Melt Density

Polymers Expansion

Chains expand at different rates depending on their chemical structure.

Shot Calculation

The volume of the mould must match the volume of material delivered by the screw. By using the melt density of the resin, the processor can calculate the exact stroke length required for the machine. This step is vital for precision parts where the weight must be held to a fraction of a gram.

Incorrect calculations lead to flashing at the parting line or sink marks on the surface.

Buying Efficiency

Purchasing resin by weight but using it by volume creates a financial discrepancy. A resin with a lower melt density will produce more parts per tonne than a denser alternative. Procurement teams use this information to compare the true cost of different materials.

This calculation helps in selecting the most economical polymer for high volume production runs.