The subject of migrating NX CAD data into Teamcenter has come up recently in discussions I’ve been involved with. Data migrations have also been one of the more interesting projects I’ve personally worked on, so I thought it might warrant a post or two.
I’m going to start off buy discussing some of the problems I’ve seen with the raw data, the part files that needed to be migrated into Teamcenter. I suspect that many of the issues I dealt with are pretty common and not specific to any one CAD application (or even to CAD data itself).
Common Data Migration Issues
My hope is that by identifying the issues up front you’ll be able to prepare for them proactively. Here are the main problems with the source data which I have seen:
File Naming Issues
The first set of issues revolves around how files are named. Here are the types of issues I’ve cataloged:
Correctly named files
Okay, not really an issue per se, but sometimes it seems that this is the exception rather than the rule.
Prefixed or Suffixed File names
These are files that have the correct part number (or whatever) in their file name, but then there’s some sort of extra information in the form of a suffix or prefix. scotts_part.1234567 or 1234567-rework, for example.
Legacy naming rules
If your company has been around for awhile, or bought a bunch of other companies, then it’s likely that some of your legacy data conforms to rules which are no longer valid for newly created data.
This is more specific to NX data, in particular, which can have the revision of the file included in the file name, e.g. 123456_01 → Rev 01 of part 123456, 123456_A → rev A, etc. Sometimes though you’ll just have a part named 123456 and you’ll have to guess which rev it’s supposed to be.
Invalid file names
And sometimes parts have file names that don’t match any approved naming standard at all. I’ve seen three main causes for this:
Part files created to try out an idea for a project where the user didn’t pull an actual part number. The part may never have been used for a production drawing, a file with a proper file name may have been created by a save as operation, leaving this one behind, unused, or the worst case offender: the part is referenced by a drawing but called out with its “real” part number on the face of the drawing.
Customer and Supplier Parts
Parts that come from suppliers and vendors typically don’t conform to your naming rules.
In every single CAD department I’ve ever worked with sooner or later someone has brought up the idea that their archives contain the drawings for the deck somebody is building on the back of their house.
- These stories often include mention of how the person who did this was able to buy the exact amount of wood and nails to complete the project without any scrap.
- Okay, I confess, I have used CAD to layout bookcases I was installing in my basement. They came out awesome — however, I learnt that my ceiling isn’t quite as straight and as flat as in my CAD model. I may have had some scrap.
Problems with the files themselves
Once you get past the problems with the file names, you still have problems with the actual files. Examples:
Versions of a part kept in multiple directories
Usually the expectation is that all versions of the same part are kept in the same directory or in a well defined set of directories. But sometimes that doesn’t happen and what you think is the latest revision of a file is in fact not the latest because the latest is in some other directory that you don’t even know about yet.
Duplicated file names
The next item is a variation of the previous. Here, not only are there multiple directories with the same file in them, but there’s actually two or more files with the exact file name in multiple directories — and you get to figure out which of those is in fact the most “correct”. More often than not the files are not actually identical.
Different versions of same file name
This is an extension to the various part naming issues mentioned above. Now you may see more than one style of naming the same CAD file, 123456-01 and foobar.123456-01, for example. If your file naming convention includes revisions in the file name you may get lucky and there will only be one variation used per revision — curley.123456-01, larry.123456-02, moe.123456-03, where the 01, 02 and 03 are the revisions.
Next, you have files that other CAD files refer to, but which are missing from the OS. Three reasons for this are,
- The files were deleted
- The files were renamed at the OS level but other files are still looking for the original name
- The files were created in a user’s local directory and never moved to the common filing system
Finally, sometimes files just go bad and you just can’t work with them any more. These need to be repaired or replaced.
Just the beginning
Today we’ve just looked at identifying some of the common issues—and if you have more to add, please tell me about them in the comments. Later we’ll discuss some of the decisions that have to be made, such as: do you want to migrate every single file? Every version of certain files? Or, certain versions of certain files? So, please stay tuned.