Polymer Sheet Hot Incremental Forming - an Innovative Polymer Forming Approach

Abstract

Polymers are currently used as raw materials in automobile and house hold applications. Particularly in automobile parts polymers having significant percentage, because of its strength to weight ratio. But their conventional processing of heating- melting -injecting and solidifying process cycle is mainly suitable for high volume mass production1. Increasing demands for the products with low volume, best quality, less production lead time are impart the need for a new polymer processing method. This can be capable of fulfilling the current industrial requirement of agile manufacturing processing methods with short span for life cycle of parts and short design to production lead time. This paper is mainly focused on problems in conventional polymer processing and proves the opportunity to use single point incremental forming technology which is currently used for sheet metal forming applications. This method reduces and eliminates capital investment on special dies and tools. It is a highly flexible forming process and is enabled with the help of computer numerical control (CNC) technology2. In this work, a novel process namely hot incremental polymer forming (HIPF) is developed. In this process the material is heated with the help of heating element up to the required temperature and the hemispherical tool moves over the hot sheet, the tool path is controlled by CNC technology. This innovative process starts with development of low cost fixture and spherical tool, heating coil, temperature measurement device, feedback element and temperature controller. A truncated hexagonal pyramid shape is used to study the process capability regarding the geometrical accuracy and sheet thinning of the produced part. Results show that this method capable of forming polymer sheet parts at elevated temperature with good dimensional accuracy and better formability.