Parts density

[dlugi04]

Hello Everybody


I have an imported assembly which is consist of lots of imported parts. Pro/E sets up default density for each part as "1".So when I start to regenerate assembly it asks me to confirm default density or to type a new one. It is really workfull operation if you have large assembly consisting of i.e. 100 parts. Is there any way to set globaly density for eachpart. It means can I do it i.e from Assembly Mode level or maybe there is a hidden option in config.pro ?Important is when I openeach part it must havea newdensity. Thank you in advance.


DLUGI04

 

[AHA-D]

Think you're out of luck. Even had lots of problems to find the odd few parts that was defined in tonnes instead of kilos and that were freaking out the entire assembly weight. I was lucky that this -and other ill definitions - led to a weight that was totally out of line, so I noticed.

 

[dlugi04]

Yes, indeed. this is briefly what I mean

 

[AHA-D]

There is a setting you can make in config.pro to get details of the calculation :


mp_calc_level = all_models


This gives you at least some idea of what parts might be way off.

 

[markmmartinez]

I don't know if this'll help, but when I use a part model of a an assembly which we functionally treat as a part (a complete pump and motor for example) I create a parameter called "WEIGHT" in the model. I also create the relationship "MP_DENSITY=WEIGHT/PRO_MP_VOLUME". This forces the part density which will result in a correct value for "PRO_MP_MASS". It also give me the ability to determine the mass of my entire assembly even if I have mixed "purchased" parts like the pump above and constant density part such as structural steel. It also gives me a reasonable COG for those "purchased" parts. When assembled on a larger scale (pumps on a large skid) the difference in location of the calculated COG vs, actual is pretty small.

Back to your original question. My start part has the WEIGHT parameter as well as the relationship above. I normally create a new part an then import a SAT model of the component I'm going to use.
When I have assembly open I go to the browser and show the weight parameter by selecting Settings-->Tree Columns-->Model Parameters (from Not Displayed, Type pull-down)--> WEIGHT. You can now quickly change the model weights from your Browser.

(Note you will have enter a dummy placeholder weight in your start model file)

 

[jelston]

... the pump above and constant density part such as structural steel. It also gives me a reasonable COG for those "purchased" parts. When assembled on a larger scale (pumps on a large skid) the difference in location of the calculated COG vs, actual is pretty small.

Mark,


Just wondering, what do you design?

 

[dlugi04]

Mark !


Thank you very mach for your answer.


This is standard problem in my company. When we recieve assembly from a supplier. We openn in it from *stp file. Stp file opened as a assembly in Proe gives you mostly good solids geometry. When you open infrom *. stp. as a part in most cases you receive expoled part with degradated surfaces. So going back to aasembly which I have from imported stp file. I have in Proe i.e. turgocharger consisting ofa hundred partswhich I must set density to calculate proper weight. Even when I changeweight of the assembly and mass properties manualy fromassemblylevelPro/e takes its calcutions mass poperties base on mass properties of each model. So my qestion is how to change assembly weight that Proe will take it for its calculations? Please mark that my assemblyis sub-assemblyfor another assembly. Or how to change automaticly each part density?

 

[markmmartinez]

jelston:
My company builds pump stations under our brand name and for several of our sister compnies; water booster stations, heat transfer stations, HVAC pumping units, firepump stations, RO systems, and municipal pump stations
I work for the Flowtronex division of ITT Corporation (formerly ITT Industries). Some of the stations above are built for Bell and Gossett, Goulds Pumps, AC Firepump, and WET.

 

[markmmartinez]

dlugi04:
You might want to try using the same method I used for forcing a part density based on volume and a weight parameter. Normally we don't use customer assembly files because of their size. We'll create a simplified part to represent the assembly. This also makes creating a family table of the vendors product line much easier.

 

[gkbeer]

1.0 is the default density for parts.

The prompting for a density for all the imported parts happens as a side effect of having "mass_property_calculate automatic" in your config.pro.

 

[edmondally]

I also have a problem related to this one: we changed from an old commercials system to a new one, one of the changes made was that we insert the density of commercials in tonne/mm^3, instead of kilograms/mm^3. We do not update the old ones, and when doing a Model Analysis of an assembly to generate weight, some of assemblies parts are calculated in kilograms, some in tonne. If I convert to Tonne, the result is correct. Question: does Pro/E know it has to convert, or not? if not, it sums kilos with tonne, and end result is totally wrong!!View attachment 4257