Below are typical valves for various generic plastics. For more precise values, please consult your resin supplier.

Material Extrusion Injection Mold Shrinkage
in Inches
Specific
Gravity
Density
Lbs/In
ABS 435 500 .005 1.03 .037
Acetel   390 .020 1.41 .051
Acrylic 375 450 .0045 1.17 .0422
FEP 600 600 .010 2.11 .0775
Nylon 6 520 550 .013 1.13 .0405
Nylon 6/12 475 500 .011 1.07 .039
Nylon 12 475 445 .003 1.04 .038
Polycarbonate 550 575 .006 1.20 .0434
PBT   460 .020 1.34 .0484
PET 480 490 .002 1.31 .0482
HDPE 410 480 .025 .955 .0345
LDPE 600 400 .027 .92 .033
LLDPE 500 425 .025 .92 .034
Polypropolene 450 490 .005/.018 .91 .033
PVC-Rigid 380 380 .025 1.29/1.4 .050
PVC- Flexible 365 300 .025 1.23/1.37 .050
Polyurethane 400 400 .02 1.2 .0433
PTFE       2.16 .0785
Kynar