaster.com/nuts/hex-nuts/thread-size~10-32/thread-size~1-4-20/thread-size~1-4-28/thread-size~1-4-32/medium-strength-steel-hex-nuts-grade-5/

https://www.mcmaster.com/nuts/hex-nuts/thread-size~10-32/thread-size~1-4-20/thread-size~1-4-28/thread-size~1-4-32/medium-strength-steel-hex-nuts-grade-5/

https://youtu.be/RSZKWf1FJ-c

https://youtu.be/x8cvvGAOm84

https://youtu.be/DeaLk9zBOrE

https://youtu.be/R45zu0PEFkQ

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S: Assembly Instructions

Baseplate

1: Starting from the side with 30 insert cavities, place support plates over the ¾ in. holes along

the long sides of the base plate in the following order:

a. Small Diameter Support Plate (¾ in. wide, 2 in. diameter semicircle cavity)

b. 4 Large Diameter Support Plates (¾ in. wide, 4 in. diameter semicircle cavity)

c. Tallest Support Plate (contains bolt holes for hopper bearing)

d. 4 in. wide Motor Support Block

e. Support Plate with side panel for E-Stop and RPM Knob

The Support Plate positions can be seen in the full assembly picture below:

2: Insert ¾” long bolts through each support plate and base plate.

2: Thread a nut onto each bolt underneath the base plate and tighten.

3: Hammer/Press Press-Fit inserts into each of the 30 cavities

4: Insert E-Stop and RPM Knob (Potentiometer) into the correct positions within the side panel

of the Support Plate. The back view of the control panel should look like the picture below:

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Hopper:

1: Place the hopper into position with the collection portion sitting on the tallest support plate

and the flange sitting between the two close proximity support plates.

2: Attach the large bearing with a bore diameter of 1 in. on the opposite side of the tallest support

plate, so that the bore lines up with the existing hole in the hopper

a. Nut and Bolt the bearing to the support plate using the only 2 larger diameter bolts and

nuts. The hopper should be pushed up against this bearing to be in the correct place.

3: After successful attachment of the bearing, the feed screw can be inserted through the large

opening in the hopper, with the 1 in. diameter shaft feeding through the bearing.

Progress thus far will resemble the picture below:

Feed Screw Shaft:

1: Once the Feed Screw has been fed through the bearing, slide on the two 1 in. bore diameter

sprockets, the first with its gear facing the hopper, and the second the gear facing away from the

hopper. These should come into direct contact with each other.

2: Slide the sprockets so that the gear side of the second sprocket lines up with the end of the

feed screw shaft

a. Insert Set screws into the sprockets to hold them in place on the feed screw shaft.

Motor:

1: Slide the ⅝ in. bore diameter sprocket onto the motor driveshaft, so that the gear side lines up

directly with the end of the motor shaft.

a. Insert a Set screw into the sprocket to hold it in place on the motor driveshaft.

2: Place the motor onto the 4” wide support plate, with the shaft pointing toward the hopper and

the fat end sitting on the support plate with the control panel.

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3: Maneuver the feed screw shaft so that the sprockets on the feed screw shaft and motor drive

shaft are mated on their gear sides.

4: Wrap the coupling chain around both gears and insert the locking pin to couple the two shafts

together as one.

Progress to this point would look similar to the rendered pictures below:

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Throat:

1: Take one half of the clam-shell throat and place the end flanges in between the sets of support

plates right next to the hopper.

2: 1 ½ in. bolts can now be fed through the support plates between the hopper and throat, and a

nut can be tightened on the opposite side, securing both the hopper and bottom half of the throat

to the support plates.

3: The top half of the throat can now be placed directly on top of the bottom half, and secured

through the 4 coinciding flaps with strain gauge inserted ¾ in. bolts, and tightened with a nut on

the bottom.

4: The same can be done through the coinciding top flange holes of the hopper, also with strain

gauge inserted bolts and a nut to tighten.

Plug:

1: Repeat the same steps as previously listed for the throat, first installing the bottom half of the

clam shelled plug and using a 1 ½ in. bolt and nut to secure it to the supporting plates holding the

throat.

2: The top half can again be laid on top of the bottom half, with flaps and flange connections

secured by strain gauge inserted ¾ in. bolts and nuts on the opposite sides

When finished with the throat and plug, the assembly should resemble the picture below, with

feed screw inside:

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Mass Flow Load Cells:

1: As seen above just to the left of the plug, 4 load cells should be attached to the baseplate, so

that pressed together they form a rectangle. The shorter sides of the load cells should be parallel

to the long sides of the base plate.

a. Later on when ready for testing, a simple container of any kind may be placed on these

load cells, which will measure the mass flow as a function of time.

Pressure Plate:

1: The 4 steel rods are to be inserted through the flange holes on the end of the plug, and bolts

are to be inserted into the threaded holes in the rods to secure them to the flange.

2: Once the rods are in place, the conical plug plate may be inserted onto the rods with the cone

side facing into the end of the plug.

3: Next, 4 springs are to be threaded onto the rods.

4: The 3 in. by 3 in. simple steel plate follows the springs

5: One singular load cell is to be attached in the exact center of the 9.5 in. by 9.5 in. steel plate,

which is then pushed onto the rods where the load cell will butt up against the simple plate,

which will butt up against the springs, which butt up against the conical plug plate, which will

butt up against the end of the plug.

Progress thus far will result in the pictures shown below:

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Shelf Supports (Brackets):

1: Finally, the 9.5 in. by 9.5 in. plate will be secured in place to the base plate using ¾ in. bolts.

As apparent, the base plate offers 5 sets of holes for each bracket. These sets are meant to

provide the springs with a specific displacement to cause a specific pressure on the exit of the

feed screw. The sets of holes produce the following pressures, moving from the most outer set to

the most inward set (Opposite bracket always mounts in the set of holes equidistant from the

center line):

● Outer Set: 50 psi for 1.5 in. inner diameter exit

● 30 psi for 1.5 in. inner diameter exit



● Inner Set: 15 psi for 1.25 in. inner diameter exit

○ NOTE: In order to achieve 30 psi for 1.25 in. inner diameter exit, the outermost

set of holes can be used.

2: Once the set of mounting holes has been chosen, secure the brackets to the base plate.

3: Use all 6 of the 10-32 bolts and nuts to attach the brackets to the 9.5 in. by 9.5 in. A36 Steel

Plate.

Through this step, the assembly should resemble the following picture:

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Electronics:

The following wiring diagram should be followed when assembling the circuit:

The location of most components will be the open portion of the base plate next to the motor.

However, the Hall-Effect Sensor should be located directly under the open geared sprocket,

mounted on the support plate with a side panel. Obviously, the strain gauges and load cells were

previously attached, and have specific locations that can be reached with wiring. Otherwise, the

circuit can be created resembling the picture below:

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It is important to note that only one set of resistors and Amplifiers are shown for simplicity of the

3D model, but each strain gauge and set of load cells will have its own set of each.

The final product should closely resemble the final prototype illustrated below:

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T: Manufacturing Plan

Appendix T lists the manufacturing plans for parts manufactured on-site by our clients.

These include all support plates and the baseplate, and exclude the complex parts sent to

Xometry for machining.

Table 4: Base Manufacturing

DRAWING NO: BASE

STE

P OPERATION DESCRIPTION EQUIPMENT

1 SECURE PART

Screw outer edges of stock plate to base of CNC

cutting surface

Bolts attached to CNC

base

2 CUT PROFILE 1/4 inch tool, multiple passes at 1/8 inch CNC Mill

3 DRILL HOLES 1/4 inch tool CNC Mill

4 SMOOTH Smooth edges to prevent sharp surfaces CNC Mill

Table 5: Frame Manufacturing (1 of 3)

DRAWING NO: SMALL PLUG FRAME, BIG PLUG FRAME, HOPPER FRAME, MID MOTOR FRAME

STE

P OPERATION DESCRIPTION EQUIPMENT

1

SECURE

PART


cutting surface


base


3 DRILL HOLES on the same face as step 2, using a 1/4 inch tool CNC Mill

4

SECURE

PART

Stand part vertically, Screw outer edges of stock

plate to base of CNC cutting surface


base

5 DRILL HOLES 1/4 inch tool, multiple passes at 1/8 inch CNC Mill


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DRAWING NO: BIG HOPPER FRAME

STEP OPERATION DESCRIPTION EQUIPMENT

1 SECURE PART


cutting surface

Bolts attached to

CNC base


3 SECURE PART

Flip over, screw outer edges of stock plate to

base of CNC cutting surface CNC Mill


5 SECURE PART



Bolts attached to

CNC base



Table 7: Back Plate Manufacturing

DRAWING NO: BACK PLATE


1 SECURE PART


cutting surface


base



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Table 8: Pressure Plate Manufacturing

DRAWING NO: PRESSURE PLATE


1 SECURE PART


cutting surface

Bolts attached to

CNC base

2

CUT VERTICAL

PROFILE 1/4 inch tool, multiple passes at 1/8 inch CNC Mill




DRAWING NO: MOTOR BACK FRAME


1 SECURE PART


cutting surface

Bolts attached to

CNC base


3 SECURE PART



Bolts attached to

CNC base



Table 10: Bolt Manufacturing

DRAWING NO: BOLT


1 SECURE PART Clamp screw Vertical Milling Machine Clamp

2 DRILL HOLE 2 mm tool Vertical Milling Machine

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U: Table of Fits and Tolerances

Appendix U lists the fits and tolerances required by the system. It allows the team to plan how it

will manufacture the parts and how tightly dimensions must be controlled.

Table 11 below lists the two shaft/hole fits present in our design post critical design. It

includes tolerances for both the hole in the hopper through which the feed screw shaft extrudes,

as well as the typical bolt connection present between flanges and clamshells.

Table 11: Fits and Tolerances

Fit Hole Size/Tolerance Shaft Size/Tolerance

Feed Screw into Hopper Hole MMC 4.5022 4.5 +0.0022, -0.0000

4.4981 4.495 -0.0014 -0.0050 LMC 4.5000 4.4900

1/4" Bolt into Flange Hole MMC 0.2509 0.25

+0.0006, -0.0000

0.2495 0.2495 -0.0006 -0.0000 LMC 0.2500 0.2489

Final Design Review Report - Purdue University...2020/08/04 · cause 50 psi, 30 psi, and 15 psi of...

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Transcript of Final Design Review Report - Purdue University...2020/08/04 · cause 50 psi, 30 psi, and 15 psi of...