With the design done, one turns to CAM. First considerations:
To make this simple, we select HDPE, and a 1/4" #201, so that we may use the numbers from the official Carbide 3D feeds and speeds chart: http://carbide3d.com/shapeoko/feedandspeed/
- Depth per Pass: 0.125"
- RPM: 21500 (4 or so on either a Makita or Dewalt dial)
- Feed: 80" / min.
- Plunge rate: 40" / min.
Go into Job Setup and change to Imperial measure (and set the material thickness to match the material you will be machining), then select an inner circle for a bearing and go into Toolpaths and set the feeds and speeds:
Then set the Toolpath options:
- Cutting Depth --- click "Use Stock Bottom"
- Offset Direction --- select the radio checkbox for "Inside / Left" for the bearings
- Name --- always enter an appropriate name for the Toolpath, if feasible, only select one region of geometry at a time to cut (otherwise the machine will lift out and move to the next with each pass, potentially greatly increasing the machining time).
Repeat for the balance of the inner bearing holes: