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#130 Guidelines of Molding Shrinkage Ratios of Major Plastic Resin (2)

Category : Mold Materials
July 6, 2012

Although the guidelines for the molding shrinkage ratios of typical plastic resins were explained in the last lesson, we would like to add some more information. This time, we provide the values for some engineering plastics resins.

The table shows the major thermoplastic resins and their molding shrinkage ratios, cavity surface temperatures, and injection molding pressures. For more details, it is common to obtain the material catalogs or technical documents for each material grade from the manufacturer of the material, and to use them as the documents for making decisions.

* The values given here are for natural resins unless otherwise stated.

Table of molding shrinkage ratios of major plastic resins (2)

Name of plastic resin Molding shrinkage ratio (%) Cavity surface temperature (°C) Injection molding pressure
(kgf/cm2) (MPa)
Polyamide
(Nylon 6) PA6
0.5 - 1.5 40 - 120 350 - 1400 34.34 - 137.4
Polyamide
(Nylon 66) PA66
0.8 - 1.5 30 - 90 350 - 1400 34.34 - 137.4
Polyacetal POM 2.0 - 2.5 60 - 120 700 - 1400 68.69 - 137.4
Polybutylene terephthalate PBT
30% glass fiber
0.2 - 0.8 40 - 80 560 - 1800 54.95 - 176.6
Polycarbonate PC 0.5 - 0.7 80 - 120 700 - 1400 68.69 - 137.8
Polyphenylene sulfide PPS 40% glass fiber 0.2 - 0.4 130 - 150 350 - 1400 34.34 - 137.8
Liquid crystal polymer LCP 40% glass fiber 0.2 - 0.8 70 - 110 700 - 1400 68.69 - 137.8

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