Factors Affecting The Plastic Shrinkage

- Sep 03, 2018-

3. The effect of plastic structure on the shrinkage of products


(1) Thick-walled plastic parts have higher shrinkage than thin-walled plastic parts (but most plastic 1mm thin-walled parts have a larger shrinkage than 2mm, which is due to the increased resistance of the melt in the cavity);


(2) The shrinkage ratio of the insert with the insert on the plastic part is smaller than that without the insert;


(3) The shape of the plastic part is complicated, and the shrinkage rate is simpler than that of the simple shape;


(4) The height direction of the plastic part is generally smaller than the horizontal direction;


(5) The shrinkage rate of the elongated plastic part in the longitudinal direction is small;


(6) The dimension in the longitudinal direction of the plastic part is smaller than the shrinkage ratio in the thickness direction dimension;


(7) The inner hole shrinkage rate is large, and the shape shrinkage rate is small.


4. Effect of plastic properties on shrinkage of products


(1) The shrinkage rate of crystalline plastics is greater than that of amorphous plastics;


(2) Plastics with good fluidity, low molding shrinkage;


(3) Adding filler to the plastic, the molding shrinkage rate is significantly reduced;


(4) The same plastics in different batches have different molding shrinkage rates.