Final Design Report LabView Control for the Inertia Friction Welder

Submitted by: Daniel Barton, Erin Calpin and Earl Swope

Submitted to: Dr. Donald Pratt Advisor: Dr. Timothy Whitmoyer

Monday, May 13, 2002 Messiah College Engineering Department

ENGR 492, Senior Project II

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ABSTRACT

Friction changes mechanical energy into thermal energy. The energy stored in a

rotating flywheel is released thermally through friction at the weld area. The friction

heats the metal, which mixes and cools to form a solid rod. For round stock, friction

welding is better than conventional welding because it reduces the occurrence of hollow

spots inside the weld area. As an added benefit, a friction weld is stronger than a

conventional weld because friction welding does not use a filler material.

Carmen (Hartz) Pettitt and William Pettitt introduced friction welding to the

Messiah College Engineering Department in 1996. The process to automate the first

friction-welding prototype was initiated the next year. Jeremy Lauer and Steven Kriebel

(’97 – ’98) and Dan Hallowell and Jonathan Knight (’98 – ‘99) both worked on

automating the process. Our project improved the automation of the friction welding

process in each of the process’ five areas: control, safety, rotation, pressure, and weld

area. Our team consists of Daniel Barton, Erin Calpin and Earl Swope. Dr. Timothy

Whitmoyer will advise us. This project is sponsored by the Messiah College Engineering

Department.

We have also enlisted the help of several consultants: Mr. Greg Hewitt from

Rockwell Automation; Mr. Ken Gossett from CEI; Mr. Dan Kuruzar from Manufacturing

Technologies INC; Dr. Charles Albright from Ohio State University; Mr. Len Kapp from

Ram Motors and Controls; and Mr. John Meyer from Messiah College.

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ACKNOWLEDGMENTS

Dr. Timothy Whitmoyer, Messiah College Engineering Dr. Donald Pratt, Messiah College Engineering Mr. John Meyer, Messiah College Engineering Mr. Greg Hewitt, Rockwell Automation Mr. Dan Kuruzar, Manufacturing Technology INC. Mr. Ken Gossett, CEI Electro-hydraulic Controls Mr. & Mrs. Bill Pettitt, Messiah College Alumni Dr. Charles Albright, Ohio State University Mr. Len Kapp, Ram Motors and Controls

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Table of Contents

1. Introduction pg. 5

1.1. Description of the Problem pg. 5 1.2. Literature Review To Find State-Of-The-Art pg. 7 1.3. Solution pg. 10

2. Design Process pg. 13 3. Implementation pg. 14

3.1. Construction pg. 14 3.2. Operation pg. 17

4. Schedule pg. 19 5. Budget pg. 19 6. Conclusions pg. 21 7. Recommendations for Future Work pg. 21 8. Appendix pg. 25

8.1. Gantt Chart pg. 26 8.2. Specifications and Objectives pg. 29 8.3. Drawings/ Schematic pg. 31 8.4. Operation pg. 48 8.5. Reference and Bibliography pg. 54 8.6. Resumes of team members pg. 56

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1 INTRODUCTION 1.1 Description of the Problem

Our project was fortunate to have been given a prototype from the earlier projects.

This year, the ’01 – ’02 school year, our team, Dan Barton, Erin Calpin and Earl Swope,

improved the automation of the friction welding process in each of the process’ five

areas: control, safety, rotation, pressure, and weld area.

There are a series of complicated equations that govern the process of friction

welding. The student who wishes to friction weld must work through these equations in

order to determine the correct parameters (both angular velocity and pressure). This

control device that was installed on the prototype that we were given was designed to

compute these equations and set the parameters based upon data entered by the student.

This device was a microcomputer built using a Motorola 68HC11. However, the control

device was unstable in that it tended to lose its programming. Unfortunately, the program

was written in assembly code, therefore it was a tedious and precise task. One who

wished to reenter the code would have to type lines and lines of hexadecimal numbers

exactly as they have been entered before. We focused on designing a control system that

would be more stable and easier to reload if mistakes occurred.

The safety on the prototype that we received was just a single red “stop” button.

Users of the friction welder were also vulnerable to debris from the weld area as well as

projectiles that might be produced in the event of a failure. There were a lot of dangerous

areas include areas where students could be exposed to rotating parts. This includes the

weld area, the entire shaft (including the flywheel), and the shafts of the shaft and pump

motors. Other areas that are considered dangerous are areas where students can be

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exposed to high voltage. The weld area is also an area where student can be exposed to

the possibility of pinching.

We plan to use the original shaft, flywheels, pulleys and spindle motor that are

already on the prototype. The angular velocity of the motor will be adjusted by sending

an adjustable electric signal from LabView through the DAQ card to the VeeArc PWM

7000 motor controller that is already on the prototype. The actual angular velocity will be

monitored with a magnetic pick-up sensor. However, there were three areas that needed

to be addressed. The original bearings, on the prototype that we were given would get hot

(1900 F) when the shaft was at one-quarter of top speed. The original belts were cracked

due to age. The third area that needed to be addressed was the fact that the VeeArc PWM

7000 has a feature that stops the motor was the “motor run” input is removed. In order to

friction weld, the inertia of the motor shaft needs to be stopped by the welding process.

This added deceleration was hindering the welding process.

The adjustment and application of pressure on the original prototype, was controlled

by a combination of two manual valves. Currently, the changing of and application of

pressure is accomplished by manual controls. Unfortunately, the process in which

pressure was adjusted and applied was too long. By the time that the student applied the

correct pressure, the inertia left in the flywheel was less than desired (due to the small

amount of friction in the flywheel and shaft system). Also, we needed to design a system

that would adjust and apply pressure based upon the small current signals coming from

the DAQ card.

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The original chucks require that the pieces of stock, to be welded, need to be

modified so that the chucks will hold the pieces without them rotating in the chuck and

pushing back into the chuck.

1.2 Literature Review To Find State-Of-The-Art

“Integrated sensors and control systems are the way of the future” (Sensors and

Control Systems in Manufacturing). There is one main objective that must be met when

understanding controls systems. It is establishing an automated program. This entails

much more than writing a program. The people writing the program must first solve the

problem of forming the question “what are we trying to accomplish in our control

system”. They must look at what variables there are in the system (i.e. the rate of water

leaving a tank). One must analyze the variables, determine the driving factors that control

the variables (i.e. a flow control valve), and then make a decision on what is the best

method analysis. Most control systems in industry today are closed loop systems. An

example to this is an H VA/C system. When a person set a thermostat in a room in order

control the system one must have a comparator to judge the actual room temperature. In

order to do this we set the desired temperature the system compares our temp with that of

the actual and based on the comparison the heating or cooling is turned on. In order to

continually control this there must be a feedback loop within the system in order to have

a constant comparison.

In our system we use lab View for our control module. LabView is a graphical

programming development environment based on the G programming language for data

acquisition and control, data analysis, and data presentation. LabView gives you the

flexibility of a powerful programming language without the associated difficulty and

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complexity because its graphical programming methodology is inherently intuitive to

scientists and engineers. (LabView 6i Manual)

LabView has a variety of application uses. They vary widely from transportation

systems monitoring to university laboratory classes; from automated parts testing to

industrial process control. LabView allows you to control your system and present your

results through interactive graphical front panels. You can acquire data from thousands of

devices, including GPIB, VXI, PXI, serial devices, Ply’s, and plug-in data acquisition

(DAQ) boards. You can also connect to other data sources via the Internet, inter-

application communication such as ActiveX, DDE (dynamic data exchange), and SQL

(structured query language) database links.

LabView provides complete flexibility in the open development environment;

you can call any external or existing code in the form of a DLL (dynamic linked library)

under Windows or a shared library on any other platform. After you have acquired the

data, you can convert your raw measurements into polished results by using the powerful

data analysis and visualization capabilities of LabView. LabView simplifies and reduces

the development time of a complete system. By using LabView we are able to push the

envelope of automation with as little time possible in creating the actual program.

The two main issues concerning friction welding are the control of pressure and angular

velocity.

In industry, pressure is controlled by either an electro-hydraulic valve or by a

servomotor connected to a manual valve. We have purchased an electro-hydraulic valve

like the ones used in industry. The electro-hydraulic valve is a solenoid type device that

consists of two coils, two springs, a spool and a valve body. The spool is connected

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magnetically to the coils and physically to the springs. When electrical current is allowed

to flow through the coils, a magnetic field is produced. This magnetic field pushes or

pulls on the spool. When the force of the magnetic field is strong enough to overcome the

force of the return spring, the spool moves away from center. The spool is fashioned so

that when the spool is in the center position, fluid flow is not allowed. By moving the

spool to one extreme or the other, one enables a proportional amount of fluid to flow

between the spool and the valve body. In this fashion, one is able to regulate the flow of

the system fluid, by regulating the flow of electric current.

Sources: http://www.mathworks.com/company/digest/march98/electro.shtml

Daniel Kuruzar, Manufacturing Technology INC, South Bend, IN 46628

(219) 233-9490

In industry, the specific control of angular velocity is delegated to a motor

controller (for example, a Siemens #6SE70-21-1CA60Z+C20). This type of controller

has the capability to output a pulse width to run a motor and receive an input signal from

the shaft. Therefore, the controller would regulate itself. This type of controller also has

the option of allowing the shaft to coast or slowing the motor down to a complete stop

when the output goes to zero. This feature is beneficial to friction welding because the

motor is only needed to bring the shaft up to the desired angular velocity. In theory, and

in practice, the shaft is slowed to a complete stop by the act of friction welding. Our

welder will not have this feature available on it. Our motor controller always brings the

shaft to a complete stop when the output goes to zero. To combat this, we will need to

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automatically remove the motor from the system when the desired angular velocity is

reached.

Sources: http://www.aut.sea.siemens.com/drives

Daniel Kuruzar, Manufacturing Technology INC, South Bend, IN 46628

(219) 233-9490

Robert Flynn, Vee-Arc (a division of Furnas Electric Co.), Milford, MA 01757

(508) 478-1220 1.3 Solution

Our work was designed to accomplish five objectives. First, we became able to adjust

pressure from 0 to 2500 psi, to apply this pressure using an electronic signal and to hold

this pressure within plus or minus 50 psi. Second, we became able to adjust flywheel

speed from 0 to 3840 rpm and to hold this speed within plus or minus 50 rpm. Third, we

covered dangerous areas with safety shielding and installed switches that disconnected

main power when certain shields were removed. Fourth, with these three in place, we

became able to enable students to complete a weld within seven steps. Fifth, by following

our own program, we were able to complete one friction weld. We were the first team to

actually weld out of the four teams that have worked on the friction welder.

We are improved control by creating a reliable accurate system surrounding National

Instruments’ LabView, a computer and a DAQ card. This control system is the interface

between the students and the friction welding process. The computer’s monitor acts as the

friction welder’s instrumentation panel. The output of the friction welder’s sensors will

be displayed on the computer’s monitor. The current status of the friction welder will also

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be displayed on the computer monitor. To control the friction welder, students will enter

commands and data through the computer’s keyboard and mouse. The LabView program

will accept the commands and data from the student and compute the appropriate angular

velocity and pressure needed to complete a weld. The LabView program will then send

the respective outputs to the friction welder through the DAQ card. A printed circuit

board (PCB) is used to condition the signals passing from the DAQ to the motor and

pressure controllers and the signals passing from the sensors on the friction welder to the

DAQ card. We made this PCB in house. (For a schematic of the PCB see Appendix

8.3.2.) With this work we enabled the users of the friction welder to complete a weld in

less than seven steps. (To see these steps, please refer to Appendix 8.4.1.)

We improved safety by enclosing dangerous areas behind polycarbonate shields.

Most of the areas on the bottom of the friction welder (below the workbench) are

enclosed behind permanently fixed shielding. A hinged hood protects the weld area

because the operation of the friction welder requires that students have access to this area

at certain appropriate moments. We chose polycarbonate shielding because it was both

strong and transparent. With this type of shielding we could allow the user to view the

welding operation without compromising the safety of the user. The hood is equipped

with a pressure sensitive button that will both send a signal to LabView through the DAQ

card (when depressed) that will alert the user of the missing shield and shut off main

power. The panel the covers the electrical connections box is also equipped with one of

these switches. There is also a relay reserved that will shut off main power.

Pressure is adjusted by adjusting flow by sending an adjustable electric signal from

LabView through the DAQ card to a proportional electro-hydraulic valve. We chose the

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model #V52-1-S-B-I-2-1-B (manufactured by CEI Electro Hydraulic Controls in

Oakhurst, California) for our proportional electro-hydraulic valve. This valve allows flow

that is proportional to the amplitude and relational to the polarity of the signal inputted

into the valve. The original NoShok pressure transducer monitors the actual pressure and

will send a signal back to LabView. The LabView programming monitors the signal

coming from the pressure transducer and adjusts the signal sent to the valve to keep a

constant desired pressure. Changing the pressure output is as easy as changing an analog

output signal. Because of the required fittings needed to interface the electro-hydraulic

valve with the prototype’s hydraulic system we also purchased and installed brass

hydraulic fittings and needed to shorten a hydraulic hose. Due to the fragility of the

electro-hydraulic valve, a hydraulic filter also needed to be installed. With this work we

were able to adjust, apply and hold pressure. To see the items required to enable us to

adjust, apply and hold pressure, please refer to Appendix 8.3.4.

To improve the rotational capabilities of the friction welder, we installed new

bearings to replace the bearings that were getting hot. We also installed new belts to

replace the belts that were cracked. With this work, using the original motor controller,

we were able to adjust flywheel speed. We need to add a clutch needle roller bearing and

thrust bearing assembly to become able to hold flywheel speed. To see the items required

to enable us to adjust and hold flywheel speed, please refer to Appendix 8.3.3.

We were not able to improve the clamping force in our weld area due to money and

time restrictions.

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2 DESIGN PROCESS

There were three students working on this project. Each student had a specific area of

design. The three areas were software design, circuit board design and mechanical

design.

In order for the student to have the most enjoyable and intuitive interface with the

welder, labView was used in order to implement this strategy. The basic premise behind

the software was to control the welder in three ways: safety, speed and pressure. Since

the circuit board modified the voltage levels before sending them to the computer the

DAQ card was able to process most functions on the welder from 0-5 volts. Once the

voltage level was processed by the DAQ the program had to be able to understand the

meaning of each voltage and then control the output using a control system to compare

incoming voltages with outgoing voltages. One of the major design hurdles that we came

across when deciding the programmatic layout of the program was the use of the DAQ

buffer in storing information. Since the welder had to be run through a series of steps in

order to complete a weld, information from the sensors had to taken in and analyzed at

each step. The other difficulty in the design was the reuse of information after that

information had been already processed. To finally get a software design that would

accomplish this problem we used two while loops running simultaneously. One of the

while loops would run all of the DAQ interface subVI’s while the other while loop would

run the process of the welding itself.

The concerns in designing the circuit board were both space available and power

required. First, because we were working with the prototype given to us by the past

project teams, we needed to design a printed circuit board (PCB) that would fit within the

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space available on the original prototype. We also needed to take into consideration the

limitations of the PCB fabrication laboratory. The PCB fabrication laboratory has an

inventory of specific sized circuit boards. We needed to design our circuit so that it would

be able to fit on one of these pre-sized circuit boards. Second, we needed to be able to

control our devices with the signals coming out of the DAQ card. In order to do this,

through our PCB, we needed to amplify either current or voltage. We also needed to

consider the “speed” input to the PWM 7000. This input could not go above 5 volts DC

or below 0 volts. The circuit board that was created fit on a six inch by six inch PCB.

This fit underneath the workbench after a slight modification that removed an eighth of

an inch from one side. The amplification of current was originally done with op amps,

but these did not seem to supply enough current. Therefore current amplification was

done with transistors. Limiting the input to the PWM 7000 was done with a zener diode.

In order to meet one of our objectives, we needed to design safety measures. We

considered different materials and orientations for the safety shields. After consulting

our advisor and Mr. John Meyer, we finalized the design of the safety hood using

polycarbonate. We chose polycarbonate for its high impact resistance and machinability.

To cover the safety hazards present below the workbench, we chose sheet metal due to its

low cost and ease of use. By implementing our design, we’ve reduced the risk of injury.

3 IMPLEMENTATION 3.1 Construction

There were three items that we considered while we constructed our project. These

items are (1) space, (2) safety and (3) input AC power.

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Since we already had a prototype (from previous project teams), we had a limited

amount of space in which to place the components that make up our project. Some of our

components (like the PWM 7000 motor controller) require space around them so that

heat can dissipate. To follow our safety measure design (using flat pieces of poly

carbonate and sheet metal as shields), we needed to keep all of the components within the

skeleton on the prototype. Space is also an issue if one considers the addition of hoses

and wires into the cavity of the friction welder. Finally, the belts, rotating at a possible

3840 rpm’s, require a certain amount of free space surrounding them so that they do not

pull on wires or cut through hoses. We needed to consider the efficient use of space as we

constructed our project.

The second consideration was safety. The safety measures that we placed around

the belts were designed to be able to contain the debris that would result in the event that

a belt would tear while rotating at 3840 rpm's. Also, the safety measures that we placed

around our weld area were designed to prevent injury in the event of a weld gone badly.

We are going to need to consider the practicality of our safety measures as we construct

our project. Another safety issue that we had to consider was the presence of high

voltage. Our safety measures are also designed to lower the risk of electrical shock.

The third consideration is the 3-phase AC input power. We cannot use any other

power if we continue to use the original spindle motor and motor controller.

Unfortunately, not all of our components operated directly off of 3-phase AC power. As

we constructed our project, we needed to consider the necessary conversions from 3-

phase AC power to the appropriate power required to run our various components.

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Keeping all of these considerations in mind, we proceeded to construct our

project. The following paragraphs will describe how we addressed these three areas.

We were able to use the space under the workbench and above the hydraulic

system for all of our control system additions. Furthermore, in order to implement our

control design (utilizing an electro-hydraulic valve), we needed to remove the two

manual valves that were already in place. This removal opened up more space for us to

use. The additions that we needed to add to our control system were the electro-hydraulic

valve and the control interface PCB. Both of these items were able to fit nicely bolted to

the underside of the workbench. Additional space was made available due to the fact that

the location of the valve allowed for shorter hydraulic hoses. Wires to and from the

control interface PCB to the controls and sensors on the Friction Welder and to the DAQ

card were cut to be as short as possible and were wire tied and fastened to the frame of

the friction welder. Shorter hoses and fastened wires created a cushion of air around the

pulleys on the spindle motor. Therefore, there is no danger of the hoses coming contact

with the belts and being cut.

To insure that flying debris would not injure the users of the friction welder, we

installed a quarter inch thick polycarbonate hood over top of the rotating shaft, the

rotating belts, the weld area and the hydraulic hoses going into the cylinder. We also

installed sheet metal shields around the three open sides of the bottom of the friction

welder. These shields will also reduce the risk of friction welder users pinching their

fingers underneath the spinning chucks or in between the belts and pulleys. These shields

also will reduce the risk of electric shock. In addition to the shields, we installed two

safety switches that will disconnect main power when depressed. One switch is located

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underneath the rim of the hood, and the other switch is located behind the cover of the

electrical connection box. Main power will be disconnected from the friction welder if

either the hood is raised or the cover is removed from the electrical connection box.

Converting three-phase electrical power into the direct current that is needed to

run the control interface PCB was accomplished through the use of transformers and

rectifier diodes. The control interface PCB draws off of one of the phases, while the

pump draws off the other two phases. The pump contactor, main power contactor and

PWM 7000 input are all controlled by relays. Transistors are used (because op amp’s did

not have enough output power) to amplify and de-amplify the signals moving from and to

the DAQ card.

3.2 Operation

To ensure the quality of the result of our friction welds we performed several test

welds. In all, we performed eight welds. These eight welds can be grouped into three

different sets of attempts. (Please refer to Appendices 8.4.3, 8.4.4 and 8.4.5 to view the

results of these groups.) The general operation of the friction welder remained basically

the same through out all eight attempts. First the friction welder pushes the one specimen

into the other specimen in order to “see” where the meeting point is. Then, second, the

friction welder pulls the horizontally moving specimen back in order to allow the rotating

specimen to spin. Then, third, the LabView program spins the flywheel up to the desired

rpm needed for a weld. Fourth, after a time delay to ensure that the flywheel has

stabilized at optimal speed, the LabView program pushes the horizontally moving

specimen into the rotating specimen to initiate the friction weld. The major difference

between the groups of attempts is what happens next.

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In the first group, the LabView program was not programmed to monitor the pressure

being applied to the cylinder. During these attempts, the program would push the

horizontally moving specimen for a certain time. Because the metal was plastic due to the

high temperatures present at the friction point, the metal experienced plastic deformation

and the resulting weld was grossly off center. (Please refer to Appendix 8.4.3 to see a

result of this set of attempts.) It was also observed during this set of attempts that the base

of the spinning shaft and the hydraulic cylinder would flex under pressure. In order to fix

the problems that occurred during this set of attempts, LabView was reprogrammed to

monitor the pressure that was being applied to the hydraulic cylinder.

Therefore in the second group of attempts, after the basic operation LabView was

programmed to allow hydraulic flow until the desired pressure was reached and then flow

was turned off. Also the rate of approach was reduced to a slower rate. Unfortunately this

change did not produce the desired results. (Please refer to Appendix 8.4.4 to see a result

from this group of attempts.) While monitoring pressure and system flow using an

oscilloscope, it was observed that there was a 60 ms delay between LabView “seeing” the

desired pressure and LabView disallowing flow. (Please refer to Appendix 8.4.2 to see

the graphs from the oscilloscope.) In order to fix the problems encountered during this set

of attempts, the program in LabView remained the same, but the variable that was

entered as the desired pressure was reduced to the pressure that occurred 60 ms before the

desired pressure. The rate of approach was set back to the rate in the first group of

attempts. Unfortunately, this change also did not produce the desired results. The test

with the oscilloscope was performed with the specimens stationary. We assume that

because the metal is getting hot as the pressure is nearing the desired pressure, LabView

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never sees the desired pressure. Therefore the hydraulic cylinder keeps pushing causing

plastic deformation. To fix this, LabView was reprogrammed to record how long it pulls

after the interface between the specimens is found. After the flywheel speed has

stabilized, LabView pushes until the specimens meet (based upon the time that it has

back away from this point) and continues to push for 0.1 seconds.

This version of the operating program produced the best results. (Please refer to

Appendix 8.4.5 to see a result from this set of attempts.) These results still were not the

same as the desired result because of the flexing on the base of the friction welder, the

slipping of the metal in the chucks and the “play” the chucks. These problems will have

to be fixed by future work.

To see the specific steps that a student must go through in order to complete a friction

weld, see Appendix 8.4.1.

4 SCHEDULE

For the scheduling of the project and the actual timeline, please see Appendix 8.1.

5 BUDGET Budget Funding Product Name, Number Price Source Quantity COMPUTER AUTOMATION DELL DIMENSION 2100 or similar priced computer $619.00 ENGR. 1 National Instruments LabView 6i $3,200.00 ENGR. 1 PCI-6025E Multifunction DAQ Card By Nation Instruments $625.00 ENGR. 1 120 VAC Relays 5Vdc coil $7.00 ENGR. 4 Electronic Components $25.00 PROJ. $ 1 PRESSURE CONTROL V52-SB by CEI Electro-Hydraulic Controls, Oakhurst CA $898.34 ENGR. 1 Hydraulic Hoses - R.F. Fager CO. (717) 761-0660 $4.80 PROJ. $ 1 Brass Hardware - R.F. Fager CO. (717) 761-0660 $35.03 PROJ. $ 1

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Hydraulic System Filter – McMaster-Carr P/N’s 9800K43 & 9800K12 (10 microns)

$35.65

PROJ. $

1

SAFETY PRECAUTIONS Safety Signs $0.25 PROJ. $ 6 Shroud for Base - 20 ft^2 of 12 gauge metal - 4 ft. x 8ft. $3.06/sq ft PROJ. $ 32 Sq. ft. Cover for Top of Welder - Poly-Carbonate Formed Hood $0.63/sq ft ENGR. 32 Sq. ft. Mounting and Securing Hardware for Shields $20.00 PROJ. $ 1 ROTATIONAL ENHANCEMENTS 6392K29 from McMaster-Carr - Needle-Roller Clutch Bearings $16.67 PROJ. $ 1 6191K42 from McMaster-Carr - Replacement belts $5.50 PROJ. $ 2 64865K1 (130 lb loading) - Anti-vibration bushings $1.22 PROJ. $ 4 Replacement Shaft Bearings $250.00 SAMPLE 2 6681K15 from McMaster-Carr – Thrust bearings

$18.98 PROJ. $

2

MISCELLANEOUS ITEMS Hardware $20.00 PROJ. $ 1 Phone Usage $0.10 / min. ENGR. 300 Minutes Professional Consultation $20.00 / hr. SAMPLE 100 Hours Travel Expenses $0.10 / mile PROJ. $ 50 miles TOTAL BUDGET (see breakdown below) $8235.99 The totals from the table above are as follows: ENGR. (Money paid by the Messiah College Engineering Department) $ 898.34 X 1 $ 898.34 $3200.00 X 1 $3200.00 $ 619.00 X 1 $ 619.00 $ 625.00 X 1 $ 625.00 $ 7.00 X 4 $ 28.00 $ 0.63 X 32 $ 20.16 10 cents X 300 $ 30.00 TOTAL $5420.50 PROJ. $ (Money paid out of the money allotted to the Senior Project Team.) 10 cents X 50 $ 5.00 $ 25.00 X 1 $ 25.00 $ 20.00 X 1 $ 20.00 $ 4.80 X 1 $ 4.80 $ 35.03 X 1 $ 35.03 $ 0.25 X 6 $ 1.50 $ 3.06 X 32 $ 98.00 $ 20.00 X 1 $ 20.00

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$ 16.67 X 1 $ 16.67 $ 5.50 X 2 $ 11.00 $ 1.22 X 4 $ 4.88 $ 18.98 X 2 $ 37.96 $ 35.65 X 1 $ 35.65 TOTAL $ 315.49 SAMPLE (These items were received free of charge from industry) $ 250.00 X 2 $ 500.00 $ 20.00 X 100 $2000.00 TOTAL $2500.00 6 CONCLUSIONS

By following our design process and doing analysis on our preliminary weld

attempts, we were able to accomplish all of our objectives. We became the first team, out

of four teams, to produce a friction weld. Because of our work, the Messiah College

Engineering Department has a friction welder that functions and is safer to use.

Through the process of design and implementation we have worked through many

problems. Some were fixable and some were not. The goals and expectations that our

team set out to accomplish were met. Our accuracy in the friction weld did not return a

perfect weld. We have come to conclude that the factors hindering the perfection of this

process would be to large to fix in our amount of time. It from the assessment of our team

that if the welder was to have perfect welding capabilities that the whole welder would

have to be rebuilt from the ground up in order for the machine to have capabilities that

are necessary to complete a perfect friction weld.

7 RECOMMENDATIONS FOR FUTURE WORK

There are six projects that we would like to recommend for future work. The first is a

complete redesign upgrade of the hydraulic system. Second, one could redesign the way

that the motor mount adjusts the belt tension. Third, it may be helpful to exchange the

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belt-pulley system for a chain-gear system. Fourth, to increase safety and ease of use, one

could design and install a flywheel storage and lift system. Fifth, the workbench top

(under the weld area) is not stable enough to hold against the pressure of the friction

welding. A project team may want to redesign or modify this workbench top in order to

make it structurally sound. The sixth project would be fabricating an updated rendition of

the control interface board between the DAQ card and the friction welder.

The present system has a flow of only one gallon per minute. The upgrade is

necessary if other project team desire to add items to the hydraulic system (such as

hydraulic chucks, a hydraulic brake and/or a hydraulic lift for the flywheels). The present

flow is not enough to support addition because of the big cylinder that is use in the

welding process. (The present system might work if nothing else is allowed to run while

the cylinder is running.) A big cylinder is essential to the friction welder due to the huge

amount of force needed to complete a weld. Operating too many things by the present

hydraulic system might cause the flow in the valve (the electro-hydraulic valve) to drop,

causing the pressure on the valve’s pilot to decrease, causing the valve to malfunction.

These additions may also be necessary in order to weld with the welder. For example,

hydraulic chucks may be required to supply enough clamping force in order to hold the

specimens so that the specimens do not push into the chuck or rotate in the chuck. The

valve can be easily upgraded to work with flow rates up to 10 gallons per minute. (For

more information on this operation contact Mr. Ken Gossett, CEI Electro-Hydraulic

Controls, Oakhurst, CA 93644, (559) 683 – 2044.) The current pump/pump motor can be

upgraded to output two gallons per minute by exchanging the current motor for a plug-n-

play motor (p/n 08760). (For more information on this operation contact Mr. Doug Stine,

22

Airline Hydraulics, York, PA, (717) 767 – 6466, ext. 2311.) The senior project team

would have to design and build, or research and buy, an ample reservoir so that the fluid

does not go above 160 degrees Fahrenheit. (This condition must be met with the valve in

the off position for a couple of minutes. If the fluid in the system goes above 160 degrees,

the electro-hydraulic valve will be damaged.)

The current motor mount is fixed on one end and adjusted on the other end. This

causes the motor to move in a circular pattern. Therefore the belts move both vertically

and horizontally. Due to the very small amount of clearance between the belts and the

base of the shaft, any horizontal movement could cause the belts to be positioned next to

the shaft base and that may cause rubbing. Rubbing is undesirable for two reasons. First,

rubbing will cause premature failure in the belts. Second, rubbing will introduce

additional friction into the system that will subtract from the energy stored in the

flywheel. The new design should only move in the vertical direction (like a scissors jack)

in order to minimize the risk of contact between the belts and the shaft base. The new

design should also be easy to adjust.

The current belt-pulley system is undesirable because of the risk of a misaligned

shaft. In order to replace, remove or re-install the belts, one must remove the bearing that

supports the shaft near the flywheel. Not only is this an extra step that may not be needed

with a chain-gear system, there is a large risk of misaligning the shaft while re-installing

the bearing. With a chain-gear system, one could remove and reinstall the chain just by

undoing and redoing a link in the chain. Therefore the shaft could be aligned once and the

bearing could be permanently installed. A misaligned shaft could cause a misaligned

weld, excessive vibration and/or damage to the shaft bearings.

23

A fourth recommendation for future work would be a device that is designed to lift

and maybe store the flywheels. A major safety concern is a student dropping a 60-pound

flywheel on his/her foot while attempting to install the flywheel on the end of the shaft. If

a senior project team could design a device to safely lift the flywheel and hold the

flywheel by the end of the shaft, one could install the flywheel safely. If this device could

also store the flywheels, the friction welder could become a more compact unit.

Presently, the flywheel must be stored elsewhere on a table or on the floor or in the

bottom of a cabinet. Having a device that would lift the flywheels will also reduce the

risk of back strain.

Our first attempt at welding was offset because the workbench bent due to the

pressure of the weld. This area will need to be modified or redesigned in order to stay

rigid during the friction welding process.

The final recommendations for future work is redesigning the interface control PCB

to take into account all of the circuit modifications required. An option to this project is

researching other means of data acquisition and control.

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8 APPENDICES

25

8.1 Gantt Chart (Task List)

26

Appendix 8.1.1 Gantt Chart

27

Appendix 8.1.2 Task List Task List for Lab View Automation Project Task Team Date Description Mem. Done Research electro-hydraulic valves S 10/5/01 Write Project Proposal BCS 9/21/01 Write Extra Money Proposal BCS 9/21/01 Current Industrial procedure review BCS 10/28/01 Literature review BS 10/28/01 Align shaft C 9/28/01 Research chucks C 2/22/02 Write Specification BCS 10/12/01 Research bearings C 10/12/01 Purchase and receive bearings C 10/19/01 Purchase and receive chucks C Incomp. Purchase and receive electro-hydraulic valve S 11/30/01 Write EDR first draft BCS 10/30/01 Compute and draw rotational control diagram S 10/19/01 Compute and draw pressure control diagram S 10/19/01 Matlab analysis of both control systems S Incomp. Build rotational interface B 10/26/01 Program rotational sub-VI B 10/26/01 Compare control analysis to real life (rotational) S Incomp. Prepare oral presentation for fall semester BCS 11/30/01 Make pressure interface S 11/15/01 Program pressure sub-VI B 11/9/01 Compare control analysis to real life (pressure) S Incomp. Compute and draw total control diagram S Incomp. Design safety measures BC 2/8/02 Program safety sub-VI B 4/25/02 Purchase and receive shielding material C 4/5/02 Write EDR final draft BCS 12/5/01 Build safety measures BC 4/25/02 Learn welding techniques (conventional) BC 3/1/02 Thermodynamic analysis BCS Incomp. Total welding program BS 4/19/02 Compare control system analysis to real life (total) S Incomp. Make welding specimens (conventional) BC 4/12/02 Make welding specimens (friction) BS 4/19/02 Weld analysis BCS 4/19/02 Prepare final oral presentation BCS 4/25/02 Write final report TEAM MEMBER LEGEND B = Daniel Barton C = Erin Calpin S = Earl Swope

BCS 5/13/02

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8.2 Specifications and Objectives

29

Specifications for LabView Automation Project

Main Power input voltage: 208V AC, three phase Operating System: WindowsTM 95, or higher Processor: PentiumTM or equivalent Memory Requirements: 32 MB RAM minimum, 64 MB recommended

65 MB disk space needed for minimal installation (200 MB, full installation) Analog input: 1, 12 bit resolution, 256 S/s sampling rate Analog input range: +/- 5 volts DC Analog outputs: 2, 12 bit resolution, 64 S/s sampling rate Analog output range: +/- 5 volts DC Digital I/O ports: 6, 4 outputs/2 inputs, TTL Three phase shut-off relay: 120V AC actuation, 208V AC 40A three phase across contacts Pump power shut-off relay: 120V AC actuation, 220V AC 40A two phase across contacts Operating velocity: 420 to 3800 rpm Flywheels: BIG: 64.9 lbs, 3" thick, 10" diameter SMALL: 44.0 lbs, 2" thick, 10" dia. Chuck weight: 7 lbs. Maximum Chuck diameter: 4 inches Min. chuck clamping force: 4,867 pounds Hydraulic fluid: Petroleum based hydraulic fluid

Indoor use: MobilTM DTE 24 or equivalent Outdoor use: MobilTM DTE 13 or equivalent

Operating pressure: 300 to 3000 psi Maximum fluid temperature: 1600 F

Objectives for LabView Automation Project

1. Complete at least one complete friction weld 2. Adjust and apply pressure using an electronic signal. Hold the desired pressure

within +/- 50 psi.

3. Adjust rotational velocity using an electronic signal. Hold the desired rotational velocity within +/- 50 rpm.

4. Complete a weld in seven steps or less.

5. Protect friction welder users by safety measures.

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8.3 Drawings and Schematics

31

8.3.1 (Picture of the type of bolt holes needed for safety shielding)

32

Appendix 8.3.2 (Schematics and Control Block Diagrams)

33

Appendix 8.3.2.1 Rotational Control Diagram (copied from log book)

34

Appendix 8.3.2.2 Pressure Control Diagram (copied from log book)

Pressure Curves (as the piston nears end of travel)

Note: In this picture, high voltage represents low pressure and low voltage represents

high pressure.

35

Appendix 8.3.2.3 Control Schematic (Relays)

Pin Out of J1 1 – N/C 2 – N/C 3 – To PWM 7000 input 4 – To PWM 7000 input 5 – To Contactor for pump motor 6 – To Contactor for pump motor 7 – To Contactor for main power 8 – To Contactor for main power 9 – To Safety Switches 10 – From Safety Switches

36

Appendix 8.3.2.4 Interface Schematic (Sensors & Controls)

Pin Out of J2 1 – Red wire of Hall effect sensor 2 – White wire of Hall effect sensor 3 – Black wire of Hall effect sensor 4 – Shield of Hall effect sensor 5 – Black wire of Pressure Transducer 6 – Clear wire of Pressure Transducer 7 – Shield of Pressure Transducer 8 – To PWM 7000 Speed Input 9 – GND 10 – To the Electro-hydraulic Valve

37

Appendix 8.3.2.5 Hydraulic Schematic (copied from log book)

38

Appendix 8.3.3 (Items needed for rotational control)

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Appendix 8.3.3.1 Anti-vibration Bushings

Part Number 64865K1

40

Appendix 8.3.3.2 Thrust Bearings for Motor Shaft

Part Number 6681K15

41

Appendix 8.3.3.3 Needle Roller Clutch Bearing for Motor Shaft

Part Number 6392K29

42

Appendix 8.3.3.4 Picture of Assembly

43

Appendix 8.3.4 (Items needed for pressure adjustment and application)

44

Appendix 8.3.4.1 (wiring hook up for electro-hydraulic valve).

This is the setting for our valve

45

Appendix 8.3.4.2 Electro-hydraulic Valve

Part Number VS5201SBI21B from CEI Electro-hydraulic Controls

Address: 40124 Highway 49, Oakhurst, CA 93644 (559) 683-2044

NOTE: Mounting plate P/N 62593 is required!!

46

Appendix 8.3.4.3 Hydraulic Filter

Part Number 9800K43 (Note: the valve requires a 10 micron cartridge)

47

8.4 Operation

48

8.4.1 Operation Procedure

Step one: Open safety hood, load specimens, tighten chucks.

Step two: Close and lock hood.

Step three: Open friction-welding program.

Step four: Set input and output channels.

Step five: Push “start” .

Step six: When flywheel is COMPLETELY stopped, open hood and loosen specimens.

Step seven: Close and lock hood, push “back-up” button.

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8.4.2 Operation Curve

Trial One (overshoot)

Good Operation (with cut-off point adjusted)

50

Pressure Transducer

Valve Control: Positive is reverse Negative is forward

8.4.3 Result of first set of friction weld attempts

51

8.4.4 Result of second set of friction weld attempts

52

8.4.5 Result of third (and final) set of friction weld attempts

53

8.5 References and Bibliography

54

The engineering design process Atila Ertas, Jesse C. Jones, New York : John Wiley & Sons, c1996. 2nd ed. Safety engineering, CoVan, James, 1940- New York : J. Wiley, c1995. Introduction to control system technology Bateson, Robert. Upper Saddle River, N.J. : Prentice Hall, c1999 6th ed. Modern control system theory and design, Shinners, Stanley M New York : J. Wiley, c1992. Control system design and simulation, Golten, Jack and Verwer, Andy London ; New York : McGraw-Hill, c1991 Basic control system technology, Chesmond, C.J. New York : Van Nostrand Reinhold, c1990. The design of automatic control systems, Rubin Olis Norwood, MA : Artech House, c1986

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8.6 Resumes of Team Members

56