CNC Milling

Othermill Desktop CNC

The parts for the combadge were machined using the Othermill Desktop CNC, but they should be machinable on other mills, such as the Carvey, X-Carve or Shapeoko.

This portion of the tutorial will be specifically on using the Othermill.

Stock Materials

We suggest getting the material from the Othermachine.co website because they're pre-cut and ready to machine. In this project, we used the following stock.

Measure Stock Thickness

Use a caliper to measure the thickness of the brass and aluminum and note them down. If they are really close to the specified thickness, then you won't need to regenerate the GCODE. If they're off by +/-0.05in, then we recommend regenerating the GCODE.

CAM and GCODE

Since stock material thickness tend to vary, you may need to regenerate GCODE for each part. If you're new to Fusion 360 and using CAM tools, don't worry! We'll guide you through the process.

Install Othermill Fusion 360 Tool Library

The Othermill Tool Library makes it easy to get started with CAM in Fusion 360. You'll need to download and import the file. To do so, we suggest following the guide on the Othermachine website. This will walk you through the process.

Changing Tools

Otherplan will prompt you when to change out tools. For this project, you'll need the following tools.

  • 1/8" Flat-End Mill
  • 1/32" Flat-End Mill
  • 80º Engraving Bit

GCODE for Brass and Aluminum 

Open up the Combadge Fusion 360 Archive and goto the CAM workspace. Right click on "Brass" under the Setups dropdown in the Browser panel. Then, in the Setup:Brass panel, goto the Stock tab. Look for the Height (Z) label and type in the thickness of the brass you measured with your calipers. Then, click "OK". Next, right-click on the "Brass" setup and choose "Generate Toolpath".

Click on the arrow next to the "Brass" setup, you'll see several items (Face1, 2D Pocket, 2D Contour, etc.). Now you can right-click on each item and select "Post Process". In the Post Process panel, choose othermill.cps in the Post processor section. Then, click OK. Rename the file, relative to the tool (ie. brass-face-1-8.nc). You can tell which sized tool is being used when you right-click to edit the item (ie. Face1) and see under the Tool tab. Do this for each item (export via post process).

Repeat this process for Aluminum.

Import GCODE into Otherplan

Open Otherplan and select the Generic profile under Material. Under the size dropown, type in the width, height and thickness of the stock. Under placement, set the X and Y to "0". For Z, measure the thickness of your double-sided tape and input that here. This will effectively "raise" the material to compensate for the extra thickness.

Under plans, select Open Files and choose the brass-face-1-8.nc file. Under tool, select Set or Change and choose the 1/8" flat-end mill. The Otherplan will then walk you through the tool changing process. Under the brass-face-1-8.nc plan, select the 1/8" flat-end mill tool under Milling Tools. Now you're ready to secure the stock to the spoilboard.

Secure Stock to Spoilboard

We suggest using Nitto tape to secure the stock to the spoildboard. 3 stips is plenty! Apply strips to surface of the stock and peel back the protection layer. Then, line up the corner of the stock with the lower left corner of the spoilboard. Firmly apply pressure to the spoilboard to secure the stock in place. Now you're ready to mill!

Milling Checklist

Before starting the job, make sure you run through the following checklist:

  • Ensure 1/8" flat-end mill is installed correctly.
  • Ensure material size and placement is set correctly.
  • Ensure Brass is firmly secured to spoilboard.
  • Ensure GCODE file is loaded.

If everything check outs, then you're ready to mill! Click the "Start Milling" button under the GCODE plan.

Order of GCODE

The order of milling gcode files is very important. We suggest following the order below. 

360 Brass

  1. Face
  2. Pocket
  3. Contour
  4. Chamfer

6061 Aluminum

  1. Pocket
  2. Contour
  3. Chamfer

Removing Parts from Stock

Do not remove the stock from the spoilboard until all of the GOCDE jobs have been preformed. Once they're complete, you can use a thin spatula to get underneath the stock to pry it loose. Be careful when doing this! Remove slowly. Once you've taken it off the bed, you should be able to remove the part from the stock.

Polishing Parts

When the parts have been milled, you'll notice they have patterns on the surface. These lines are results from the machining process. You can optionally remove them using a rotary tool and polishing wheels. 

A few minutes with a scotchbrite wheel will remove the machining lines. A buffing wheel can give the surface a mirror like finish.

This guide was first published on Aug 24, 2016. It was last updated on Aug 24, 2016. This page (CNC Milling) was last updated on Apr 07, 2019.