The Othermill is a small 3-axis CNC mill primarily intended for circuit board prototyping – although by no means limited to circuit board work. 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 g-code to the mill. It’s also used to control and position the mill. Bantam’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. You can read more about making circuit boards with Eagle on Bantam’s website!
Staff will use HSMworks to generate tool paths for your project. If you bring CAD files (Solidworks or Inventor) and we will do the necessary conversions. Toolpath planning takes a long time and it is required that you are present.
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:
Dual sided boards are possible to do but they are more vastly more difficult than single-sided boards because of alignment issues. If possible, design a single-sided board instead of a double-sided one.
VIAs are not plated so you’ll need to manually run wire and solder them if you want connectivity through the board.