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Mixed part units in assembly results in incorrect weight calculation for the assembly. Fix?

SOLVED

Mixed part units in assembly results in incorrect weight calculation for the assembly. Fix?

Is there a fix for this? Getting an incorrect weight result for the overall assembly when using part files that have been created with different units.

Thanks.

1 ACCEPTED SOLUTION

Accepted Solutions

Re: Mixed part units in assembly results in incorrect weight calculation for the assembly. Fix?

I've found that Proe / Creo does not handle mixed units well if some are mass based and others are force based. If all are one or the other, things generally go well.

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Doug Schaefer | Engineering Manager
Crow Works
7 REPLIES 7

Re: Mixed part units in assembly results in incorrect weight calculation for the assembly. Fix?

You may need to change the units of all parts in assembly. If you are working with Creo 2.0, you can change the units of all part in one step from assembly using File > Prepare > Model Properties > Units > Change > Check Include Submodels > Set

Re: Mixed part units in assembly results in incorrect weight calculation for the assembly. Fix?

Why do you think you have the incorrect mass?

Are there simplified reps involved?

Look at the output of the analysis to see what components were included, what their density is, and what their calculated mass is.

Re: Mixed part units in assembly results in incorrect weight calculation for the assembly. Fix?

I usually have pretty good luck with mixed unit assemblies calculating correctly. I would look to see if there is a component model that doesn't have a material or density assigned.

Another thing to check are the units of the assembly itself. Are the units set to what you expect.

Another thing are unregenerated parts, or failed features that can mess up the mass calculation as well.

Re: Mixed part units in assembly results in incorrect weight calculation for the assembly. Fix?

I've found that Proe / Creo does not handle mixed units well if some are mass based and others are force based. If all are one or the other, things generally go well.

--
Doug Schaefer | Engineering Manager
Crow Works

Re: Mixed part units in assembly results in incorrect weight calculation for the assembly. Fix?

Thank you, that's exactly the issue I am having. We have legacy data that is in forced based units and our new models are mass based. The assembly weight is incorrect and most of the older files are released in Windchill and can't be changed without a major process.

Re: Mixed part units in assembly results in incorrect weight calculation for the assembly. Fix?

It's frustrating, because there's no reason why Creo shouldn't be able to figure this out. Gravity is pretty consistent for most users outside of aerospace. i would think that they could make this work for the vast majority that only think of gravity as a single constant and provide a few simple config options could account for the few users that need varying values for gravity.

--
Doug Schaefer | Engineering Manager
Crow Works

Re: Mixed part units in assembly results in incorrect weight calculation for the assembly. Fix?

Conversions of force-based descriptions to mass-based descriptions are done all the time. If this isn't working then SPRs should be issued every day until it is fixed.

Most of the time the problem is someone has entered metric-tonnes per cubic millimeter wrong or something else like it, which is why an examination of the mass properties report to see which parts are reported wrong and what their assigned density/unit system is important.