BMC vs. Polyamides (Nylon) in Engine Covers

摘要

In conclusion, I would like to use words taken from a recent study by James F. Wzorek and Mr. Paul Palmer, GP '98, IBIS Associates, Inc. "The analyses for the powertrain cover applications show a clear manufacturing cost advantage for plastics. Additional factors that favor substitution are the resulting weight advantage over metals (～30% lower than aluminum), and downstream advantages not included in these analyses. Downstream cost savings due to part consolidation and molded in features have not been qualified in these analyses, but it can be shown using similar analysis methods that these factors will generally favor the use of plastics over metals for the classes of applications covered in this paper. Regarding thermosets versus thermoplastics: thermoset materials are generally half the cost of thermoplastics measured on a cost per unit volume basis. Material cost is by far the largest component of manufacturing cost, so at least for the medium to large part sizes, compression and injection compression of thermoset resins should always have the cost advantage. A major hurdle, whether perceived or real, against thermosets is the issue of recyclability. This is an area where thermoplastic resin suppliers have focussed a great deal of marketing attention. In practice, recycled thermoplastics are only used in lower performance applications than their original use. thus, while it is conceivable that an aluminum cover could one day be re-processed into another aluminum engine part, this will not happen for a thermoplastic engine component. In actuality, more thermosetting materials are re-ground for use in higher value added end uses than thermoplastics. Given the favorable economics and weight savings potential of SMC / BMC cover-type parts, the industry should look for an increasing use of these material systems in powertrain applications."