[adamshive]

Now that I got your attention.



We are planning to build a CNC router.

We have everything placed in theory but have no idea how to get the programs into the machine. How do I build the decoder, or actual CNC computer itself? The process would go something like -> drawing, program, dnc, (cnc computer), mechanical system/program executed. The "cnc computer" is the missing link. Thanks.

[wilkomedic]

most times you have a program like mach3 to run the g code its just a normal PC with the program installed hope this helps

[Odiug]

Catchy title...

OK, in my setup I even use multiple computers:

- PC controlling the CNC machine:
This one is responsible for generating the right output to the stepper motor drivers (connected to the parallel port) from a language called GCode. GCode just knows commands like: go to XYZ with speed V, move in an arc with a certain start and end point and a given radius, etc.
In my case I use EMC2 (Linux based CNC control system)

- PC for drawing the pieces you want to mill:
Use a CAD program, which can output DXF files. E.g. I use QCad (freeware)

Now the interesting part starts. The missing link: How to get from DXF to GCode?

DXF is just 2D, but we want to mill 2.5D (additional depth information). There are various programs out there to handle that task (e.g. SheetCam, CamBam, ...).
In order to generate GCode the program needs to have some additional information:
- Diameter of your tool
- Thickness of your material
- How deep to mill in one pass
- How fast to go (depends on meterial, tool diameter, number of cutting surfaces, capability of your machine, etc.)
Knowing this, it can generate code (GCode) to control the CNC machine.

Does this clearify a bit?

Cheers,
Guido