SW mass properties

[vscid]

When you have a purchased part in your assembly (directly pulled off the vendor's website), how does SW account for it in its centre of gravity calculations? This could either be a shell model or a regular part.
Can you assign material properties to a shell model?

 

[TheTick]

Inspect, don't expect.

 

[ShaggyPE]

You can assign different material properties to solid models, but not surface models (surfaces have no volume). I seem to remember that newer versions of SW have the ability to assign a center of mass and mass value, but I have not sought out that technique (I am using 2006 still). Otherwise you could add an internal volume to the part at a location that would make the center of mass correct. Assign a material that would make the actual mass work out as well.

-Dustin
Professional Engineer
Certified SolidWorks Professional

 

[vscid]

Say I am using all solid models and no surface models.
I do not wish to assign CG value but want SW to calculate it for me. The only thing that I wish to assign is the density. So, if I do mass properties on an assembly with 3 parts, each having different densities, do I expect SW to show me a density which is average of the 3?

 

[TheTick]

I would guess an assembly's density = total mass / total volume. The only way to know for certain what SW is up to is experiment. Try some rudimentary experiments with a few simple parts like cubes of varying densities.

I do have a macro for assigning density to multiple components of an assembly. It's old but still works OK if you don't have material properties locked in some other way. It's on my website (see below) under "Freeware".

Honesty may be the best policy, but insanity is a better defense.

http://www.EsoxRepublic.com

-SolidWorks API VB programming help

 

[vscid]

I just finished those 'experiments' and you are right.
It is indeed total mass/ total volume.
Which means, i need to ensure that each and every part in my assembly in sub-assembly has the correct mass and hence the correct density. Right?
Problem is I have 500 parts. Will the macro work here?
Looks like there is a 'default' density set on parts which obviously have no 'assigned' density.
Will the macro override the default density?
Or do I somehow make the default density inactive?
I am using '06.

 

[TheTick]

Last I tried, the macro was still working in SW2007.

The macro only changes the parts' density property (the one you find under document options). I did use it in SW2006 no problems. I'm not sure how it behaves if there is a material assigned.

 

[vscid]

This macro would not address an assembly with different materials would it? I mean some of my parts are plastic, some aluminum, some stainless etc.

 

[ShaggyPE]

Tick,
What macro is that? I just did a quick scour of the usual suspects and didn't find a macro that would traverse an assembly or directory and assign material (or density). I sure thought there was one out there, but I couldn't find it.


-Dustin
Professional Engineer
Certified SolidWorks Professional

 

[ShaggyPE]

duh. I just reread your post... nevermind.

-Dustin
Professional Engineer
Certified SolidWorks Professional

 

[TheTick]

Usual suspects? Where are you looking? My macro on my website! "Density Manager" allows user to pre-select parts in an assembly and also presents a list of parts in an assembly for selection/deselection. Selected parts will all have same density assigned.

<

http://www.esoxrepublic.com/freeware/DensMgrDownload.php>

Honesty may be the best policy, but insanity is a better defense.

http://www.EsoxRepublic.com

-SolidWorks API VB programming help

 

[ShaggyPE]

My usual suspects when I am looking for a macro that I thought I have come across before are:

http://www.cadimensions.com/Resources/macros.cfm

http://www.esoxrepublic.com/

http://www.goengineer.com/support/downloads.aspx

http://www.lennyworks.com/solidworks/default.asp?ID=20

http://sw.fcsuper.com/index.php

http://mysite.verizon.net/mjlombard/macros.html

http://swtools.cad.de/us_prog_pac.htm

http://www.rhapsodydesignsolutions.com/programming-1.html

I just missed it when I went to your site.

-Dustin
Professional Engineer
Certified SolidWorks Professional

 

[TheTick]

Couple new sites to me. I'll have to check them out. Thanks.

 

[vscid]

TheTick,

Does the macro take care of multiple materials or just a single material?

 

[TheTick]

It adjusts density.

 

[kartikmech]

Can we assign different maas or densities in a single part file

thankign you
kartik

 

[CorBlimeyLimey]

Configurations can be of different densities by assigning different materials, but individual features cannot be assigned different materials/densities.

 

[vscid]

kartikmech,
yes the best way is to assign different properties to different configurations.

 

[kartikmech]

that means i can have multiple configuration in once single part file.
i could only see one button for the mass properties for the whole part file. how do i then create multiple configuration

 

[vscid]

What version of SW are you using? I am not sure if older versions have config. options.
In any case, try the help files to add multiple configurations.