Welcome to MCAD Central

Join our MCAD Central community forums, the largest resource for MCAD (Mechanical Computer-Aided Design) professionals, including files, forums, jobs, articles, calendar, and more.

Register Log in

mass properties and relations

piase

New member
Hi,

i'm modeling a metal cast part. I would like to set a relation between the model mass and some feature's parameters.

(i.e.: length_channel=function(mass))



I tried with mp_mass, but it doesn't work.



francesco
 

MFegenbush

New member
My first thought on this is that you could (or maybe are required to)
use BMX for this. Even though it is a different relation/feature
combination, the video tip on using BMX to find the fluid level in the
jar might be a good place to start. I remember one of the (non)
training sessions I attended showed how to manipulate a feature
dimension on a crankshaft in order to get the center of gravity to fall
on the axis of rotation (i.e. perfectly balanced).



I hope this helps to guide you in the right direction.



Matt
 

tomislav

New member
Try this:


1. Relation: tezina(or other word)=mp_mass("")


2. In drawing template for formats set: &tezina for mass cell


3. In model: Analysis-Model Analysis-Model Mass Properties-Compute


4. Update drawing and you will see mass prop.


I hope that helps


Regards
 

piase

New member
jrobi said:
are you trying to determine the length of the channel driven by an assigned mass property?


more precisely, the channels section should be driven by the casting weight.

something like: area=f(weigth_casting)/f(height)



this is an example:

View attachment 1010



maybe the mold modeller has implemented it: I don't know.
 

piase

New member
many thanks, first of all.

what do you mean by drawing template for formats?




tomislav said:
2. In drawing template for formats set: &tezina for mass cell


when camputing relation, it tell me that:

"errorMass properties for this model are not calculated yet."



regards



francesco
 

mstols

New member
Piase,


I don't know what version of proe you are using. If WF/WF2 you can do the following.


When you do a normal mass analysis to see the mass, proe can report these values as parameters.


Set the follwing config .pro option.


mass_property_calculate to automatic.


If you change the model and regenerate, The model mass will update as a parameter in the part.


You can get to these parameters in your parameter window by changing the value in the dropdown box from MAIN to REPORTED MASS PROMERTIES.


The parameter for the mass is called PRO_MP_MASS.


You may have to regenerate your model twice to get it to update. This needs to happen because the mass is only calculated after regenration, so the new value for the feature has been assigned but the model hasn't updated
 

tomislav

New member
For drawing template I mean formats for drawings - A4, A3, A2... formats


-when you open formats template you can see many words with &name (f.e. &model_name) This parameters you can find in model: Tools - Parameters


For example when you in Parameters change model_name, new name you can see on drawings. Model_name can be relation also.


For mass properties: did you define density (for wf2 Mass Props)?


Edit - Setup - Mass Props (units depend on config.pro param. kg/m3 or g/m3 or?) - wf2


or SetUp - Density (ProE2001 and earlier)


So, first of all you must calculate mass prop. then comes next step!


Regards
 

AHA-D

New member
If there is ONE part then you cannot simply use mass to drive the model through a simple relation. It is simple logic. Mass sets parameter L through a relation -> parameter L sets the length of a feature -> the feature changes -> the mass of the part changes -> parameter L is recalculated out of mass, so it changes -> model changes when L gets reinserted in the feature ... etc ... etc ...


You could however use the mass at an intermediate state or as an external reference. In simple words. Model the part to the point before you determine the length of the channel. Calculate mass properties there and insert this as a feature. Create the channel and make a relation with the mass calculated before. This should work.


I've read about BMX mentioned above. As I understand it this is an iteration procedure. Mathematical this can only work if there is a solution, meaning that increasing one item should decrease another so that an equilibrium can be found.


Alex
 

piase

New member
thanks everybody!



I succeed in doing that
.

No problem with iterative calculation.



I'using WF1



kind regards
 

Sponsor

Top