Home  
   

SHRINKAGE VALUES FOR MISCELLANEOUS RESINS

MATERIAL SHRINK in/in
ABS High Impact 0.005 - 0.007
ABS Heat Resistant 0.004 - 0.005
ABS Medium Impact 0.005
ACETAL 0.020 - 0.035
ACRYLIC General Purpose 0.002 - 0.009
ACRYLIC Heat Resistant 0.003 - 0.010
ACRYLIC High Impact 0.004 - 0.008
ETHYLENE VINYL ACETATE 0.010 - 0.030
IONOMER 0.003 - 0.020
NYLON 6/6 0.010 - 0.025
NYLON 6/6 0.007 - 0.015
NYLON 6/10 0.010 - 0.025
NYLON 11 0.010 - 0.025
NYLON 12 0.008 - 0.020
NYLON Glass Filled 0.005 - 0.010
POLYBUTYLENE 0.020 (molded)
POLYBUTYLENE 0.040 (aged)
POLYCARBONATE 0.005 - 0.007
PET (Amorphous, petg, pctg) 0.003 - 0.005
POLYESTER .025 - .050 THICK 0.006 - 0.012
POLYESTER .050 - .100 THICK 0.012 - 0.017
POLYESTER .100 - .180 THICK 0.016 - 0.022
POLYESTER PBT 0.010 - 0.020
POLYESTER PET 30% GF 0.001 - 0.002
POLYESTER PBT 30% GF 0.003 - 0.005
POLYETHERIMIDE 0.005 - 0.007
POLYETHYLENE Low Density 0.015 - 0.035
POLYETHYLENE High Density 0.015 - 0.030
PPO/STYRENE CO (NORYL) 0.005 - 0.007
POLYPROPYLENE 0.010 - 0.030
PPO/STYRENE G.P. 0.002 - 0.008
PPO/STYRENE Heat Resistant 0.002 - 0.008
PPO/STYRENE Impact Mod 0.003 - 0.006
POLYSULPHONE 0.008
POLYURETHANE 0.010 - 0.020
PVC Rigid 0.002 - 0.004
PVC Semi-Rigid 0.005 - 0.025
PVC Flexible 0.015 - 0.030
SAN 0.002 - 0.006
   
    NOTES:
  1. Shrink rates can vary with process conditions,mold design, etc.
  2. Shrink may be less in direction perpendicular to the flow due to differences in orientation(divide by 1.6 for transversedirection; more pronounced with crystalline resins: i.e. PP) Does not apply for glass filled resins.
  3. When possible, prototype the job to better determine shrink for a given mold and product design.
  4. Refer also to manufacturer's guidelines, if available.
  5. Shrink may be affected by additives such as color or filler.
Injection Molding Refernce Guide, 3rd Edition.
Published with permission from Jay Carender and Advanced Process Engineering - advproeng@aol.com