METHOD TO DETERMINE SCREW PERFORMANCE AND PRODUCT QUALITY DURING MANUFACTURING PROCESS

摘要

During the extrusion process, whether it is film, sheet or injection molding, the need to obtain consistent quality and output requires an extensive quality control program. Unfortunately, these operations are time consuming and wasteful, often requiring many pounds of extrudate be expended before the desired result is achieved. Also, as extrusion equipment becomes worn, output rates decline and product quality gradually falls, often going unnoticed, until significant problems occur. Thirdly, when a new screw purchase is required, time-consuming laboratory trials are normally set up to evaluate screws from different manufacturers before deciding the best one for that particular operation. To quickly assess changes in operation conditions, whether from day-to-day running, equipment performance or assessing new equipment, a concept has been developed for an extrusion product, which utilizes the principal of mixing two colors to achieve a homogeneous third color. Observing the homogeneity of the third color mix and the flow pattern it generates will indicate the screw performance and the quality of the product. This is a quick, efficient way to test the process without sacrificing product or running time. A series of experiments was performed to evaluate two different screw designs in an injection molding process. In addition, molded parts from the same mold but the different screw designs were evaluated for quality consistency. In a separate trial, the amount of wear on production screws and barrels in a color compounding process were evaluated. This paper is based on these experiments and prospective new products.