Control of Thermoforming Process Parameters to Increase Quality of Surfaces Using Pin-Based Tooling

Abstract

Tooling is a significant time and cost investment in manufacturing processes that include casting, injection molding, sheet metal forming, and plastic thermo-forming. These tooling investments are often justified for large production volumes. However, for small volume, prototyping, and custom manufacturing, the tooling investments are hard to justify. To meet the needs of smaller volume production, several adaptable tooling technologies has been developed. One solution, pin-based tooling enables adaptable surfaces for use in plastic thermoforming and composites. However, a key challenge in pin-based tooling is achieving accurate high quality surfaces. The objective in this research is to study the effects of process parameters on surface quality using pin-based tooling. Specifically, in this research polymer surfaces are manufactured without the use of an interpolating layer. A set of experiments was conducted by keeping the shape constant, with and without an interpolator, and varying the process parameters to check the feasibility of producing smooth surfaces. It was observed that smooth, shape-specific surfaces can be produced by optimizing the process parameters. The parameters thus optimized would be shape-specific and optimizing the process parameters for surfaces having complex shapes is a new research challenge that comes out of this work. Future work involves continuing the experiments, measuring the resulting parts and controlling process parameters to increase surface quality.