tailieunhanh - Coatings of Polymers and Plastics part 13

Tham khảo tài liệu 'coatings of polymers and plastics part 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Process sequence Coextrusion Multipff ttyfi him ỆXUuiOn St Of op In Ua d him Film preforming lh if nn loaning Trimming Component production film mseition into mold Finished PFM-System body component Fig. 3 In-mold process sequence. From Ref. 7. 289 Copyright Marcel Dekker Inc. All rights reserved. Marcel Dekker Inc. 270 Madison Avenue New York New York 10016 290 Kakarala and Pickett trimmed placed in an injection mold and back injected with a thermoplastic material. The film has met the colorfastness UV weathering gloss abrasion resistance water jet car wash crosshatch and gravelometer tests required by automobile manufacturers 9 . This technology is used for the roof of the European Smart Car subcompact 10 . There exists advantages of films compared to coating. There is easier color matching between different production sites. Allows for rapid color changes. It eliminates the cost and maintenance of a paint line. It is environmentally friendly. Extrusion Compression Molding with Film Inserts A film is placed in a compression mold. Plastic is extruded onto the film. Often times a reinforcing layer such as glass fiber matt is added. The mold is closed. The heat from the extruded plastic will heat the film for forming. The film provides a class A surface part. Films such as polyvinalinedifloride acrylic polyester ionomer and ASA have been used. The Valyi SFC Surface Finishing Compression Molding SFC process has demonstrated the capability to manufacture large structural panels such as automotive roof tops hoods and trunk deck lids 11 . The SFC process can be used to manufacture large class A exterior finishes parts at a low clamp force. The precolor matched films offer the part appearance in the mold thus eliminating painting. Thermoform Coextruded Sheets A coextruded multilayer sheet is thermoformed. As with films each layer of the sheet has a specific function. The top layer provides the weathering and UV resistance scratch-and-mar resistance hardness and .