Static Mass Balancing: Procedure for Assemblies of 2.5-10kg

AI Thread Summary
The discussion focuses on the procedure for static mass balancing of assemblies weighing between 2.5 to 10 kg, with a total mass of 100 kg. A recommended method is to hang the assembly freely and check the center of gravity (CG) by suspending it from three points. The intersection of vertical lines drawn from these points indicates the CG, which is particularly effective for extruded or cubical shapes. While there is no specific ASTM standard mentioned for this method, it is noted that similar techniques were used for determining the mass moment of inertia in legacy systems. The conversation highlights the relevance of practical testing methods despite advancements in modeling software.
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What is the procedure of static Mass Balancing of any assembly which has a total mass of 100 kg with subsystems which would assemble in it is ranging from 2.5 to 10 kg ...
i think to hang the complete system freely in air and then checking the placement of exact cenetr is an appropriate method.
Is there any standard (like ASTM etc) for this particular testing.
 
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We used to hang objects from three different points to determine CG. I can't think of anASTM spec for that though.
 
What would those three points...Our Assembly is just like a cubical box...so whould we hang copmlete assembly form its top surface?
 
It's been a while since I have done this (college) but, IIRC they were just random points spread out over the body. We used to do this for weird shapes like automotive seat assemblies.
 
Yes, hand the object from three points. If the object is an extruded object (like...a 2-D object with constant cross section and some thicknes), then you simply hang the object from three points and draw a vertical line from that point straight down. Where the three lines intersect is the CG (in the center of the body of course). If your three lines intersect to form a triangle, then simply find the center of the triangle to find the center of the body.

Try this link for a lecture I remember for a lab that was on finding an objects center of gravity and moment of intertia:
http://www.eng.utoledo.edu/~cciocane/courses/mime3390_041sp/lec/m3_center_of_mass_and_mass_moment_of_inertia_lecture.doc
 
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Minger,
After browsing that you reminded me of the test we would do to determine the mass moment of inertia of rotor disk assemblies. The pendulum test works pretty well once you get the hang of it. It really isn't necessary now with complex models and Pro/E. Occasionally we have a legacy piece that that test still needs to be performed.
 
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