Resin Mold Shrink-Rate Chart

ALL RESINS HAVE DIFFERENT SHRINK RATES DEPENDING ON THE PLASTIC FAMILY. AMORPHOUS VS. CRYSTALLINE PLASTICS, TOOLING DESIGN, PROCESS CONDITIONS (CYCLE TEMPERATURE AND TIME) ALONG WITH THE DESIGN OF PART (WALL THICKNESS AND WALL CONSISTENCY). PLASTICS ALSO SHRINK DIFFERENTLY WITH THE DIRECTION OF FLOW. THE CHART REFLECTS TYPICAL SHRINKAGE RATES FOR THE MOST COMMONLY USED PLASTICS.

RESIN TYPE SHRINK INCH/INCH
POLYPROPYLENE-UNFILLED .015”/.018”
POLYETHYLENE .020”/.025”
ABS .0035”
HIPS .0035”
GPPS .0035”
POLYCARBONATE .007”
PC-ABS .007”
ACRYLIC .003”/.004”
NYLON 6/6 -UNFILLED .020”
NYLON 6/6 (33% SHORT GLASS) .0035”
PBT .015”
ACETAL (POM) .020”
ACETAL HOMOPOLYMER .018”/.020”
PVC RIGID .0035”
TPE SANTOPRENE .014”/.018”
NORYL .005”/.007”
NORYL (30% GLASS FILLED) .001”
TPU .007”/.010”
POLYSULFONE .007”