Joel MeisingerHarout HedeshianFrankie NingDominic BoikoChing-Han Tseng

1

Design of a 3D printer for affordable prototyping.

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

Three axis motion in a 2x2 feet chassis for large scale modeling

Use of accurate stepping motors for high precision printing

Network communication

Job File

User Controls

3D prototype

Status

Inputs Outputs

Low Level: Position printer head

from basic raw commands

Layout material Display printer status

Mid Level: Print Simple 3D

objects Position Feedback

High Level: Print objects base on

STL job files Independent power

system

Printer Objective Resolution 25mm/s linear write

speed 0.5mm deposition

resolution 5mm3/s (0.3 in3/s) Capable of printing a

10cm3 object Capable of printing

functional prototypes

3

4

Stepper Motor

Controller

Position Sensing

Controller

Material DepositionContr

oller

RS422 Bus

Interrupt

I/O

Command and Data Handling

Electrical PowerSystem

PowerRS422

InterruptGPIO

Electrical Power System

5

Provide each sub-system with appropriate power levelIsolated Power System

Reduced Shock Hazard Continuity of power Noise Reduction

Open and short circuit protectionFunction DecompositionTransformer Design

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

•Open CircuitSnubber Circuit will be implemented by the transformer and output to prevent “inductive kick” effect.Bleed Resistor for discharging capacitor and prevent OC.

•Short Circuit (FPS IC)Latch Mode Protection: FPS shuts down SMPS till AC power is reconnectedAuto Restart Mode Protection: Under Voltage Lockout(UVLO)

•OtherOverload ProtectionOver Voltage/Current ProtectionMetallic enclosure grounding

Module EMI FilterInputs 120VAC from Wall outletOutputs 120VAC to RectifierFunctionality The process that filters out high frequency noises comes in from the wall outlet.

EMI dedicates a return-path especially for noises, and therefore greatly reduces the unwanted spike when proceeds.

Module Full-Wave Rectifier BridgeInputs EMI FilterOutputs 170VDC with approximated voltage ripple to FPSFunctionality The function that generates full positive waves. The smoothing capacitor, locates

at the output of the rectifier, converts the full-wave rippled output of the rectifier into a smooth DC output voltage.

Module FPS (Power Switch)Inputs 170VDC from Rectifier, Isolated Feedback from outputOutputs Primary, Reset, Vcc and Secondary windings on the transformerFunctionality The FPS has the internal switching frequency of 67KHz on MOSFET to makes DC-DC

converter. It requires about 15VDC on Vcc winding to drive the chip and startup various functions.

Module TransformerInputs FPSOutputs 5VDC, 12VDC ConverterFunctionality Base on the turn ratio on the windings, this module may step up or down on

voltage

Module DC-DC converterInputs TransformerOutputs 5VDC, 12VDC rail to each subsystemsFunctionality With manipulations on passive parts, these modules output desired voltage rail

and current.

Module FeedbackInputs 5VDC, 12VDC railsOutputs FPSFunctionality This module supplies or reduce amount of gains to stabilize the output in case of

any drastic changes.

Primary risk:•Hand-made Transformers might not operate as ideal as the calculation•Fall back to more detailed analysis, calculation, component upgrade, and proper circuit protection•Over-current/short current protection, metallic enclosure grounding and isolation are part of considerations to prevent this hazard

Goal•Redesign Transformer and find the better ferrite core•Fully test out the circuits on the perf-board •Power management•Proper debug/Test procedures documented•PCB

Command and Data Handling

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Coordinate all events on printer

Communications interface for daughter boards

Provide a physical human interface for high level control

Platform independent and driverless communications to host computer

ARM Cortex M3(Stellaris

LM3S6965)Main CPU

SPI4Mb

6-DIN

6-DIN

6-DIN

RS232

DEBUG

Reset linesEthernet

USB->RS232

LCD Buttons

Buzzer

RS232

I2C

GPIO

GPIO

EPS

5V 5->3.3 Buck

5->2.5 Buck RS42

2 Drive

rRS42

2 Drive

rRS42

2 Drive

r

Power Sequenci

ng

CY8C9560AGPIO

Expander

AVR MCU(ATXMEGA128A1

)IO Hub

Not populated on Rev A

Not populated on Rev A

SRAM Data Buffer

Module Buck ConvertersInputs 5VDCOutputs 3.3VDC, 2.5VDCFunctionality

Take 5V from the power bus and step it down to 3.3V and 2.5V noting the correct power up sequence.

Module ARM Cortex M3 LM3S9595Inputs USB, Ethernet, COM from AVROutputs LCD, COM to AVRFunctionality

Primary processor on 3DP responsible for interfacing 3DP to the real world. Process vectors and coordinate subsystems.

Module SRAM BufferInputs Address, DataOutputs DataFunctionality

Space to store circular buffers of packet data for relay and transmission, and retransmission

Module AVR MCUInputs COM from CDH, I2C from CY8C9560A, COM(0-3)Outputs COM to CDH, I2C to CY8C9560A, COM(0-3)Functionality

Responsibly for ensuring reliable message packet delivery between all subsystems. Also relay button presses and sends back to CDH

Module CY8C9560AInputs I2C from AVR MCU, ButtonsOutputs I2C to AVR MCU, BuzzerFunctionality

Encodes buttons and drives buzzer. I wanted to play with this chip.

Stellaris: FreeRTOS uIP Web server Using a highly

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

• XMEGA:–Mostly interrupt

driven custom firmware

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

– Nobody has ported an RTOS to the XMega?!

RTOS Kernel Managed TasksRTOS Kernel Managed Tasks InterruptsInterrupts

System Tick

Ethernet

USB/UART

COM

MAC Manageme

ntHTTPDTELNE

T

uIP

Shell/Protocol

Event Dispatch

LCD Messag

e Queue

Lots ofCool

Blinking LEDs

Main LoopMain Loop InterruptsInterrupts

System Tick

COM1

COM2

COM3

COM4

LED Management

MessageRouting

Keypad

COMV1AVR

Management

Original risks from PDR:Primary risk: Ethernet non-functional

WorkingSecondary Risk: USB-UART non-

functional▪ Working New risks:▪ Getting bored and making LEDs blink in funny

patterns

Material Deposition Controller

23

Joel Meisinger

Objective Keep constant print head tip temperature Keep constant torque on fed printing material

Requirements Supply consistent material delivery to the

printing area(.5mm diameter +/- .1mm) Be able to start and stop printing material

reliably. Notify CDH(main system) when print head is

up to temperature and ready to print or when the printer out of material.

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25

26

XMEGA MCU

CDH

Deposition Motor

Driver

EPS

3.3V DC/DC convert

er

12V

MDCRS422 Driver5V

Deposition

Thermal Driver

Print headThermalFeedba

ck

5V DC/DC convert

er

RS232Debug

Micro data lines

Power

Print head control

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Module 3.3V DC/DC ConverterInputs 5V supplied from EPS, DGNDOutputs 3.3V Functionality Provides power for Xmega MCU and

drive signal to motor driver controller. Low current requirement.

Module 5V DC/DC ConverterInputs 12V supplied from EPS, AGNDOutputs 5V Functionality Provides power to motor driver

controller/stepper motor. High current requirement.

Module RS422 DriverInputs Xmega TX and PC TX, DGNDOutputs Xmega RX and PC RXFunctionality Communication driver between

CDH and XMEGA for drive commands.

Module RS232 DriverInputs Xmega TX and PC TX, DGNDOutputs Xmega RX and PC RXFunctionality Debug port for Xmega and

development environment.

Module XMEGA MCU

Inputs 3.3V, DGND, RS422 TX(CDH), Thermal feedback

Outputs RS422 RX(CDH), Motor Driver, Thermal driver

Functionality Controller for the material deposition unit/print head. Regulates temperature and constant torque for the material feed.

Module Motor DriverInputs 5V, AGND, drive signalOutputs Stepper motor driving signal.Functionality Drives the motor to feed the

deposition material.

Module Thermal DriverInputs 12V, AGND, drive signalOutputs PWM Power to the print head

nozzle.Functionality Drives the heater on the print

head.

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MDCMain

Init_sys()Packet

HandlersLED

Init_CLK()Init_IO_PIN()Init_USART_RS232Init_USART_RS422Init_Timer0( )

read_packet(…)write_packet(…)

LED_On(…)LED_Off(…)

Temp Sensor

adc_read(…)

MotorDrive

PWM Temp Drive

PWM_Rate(.)

SM_Drive(…)QDEC_EVSYS(…)QDEC_Index(…)

Print-head is completely custom.

Thermal controlled brass tip heated by NiChrome wire at temperatures 221°F - 300°F

ABS plastic: Possesses outstanding impact strength and high mechanical strength making it well suited for working mechanical parts.

Stepper motor with feed gear that will supply constant torque(TBD).

Compact having the ability to adapt to most 3d axis systems. 12 square inches.

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• ABS not working for dependable deposition

• Nozzle tip temperature not constant1.Use other material type such as a PVC or

epoxy resin. Also try a variable torque routine that will be suited for changing speed and direction of the print-head when moving from one vertices to another.

2.Use other tip sizes, apertures and heater materials.

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Position Sensor Controller

31

Frankie Ning

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

provide limit warnings Keep track of temperature on stepper

motors and motor driver heat sinks Requirements

Supply CDH Controller with 3 axis position of the extruder within 1/200th of a rotation

Supply motor status to CDH Controller Supply limit warnings and movement

verification to Stepper Motor Controller

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33

SMC

CDH

Encoder X

Encoder Y

Encoder Z

EPS

3.3V DC/DC convert

er5V

RS422

6 GPIO

PSC

34

RS422 Driver

ISPRS23

2

RS232 Driver

XMEGA MCU

2 Limit X

2 Limit

Z

2Limit Y

MotorTemp XYZ

5V3.3V

GPIOADC

USART

35

Module XMEGA MCUInputs 3.3V, GND, RS232 TX(PC), RS422 TX(CDH), Encoder

A,B, index signals from Encoder X,Y,Z, ISPOutputs ISP, RS232 TX(PC), RS422 TX(CDH)Functionality

Gathers data from limit, temperature, and encoder sensors. Controls the RS232 and RS422 driver to communicate with the PC or CDH. Also includes GPIO to SMC for temperature and limit warnings

Module Encoder X,Y,ZInputs Rotary disc in encoderOutputs Quadrature A and B, 90o off phaseFunctionality

keep track of motor movement and position

Module Limit X,Y,ZInputs Limit flagOutputs Quadrature A and B, 90o off phaseFunctionality

keep track of motor movement and position

Module Motor Temp X,Y,ZInputs Temperature sensor mounted on

stepper motorOutputs Analog output 200mV – 1.75V at

10mV/oCFunctionality

keep track of motor temepratures

Module ISPInputs PDI_CLK, PDI_RESET, power, groundOutputs PDI_Data,Functionality AVRISP MkII Programming module for Xmega

Module RS422 DriverInputs Xmega TX and CDH TXOutputs Xmega RX and CDH RXFunctionality

Communication driver between CDH and PSC, command and data is sent using the RS422 driver

Module RS232 DriverInputs Xmega TX and PC TXOutputs Xmega RX and PC RXFunctionality Communication driver between PC RS232 and

XMEGA UART

Module 3.3V DC/DC ConverterInputs 5V Outputs Regulated 3.3V Functionality

supply power to on board ICs

36

PSCMain

Init_sys()Packet

HandlersLED

Init_CLK()Init_IO_PIN()Init_USART_RS232Init_USART_RS422Init_QDEC( )Init_Timer0( )

read_packet(…)write_packet(…)

toggle_heartbeat(…)

Temp Sensor

adc_read(…)

Encoder Limit

Limit_detect(…)

QDEC_Direction(…)QDEC_EVSYS(…)QDEC_Index(…)

US-Digital E5Optical Rotary Encoder IndexQuadrature512 CPR (cycles per revolution)2048 PPR (pulses per revolution)Max detectable rpm = 11718Fits ACME threaded rod

2mm – 10mm or 1/8” – 3/8” shaftMax Frequency Response 100kHz

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Limited Funding Remove Encoders, reduce cost▪ Not critical to design/ Good to have feedback▪ Stepper motors with fine resolution

Minimum cost PSC would include▪ Temperature Sensor ▪ Track temperature of motors and drivers

▪ Photointerrupt Sensor ▪ Detect when print head moves to a X, Y, or Z axis limit

Apply to EEF Personal donation

38

Stepper Motor Controller

39

Objective Control motion of extrude head along 3 axis

(X,Y,Z) Control speeds of motors using constant current

motor drivers Accurate positional translations using high

resolution stepper motors as opposed to simple DC motors

Requirements Drive steppers motors based on instructions given

by CDH controller Provide current motor status when queried by CDH Able to drive motors accurately with enough

torque to control extrude head position

40

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

Legend12V5V3.3VGPIOIsolated SignalsUART

Module RS232 DriverInputs Xmega TX and PC TXOutputs Xmega RX and PC RXFunctionality Communication driver between PC RS232 and

XMEGA UART

Module ISPInputs PDI_CLK, PDI_RESET, power, groundOutputs PDI_Data,Functionality AVRISP mkII Programming module for Xmega

Module XMEGA MCUInputs 3.3V, DGND, RS232 TX(PC), RS422 TX(CDH), ISP,

PSC limit sense GPIOOutputs ISP, RS232 TX(PC), RS422 TX(CDH), Motor Driver

Control SignalsFunctionality Communication driver between PC RS232 and

XMEGA UART, Configure motor driver operation

Module Motor driver TB65605AHQInputs 5V, 12V, AGND, motor driver control signalsOutputs PWM current waveform for 2 phase stepper

motorFunctionality Take digital control signals and drive a single

stepper motor and defined torques, speeds, and resolution.

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

management Capable of half stepping and

microstepping Digital control inputs Stepping speed determined by input

clock Success!!!

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45

SMCMain

init_sys()Packet Handler

Motor controlle

r

Init_CLK()Init_IO_PIN()Init_USART_RSxxx()Init_Timer0( … )

read_packet(…)write_packet(…)execute(…)

Check limitsSet control signals

Module MainInputs None.Outputs None.Functionality Call init_sys() to bring XMEGA online. Call

read_packet() and write_packet() for interboard communications. Call execute() on commands received from CDH. Call the motor driver handling functions.

Module Init_sys()Inputs None.Outputs None.Functionality Initializes the clock, IO pins, USARTs, and timers.

Module Packet HandlerInputs Packet by serial (see struct for packet)Outputs Response packetFunctionality The packet handler will read bytes from the serial

communication and construct a packet based off our defined protocol. Also execute any commands sent in the packet.

Module Motor ControllerInputs Limit sense GPIO from PSC. Motor axis states for

control signals (see motor_driver struct)Outputs Control signals to the motor drivers.Functionality Sets the control signals to the motor drivers based

on each motor axis current state as defined by the motor_driver struct. Stop motion and alert CDH when limits of motors have been reached.

// Packet structtypedef struct{

uint8_t to;uint8_t from;uint8_t size;uint8_t proto_ver;uint8_t reserved_byte_4;uint8_t payload[32];

} packet;

// motor_driver structtypedef struct{

uint8_t tq1;uint8_t tq2;uint8_t dcy1;uint8_t dcy2;uint8_t m1;uint8_t m2;uint8_t cw_ccw;//uint8_t clk; //possibly implemented as a single line to all motorsuint8_t reset;uint8_t en;

} motor_driver;

Schedule Maintaining with schedule SMC is ahead of schedule▪ Original goal: have flashing LEDs (complete)▪ Current status: stepper motor driving capability

tested and working▪ Most configuration signals tested (need to test decay mode)

Current goal: ▪ establish packet handling (started)▪ Design motor driver handling firmware

51

Task Ching Dominic Frankie Harout Joel

CDH Secondary

Secondary

Primary

EPS Primary Secondary

Secondary

MDC Secondary

Secondary

Primary

PSC Secondary

Secondary

Primary

SMC Primary Secondary

Secondary

Mechanical

Secondary

Primary Secondary

Primary Primary

User Interface

Primary Secondary

Secondary 52

CDH LCD display RS422 USB Ethernet

EPS First Sage AC Power and

EMI Filter Second stage Rectifier

working (not transformer)

MDC Blinking LEDs

PSC Timer interrupt driven

LEDs RS422 Temperature sensor data

sent to PC Limit Sensor (toggle LED)

SMC Blinking LEDs Driving stepper motors RS422

53

Gant chart

54

Item Name Description Unit Price

Quantity

Total Amount

STR-MTR-17048 Stepper Motors 19.00 3 57ATSTK600 STK 600 development kit 206.96 1 206.96ATSTK600-TQFP64-2 STK600 socket adapter 102.96 1 102.96LM3S6965 CORTEX MCU 15.29 2 30.58ATXMEGA128A1-AU XMEGA MCU 10.2 2 20.40ATXMEGA64A-AU XMEGA MCU 8.21 8 65.68MCP9700A-E/To Temperature Sensors 0.34 5 1.70GP1S53VJ000F Photo-interrupt Sensors 0.85 3 2.55E5 USDIGITAL Optical Encoders 62.32 3 62.32LTV-846S Optocouplers 0.73 25 18.25FAN8303 DC/DC Converter 1.12 25 28.00B230A Schottky Diodes 0.413 14 5.78DN759x Inductors 2.73 5 23.76ASV-xxxxxMHZ Oscillator 2.63 10 26.30TB6560 Stepper Motor Driver 4.73 5 23.65ADM3071EARZ RS422 Driver 3.4 10 34.00DMN601DMK N-CH MOSFET 0.61 20 12.32GBU6J-BPMS Rectifier bridge 1.4 3 4.20FS7M0880YDTU PWM Switching Reg 3.64 4 14.56ACM9070-701 Common Mode Choke 1.58 2 3.16598-8710-307F LED 2.17 10 21.701N400xDICT-ND Rectifier 0.31 8 10.52WK6249 Fuseholder 1.88 2 3.76FOD817A High power Optocoupler 0.5 4 2M9975 High power Inductor 3.47 3 10.41ASM69AC Linear slide 766.00 1 766.00C0816X7R1Cxxxx Passive Capacitors 0.03 1000 30ERJ-3GEYxxx4V Passive Resistors 0.03 1000 30161-2306 Mini-DIN connectors 0.93 10 9.3A35109 DB9 Connectors 0.95 4 3.8Cat5e/ PS2/ DB9/ USB Cables 41.53 1 41.53EE80251S3-0000 Fan 3.27 1 3.27EPS/SMC/PSC/MDC 2 Layer PCB 33 8 264CDH 4 Layer PCB 66 2 132

Total 2175.52255

Expense Breakdown

Subsystem TotalCDH 246

SMC 273

PSC 251

MDC 250

EPS 200

Mechanical 151

Development Kits 310

Board Order 495

Total 2176

Financial SupportUROP 1000

Halleck Willard Inc.

826

ECEE Department

367

Total : 2193

MILESTONE 1

Blinking (naked eye) LEDs on SMC, MDC, PSC, CDH

Display functional interboard communication on RS422

Display one temperature reading on Realterm through RS232

Display one limit sensor by turning off LED when limit sensor is triggered

Drive one motor via command from CDH

Ready for Revision B board orders

MILESTONE2

Display Encoders data via RS232 or CDH Direction Position

Display valid C3DP defined protocols via logic analyzer for SMC, MDC, PSC, CDH

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