CNC-3018Pro cheap CNC milling machine

Introduction

• 

  Engraving on plastic

• 

  Plywood

• 

  The cylidrical bit weared out and dug itself into the plywood

Aim to do graving and milling PCB boards.

Maximum size of the material: 300 x 180 x 50 mm³.

Workflow

1. Design the cut
2. Use Inkscape's GCodeTool to generate the path
3. Use Candle (1.2.13b works) to
   1. Simulate
   2. Test run above the material
   3. Do the milling

Speed and materials

1. Plastic: Slow speed. 400 / 3400 too much: Burns.

Acrylic (plexigalas, Lucitem PMMA). Other plastics incluce ABS, Delrin, HDPE. . .

• Do not cut deep (melts). Set the to about .004 depth (which units).
• Use ACR or FLX bits (they are the same).
• Use a low spindle speed for best results. (Burnishing uses a very high spindle speed.)

Caption text

Material (bit)	Feed speed	Spindle rpm	Depth
Plastic/ Acrylic		Low (plastic melts)
Wood	Example	High (less burning)
Metal	Example	High
Al/ Cu/	Example	Often high. Lubricant

Cutters

The supplied engraving cutters are a really bad choice.

Vinyl

Drag Knife

• Blade holder for
• Graphtec Vinyl Cutter Plotter CB09 Klingenhalter 15 Stk. 45° Klingen
• Blade Holder Summa Vinyl Cutter Blades For Summa Blades Vinyl Cutter
• 5x30°+5x45°+5x60° CB09 Klingenhalter Plottermesser Für Graphtec Schneideplotter

Heat Transfer Vinyl (Wärmeübertragung Vinyl HTV)

Application Instructions (HOME IRON):

1. Set iron dial between Wool and Cotton
2. Cover design with cover sheet (Teflon Sheet)
3. Place on a flat, hard surface (ironing board not recommended)
4. Press iron with medium/firm pressure (do not slide iron)
5. Press each section of the design for 10-15 seconds, apply design at 305 °F
6. If area of design lift after application, apply cover sheet and repress for 10-15 seconds
7. Peel carrier cold
8. Cover completed design and press for 5-10 seconds

Software

Software for controlling the machine (3axis)

• CH340SER
• Grblcontrol(Candle_1.1.7 ) is used to send the command to the CNC mill using premade G Code.
  • https://github.com/gnea/grbl
  • https://github.com/Denvi/Candle
  • https://cncphilosophy.com/candle-grbl-software-tutorial/
• Baud rate: 11500

G Code

• https://jscut.org/jscut.html#
  • Works only with closed paths; thus use Stroke to path to generate closed loop.

• Inkscape Gcodetools
  • The default origin is the lower left corner of the image. Set the origin (orientation points) into a suitable place
  • Check the origin at the Candle!

• Inkscape GCodePlot

• CadToCNC

• Online
  • GCode creator https://sameer.github.io/svg2gcode/ and github at https://github.com/sameer/svg2gcode
  • Gcode viewer https://ncviewer.com/

• Python
  • svg-to-gcode 1.5.4

• Carbide Create

Svg to STL and to GCode

• https://svg2stl.com/
• https://anyconv.com/svg-to-stl-converter/

GCode short tutorial

Simple svg file with two closed paths

Some commands

• G21 Metric system
• G90 Absolute mode. All movements are relative to a fixed zero or machine home location.
• G1 Linear interpolation. Move in a straight line to a specific location. The speed is the feed rate (F).
• G3 Circle: The target coordinates at the end of the movement. I, J – The arc’s center point coordinates relative to the starting coordinates.

• M2 End of code.
• M3 Spindle on clockwise.
• M4 Spindle on counterclockwise.

Generated by JsCUT

Problem; No open paths. Could be fixed by manipulating the gcode afterwards.

G21         ; Set units to mm
G90         ; Absolute positioning
G1 Z2.54 F2540      ; Move to clearance level

; Operation:    0
; Name:         
; Type:         Inside

; Path 0
; Rapid to initial position
G1 X40.8960 Y-24.8468 F2540
G1 Z0.0000
; plunge
G1 Z-3.1750 F127
; cut
G1 X40.8051 Y-24.9034 F1016
G1 X40.6768 Y-24.9809
. . .
G1 X40.8960 Y-24.8468
; Retract
G1 Z2.5400 F2540

;
; Operation:    1
; Cut Depth:    3.175
; Rapid to initial position
G1 X16.9248 Y-11.6624 F2540
G1 Z0.0000
; plunge
G1 Z-3.1750 F127
; cut
G1 X16.9581 Y-11.6253 F1016
. . .
G1 X16.9248 Y-11.6624
; Retract
G1 Z2.5400 F2540
M2

Generated by svg2gcode

No z movement. No end mark. However, "users can now specify a G-Code sequence to run at the beginning/end of a program and when the tool is turned on/off."

G21
G90;svg#svg1 > g#layer1 > path#path1
G0 X0.04645099999999763 Y0.13227800000000317
G1 X0.11730768492817545 Y0.1655076085116844 F300
. . .
G1 X0.0464510000000161 Y0.13227800000000342 F300;svg#svg1 > g#layer1 > path#path2
G0 X15.828818999999998 Y16.684519000000005
G1 X15.958402417724608 Y16.436593348144537 F300
. . .
G1 X15.828818999999998 Y16.684519000000005 F300

Generated by Inkscape

The first test is short and simple. Does all the things I want.

M3
(Header end.)
G21 (All units in mm)

(Start cutting path id: path2)
(Change tool to Default tool)

G00 Z5.000000
G00 X15.828841 Y16.684450

G01 Z-0.125000 F100.0(Penetrate)
G03 X18.692664 Y11.495468 Z-0.125000 I96.722379 J49.996752 F400.000000
G03 X21.465422 Y7.194707 Z-0.125000 I53.645546 J31.541811
. . . 
G03 X15.828841 Y16.684450 Z-0.125000 I1.837010 J-3.751889
G01 X15.828841 Y16.684450 Z-0.125000
G00 Z5.000000

(End cutting path id: path2)


(Start cutting path id: path1)
(Change tool to Default tool)

G00 Z5.000000
G00 X0.046473 Y0.132209

G01 Z-0.125000 F100.0(Penetrate)
G03 X1.990544 Y2.288690 Z-0.125000 I-1.107281 J2.952747 F400.000000
G02 X9.092465 Y19.860171 Z-0.125000 I71.366306 J-18.623402
. . .
G02 X0.046473 Y0.132209 Z-0.125000 I-41.512153 J291.572431
G01 X0.046473 Y0.132209 Z-0.125000
G00 Z5.000000

(End cutting path id: path1)

(Footer)
M5
G00 X0.0000 Y0.0000
M2

References

• https://cncphilosophy.com/3018-cnc/
  • Great