Molding shrinkage rate refers to the injection molding products compared with the corresponding volume mold, what happened to shrink ratio.
Metal clothes peg after melting, heating due to heat expansion.
And after injection molding, because the injection pressure and contraction by compression.
FRP products in the mold internal cooling solidification, shrinkage again, but when the mold again due to pressure recovery after several expansion phenomenon.
Summary of the volume of the poor, known as the molding shrinkage.
Under the molding shrinkage can type said: the molding shrinkage rate = mold size molding product size/size initiative shrinkage with/for the units or in percentage of said (
Resin flow direction vertical shrinkage is larger, and the contract law of rate of flow is smaller.
Crystalline resin (
Than an amorphous resin (
Molding shrinkage rate.
The reinforcement material than reinforced metal clothes peg molding shrinkage rate is big.
Even the same kind of material, under the condition of different molding shrinkage rate also have change, non-crystalline resin is affected by pressure, crystalline resin are susceptible to the influence of temperature condition.