LOUISVILLE, COLO.-Trouble-shooting Injection Molded Parts is the latest publication by William J. Tobin of WJT Associates Ltd. in Louisville. The 82-page paperback book offers an easy-to-read guide to discovering and correcting de-fects in plastic parts and processing. Tobin said he wrote the book because of a demand among molders for a basic training manual that explains the ``whys'' of plastics processing and trouble-shooting.
Tobin covers issues that affect the molding process, tooling and processing variables. Defects such as black specks, bubbles, degraded material, flash, orange peel, short shots, sinks and stress cracking are defined. The book also tells what defect ``family'' the problem belongs to, such as whether it is a material problem, an ejection problem, a filling-packing problem or a pressure problem.
One section provides experiments that allow readers to dem-onstrate the principles explained in the book, such as decreasing the restriction in the flow path in the gate land and gate width, creating flash from changes in viscosity, and determining the mold open time and distance.
The book costs $25 for a single copy. Quantity discounts are available by contacting WJT Associates Ltd., P.O. Box 597, Louisville, Colo. 80027; Tel. (303) 499-3350, fax (303) 499-4116 or e-mail [email protected]