Additive Manufacturing Module 4

Transcription

1 Additive Manufacturing Module 4 Spring 2015 Wenchao Zhou zhouw@uark.edu (479) The Department of Mechanical Engineering University of Arkansas, Fayetteville 1

2 Tool Chain G-code interpreter (firmware) Host software Slicer(G-code and/or other code for printhead) Software system CAD 2

3 Tool Chain 3

4 Firmware Marlin 4

5 Firmware Like an OS of Arduino 5

6 Firmware 6

7 Firmware Supported board Different board has different pin map 7

8 Firmware G-code for SD card 8

9 Firmware Main loop Marlin 9

10 Firmware Main loop Disable every function for startup Power management Check if startup is successful Version info Memory info 10

11 Firmware Main loop 11

12 Firmware Main loop 12

13 Software Firmware Main loop get_command(): Getting g-code from serial port 13

14 Firmware Main loop process_commands(): process g-code 14

15 Firmware Motion plan G01 command Read dest. coords. Plan straight line path Look-ahead Pulse generate Look-ahead will only decelerate and accelerate to some non-zero velocity, but not completely stop 15

16 Host software send g-code Repetier host ReplicatorG Printrun 16

17 Host software serial communication 17

18 Host software serial communication Repetier-Host: Sending g-code to serial port from PC (C#) 18

19 Software Host software serial communication Simple example of serial.read 19

20 Slicing Input Model (STL or AMF) Orientation Slicing Support structure design Orientation Support structure Slicing Path planning Machine instructions Path planning Machine Instructions 20

21 Slicing Picture credit: Raveh Gonen Sliced results 21

22 Software Slicing Data structure v3 -> a vector with 3 floats {x,y,z} LineSegment -> {v3 point0, point1} Plane -> {v3 normal, float distance} Triangle -> {v3 vertices[3], normal} TriangleMesh -> {vector of Triangle} nslices -> compute-number-of-slices using slice-size Z-plane intersects model 22

23 Slicing analysis Picture credit: Raveh Gonen 23

24 Slicing algorithm Picture credit: Raveh Gonen 24

25 Slicing algorithm Picture credit: Raveh Gonen 25

26 Printhead Extrusion (a) Filament based extrusion; (b) Syringe based extrusion; (c) screw based extrusion 26

27 Printhead Extrusion A simple design of cold end A design of hot end Pictures from google image A compact design A multi-head design 27

28 Printhead FDM Control Extrusion temperature Extrusion speed Problems caused by the filament: a), b) improper diameter filament, c) buckling 28

29 Printhead SLA 4 Mirrors 2 stationary 2 mobile on XYZ table Total 7 DOF Courtesy: Dr. David Rosen 29

30 Printhead SLA From Formlabs 30

31 Printhead SLA control galvo mirror 31

32 Printhead Inkjet Continuous Inkjet (CIJ) Drop-on-Demand (DoD) Inkjet Common DoD Inkjets Thermo/Bubble jet: HP, Canon Viscosity limitation: up to ~40cP Printing frequency: ~10 to ~100 khz Piezoelectric Inkjet: Epson 32

33 Printhead Inkjet Printhead sectional drawing (from Epson service manual) 33

34 Printhead Inkjet Printing process (from Epson service manual) 34

35 Printhead Inkjet Carriage Page feed Electric circuit (from Epson service manual) 35

36 Printhead Inkjet Block diagram C383 Mainboard (from Epson service manual) 36

37 Printhead Inkjet Printhead driver circuit (from Epson service manual) 37

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