The study of shrinkage percentage HDPE based on the ASTM D955 Standard test method

Abstract

The shrinkage depended on the product shape and the type of plastic used in injection, melting temperature, injection speed, holding pressure, and mold cooling. Different surroundings during the injection resulted in differences shrinkage so the exact shrinkage value hadn’t been known. This was the cause of Try out and error work that produced Injection products that were not in correct size. This research aims to find the shrinkage percentage based on the ASTM D955 standard test method from high density polyethylene (HDPE) which has partial crystalline structure and high shrinkage. The results were as follows: The specimen size 60x60 mm shrinkage was at 2.57 percentage and with 2 mm thickness the shrinkage was 3.60 percentage. The specimen size 12.7x127 mm shrinkage was between 2.76 percentage and 2.91 percentage, with 3.20 mm thickness the shrinkage was 2.48 percentage. For the 100 mm circular specimen, the shrinkage was from 4.35 to 4.39 percentage and with 3.20 mm thickness the shrinkage was 2.56 percentage