DESIGN AND DEVELOPMENT OF 3D PRINTER

Guided by By Dr. L. BALA MURUGAN S.AAKASH - 312311114001 Associate Professor G.VIGNESH- 312311114130

Department of Mechanical Engineering

MOTIVATION• Lead time • Unaffordable for the masses• Manufacturing of complex shapes• Customized digital manufacturing

Image Source: Google Images

Conventional Lathe Makerbot Replicator – 3D Printer

ABSTRACT

Digital desktop fabrication technologies such as 3D printing are currently being lauded in the popular press as a potential socially transformative technology.This work discusses the design and development of an affordable Fused Deposition Modeling machine. This particular design includes carriage and roller drive on aluminium extrusion which best meets the functional requirements after comparing the designs based on factors such as complexity and controllability. This design aims at providing an extremely compact and portable 3D printer which holds all features such as auto bed leveling and no filament blockage. This machine can be upgraded as required which will provide way for fully customizable digital fabrication.

OUTLINE Motivation

Current Scenario

Proposed design Design calculations of carriage for X and Y motions Design of V-rollers Design of direct drive filament feed mechanism Design of extruder head

Advantages from existing design

Timeline

Conclusion Future steps ahead

STUDY OF EXISTING DESIGNSPrint technology : Fused deposition modellingPrice : 93,870 INRPrint area : 180x150x300 mmX,Y,Z motion drive mechanism :Timing belt and pulley driveFilament drive mechanism : Lego worm drive extruderExtruder cooling : Air cooledWeight : 15 Kg.Firmware : Marlin derivative firmwareMicrocontroller : Standard arduino board Advantages:1. Inbuild power supply unit2. Stable aluminium chassis3. Heated print bed can print ABSDisadvantage:4. Unaffordable5. Printer must be build with high precision6. Greater printer height7. Cannot be upgraded to dual extruder8. Not portable9. Problem of filament block

Spiderbot Delta 3D Printer

Info source: www.3ders.org

Makerbot replicator 2

Info source: www.makerbot.com

Print technology : Fused deposition modellingPrice : 1,55,000 INRPrint volume : 250 X 152 X 152mmX,Y,Z motion drive mechanism : Timing belt and pulley driveFilament drive mechanism : Spring type extruderExtruder cooling : Air cooledWeight : 12.6 Kg.Firmware : Makerbot makerwareMicrocontroller : Standard arduino board Filament diameter : 1.75mmNozzle diameter : 0.4mmAdvantages:1. Stable powder coated steel chassis2. Heated print bed can print ABS3. High precision4. Dual extruderDisadvantage:5. Unaffordable6. Not portable7. Cannot be further upgraded8. Firmware is not user friendly9. No autobed levelling feature

FabX 3D Printer

Print technology : Fused deposition modellingPrice : 20,000 INRPrint volume : 100 X 100 X 100mmX,Y,Z motion drive mechanism : Series rails and blockFilament drive mechanism : Gear type extruder driveExtruder cooling : Air cooledWeight : 5.5 Kg.Firmware : Marlin firmwareMicrocontroller : Standard arduino board Filament diameter : 1.75mmNozzle diameter : 0.3mmAdvantages:1. Acrylic chassis2. Affordable3. PortableDisadvantage:4. No heated bed5. Problem of filament block6. No autobed levelling feature7. Print volume is too small

Info source: www.3ding.in

PROPOSED DESIGN

Vertical carriage Split to accommodate smooth rod

Printer base Horizontal carriage

Y motor mount Z motor mount

3D printed horizontal carriage Manufactured delrin rollers

DESIGN CALCULATIONS

• Drive selection X and Y movement Z movement Filament feed

• Positioning of end stops• Auto bed Levelling• Assembly of electronic circuit• Microcontroller coding

SELECTION OF STEPPER MOTOR

X MOTION CALCULATIONS1. DETERMINATION OF DESIGN LOADP = VI =12*2=24W=0.032HPDESIGN HP = P * SERVICE FACTOR= 0.032*1.4 = 0.045 HP2. SELECTION OF BELT PITCHCHECKING BELT PITCH SELECTION BASED ON THE INDIVIDUAL GRAPHSRated speed = V/L*I/Steps/rev = 8.33rps = 500rpmRated torque = 4.2Kg cm =0.412 N mFor the rated torque and corresponding rated speed the belt pitch selection is GT2 2mm pitch and hence the design never conflicts.3. DETERMINE SPEED RATIOSpeed ratio = Diameter of drive/ Diameter of Driven = 15/15 = 1Pulley Pitch Diameter = = 1.732mm4. BELT SPEEDV=0.0000524*Pitch Diameter (mm) * Pulley RPMV = 0.0000524*12.732*500 = 0.333526 m/s

X motion – Timing belt and pulley drive

Fabricated X-motion mechanism

Idler pulley Stepper driven GT2 pulley

Linear bearing for x motion

Y motion – Timing belt and pulley drive

Idler pulley

Bed mount to accommodate toothed belt

Sliding rollers on Al extrusion

Z MOTION CALCULATIONS1.CALCULATION OF LOAD TORQUE

We used M5 Threaded rod with 0.8mm pitch.F-Frictional Force needed to overcomeE-EfficiencyC=0.16 (steel) = 3.19 N

= 1.35 x 10-3 Nm

2.DUE TO THE EFFECT OF ROTARY MOTION THE EFFECT OF INERTIA IS SEENInertia due to load, J = 0.032 *10-3 kg m2

Inertia of Screw,

Mass of the screw,

M = 0.153 KgInertia of screw, J = 4.78 * 10-7Kg m2

3. MAXIMUM TRAVERSE SPEED Smax = RPM max *p

Smax = 500 *0.8

Smax = 400 rpm

4. MAXIMUM LINEAR SPEEDFor 200 step motor linear speed = 1000*60*0.8*10-3 / 200Max. Linear speed = 240mm/min

5. ANGULAR VELOCITY OF THE SCREW

6. TORQUE NEEDED TO ACHIEVE ACCELERATIONIf we need acceleration of about 3000 rad/s2 , The torque required to achieve isT = J*aT = (4.78 * 10-7+ (2* 0.032 *10-3 )) * 3000T=0.1934 Nm is required to achieve acceleration of 3000 rad/s2

Z motion – Lead screw mechanism

Fabricated Z drive mechanism

Sliding rollers on Al extrusion

Flexible coupling

Spring tensioned carriage

Code snippets for drive control//// MOVEMENT SETTINGS#define NUM_AXIS 4 // The axis order in all axis related arrays is X, Y, Z, E#define HOMING_FEEDRATE 50*60, 50*60, 4*60, 0 // set the homing speeds (mm/min)#define DEFAULT_AXIS_STEPS_PER_UNIT 80,80,4000,148 #define DEFAULT_MAX_FEEDRATE 500,500,2.5,25 // (mm/sec)#define DEFAULT_MAX_ACCELERATION 1000,1000,100,500 // X, Y, Z, E maximum start speed for accelerated moves.

#define DEFAULT_ACCELERATION 800 // X, Y, Z and E max acceleration in mm/s^2 for printing moves#define DEFAULT_RETRACT_ACCELERATION 800 // X, Y, Z and E max acceleration in mm/s^2 for retracts

X, Y, Z drive connections to Arduino

Potentiometer to limit current to stepper driver

Stepper driver (1/16th microstepping)

Stepper motor connections

Heated bed calculationResistance, R = U2/P = 122/140 = 1.02 ΩThe width of one track part,

Where Rs,Cu, Specific resistance of copper = 1.68 x 10-5Ω mm

tCu, Thickness of copper = 35μm=0.035mm

2wtr =

wtr = 2.62 mm

Number of tracks, ntr = = 46.53

Length of entire track, ltr = lb n⋅ tr

ltr = 215 x 46 = 9890 mm (approx.)

Wtr = 2.62mm ; Ltr = 9890 mmNtr = 47 ; R = 1.02 ohm

Extruder head designServo Motor to

actuate bed level probe

Z probeNozzle head

Extruder Head Fabricated extruder head

Heater catridge

Duct to cool printed layers

Fan to cool extruder head

Connecting thermistors, heated bed and heater catridge

Connections to thermistors Connections to heated bed, fan and heater catridge

Configuring temperature sensors and heated bed

#define TEMP_SENSOR_0 -1#define TEMP_SENSOR_1 -1#define TEMP_SENSOR_2 0#define TEMP_SENSOR_BED 0 If the temperatures difference between these sensors is too high the print will be aborted.

#define MAX_REDUNDANT_TEMP_SENSOR_DIFF 10// The minimal temperature defines the temperature below which the heater will not be enabled It is used// to check that the wiring to the thermistor is not broken.

#define HEATER_0_MINTEMP 5#define HEATER_1_MINTEMP 5#define HEATER_2_MINTEMP 5#define BED_MINTEMP 5

#define HEATER_0_MAXTEMP 275#define HEATER_1_MAXTEMP 275#define HEATER_2_MAXTEMP 275#define BED_MAXTEMP 150

Direct drive filament feed mechanism

Spring tensioned drive mechanism

MK8 gear Filament adapter

Indicating the delay and setting limits for filament feed rate

#define FILAMENT_SENSOR_EXTRUDER_NUM 0 //The number of the extruder that has the filament sensor (0,1,2)

#define MEASUREMENT_DELAY_CM 14 //measurement delay in cm. This is the distance from filament sensor to middle of barrel

#define DEFAULT_NOMINAL_FILAMENT_DIA 3.0 //Enter the diameter (in mm) of the filament generally used (3.0 mm or 1.75 mm) - this is then used in the slicer software. Used for sensor reading validation

#define MEASURED_UPPER_LIMIT 3.30 //upper limit factor used for sensor reading validation in mm

#define MEASURED_LOWER_LIMIT 1.90 //lower limit factor for sensor reading validation in mm

#define MAX_MEASUREMENT_DELAY 20 //delay buffer size in bytes (1 byte = 1cm)- limits maximum measurement delay allowable (must be larger than MEASUREMENT_DELAY_CM and lower number saves RAM)

Connections to Arduino Mega 2560

Connecting endstops and heated bed to Arduino

Connecting SMPS to ramps

Overall printer connections

Connecting SMPS to Arduino

Specifying the printer homing point and travel limits

// Disables axis when it's not being used.#define DISABLE_X false#define DISABLE_Y false#define DISABLE_Z false#define DISABLE_E false // For all extruders#define DISABLE_INACTIVE_EXTRUDER true //disable only inactive extruders and keep active extruder enabled

#define INVERT_X_DIR true // for Mendel set to false, for Orca set to true#define INVERT_Y_DIR false // for Mendel set to true, for Orca set to false#define INVERT_Z_DIR true // for Mendel set to false, for Orca set to true#define INVERT_E0_DIR false // for direct drive extruder v9 set to true, for geared extruder set to false#define INVERT_E1_DIR false // for direct drive extruder v9 set to true, for geared extruder set to false#define INVERT_E2_DIR false // for direct drive extruder v9 set to true, for geared extruder set to false

// ENDSTOP SETTINGS:// Sets direction of endstops when homing; 1=MAX, -1=MIN#define X_HOME_DIR -1#define Y_HOME_DIR -1#define Z_HOME_DIR -1

// Travel limits after homing#define X_MAX_POS 205#define X_MIN_POS 0#define Y_MAX_POS 205#define Y_MIN_POS 0#define Z_MAX_POS 200#define Z_MIN_POS 0

Code snippets for Auto bed levelling and specifying grid points

#define Z_PROBE_REPEATABILITY_TEST // If not commented out, Z-Probe Repeatability test will be included if Auto Bed Leveling is Enabled.

#ifdef ENABLE_AUTO_BED_LEVELING

#define AUTO_BED_LEVELING_GRID // with AUTO_BED_LEVELING_GRID, the bed is sampled and least squares solution is calculated

#ifdef AUTO_BED_LEVELING_GRID

// set the rectangle in which to probe #define LEFT_PROBE_BED_POSITION 15 #define RIGHT_PROBE_BED_POSITION 170 #define BACK_PROBE_BED_POSITION 180 #define FRONT_PROBE_BED_POSITION 20

#define X_PROBE_OFFSET_FROM_EXTRUDER -25 #define Y_PROBE_OFFSET_FROM_EXTRUDER -29 #define Z_PROBE_OFFSET_FROM_EXTRUDER -12.35

#define Z_RAISE_BEFORE_HOMING 4 // (in mm) Raise Z before homing (G28) for Probe Clearance. #define XY_TRAVEL_SPEED 8000 // X and Y axis travel speed between probes, in mm/min

#define Z_RAISE_BEFORE_PROBING 15 //How much the extruder will be raised before traveling to the first probing point. #define Z_RAISE_BETWEEN_PROBINGS 5 //How much the extruder will be raised when traveling from between next probing points

Code snippets for specifying acceleration and feed rate

//Manual homing switch locations:#define MANUAL_X_HOME_POS 0#define MANUAL_Y_HOME_POS 0#define MANUAL_Z_HOME_POS 0// MOVEMENT SETTINGS#define DEFAULT_AXIS_STEPS_PER_UNIT 78.7402,78.7402,200.0*8/3,760*1.1 // default steps per unit for printing#define DEFAULT_MAX_FEEDRATE 500, 500, 5, 25 // (mm/sec)#define DEFAULT_MAX_ACCELERATION 9000,9000,100,10000

#define DEFAULT_XYJERK 20.0 // (mm/sec)#define DEFAULT_ZJERK 0.4 // (mm/sec)#define DEFAULT_EJERK 5.0 // (mm/sec)

// Custom M code points#define CUSTOM_M_CODES#ifdef CUSTOM_M_CODES #define CUSTOM_M_CODE_SET_Z_PROBE_OFFSET 851 #define Z_PROBE_OFFSET_RANGE_MIN -15 #define Z_PROBE_OFFSET_RANGE_MAX -5#endif

Bill of materials

Fabricated Printer without heated bed

Printer Specifications

Print technology : Fused deposition modellingPrice : 28000 INRDimentions : 250x250x300Print volume : 200x200x250mmX,Y drive mechanism : Timing belt and pulley driveFilament drive mechanism : Spring type extruderExtruder cooling : Air cooledWeight : 1.5 kgs.Firmware : MarlinMicrocontroller : Standard arduino board Filament diameter : 1.75mmNozzle diameter : 0.4mmPower consumed : 210 W

Advantages of new design over existing design

• Affordability• Auto bed levelling feature• Portable• Self powered data transmission• Adaptability to different firmwares• Simpler X and Y motion mechanisms• Can be upgraded to dual extruder

References• How Stuff Works Website

www.computer.howstuffworks.com/3-d-printing.htm • How 3d printing Actually works

www.mashable.com/2013/03/28/3d-printing-explained• Stratasys the developer of FDM www.stratasys.com/3D_Printing• Rapid prototyping-assisted fabrication of the customized

metatarsophalangeal joint implant (SamKu), C. Raghatate Sameer, M. Kuthe Abhaykumar, R. Deshmukh Tushar, W. Dahake Sandeep. 2014

• Issues in additive manufacturing, E.S.A. Nasr, A. Al-Ahmari, K. MoiduddinCAD 375-399.

• Dario Croccolo, Massimiliano De Agostinis, Giorgio Olmi. 2013. Experimental characterization and analytical modelling of the mechanical behaviour of fused deposition processed parts made of ABS-M30. Computational Materials Science.

Timeline