I am working on our procedures for document and data control. Does anyone have a good strategy for controling CNC files. Our files do not allow any space for comments and can only have a 4 digit numeric number. So it have not been able to use a document number. We do backup these files on a pc were we can have comments. When the program is in the machine it can be freely edited and it usually is changed a little every time we use it.

You probably have a "common sense" solution to this already. You must have some guarantee that your NC machines use the latest revision of a program (with its data), otherwise you would be making parts that are not to the current drawing revision. How do you do that? Document your system for this and it will probably provide a good solution for NC program control. Other issues you must consider should be disposition of obsolete or superseded prorams, your system for changing currently running programs,etc. Names for your programs should correspond to either the part being made or the NC machine. If you look at the "Old Forum", you can do a search for this topic, because it was addressed about 1.5 years ago (I think!).

My concern is where you say:

"When the program is in the machine it can be freely edited and it usually is changed a little every time we use it."

This changes the nature of the whole control issue. I would look closely at what you have and what you are changing. If you're changing parameters every setup I would look at the very need to control the program. How do you verify you have the right program - a first off inspection or what? An additional question is: Is there a need for documenting each change and history expectations.

Any of you folks have some experience you could relate here?

Marc, I think the changes being referred to here are machine related. In other words, the moves, i.e. the circular and/or linear interpolations remain constant, but machine capabilities, tooling, and material are requiring minor changes to speeds (rpm) and feeds to accomplish the job. IMHO, these are done through the machinists' experience and do not require documentation as the program itself (the moves) have not changed in relation to the profiles being machined...just the certain aspects in which it was machined.

------------------
Richard T.(Dusty)Rhoads, Jr.