Method and apparatus for polishing a curved edge

Abstract

A method and an apparatus for polishing a curved edge of a molded part. A surface of the curved edge is abraded by contacting a polishing surface of a first polishing wheel to the curved edge repeatedly in a first direction concurrent with a rotational spinning direction of the first polishing wheel. The abraded surface of the curved edge is polished by contacting a polishing surface of a second polishing wheel to the curved edge in the first direction and in a second direction opposite to the first direction. The polishing surfaces of the first and second polishing wheels are shaped to conform to a portion of the surface of the curved edge of the molded part. The polishing wheel is maintained at a constant rotational speed by a controller when contacting the curved edge. The polished surface of the curved edge is visually smoothly uniform in reflective appearance.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This U.S. patent application Ser. No. ______ (APL1P607) entitled “METHOD AND APPARATUS FOR POLISHING A CURVED EDGE” by Lancaster et al. takes priority under 35 U.S.C. 119(e) to U.S. Provisional Patent Application Ser. No. 61 / 249,200 entitled “COMPLEX GEOGRAPHICAL EDGE POLISHING” by Johannessen filed Oct. 6, 2009 and incorporated by reference in its entirety.[0002]This U.S. patent application is also related to and incorporates by reference in their entireties for all purposes the following co-pending patent applications filed concurrently herewith:[0003](i) U.S. patent application Ser. No. ______ (APL1P602) entitled “PORTABLE COMPUTER DISPLAY HOUSING” by Bergeron et al.;[0004](ii) U.S. patent application Ser. No. ______ (APL1P603) entitled “PORTABLE COMPUTER ELECTRICAL GROUNDING AND AUDIO SYSTEM ARCHITECTURES” by Thomason et al.;[0005](iii) U.S. patent application Ser. No. ______ (APL1P604) entitled “PORTABLE COMPUTER HOUSING” by Casebolt...

AI Technical Summary

Benefits of technology

[0014]In a second embodiment, a method for polishing at least two surfaces of a three dimensional curved edge of a molded part is disclosed. The method can include abrading a first surface and a second surface of the curved edge using at least two different polishing surfaces on a first polishing wheel. Each polishing surface on the first polishing wheel can be shaped to substantially conform to a corresponding portion of the surface of the curved edge of the molded part. The abrading can be carried out by contacting the polishing surfaces of the first polishing wheel with the surfaces of the curved edge of the molded part repeatedly in a direction concurrent with a rotational spinning direction of the first polishing wheel. The method can also include polishing the first and second surfaces using different polishing surfaces on a second polishing wheel. Each polishing surface on the second polishing wheel can be shaped to substantially conform to a corresponding portion of the surface of the curved edge of the molded part. The polishing can be carried out by contacting the polishing surfaces of the second polishing wheel to the abraded surface, alternately in the first direction and in a second direction opposite to the first direction. In an embodiment, molded parts can be formed from an injection molded thermoplastic compound. The surface of the three dimensional curved edge of the molded part to be polished can include a parting line surface defect. The parting line surface defect can have a vertical displacement greater than 10 microns approximately perpendicular to the surface of the curved edge of the molded part.In an embodiment, the polishing wheel can be maintained at a constant rotational speed by a controller when contacting the surface of the curved edge of the molded part. The polished surface of the curved edge of the molded part can be visually smoothly uniform in reflective appearance.

[0019]In an embodiment, the computer program code can maintain the polishing wheels at a constant rotational speed when in contact with the surfaces of the curved edge of the molded part. The computer program code can also vary the position of the polishing wheels with respect to the surfaces of the curved edge of the molded part while abrading or polishing.

Problems solved by technology

Molded casings can include complex geometric shapes that are difficult to finish to a uniform surface appearance.

Prior art techniques can result in a tactilely smooth finish with an undesirable variation in visual reflective appearance.

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