Ching-Han Tseng Dominic BoikoFrankie NingHarout HedeshianJoel Meisinger

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Design of a 3D printer for affordable prototyping.

Prints each cross section of a 3D object layer by layer

Three axis motion in a 3x3 feet chassis for large scale modeling

Use of accurate stepping motors for high precision printing

Network communication2

25mm/s linear write speed0.5mm deposition resolution5mm3/s (0.3 in3/s)Capable of printing a 10cm3 objectCapable of printing functional

prototypes

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4

Expected Dimension: 3 ft x 3ft x 3ft3 stepping motors

5

6

Motor Controlle

r

Encoder Controller

Extrude Header

Controller

RS422 Bus Interrupt

5V

5V

I/O

12V

Wall

7

CDH Controller

Power

Command and Data Handling

8

Coordinate all events on printerCommunications interface for

daughter boardsProvide a physical human interface

for high level controlPlatform independent and driverless

communications to host computer

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ARM Cortex M3(Stellaris

LM3S6965)Main CPU

AVR MCU(ATXMEGA128A1

)IO Hub

SPI4Mb

6-DIN

6-DIN

6-DIN

RS232

DEBUG

Reset linesEthernet

USB->RS232

LCDButto

nsBuzze

r

RS232 I2CGP

IO GPIO

EPS

5V 5->3.3 Buck

5->2.5 Buck RS42

2 Drive

rRS42

2 Drive

rRS42

2 Drive

r

Power Sequenci

ng

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Choosing the Stellaris: On die Ethernet MAC and PHY Ethernet drivers already written by TI Have working code for MCU from prior

projects Choosing the XMEGA-A1

Cheaper to use XMEGA than purchasing SPI-UART converters.

Allows Stellaris to be bypassed for fallback

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•50MHz ARM Cortex M3• 256KB Flash• 64KB Single Cycle SRAM• On die Ethernet MAC and PHY• 3 x UART• 1 x SPI• 2 x I2C

I/O: ATXMEGA128A

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• Why the 128 and not the 64: It’s in stock• 32MHz • 128KB Flash• 8KB Single Cycle SRAM• EBI for external buffer memory• 4 x UART• 4 x SPI• 4 x I2C

Stellaris: FreeRTOS uIP Time permitting: lwIP Using a highly

modified Telnet server implementation to provide raw TCP socket for communication.

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• XMEGA:–Mostly interrupt

driven custom firmware

– Simple functionality acting as a “smart” I/O controller.

–May use YAVRTOS

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Single Price Estimate

Quantity

Stellaris 15 1 30

XMEGA 10 1 10

RS422 Drivers 4 3 12

USB Transceiver 5 1 5

Inter-board connectors 1 3 3

Other connectors 7 1 7

Passives 5 1 5

Other Misc 10 1 10

Total 82

Primary risk: Ethernet non-functional Likelihood of success: 90% [Software working

on dev board, hardware design untested] Fall back to USB-UART

Secondary Risk: USB-UART non-functional Likelihood of success: 6.022E23% [Used

controller IC before and have several working designs using said device]

Fall back to UART on AVR

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Electrical Power System

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Power Supply Provide each sub-system with appropriate power level Maintain UL compliance Isolated Power System

Reduced Shock Hazard Continuity of power Noise Reduction

Over-current and short circuit protection

Wall Outlet120VA

C

5V Forward

converter (Isolated)

CDH

MDC

PSC

SMC

12V Forward

converter (Isolated)

Rectifier Bridge

FPS

EMI Filter

Transformer/Reset Winding

Metallic Enclosure For GroundingRelay(Enable)

Feedback

Isol

ated

Single Price Estimate

Quantity

Full Wave Rectifier 2 1 2

Power Switch 4 1 4

Common Mode Choke 2 1 2

Diode(Rectifier, Vcc, Reset..)

2 4 8

Phototransistor 1 1 1

Bobbin/EE Core 15 1 15

Other Misc 18 1 18

Total 50

RiskPrimary risk: Shock/Explosion Hazard

•Example

•Over-current/short current protection, metallic enclosure grounding and isolation are part of considerations to prevent this hazard

Secondary risk: Components go “Pooof-Hazard” •Hand-made Transformers might not operate as ideal as the calculation•Fall back to more detailed analysis, calculation, component upgrade, and proper circuit protection.

Material Deposition Controller

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Purpose of Subsystem Lay down the

material of choice (ABS plastic, Epoxy) at a constant rate.

Be able to stop and start new point.

Provide system feedback CDH such as material empty signal and motor error signal.

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CDH

Deposition Motor Driver

EPS

3.3V DC/DC convert

er

12V

MDC FBD

RS422 Driver

5V

Deposition

Thermal Driver

Print head

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XMEGA MCU

ThermalFeedbac

k

Moderate melting point: 221°F, 105°C ABS possesses outstanding impact strength and

high mechanical strength, which makes it so suitable for tough consumer products.

Many colors.

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Risk:• ABS not working for dependable deposition• Nozzle tip temperature not constant

Contingency plan:1.Use other material type such as a epoxy plunger feed.2.Use other tip sizes and materials.

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Part Description Part Number Single Price Estimate

Quantity Total

Microcontroller ATXMEGA64A3 5.47 1 5.47

Motor Driver TB6560AHQ 4.73 1 4.73

RS422 Driver ADM3071EARZ 4.00 1 4.00

RS232 Driver TRS3221E 1.99 1 1.99

Optoisolator LTV-847 1.00 9 9.00

DC-DC Regulator FAN8303MX 1.35 1 1.35

External Oscillator EFJ-N3385xxx 1.00 1 1.00

DB9 connector 1734348-1 1.00 1 1.00

Passives -/- 5.00 5.00

Mechanical -/- 30.00 30.00

Total 63.54

Position Sensor Controller

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Objective Keep track of extruder head location Keep track of motor movements and

provide limit warnings

Requirements Supply CDH Controller with 3 axis position

of the extruder within 1/200th of a rotation Supply limit warnings and movement

verification to Stepper Motor Controller 27

SMC

CDH

Encoder X

Encoder Y

Encoder Z

EPS

3.3V DC/DC convert

er5VRS422

6 GPIO

PSC

28

RS422 Driver

ISPRS23

2

RS232 Driver

XMEGA MCU

Specs Optical Resolution (>200 count per motor cycle) Fits ACME threaded rod

Considerations Index preferred Quadrature preferred Ease of Mounting/flexibility Max Frequency Response Low Cost

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Part

Supplier

Cost

Resolution(CPR x Quadrecture)

Max Frequency Response

Mounting Signal Integrity

Index

1250DI

Anaheim

70.88

1250x4 100000 Fixed Differential

Yes

500DN

Anaheim

61.60

500x4 100000 Fixed Differential

No

E8P USDigital

37.34

512x4 60000 Custom fit Single Ended

Yes

E5 US Digital

51.50

540x4 60000 Custom fit Single Ended

Yes

500SN

Anaheim

47.95

500x4 100000 Fixed SingleEnded No

Part Description

Part Number

Single Price

Quantity

Total

Microcontroller ATXMega64A3 5.47 1 5.47

Encoder E8P 37.34 4 149.36

RS422 Driver ADM3071EARZ 4 4 16

RS232 Driver TRS3221E 1.99 1 1.99

DC/DC Regulator

FAN8303MX 1.35 1 1.35

External Oscillator

EFJ-N3385xxx 1 1 1

DB9 Connector 1734348-1 1 1 1

Inter-Board Connector

555051-1 2 1 2

Passives -/- 5 1 5

Total 183.17

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Stepper Motor Controller

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Controller for the three axis stage moving the print head

Drives three 2-phase bipolar stepper motors, one for each axis

Monitor motor current and temperature

Interface with main command and data handling module

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XMEGA MCU

PSC

CDH

Linear Actuator

X

Linear Actuator

Y

Linear Actuator Z

EPS

3.3V DC/DC convert

er5V

RS422

6 GPIO

SMC

RS422 Driver

ISPRS23

2

RS232 Driver

Motor Driver

Motor Driver

Motor Driver

34

Temp sensor

Communication with CDH using RS-422

I/O to Toshiba Stepper Driver IC (TB6560AHQ) that drive the motors

I/O from PSC for motor limits and motor moving information

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Single 2-phase bipolar motor driver chip Controllable current for torque

management Capable of half stepping and

microsteppingDigital control inputsStepping speed determined by input

clock

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37

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Part Description Part Number Single Price Estimate

Quantity Total

Microcontroller ATXMEGA64A3 5.47 1 5.47

Motor Driver TB6560AHQ 4.73 3 14.19

RS422 Driver ADM3071EARZ 4.00 4 16

RS232 Driver TRS3221E 1.99 1 1.99

Optoisolator LTV-847 1.00 33 33.00

DC-DC Regulator FAN8303MX 1.35 1 1.35

External Oscillator EFJ-N3385xxx 1 1 1

DB9 connector 1734348-1 1 1 1

Inter-Board Connector

2 1 2

Passives -/- 5 1 5

Other 10 1 10

Total 91

Current stepper motors might not produce enough torque to move extrude head Very low risk

Current spikes of the motors damaging the microcontroller Low risk with proper opotoisolation

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Task Primary Secondary

CDH Harout Frankie/Joel

EPS Ching Dominic/Joel

MDC Joel Frankie /Harout

PSC Frankie Ching/Dominic

SMC Dominic Frankie/Harout

Mechanical Harout / Dominic/ Joel Ching/Frankie

User Interface Harout Dominic/Frankie

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Gant chart

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Category Single Price Estimate

Quantity Total

General 20 3 60

CDH 82 3 246

SMC 91 3 273

PSC 139 3(*) 251

EPS 50 3 250

Board Order 165 3 495

Total: 1575

Financial Support

UROP 800

Halleck Willard Inc. ComponentDonations (200)

Total : 1000

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