CNC Router

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CNC router.gif

A CNC router is a computerized woodworking machine - basically a router mounted on a positioning system. While it may also be able to handle other materials than wood depending on the bits you use, a proper CNC mill is more precise for machining parts out of metals and other non-wood materials.

To use this machine, you need to familiarize yourself with at least two pieces of software:

There is also an interesting new approach of handheld CNC routing coming out which may remove the size constraints that come with any fixed-frame machine.

Uses

You can make furniture or even build a house. For more ideas, check out the CNC Milling Ideas.

WorkBee

MachineInfoBox

Ooznest WorkBee CNC

Workbee frame.JPG
Synonyms: DE: CNC-Fräse, Portalfräsmaschine
Material: wood
Used with: 6 mm, 8 mm, 1/4" or 1/8" end mills;
some kinds of router bits
Location: CNC room
Access: upon introduction
Status: under construction (see issue #8)
Firmware: grbl
Software: LaserWeb, Fusion360, see G-Code Sender
Manual: product page, click "documentation" tab
Tutors: (?) Patrick
Similar (More or Less): router, CNC mill

We built the 1500mm x 1500mm version of the WorkBee CNC, which is based on the Openbuilds OX. It can currently cut sheet material of up to 20 mm thickness on a work area of approximately 1250 × 1250 mm.

Details on setting it up can be found in issue #8 - maybe you would like to help?

Router

The router mounted to it is a Dewalt D26200 (GB). You need to consider the sizes of its collets (Spannzangen) when buying your router bits.

  • no-load speed: 16000 - 27000 rpm
  • max cutter diameter: 30 mm
  • available collet diameters:
    • 6 mm
    • 8 mm
    • 1/4 inch (6.35 mm)
    • 1/8 inch (3.175 mm)

The collets of the DW613, DW620 and DW621 also fit the router and are easier to get in Germany than the original ones.

G-Code Sender

After creating the tool paths in a suitable CAM software (e.g. Fusion 360) they need to be sent to the router in real time via the serial interface (USB).
Our experiences can be found on: G-Code Sender


Tips & Tricks

  • to avoid tear-out at the edge of a sensitive workpiece, it may be worthwhile to surround it with some sacrificial material (like MDF) before routing [1]

Spoiler board

Ooznest recommends a 6mm spoiler board, our first one is 20mm thick. It is mounted to the frame using 4 drop-in T-slot nuts. Cutting into the boards will make it uneven, from time to time it is neccessary to surface the spoiler board again.

Materials

Aluminum

With a lot of patience an the correct bits possible but check if it's millable aluminum

  • differnt alloys of containing Cu, Si, Pb

Bits

maximum two cutting sides carbide is more rigid than HSS and advised by some online guides Tested 4mm 2-sided pointy-end bit with acceptable success

RPM, Speeds, etc.

Values are only the tested ones, faster CAN be possible as well

  • slow RPM: 16 000 is our minimum but e.g. for a 4mm bit, 6000 RPM would be better
    • different mill or PID-ing?
  • Feed Rate/Schnittvorschub: ~200 mm/min
  • Einfahrvorschub: 15-20 mm/min
  • Ausfahrvorschub: 200 mm/min
  • Helixvorschub: 15-25 mm/min
  • Eintauchvorschub: 15 mm/min
  • Depths: 0.25mm per pass

Milling directions (to be tested): Conventional/Up-Cut (Gleichlauf) milling milling for the basic different passes with a finish using Climb-milling/Down-Cut milling (= Gegenlauf)

Cooling

Not yet tested

  • any sort of lubricant or coolant will increase the efficiency of aluminum milling
    • there are suggestions ranging from cutting fluid over WD-40 to candle wax for lubing
    • As coolant, a water or alcohol mist seems unsuitable with our pressboard
      • instead, using the air compressor might be a possiblity

POM/Acetal/Delrin

Bits

tested with 2 and 3 sided HSS Bits 4mm-6mm but no indication against any other diameters

RPM, Speeds, etc.

Spindle on level 1 (=16 000rpm)

  • Schnittvorschub: 500mm/min +
  • Einfahrvorschub: 500mm/min +
  • Ausfahrvorschub: 500mm/min +
  • Helixvorschub: 200mm/min +
  • Eintauchvorschub: 30mm/min
  • Depths: 2-3mm

Strongly advise a horizontal Rohteilaufmaß and a final finishing cut to remove any "layer" marks.

Cooling

Not neccessary with the current settings but might increase the cutting speeds drastically

Helpful Links