FRICTION INDUCED PAINT DAMAGE - A NOVEL METHOD FOR OBJECTIVE ASSESSMENT OF PAINTED ENGINEERING PLASTICS

Engineered injection molded plastics are now common substrates of choi ce for painted bumper fascias in the automotive industry. A major chal lenge for painted fascias involves potential warranty costs associated with various tribological scenarios that can result in moderate to se vere paint delamination. Preliminary failure analysis performed on fie ld specimens indicate surface damage in majority of cases to be 'cohes ive', within the surface layers of the substrate. This failure mode is typical of polyolefinic substrates such as impact modified polypropyl enes and referred to in this work as friction induced damage (FID). A specially designed computer controlled laboratory device and an approa ch to objectively assess FID to painted plastics based on optical obse rvations of test specimens and measurements of total energy consumed d uring the sliding process are described in this paper. This device sim ulates FID performance similar to those observed in the field. This wo rk, to our knowledge, is the first of its kind describing FID phenomen on, and its quantitative assessment. Ranking of painted plastics for F ID based on this device has aided in the implementation of robust subs trate/painted material systems with proven improvement in surface dura bility. (C) 1997 Elsevier Science S.A.