Novel instrumentation for evaluating stone impact wear of automotive paintsystems

Stone impact damage to painted automotive exteriors is an area of significa nt concern both to the automobile manufacturer and the paint supplier. Dama ge occurs by stones that are either launched by rear tires of heavy-duty tr ucks or stones dropped from moving gravel trucks. Stone impact can result i n removal of one or more paint layers and in some cases can lead to delamin ation at the metal-polymer boundary. Removal of paint layers (referred to a s chipping) is a cosmetic issue while delamination at the metal-polymer int erface can lead to corrosion. Various methods have been described in the li terature for rapid assessment of stone impact durability. These methods are associated with one or more drawbacks. These include: (A) being phenomenol ogically inappropriate; (B) not associated with quantitative metrics; (C) i nadequate control of relevant parameters and (D) not being reproducible. Th is paper describes novel second generation instrumentation for precise and quantitative assessment of impact durability, This device overcomes many of the drawbacks associated with conventional methods. A statistically design ed experiment to assess impact durability is also described. (C) 1999 Publi shed by Elsevier Science S.A. All rights reserved.