OT: PDM for CNC code

I am curious how any of you that are involved with the CNC side of things handle the programs for various parts with particular interest in Surfcam and Mastercam. It seems to me that the machinists generate a number of programs to finish a specific part, perhaps because of the operations involved, perhaps because the part re-oriented and perhaps because multiple machines will complete a single part. This means multiple files for a single part. Added to that is the reuse of programs and it seems like documenting and tracking this stuff can become a nightmare.

TOP

Reply to
TOP
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CNC side is not all that complicated, save by part number and revision.

What I do is create a master file using the part number. EVERYTHING associated with that part number is in that ONE electronic file and is saved by part number, revision and operation. All the files are read only so if a change comes call up last revision, do a file save as, new revision, make the necessary changes to these new files and last step make file read only so they can't accidentally be changed.

Tom

Reply to
brewertr

When MS "DOS" was Boss I used to pick out a floppy and put a P/N on it and store all the files in there. The floppy was then stored in the file cabinet with the print etc.

A disk crash was then not a BIG problem. I suppose CD's would work as well.

I had my Acad generate the files ON the floppy. Nothing on the 'puter except programming files.

Regards,

Stan-

Reply to
Metalcutter

also add, programs left in the controllers, is there someone who monitors this? custom edits at controller, do they ever get documented?

Reply to
kenneth

Thanks. Some interesting insights there. And very different in philosophy from CAD files. From my own observations (more as a tourist) and from bigger operations comes the issue of multiple people getting different CAM operations to perform. Right away that shifts things to a network, not a floppy or CD.

I am wondering whether there are ever any operations so formal as to have a CAD drawing for each set of CNC operations performed?

I suppose that if "on machine" edits were to be captured there would have to be some support from the machine vendor to support capture of such events.

I think there is also the issue of tying a particular program to a particular machine with a particular set of tools in the changer.

Is there ever a document made to go with the files on the floppy that contain notes needed to reproduce whatever part is being made?

TOP

Reply to
TOP

Yes, normally associated with larger companies and high production.

Programs are normally sent and received by cable, when permanent changes are made just send that edited program back and add comments about changes made if necessary. Whatever method is used to send programs to the machine controller just reverse it back when changes are necessary and permanent.

A good argument for standardizing machinery, controls and tool positions on the shop floor.

CAM program has post processors that allow it to generate code for any machine the shop has. The CNC program itself is normally tied to a particular machine and control but not the CAM program.

Yes, CAM programs can generate setup sheets with tool information and position for setup/operators. How it is generated and in what format would be determined by shop policy. For more difficult setups and parts it may include photos or renderings of fixtures, clamp positions, special tooling, part zero etc.

Tom

Reply to
brewertr

I've seen it.

IIRC, I've seen that too.

I have not done these things first hand, so I don't know how the documents are managed. One of our customers does high-volume turnkey milling systems that quite often involve complex machining programs and even alterations to the controller's software. I'm sure all of this has to be documented for the end customer and passed on somehow.

Reply to
Dale Dunn

I don't leave part programs in the controller. I delete last program before I upload a new one.

Put part number, revision number, who created program and the date in the program header. That way if you save programs in the controller it is easy to see if it is the correct program and revision.

CNC Programs are or should be treated the same as any controlled document IMO. I don't allow editing at the controller, if a mistake was made in programming then the programmer should fix it.

I get in trouble every time I say this so I will point out that this is not always possible and shop policy should dictate who is authorized to make changes to programs and under what circumstances. Shop policy should also insure that those changes are documented and saved as necessary.

Tom

Reply to
brewertr

Another part of this question is what kind of lifetime does CAM data have? Unlike a part print, CAM data seems to be able to be obsoleted very quickly. Since the parts being made have to meet the print to be accepted the part print has to be kept and can be used to reproduce the part at any time. But CAM data could change for the same part if, for example, a different machine is used to produce the part, somebody comes up with more efficient code or a host of other reasons. When a program like Surfcam or MasterCam are used, is there a part of what they do that can be considered machine independent and another part specific to a machine? If so is the tendency to keep the machine independent part and let the machine specific part go after a while?

What event would trigger deletion of a CAM program?

TOP

Reply to
TOP

If kept by revision there is no "Lifetime".

CAM holds the model and tool path, that shouldn't change unless the part or machining strategy changes.

CAM data does not change, post (machine specific G-Code) from CAM data for new machine.

Revise the CAM model and or Tool Path so code can be posted to any machine.

The part model and finish tool path won't change unless a customer revision is made.

Machining strategy could change depending upon the CNC machines on the shop floor. It is possible feeds, speeds, tooling could change if machine HP, work envelope, rigidity or availability of machine specific tooling changes.

Don't understand the question, if its broke fix it, if its obsolete never to be used again get rid of it.

A part that will never come back, even still I may back it up to CD or DVD it's cheep enough and just in case the job that was never supposed to come back does.

Tom

Reply to
brewertr

Jon,

Your example seems a little short sighted and doesn't justify deleting a CAM program.

No reason to delete a good CAM Program for an existing and repeating job unless you can control order quantities and delivery dates. Job shops or even most shops don't know what the customer reorder quantities are going to be or delivery requirements, future machine utilization etc., these are all variables and can change over time.*

It costs next to nothing to save existing CAM programs but it costs a lot if you delete one you could use again later on down the road.

In your example it would be smart to save the vertical mill program and create a new CAM program for the horizontal mill ( or pull up the VM program, do a file save as, edit it for HM and save).

Tom

*An exception could be high production facilities with dedicated machining cells, long term agreements and minimum order/run quantities.
Reply to
brewertr

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