group2 presentation2

Group 2 | SLS 3D Printer Introduction

Andy Vopni Benjamin Cousins Brian Luptak Nima Majidifar

http://www.arptech.com.au/slshelp.htm

Additive Manufacturing- Rapid CAD to 3D Object- Made of successive 2D layers- Prototyping benefits to many industries

Methods- Stereolithography (SLA) >$5000- Fused Deposition Moulding (FDM) >$500- Selective Laser Sintering (SLS) >$10000

Selective Laser Sintering

http://news.noahraford.com/?p=1495



https://www.solidconcepts.com/resources/galleries/stereolithography-sla-gallery/

Group 2 | SLS 3D Printer Problem Formulation


There Exists a Need for an Economic SLS 3D Printer for:- Additive manufacturing research- Material scientists- Education institutions- Small businesses- Hobbyists

Develop an SLS 3D printer with comparable cost and performance to small-business FDM 3D printers currently on the market

Problem Statement:

Design Criteria:- Completely safe- Ease of Construction [hrs]- Cost [$]- Accuracy of +/- 0.5 [mm]- Print Speed [min/part]- Weight [kg]

Criteria SafetyEase of

Construction

Cost Accuracy Speed Weight Total Rank

Safety 1 1 1 1 1 5 1

Ease of Constructio

n0 1 1 1 1 4 2

Cost 0 0 1 1 1 3 3

Accuracy 0 0 0 1 1 2 4

Speed 0 0 0 0 1 1 5

Weight 0 0 0 0 0 0 6

Print Material:- Chocolate


Group 2 | SLS 3D Printer Potential Solutions

StationaryLaser

TranslatingPowder Box

XY Gantry

Aluminum Plastic Wood

CO2 Laser Laser Diode

Pan/Tilt Mirror

Optical Lens Adjustment

VerticalAdjustment

Cylindrical Roller

Wedge Slider

RadialDispensing

Subtractions SolutionsFrame Material

Safety Enclosure Fully Enclosed Laser-safe Plexiglass

Laser Type

Laser Positioning

Powder Transferring

Laser Diameter Adjustment

Temperature Control Thermo Electric Cooler (TEC) Fan

Group 2 | SLS 3D Printer Alternative Designs


Criteria Safety Ease Cost Acc. Speed Weight Total

Weighting Factor 100 90 70 60 50 40

Design 1 4x100 = 400

5x90 = 450

5x70 = 350

5x60 = 300

8x50 = 400

4x40 = 160 2060

Design 2 6x100 = 600

7x90 = 630

6x70 = 420

6x70 = 420

7x50 = 350

6x40 = 240 2660

Design 3 9x100 = 900

8x90 = 720

8x90 = 720

8x60 = 480

6x50 = 300

7x40 = 280 3240

Design 1 Design 2 Design 3WoodFull EnclosureLaser DiodePan & TiltCylindrical RollerTEC

PlasticPlexiglass EnclosureLaser DiodeXY GantryWedge SliderTEC

AluminumFull EnclosureLaser DiodeXY GantryRadial WiperFan

Decision Matrix


Group 2 | SLS 3D Printer Mechanical Systems

1. Frame2. Electrical Enclosure3. Powder Beds

4. Radial Wiper

5. Laser Gantry

6. Screws/Bolts

7. Walls

QuickTime™ and aCinepak decompressor

are needed to see this picture.


Group 2 | SLS 3D Printer Powder Beds

Two linear stepper motors

Oversized feed bed

Seal around moving box base

Top View


Group 2 | SLS 3D Printer Radial Wiper

One servo motor

Radial slot guideway

Access powder wiped into drawer

QuickTime™ and aCinepak decompressor

are needed to see this picture.

Top View


Group 2 | SLS 3D Printer Laser Gantry

QuickTime™ and aMicrosoft Video 1 decompressorare needed to see this picture.

Capstan Roller MechanismLaser

Laser Translator Two stepper motors8mm diameter rods

4 linear bearings in laser mount

Top View


Group 2 | SLS 3D Printer Laser Gantry

ResolutionStepper Motor Step Resolution = 1.8o or PI/10 [rad]

Roller radius = 4 [mm]

x = r * θ

x = 0.126 [mm/step]

XY resolution of 0.126 [mm]θ X


Group 2 | SLS 3D Printer Electronic Enclosure

Power Supply

Arduino

Motor Drivers

Cooling Fan

Vent

Top View


Group 2 | SLS 3D Printer Frame and Walls

Fully enclosed for laser safety

LCD screen (debugging and process status)

Drawer to collect access powder

Hinge lid

1/8” aluminum sheet walls

8020 aluminum T-slot beams

Top View

Radiation Heat Transfer

Rate of heat transfer to powder directly determines print

timesChocolate crystal structures melt at 45oCSpectral absorption and emission of chocolate withdiffuse grey assumption

α = ε = 0.85

Incident radiation G involves chocolate absorptivity and

laser output power [W/m2]

Differential volume is heated by:

Q”rad = m * Cd * dTemp

Heating chocolate from 20oC to 45oCCan calculate Time vs Q” (laser power) to heat a

givenvolume of chocolate


Group 2 | SLS 3D Printer Laser Heat Transfer

http://www.ebay.com/itm/2W-445nm-M140-Blue-Laser-Diode-in-Copper-Module-W-Leads-Three-Element-Glass-/170892986250?ssPageName=ADME:X:RTQ:US:1123

http://www.engineeringtoolbox.com/radiation-heat-transfer-d_431.html




http://www.enginerringtoolbox.com/

http://www.enginerringtoolbox.com/


Group 2 | SLS 3D Printer Print Time

Print area of 10,000mm2 was considered

2 Watt laser considered due to availability

10,000 [mm2] layer area * 1 [mm] thickness / 200[s] = 50 mm3/s (estimated)

Using a 2W laser, find time to print a solid hockey puck:

Example

Volume = 113,411.5 [mm3]

113,411.5 [mm3] / 50 [mm3/s] = 2,268 [s], or 38 minutes


Group 2 | SLS 3D Printer Power Flow Chart

SUN Power SupplyOutput Voltage: 12V DCMax Current: 15.0AMax Power: 180W

Part Qty Voltage [V] Current [A] Power [W]Laser Diode 1 12 1.1 13.2

Gantry Stepper

Motor2 12 0.48 11.52

Powder Bed Stepper

Motor2 12 0.48 11.52

Arduino MEGA ADK 1 12 1 12

12VDC Supply 1 12 3.06 48.24 Tota

l


Group 2 | SLS 3D Printer Power Flow Chart

12VDC Supply 1 12 40.2 48.24

Cooling Fan 1 120 0.14 16.8120VAC

Outlet Supply

65.04 Total

Group 2 | SLS 3D Printer Software


Pull instruction from USB

On G1 code: - Calculate X,Y step

frequency- Call XY gantry step

function. On Plane change- Turn off Laser- Call Z-Step function- Call Powder Swiper function- Turn on Laser

Main Loop

System Overview

Main Loop

Read Function

Z Step Powder Swiper

Laser ControlGantry Step


Group 2 | SLS 3D Printer SkeinForgeSTL Model

facet normal ni nj nkouter loopvertex v1x v1y v1zvertex v2x v2y v2zvertex v3x v3y v3zendloop endfacet

G-Code

SkeinForge

http://www.thingiverse.com/thing:3930

http://www.thingiverse.com/thing:3930

Goal is to maintain a diagonal constant speed, so x

and y movement follow the path.

Speed is limited by melting requirement of laser

Achieve constant speed with discrete steps offrequency x and y for respective directions

Timer and Interrupt Libraries

TimerOne.h and Interrupt.h are available for use

Arduino Mega has 4 timers available for general programming2 allocated to XY Gantry1 allocated to Z Stepper

Modulate frequency using SetPeriod() function

Call Xstep ISR every pulse from timer


Group 2 | SLS 3D Printer Stepper Functions

θ = atan2(y1 - y0, x1 - x0)d = (x2 + y2)1/2

Stepper Logic

vstep = vmelt / resfreqx = vstepcosθfreqy = vstepsin θt = vmeltd


Group 2 | SLS 3D Printer Data Transfer

Need a method to transmit g-code data to Arduino Board

SerialRequires constant connection to computer, communication

overhead to ensure data transferRequires application on computer to feed arduino code line

by lineAllows for feedback from printer by passing data back

USBArduino 2560 Mega ADK (Android Development Kit) has USB

port for communicating with external devices as a masterLess communication overhead as only 1 application will

access dataUSB Host Shield github repository provides library

max3421e.h for Mega to read/write to USB port

USB is preferred to minimize data transfer delays and lack of external PC requirement.

Serial will be used during debugging for feedback from printer

Communication: Serial vs USB

Gantry: 1. Cable DriveUS Patent # 4957014, April 10, 1989Edward F. Burke

2. Ilan Moyer http://web.mit.edu/imoyer/www/portfolio/foamcore/

SLS Printing: Method For Producing 3D ObjectUS Patent # 8187522, May 29, 2012Yoshikazu Higashi, et al.

Radial Wiper: No Patents Youtube video: “quadraturencoder” http://www.youtube.com/watch?v=YBqUOP-MA1Q&feature=plcp

SoftwareSkeinforge is copyrighted under GNU Affero General Public Licence, allowing it to be freely distributedNo other significant software in design is worth patenting or has been patented


Group 2 | SLS 3D Printer Patents

http://web.mit.edu/imoyer/www/portfolio/foamcore/

http://www.youtube.com/user/quadraturencoder

http://www.youtube.com/watch?v=YBqUOP-MA1Q&feature=plcp

http://www.youtube.com/watch?v=YBqUOP-MA1Q&feature=plcp


Group 2 | SLS 3D Printer ReferencesARPTECH - Rapid Prototyping Services, http://www.arptech.com.au/slshelp.htm, Oct 13th, 2012

Burke, Edward. Cable drive geometry. http://www.google.com/patents/US4957014?pg=PA3&dq=4957014&hl=en&sa=X&ei=vaqpUMQ0icTbBbmugKgO&ved=0CDcQ6AEwAA#v=onepage&q=4957014&f=false, Nov 18th, 2012

Engineering Toolbox, http://www.engineeringtoolbox.com/radiation-heat-transfer-d_431.html, Nov 18th, 2012

Higashi, Yoshikazu. Method and apparatus for producing a three-dimensional object, and three-dimensional shaped object. http://www.google.com/patents/US8187522?pg=PA10&dq=8187522&hl=en&sa=X&ei=RZipULPDIejhygH27ICQBw&ved=0CDQQ6AEwAA#v=onepage&q=8187522&f=false, Nov 18th, 2012

Ilan Moyer, http://web.mit.edu/imoyer/www/portfolio/foamcore/, Nov 18th, 2012

Introduction to Thermal Systems Engineering, http://ca.wiley.com/WileyCDA/WileyTitle/productCd-0471204900.html, Nov 18th, 2012

M140 Blue Laser Diode, http://www.ebay.com/itm/2W-445nm-M140-Blue-Laser-Diode-in-Copper-Module-W-Leads-Three-Element-Glass-/170892986250?ssPageName=ADME:X:RTQ:US:1123, Nov 18th 2012

Noah Raford, 21st Century Strategy, Policy and Design, http://news.noahraford.com/?p=1495, Nov 18th, 2012

Thingiverse, 120 Film Advance Crank http://www.thingiverse.com/thing:3930, Nov 17th, 2012


http://www.google.com/patents/US4957014?pg=PA3&dq=4957014&hl=en&sa=X&ei=vaqpUMQ0icTbBbmugKgO&ved=0CDcQ6AEwAA#v=onepage&q=4957014&f=false






http://www.google.com/patents/US8187522?pg=PA10&dq=8187522&hl=en&sa=X&ei=RZipULPDIejhygH27ICQBw&ved=0CDQQ6AEwAA#






http://ca.wiley.com/WileyCDA/WileyTitle/productCd-0471204900.html



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