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Assigning a calculated mass to a part

asecker

New member
Hi,


I have created a model of a flexible duct. From the manufacturers catalogue I have a mass per unit length. I can calculate the mass of thepart using parameters and relations so that I can display the value on the drawing but I would like to assign this calculated mass to the part.


I realise that I can assign this calculated mass to the part by typing it into the "Setup Mass Properties" dialogue box but I would like the part mass to update automatically as I vary the length.


For info I have created a new parameter called predicted_mass.Ihave thencreated an analysis feature to give me the length of the duct (analysis_length_1). Ihave then used a relation to calculate the predicted_mass as below:


PREDICTED_MASS = LENGTH:FID_ANALYSIS_LENGTH_1*0.00018


0.00018 is the mass per mm value.


Many thanks,


Adam
 
You can change your relation to use PRO_MP_ALT_MASS instead of PREDICTED_MASS. In the Setup Mass Propertiesdialog box choose Geometry and Parameters from the drop down. The value calculated by the relation is reflected in the the Steup Mass Properties dialog box. When you choose Mass Properties from the analysis menu you will be able to get mass properties based on geometry or assigned values.
 
Many thanks kdem, can't get access to ProE at the moment but I'll have a look tomorrow.

How did you come across PRO_MP_ALT_MASS? I'm not sure I'd have found that on my own. To pull out the mass of a part and use it in a drawing I normally create an analysis feature which comes up as MASS_PROP_1 in the model tree. I can then type a note as &MASS:FID_MASS_PROP_1. Does what you suggest mean if I am happy to use the density to calculate the part mass I could use PRO_MP_ALT_MASS instead?
 
If you look at the bottom left of the parameters box, there is a drop-down box with 3 settings -> Main, Alternate Mass Properties, Reported Mass Properties.
 
You could just use PRO_MP_MASS for the report parameter on the drawing. If you use theMASS parameter from an analysis feature be aware that you will get two different mass values based on the selection make on the dialog box.
 
Hey friends how to add the reported mass properties to
annotation feature... so that when ever i change the
density values it should show the updated value in
annotation note...
 
The trick to redefining the mass is to use the "PRO_MP_ALT_MASS" but you need to split the relation over the "initial" and "post regeneration" relations so that the calculated mass ie from the part density is retained. You can basically toggle between the two (calculated and assigned) when reporting the mass props for that model.

Here is the best method I have found:

Component Model Mass Re-Calculation

/*Override Mass (Initial Relations)_________________________________________________________
PRO_MP_SOURCE = "PARAMETERS"
PRO_MP_ALT_MASS = MASS:FID_MASS_PROP

/*Re-Calculate Mass (Post Regeneration Relations)___________________________________________
PRO_MP_ALT_MASS = PRO_MP_ALT_MASS*1.1

Descriptive Notes:
/*Sets Mass Prop source calculations to Parameters (default is Model)
PRO_MP_SOURCE = "PARAMETERS"
/*Feature to calc as modeled mass (named "MASS_PROP")
MASS:FID_MASS_PROP
 
You can change your relation to use PRO_MP_ALT_MASS instead of PREDICTED_MASS. In the Setup Mass Propertiesdialog box choose Geometry and Parameters from the drop down. The value calculated by the relation is reflected in the the Steup Mass Properties dialog box. When you choose Mass Properties from the analysis menu you will be able to get mass properties based on geometry or assigned values.

Thanks for such a good solution.
 
Hi,
I am wondering if there's a method for overriding the mass of an assy...specifically by subtracting the mass of some of the components in the assy?
I have some hydraulic motors in a large assy that are also used in an upper level assy. So, the mass is being added in twice. I need to subtract out the mass of these components in the lower level assy. Any ideas?
Thanks,
Andy
 
Are you saying that the hydraulic motors are duplicated in the upper assy? There's no easy way to do that that I'm aware of. If you've got two where there ought to be one, for example, I'd suggest that you rethink your assembly structure. Proe / Creo is built around a paradigm of mimicking the physical world and works best when your files mimic it as well.
 
Andy,
I had this same issue with masses added twice. The solution is to make the mass a flexible parameter of the component. Details follow:

Open the part and set your part mass properties to "Geometry and Parameters".

Then manually set the actual mass and other properties.

You can then go back to your assembly and add the mass as a flexible parameter of some components, and set to zero.

Then, when you do mass properties on the assembly, be sure to choose "Assigned" instead of "computed".

Good luck.
 

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