Factors Affecting The Shrinkage Rate Of Pet Preform

Effect of molding process on shrinkage of Pet Preform: molding temperature is constant, injection pressure is increased, shrinkage is reduced; pressure is increased, shrinkage is reduced; melt temperature is increased, shrinkage is reduced; mold temperature is high The shrinkage rate increases; the dwell time is long, and the shrinkage rate is reduced, but the shrinkage rate is not affected after the gate is closed; the in-mold cooling time is long, the shrinkage rate is decreased; the injection speed is high, and the shrinkage rate tends to increase slightly, affecting Smaller; the molding shrinkage is large, and the rear shrinkage is small. The post-contraction is large at the beginning of two days and is stable for a week or so. The plunger type injection molding machine has a large shrinkage rate. The effect of the pet structure on the shrinkage of the product: thick-walled plastic parts have a higher shrinkage ratio than thin-walled plastic parts (but most pet1mm thin-walled parts have a larger shrinkage than 2mm, which is due to the increased resistance of the melt in the cavity). Cause); the insert on the plastic part has a smaller shrinkage than the insert without the insert. The shape of the plastic part is simple, and the shrinkage rate is simple. The height direction of the plastic part is generally smaller than that of the horizontal direction; the shrinkage rate of the elongated plastic part in the longitudinal direction is small; the dimension of the length direction of the plastic part is smaller than the thickness direction. The shrinkage rate is small; the inner hole shrinkage rate is large, and the shape shrinkage rate is small. The effect of the mold structure on the shrinkage of the pet product: the gate size is large, the shrinkage rate is reduced; the vertical gate direction shrinkage is reduced, and the parallel gate direction shrinkage is increased. The shrinkage rate away from the gate is smaller than that of the near gate; the shrinkage rate of the plastic part with the mold limitation is small, and the shrinkage rate of the unrestricted plastic part is large. The effect of pet properties on the shrinkage of the product: the crystalline pet shrinkage is greater than the amorphous pet; the petity is good, the molding shrinkage is small; the filler is added to the pet, the molding shrinkage rate is significantly reduced; the same pet of different batches, the molding shrinkage The rate is also different.        Jilian Plastic Mould is a China Pet Bottle manufacturer that produces reliable quality. With our many years of experience in the market, we can bring you various models of products. Welcome customers who need it to contact us.