Mass computation error

[danwilley]

I thought this mass computation error was fixed? Or is it something I need to do? This fabrication is made from steel tubes and plates. The bottom round part is a cast iron part. All of the parts have been identified as steel or cast iron. The whole assembly probably weighs about 125 pounds... not 15,792 as reported.

Thanks,
Dan

 

[DavidJ]

Have you set material for the small sundries (screws, roll pin) ? If a material isn't set, the density is assumed 1kg/cm3, which is very high.

 

[simonb65]

As David says ... probably worth creating a BOM table and add a 'mass' column to visually see where the big numbers are coming from.

 

[sz0k30]

As David says ... probably worth creating a BOM table and add a 'mass' column to visually see where the big numbers are coming from.

All it takes is one part being wrong to mess up the whole asm.

 

[DavidJ]

If creating BoM - add Material column too, as not setting material is the most obvious potential error that may have happened.

 

[danwilley]

Ok...thanks for all the tips and suggestions. I went through every part (created and imported from McMaster Carr). A lot of parts had the wrong (high) mass. I updated all of them and now the computed mass seems correct... 157 lbs. The assembly is a little heavier than I first thought... but well within reason.

My takeaway from this is to always check the default mass settings when starting a new project. On previous (complex) projects, the defaults were generally good... mostly low carbon steel... and the mass calculations looked correct. For this project, and for whatever reason, many of the parts had the wrong mass. I also learned from you guys to always check the material setting on imported parts like screws, bolts, roll pins, and snap rings. Ever onward!

Thanks for your help!
Dan