US EPA

6634198 

Journal Article 

Vacuum forming of compound curved surfaces with a variable geometry mold 

Kleespies, HS; Crawford, RH; , 

1998 

1 

Journal of Manufacturing Systems
ISSN: 0278-6125
EISSN: 1878-6642 

SOC MANUFACTURING ENGINEERS 

DEARBORN 

325-337 

WOS:000077276800001 

Most rapid prototyping technologies focus on small three-dimensional parts and are generally not applicable to fabrication of large, thin, curved surfaces. This initial study demonstrates a method for producing prototypes of compound curved surfaces with a variable configuration vacuum forming mold composed of a number of discrete pins and a rubber interpolation sheet. A multi-parameter design study, using theoretical, numerical, and experimental results, explored the feasibility of building prototype surface parts with a variable molding process. The analyses provide fundamental design relationships for a variable geometry thermoforming mold as a function of the surface quality and the minimum achievable radii of compound curvature. Prototype parts of ABS and styrene thermoplastics were vacuum formed with the variable geometry mold. It was demonstrated that a variable configuration mold can be automated so that shapes are assumed quickly and directly from computer surface models. Rapid prototyping of curved surfaces with a variable geometry vacuum forming mold is shown to be a feasible process, but with limitations of surface smoothness and achievable curvatures.