what are post processors? Please enlighten me

[clint_so]

Hello everyone

This may seem like an extremely dumb question for most people here but I am hungry to learn.

What is a post processor and why do people need to modify them?

I always make my tool paths in mastercam X and simply post it in G-code with the little button that says G1, then a CNC interface takes the G-code and controls the CNC machine for me. But I wasn't the one who set up the CNC machine or CNC interface so mabey that is where my knowledge gap developed from.

Thank you for any information I can learn from

[tnik]

post processor takes the information of your tool paths and everything and translates that into g-code readable format.. Almost all machines vary a bit on the way the gcode needs to be, so a post processor for said machine spits out the code so you don't have to edit it..

eg. we have a fanuc controlled hmc that MUST have a G49 before sending anything home, but if we run the same program on our fanuc controlled vmc, G49 will cause Z to rapid straight into the pallet..

[clint_so]

Oh ok I get it.

So i guess whoever set up our CNC machine had to setup the post processor for mastercam, something I take for granted

I always assumed that G-code was one universal language usable by all cnc interfaces and machines, but I guess I was wrong.

Thank you very much.

[Geof]

Originally Posted by clint_so ....I always assumed that G-code was one universal language usable by all cnc interfaces and machines, but I guess I was wrong. Thank you very much.

Don't we wish .

I think back in the early dark ages on NC and CNC there was the hope that G code would be universal but then it became fragmented because different manufacturers put in their own little tweaks. I think it was a case of there was not one single manufacturer large enough to force a standard as occurred with PCs and Microsoft.

[Mike Mattera]

The postprocessor converts the "picture" of the toolpath on the screen, to the specific language for "your" machine.

Every builder can take a standard Fanuc control and make it do something a different in a way that requires a different code. I've seen machines by the same builder, with the same control, from different years, that require different postprocessors.

Mike Mattera

[Al_The_Man]

One other reason for customizing the postprocessor is that G-Code is also machine type specific.
G codes have developed for Mill,Lathe,Plasma,EDM, etc. The M codes are at the whim of the MTB, there are general standards, but again these are machine type specific also.
Al.

[JROM]

When you create a tool path on your Cam system and save it. You have writen a CL file. that's a CENTER LINE FILE. All Cam systems output CL files.
Post processors are a piece of software that converts the CL file into G code that is just for the machine you have selected to run the part. These posts vary from machine to machine. There are alot of controls that are Fanuc compatable witch means that any program that will run on a Fanuc control will run on that control also. Go into your Mastercam folder click on Mill and click on NCI files those are the CL files generated by Mastercam.

[JROM]

P.S.
You can open the NCI file in your editor if you want to see what it looks like.

[Al_The_Man]

Historically the RS-247D, G-code 'standard' for CNC programming of the 1960's, was the object of an attempt in the 1980's by GE-Fanuc to standardize the CNC programming language, this coincided with reports of Fanuc purportedly achieving then, 60% of world sales in CNC controls.
Unfortunately, Fanuc themselves did not follow their own standard, and G code changed with a Fanuc control system, at times.
This was so much for other Manuf. following Fanuc lead!!
Al.