G Code and Slicers

image/svg+xml 3 dp knox

Knox3DP

2 November 2016

image/svg+xml 3 dp knox .org knox3dp
image/svg+xml 3 dp knox

Tonight

  • Let's Talk G Code
  • Slicers
  • Peter Shankles - writing a slicer tool for microfluidics

history of g-code

  • First developed in late '50s by MIT
  • 1970s - '90s, industry standardized around 
  • '80s when printers began, followed along with NC standards
image/svg+xml 3 dp knox

Common commands

  • G
  • F
  • T
  • I / J / (K)
  • M
  • Tells what motion is wanted or offset value
  • Sets feedrate
  • Tool selection (in CAM)
  • Arc Center in X / Y / (Z)
  • Special commands (like SD card)
  • G00
  • G01
  • G02
  • G17
  • G20
  • G90
  • G92
  • Rapid positioning (max speed)
  • Linear interpolation
  • Circular interpolation (cw, G03 - ccw)
  • XY Plane Selection (G18 - XY, G19 - YZ)
  • Set units in inches (G21 - mm)
  • Absolute positioning (G91- incremental)
  • Feedrate per minute (G94 - per revolution)
image/svg+xml
image/svg+xml 3 dp knox

example

  • Initialization
  • seeking z-axis to 0.25", travel to (-0.5,0,0.1)
  • Drop z to 0, begin slow feed rate and draw circle

 

  • Finish, lift Z up, then seek back to (0,0,0.25)
image/svg+xml 3 dp knox
G17 G20 G90 G94 G54
G0 Z0.25
X-0.5 Y0.
Z0.1
G01 Z0. F5.
G02 X0. Y0.5 I0.5 J0. F2.5
X0.5 Y0. I0. J-0.5
X0. Y-0.5 I-0.5 J0.
X-0.5 Y0. I0. J0.5
G01 Z0.1 F5.
G00 X0. Y0. Z0.25
image/svg+xml

How to get from cad to g-code

  • G-code is extremely precise, at a cost of length 
  • A slicer is used to interpret CAD file (maybe just STL), and convert to G-Code
    • Needs information about
      machine ​for translation
G17 G20 G90 G94 G54
G0 Z0.25
X-0.5 Y0.
Z0.1
G01 Z0. F5.
G02 X0. Y0.5 I0.5 J0. F2.5
X0.5 Y0. I0. J-0.5
X0. Y-0.5 I-0.5 J0.
X-0.5 Y0. I0. J0.5
G01 Z0.1 F5.
G00 X0. Y0. Z0.25
circle(d = 1);
image/svg+xml 3 dp knox

How to get from cad to g-code Example

image/svg+xml 3 dp knox
G.Q. Jin, W.D. Li, C.F. Tsai, L. Wang, Adaptive tool-path generation of rapid prototyping for complex product models, Journal of Manufacturing Systems, Volume 30, Issue 3, August 2011, Pages 154-164, ISSN 0278-6125, http://dx.doi.org/10.1016/j.jmsy.2011.05.007

Slicing

Peter Shankles

image/svg+xml 3 dp knox
Made with Slides.com