documents/maker/CNC milling.md

Table of Contents

CNC

Milling Settings

Acrylic Bit: 3.175mm O flute Upcut Cutting Feedrate: 150mm/min Ramp & plunge feedrate: 120mm/min Passes: 0.5mm per pass

Walnut

  • Adaptive Clearing
  • Bit: 1/4in 2-Flute Flat
  • Cutting Feedrate: 1000mm/min
  • Ramp & plunge feedrate: 400mm/min
  • Passes: max roughing step down 1mm
  • heights: 2mm clearance height, 4mm retract height

z-probe

  • thickness: 14.14mm for circular probe, 2mm for hex probe
  • distance -15mm

Snippets

  • G1 - Linear interpolatioon. Linear mode, cut straight line.
  • G1 Z0 F50 move at feed rate 50mm/min to Z home axis
  • G1 X0 Y0 Z5 F500 go home at feed rate 500

https://www.sainsmart.com/blogs/news/grbl-v1-1-quick-reference

General

https://www.reddit.com/r/CNC/comments/78z4lo/calculating_feeds_speeds_for_18_bit CNC3018: safe = depth per pass at 0.5 to 1x bit diameter

‘Feeds and speeds’ is generally used to refer to ‘feed rate’, ‘slew rate’, ‘plunge rate’ and ‘spindle rpm’. Feed rate: how fast the machine will move the router bit through the material Slew rate: speed that machine moves when above the material (traveling between cuts) Plunge rate: speed at which router bit is driven down into material when starting a cut Spindle speed: in rpm, how fast spindle is spinning

Feed rate and spindle speed are inter-related. You can cut at a faster feed rate by increasing spindle rpm. Cutting at too low of a feed rate with too high spindle rpm may result in overheating router bit or burning/melting the workpiece.

Easel & UGS

https://easel.inventables.com/projects/ouRUce2db96tfxvCuI8gsw

UGS - Universal GCode Sender https://github.com/winder/Universal-G-Code-Sender Probe Distance is how much it should move while probing (-20mm is a good number, means move down 20mm)

James Dean’s conservative settings:

  • 450-500mm/min feed rate
  • 220mm/min plunge rate
  • 0.5mm depth per pass

Bit and plunge

Standard bit size (1/8in) = 3.175mm, recommended depth per pass = 0.5mm For bit size 1/4in = 6.35mm, try 1 to 2mm?

Fusion 360

For holes, do 3D contour, select from top of hole surface

Adaptive clearing - check STOCK TO LEAVE option

Recommended Values:

  • Spindle speed: 1000rpm
  • Feed Rate: 1000mm/min (16mm/s).
  • Plunge Rate 300mm/min

Medium Values:

  • Spindle speed: 1000rpm
  • Feed Rate: 700mm/min (11.5mm/s).
  • Plunge Rate 200mm/min

Slow Values (roughing):

  • Spindle Speed: 1000rpm
  • Feed Rate: 300mm/min (5mm/s)
  • Plunge Rate 70mm/mi

acrylic: feed rate: 200mm/min plunge rate: 120mm/min depth per pass: 0.5mm

CNC3018

Inverse Axis

In the GRBL console, type $$, check value of $3

Value Reverse X Reverse Y Reverse Z
0 NO NO NO
1 YES NO NO
2 NO YES NO
3 YES YES NO
4 NO NO YES
5 YES NO YES
6 NO YES YES
7 YES YES YES

So if it says $3 2, type $3=6 to reverse Z See http://www.diymachining.com/downloads/GRBL_Settings_Pocket_Guide_Rev_B.pdf

Z Probe

  • Connect to pin A5
  • probe: G91G21G38.2Z-50F100; G92 Z14.14; G0Z5M30

Console

  • Set Home X, Y
    • G92 x0 y0 z0
    • G92 x0 y0
    • G92 z5
  • Go Home
    • G1 X0 Y0 Z5 F500
    • G1 X0 Y0 Z14.4 F500
  • At the end of file:
    • G28 G91 Z10 to move up 10 above origin
    • delete G28 G91 X0 Y0

https://wiki.shapeoko.com/index.php/G-Code

  • G10 M Set work coordinate origin
  • G28 - go to predefined position. At the end of gcode: G28 G91 Z0 maybe change to G28 G91 Z10
  • G90 - switch to absolute distance mode.
  • G91 - switch to incremental distance mode. coordinates now relative to current position, no consideration for machine origin
  • G21 - After this, units will be in mm
  • G92 - coorindate offset G92 x0 y0 z0 makes current postiion a temporary home position
  • G38.2 Straight Probe, stop on contact
    • G38.2 Z-12 F24 // probe 12mm down at feedrate of 24mm/min

https://docs.sainsmart.com/article/j3nxnaoejh-fusion-360-quick-start-guide-for-3018-pro-prover-cnc-s https://docs.sainsmart.com/article/bj9o96wcbc-how-to-set-up-use-candle-for-multiple-operations

Bits

https://www.harveyperformance.com/in-the-loupe/flute-count-matters/ Traditionally, end mills came in either a 2 flute or 4 flute option. The widely accepted rule of thumb was to use 2 flutes for machining aluminum and non-ferrous materials, and 4 flutes for machining steel and harder alloys. As aluminum and non-ferrous alloys are typically much softer than steels, a tool’s strength is less of a concern, a tool can be fed faster, and larger material removal rates (MRR) is facilitated by the large flute valleys of 2 flute tools.

  • spiral cutting end mill for straight cuts in plywood
  • 2-flute flat head end mill for the roughing passes
  • 2-flute ball nose end mill for the finishing pass
  • V-bit for lettering or detailed sign making
    • produce narrow cuts and lines
    • ideal for sign making
    • use on all metals, wood, plastics, resin
  • HQMaster Spiral Milling Cutter are 3 Flute carbide end
    • upcut suare end mills
    • cutting slots, profiling, routing, plunge cutting
    • for aluminum and wood
  • Drillpro are router end mills fish tail
    • diamond up-cut
    • produces flat surface
    • for plunge routing and precise contours

My End Mill

Burr End Mill

  • DrillPro: Titanium
  • UnionTool: Carbide
  • Shank Diameter: 3.175mm
  • Cutting edge diameters:
    • 0.8mm
    • 1.0mm
    • 1.2mm
    • 1.4mm
    • 1.6mm
    • 1.8mm
    • 2.0mm
    • 2.2mm
    • 2.4mm
    • 3.0mm
  • Edge Length: 12mm
  • Overall Length: 37mm

My flat nose

  • Material: Carbide
  • Shank Diameter: 1/8" (3.175mm)
  • Cutting edge diameter: 3.175mm
  • Cutting edge length / flute length: 17mm
  • Overall Length: 38.5mm

My V-bit

  • 15degree
  • 0.1mm tip
  • 1/8" shank