Updating CAD Models with Molder DFM Models

[MCS_MLI]

I am wondering if anyone could suggest strategies to update solid models with DFM feedback from molders (i.e. neutral data files). I am currently using Solidworks and have tried using the Compare tool to determine the differences in material volume. It works in some cases, but I find that the edges of fillet surfaces have problems most of the time. I have also considered importing the solid model into the native SW file and creating a separate "molded" configuration.

 

[TheTick]

If you need the compare tool to suss out all the changes, your vendor needs to communicate better.

Usually we use the DFM CAD as a template. Import the neutral file into the original CAD so that you can match changes to the DFM model. Very helpful for adjusting faces to match exactly what vendor sent. Delete DFM when done.

Sometimes blend surface metadata include blend radius. Otherwise you can use curvature checking tool to get you close enough to recreate most fillets.

Figure out a reasonable limit as to what constitutes "close enough" for recreated blends. But usually you can get so close no one can tell.

Keep your DFM files neatly stored and organized. You won't regret it. Most PDM systems allow you to attach neutral files to a part's database folder.

Besides Compare Tool, you can also use body properties. First, ensure densities are same. Use body properties to check volume and also all the moment of inertia properties. Volume doesn't tell the whole story, but throw in moments and the comparison is nigh-infallible.

 

[MCS_MLI]

@TheTick - Thanks for the Reply. The ME that was here during the molding and design process is no longer with the company. There was no PDM and partial pack and Go was used liberally to put it lightly, to the point I can't trust and have to verify (research the entire history of every copy of the files).

I'll look into using the additional metadata for checking, I appreciate the suggestion. Most of the curvature issues I've seen are surface interfaces and may be import/export related. I've heard that exporting to parasolid files may yield better results but I haven't had an opportunity to ask for them.

There are sometimes I get the DFM model back and it is not in the original orientation. I suspect this may be during the mold design process and it may be WRT the mold origin. In these cases I wrap it in an assembly to orient it and run the comparison. Doing it this way limits the compare tool to volume/geometry. I haven't tried to add the DFM model to the Native file yet.

Other Concerns with updating the native model to match the DFM.
- Mates at the assembly breaking.
- Most files I've encountered so far here do not have good modeling practices and explode at a critical feature and may require a full or partial rebuild of the model (I don't have time for). In these cases I lean towards trying to utilize the compare feature to bring in all the solids.

We typically do some post mold machining operations on the more complicated parts which can be easily added to the DFM model. It can easily replace a Native model as long as the mates can also be rebuilt and there are no other files referencing the native file geometry. If there are other files that reference that geometry I would choose the compare/rebuild option even though it takes longer.