Rejection molding process

The reaction in rejection molding process (RIM), which has been used for large polyurethane moldings, may hlso be uAe d with filled polyesters (RRIM). Likewise, much hydraulic cement art may be adapted to polyester cement technology. Both of these cements have been reinforced with silica and asbestos. Actually, over 3 million tons of asbestos has been used annually, world wide, for the reinforcement of hydraulic cements to produce composite corrugated sheet and pipe. 

Even in ideal conditions, there will be rejections during the molding process, but this can be kept to a minimum needs to be carried out. If the rejection rate is more than the aeeepted level of around 5%, a systematie evaluation of the reasons for failures. Observation of the rejeeted metal bonded seals shows that, four types of failures ean be observed. 

Also called regrind and reclaiming. Most processing plants have been reclaiming/ recycling reprocessable TP materials such as molding flash, rejected products, blown... 

A new GPPS resin was tested at a customer s injection-molding plant as an Improvement over an incumbent resin manufactured by a competitor. The new resin performed well in the process except that it created parts with a 5% rejection rate due to a splay defect. The competitive resin was reported to run well but with a lower... 

An example of successful use of SPC comes from the injection molding industry where part counts are high and part values are generally low. The material in reject parts can sometimes be recycled. The process is very rapid, with few control variables and the major, often the only, criteria for quality is reproducible shape. For this situation, SPC is an excellent... 

To demonstrate the actual savings realized by a fabricator, the energy required to mold a 9 gram spark plug boot by the LPS process and by the conventional process is compared. In this calculation, it is assumed that 100% acceptable parts are produced by both processes. In practice, the rejection rate of LPS is much lower than the conventional process. The results of calculation are summarized in Table II. The ratio of energy required by the LPS process to that of the conventional process is almost 1 4. 

The diameter swell is an important processing parameter that must be controlled for BM of unsymmetrical containers and particularly with blown side-handle products. Resins with an excessively high diameter swell could experience curtaining and stripping (adherence to mold cavity) problems. An inadequate diameter swell contributes to an increase in rejects for defective handles. 

Scrap skrap [often attributive] [ME, fr. ON skrap scraps akin to ON skrapa to scrape] (14c) n. All products of a processing operation that are not present in the primary finished articles. This includes flash, runners, sprues, excess parison, and rejected articles. Scrap from thermosetting molding is generally not reusable. That from most thermoplastic operations can usually be reclaimed for reuse in the molder s own plant or can be sold to a commercial reclaimer. 

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