PCB drilling and milling with a CNC.
After long search and experiments, function of programs available (to me at least),
I come to a solution that use some different program to generate the Gcode, plus a self written function to generate the drilling data.
Camware CAM 350 gerber conversion and drill generation
Circuit CAM 5.0 from LPKF isolation path (DXF)
Visual Mill 5 isolation DXF to gcode
Cimco Edit gcode prevue
My starting point are 274D gerber files.
On the PCB CAD I generate the Top, Bottom and Border layout, with drill data embedded on the pad stack.
With CAM350 version 9.5, I convert it to 274X format.
The drill data is extracted, sorted by distance and exported in Excellon2 format.
Additional function performed by CAM350 is to change the coordinates origin suitable for my CNC configuration.
The Excellon2 data is converted to gcode by my application.
The 274X file are imported (on the relative layer) in CircuitCam.
CircuitCam calculate the isolation path, and export it to DXF (no gcode support).
My configuration use two different tools: standard 0,6 mm , small 0,25 and isolation set at 0,6 mm. Typically Circuitcam use the 0,6 mm tools to route 95% of the PCB and the 0.25 mm to complete it. This configuration let me get a good isolation in very short time. Different configuration is also possible (till 4 different tools), and also select areas to mill completely (pouring).
Circuircam is really a powerfull application, the only drawback is that It do not generate the Gcode.
From the three base layer: top, buttom and Board I generate till 5 files:
- Top standard, path for 0,6 mm
- Top small, path for 0,25 mm
- Bottom standard, path for 0,6 mm
- Bottom small, path for 0,25 mm
Once configured, CircuitCam perform all these operation by just few mouse clicks. The isolation calculation is very fast and accurate (much faster and better than Coppercam). The results can also be edited.
Visual Mill 5 take care to convert the DXF file to Gcode.
The five layer must be configured as long as the tools to be used.
I use a tricks to speed up the procedure. Once made the first project, a make a copy and then I replace all the layers data with the new one, all other assignment are kept and the generation are greatly speed up.
Cimco edit let you check the gcode generated and simulate the final result. At the beginning it is a must, it let discover errors or mistakes in the Gcode or procedure used to do it.
My CNC mill is driven by MACH3, and once configured for automatic Z axis presetting after tool change the PCB milling and drilling is now quite simple and easy to do.
The attached picture is a sample double side PCB.
CopperCAM basically perform all these operation, is small and quite easy to operate and cheap.
Unfortunately, some drawback are very annoying and serious if you want to make good PCBs.
The isolation path is not accurate and even worst non optimized, do not support different size tool, editing is poor, drilling depending the way is generated is not sorted or not referenced to the coordinate.http://rapidshare.com/files/228043958/CAM5.rar
For the other software search them in the forum.