The shrinkage of plastic was caused by the shape of the product and the type of plastic used in the injection. The plastic shrinkage difference was resulted from the temperature used in melting the injection speed mold cooling and different injection surroundings. These led to unknown exact value of plastic shrinkage and the trial and error work has been done. As a result of trial and error work the injection products were not in the determined size. This research aims to find the percentage of plastic shrinkage according to standard test ASTM D955 from (Amorphous Thermoplastic) (Acrylonitrile Butadiene Styrene ABS). The findings showed that square specimen size 60x60x2 mm measured from vertical perpendicular to flowing direction the shrinkage was at 0.86% the shrinkage was at 0.59% when measured from flowing direction and the thickness expanded at 20%. For the rectangular specimen size 12.7x127x3.2 mm measured from vertical perpendicular to flowing direction the expanding was at 0.16% the shrinkage was at 0.88% when measured from flowing direction and the thickness expanded at 14.86%. The circular specimen size 100x3.2 mm the shrinkage was at 1.26 when measured from vertical perpendicular to flowing direction the shrinkage measured from flowing direction was at 0.82% and the thickness expanded at 13.23%

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

The shrinkage depended on the product shape and the type of plastic used in blow This research aims to study the shrinkage percentage of plastic polyethylene terephthalate grade : N1 used with the make blow mold in 2 stages. The testing results were as follow. vertical shrinkage percentage ( Z axis ) was 0.787 percentage and horizontal shrinkage Percentage ( XY axis ) was 2.13 percentage