THREE TYPES OF SHRINKAGE IN PLASTIC ARE MOLD, POST- MOLDING, AND END-USE SHRINKAGE. SHRINKAGE IS INFLUENCED BY A TYPE OF PLASTIC FILLER CONTENT, PART DESIGN, TOOLING, MOLDING CONDITIONS, AND END-USE ENVIRONMENT. DIFFERENT MOLD-SHRINKAGE RATES CAN PREVENT MATERIAL SUBSTITUTIONS AFTER A TOOL IS CUT. OTHER SHRINKAGE PROBLEMS INCLUDE WARPAGE, SINK MARKS, AND OUT-OF-TOLERANCE CONDITIONS. ALTHOUGH SHRINKAGE DATA IS AVAILABLE FROM MATERIAL SUPPLIERS, MOST ACTUAL MOLDED PARTS WILL HAVE DIFFERENTIAL SHRINKAGE RATES MAKING PREDICTION MORE DIFFICULT. UNDERSTANDING THE CAUSES AND EFFECTS OF SHRINKAGE WILL HELP THE MANUFACTURER ANTICIPATE AND AVOID PROBLEMS. PROTOTYPE TOOLING SHOULD BE USED BEFORE COMMITTING TO FINAL PRODUCTION TOOLING.
| Number of Pages : | 8 |
| Published : | 06/01/1991 |
