BLOW-OUTS & HOLES

Parison too short • Lengthen parison to proper length. . Air blow not completely venting • Increase vent time. • Install "dump valve" for air venting. • Check solenoid for proper operation. • Increase I.D. size of air blow plumbing. Blow-up ratio too great • Use larger diameter die. • Use resin that has greater "die swell". Damage on head tooling • Check for nicks, burrs, scratches etc. Clamp speed • Adjust clamp speed slower or faster. Clamp pressure too low • Adjust clamp pressure. Blow pressure too high • Adjust air pressure. Moisture in the resin • Properly dry the material. Trapped air • Purge the material (may have been caused by hopper going empty). Feed zone too cold • Increase temperature of feed zone. Melt temperature too low • Check temperature of parison, adjust as needed. Fines in hopper • Reduce fines to acceptable level. Pinch-off too sharp • Widen pinch-off land. Pinch-off too wide • Decrease width of pinch-off land. Pinch-off too hot • Check cooling water temperature. • Check water flow to mold. • Check mold for blockage of water ports. • Check parison temperature. Damage on mold • Check for damage along parting lines. • Check for damage to pinch-off. Mold not closing properly • Check guide-pins and tolerances. • Realign mold halves • Install mold stops on press platens to even out clamping. Possible Causes Possible Solutions