The Othermill is a small 3-axis CNC mill primarily intended for circuit board prototyping – although by no means limited to circuit board work. In general, we will help you generate tool paths and set the machine up so bring a laptop and all of your source files.
The Othermill is a very accurate mill (.001″ easily) with small tools and as such doesn’t have much tolerance for improper setup. Stock measurements and placement need to be accurate and precise. You can, for instance, mill through stock material but not through the tape on the bottom if you set it up correctly. A tool should never contact the spoilboard (except when locating).
Otherplan is used to generate toolpaths for circuit production and to send gcode to the mill. It’s also used to control and position the mill. Othercompany’s website is extremely good as a reference for all things Othermill – including speeds and feeds for common materials and software settings.
Emergency stop is located on the right hand side of the machine.
When locating a new tool the mill MUST be a Z max or else it will rapid into the spoilboard and break the tool. Especially important for smaller tools.
The collet wrenches are kept at the top of the machine in magnetic holders. Keep them there when not in use.
When loosening a tool don’t let it fall – the smaller tools will break easily. Use a rag to catch it if you have to.
When locating the Z of the new tool use the wizard. It makes electrical contact with the spoilboard so it need to be positioned above clear aluminum. If it’s not, use the arrows to move it so that it is. If you adjust the Z to check make sure you raise it back up before running the locating cycle.
Circuit board fabrication:
You should export your files from Eagle as a .brd file using the 1/32 DRC file. Read more here:https://othermachine.co/support/pcb/eagle/
If at all possible follow those instructions so that your board can be cut using a 1/32″ end mill. The 1/64″ tools take a very long time and tend to break often. If you don’t need sharp corners radius everything so the 1/32″ mill can get to it. For some headers it’s unavoidable for clearance but try to minimize the need for the 1/64″ tools. We also have 1/100″ tools but they are even more fragile.
It is imperative that your copper-clad board is completely secured to the spoil board with nitto tape. Any vertical play will break tools almost immediately on contact. If the board is warped don’t use it.
Dual sided boards:
If possible single-sided boards work better for milling because of alignment issues with the double sided boards.
Vias are not plated so you’ll need to manually run wire and solder them if you want connectivity through the board.
Run the first side with traces and holes – but no outline. Flip the board and carefully align the Otherplan toolpaths with the actual board position. The easiest way is to carefully steer the tool into a hole and then move the paths to match up. Then repeat on a hole on the other side of the board. Use rotation to correct for skew. Then run just traces and outline on the second side – redrilling the holes tends to just make a mess.
Generate your gcode with the origin at the top front left corner of the part. Use an othermill postprocessor – autodesk products have a built-in one by default. Our version of DeskProto has one we wrote.
Pay special attention to your tool settings and your feeds. Tools for Autodesk products can be found here:https://othermachine.co/support/2d-3d-design/fusion-360-tool-library/
STLs work best through DeskProto while proper CAD files work best through 360 Fusion or Inventor. We will check all toolpaths before you run them so it’s best if you hold off on post-processing until you’re here so we can make changes. Always bring a laptop.
Once the gcode is imported into Otherplan and you select a tool you’ll see a live preview of the results. If it doesn’t look exactly correct you have stock or gcode settings wrong!
We’ve mostly milled HDPE with the machine but theoretically aluminum is possible with light cuts and the correct feeds.