Calculate Plastic Weight & find Viscosity

Determine the volume of the part and multiply by the density of the plastic.

Find the viscosity by consulting the manufacturer's literature.

Hello,

If you are lucky enough to have a cad file of the part you can do a volume analysis. Find the specific gravity and any other info from one of the following sites: Ides Prospector, affiliated with this CR4 company and /or Matweb.

Example copied from Machinery's Handbook 19th Edition.

The specific gravity is a number indicating how many times a certain volume of a material is heavier than an equal volume of water. The weight of one cubic inch of water at 62 degree F. is 0.0361pounds.

If the specific gravity of any material is known, the weight of a cubic inch of the material can, therefore be found by multiplying its specific gravity by .0361.

Example: The specific gravity of Polycarbonate is .95-1.540. Find the weight of 5 cubic inches of Polycarbonate.

.950 x .0361 x 5 =.17147 lbs - 1.54 x .0361 x 5 = .2779 lbs.

Matweb gives the Density of Polycarbonate as .0343- .055 lbs per inch cubed/ .95-1.54g/cc.

Delrin: Specific Gravity = 1.42g/cc.

Delrin Density: = 1.42 g/cc or .0513 lbs per cubic inch.

UHMW: Specific Gravity = .930 g/cc

To calculate the weight from the drawing can be only as accurate as your hand calcs if you do not have the info in a Cad File.

Hope this helps.

If viscosity is defined as shear stress divided by rate of shear, then, by definition of the term, plastics do not have a viscosity unless molten. And when molten, they do not exhibit plastic behaviour.