Sinkage characteristics of workpieces in flexible particulate bed fixtures: An experimental and numerical investigation

Abstract

The concept of flexible particulate bed fixtures (FPBFs or PBFs) in low-volume manufacturing environments has been investigated for its potential use in manufacturing environments. This paper reports findings regarding one of several performance issues that have been under investigation in the past five years, namely the displacement (sinkage) of the workpiece during the compaction process of the particulate. A bed fixture prototype was instrumented to detect the sinkage of a slender cylindrical workpiece and of the compacting plate during compaction. In addition, sinkage characteristics of finned rod workpieces as a function of fin size, rod size, and fin location were investigated to determine the effects that workpiece size and shape have on sinkage. A finite element model of the bed was also used to perform numerical tests and to study the effects of submergence depth and angular position of plain slender rod and finned rod workpieces on sinkage. Sinkage is dependent on submergence depth and workpiece initial orientation. Furthermore, fin size and location have a significant effect on the sinkage of the rod with respect to the compacting surface. These results provide trends helpful in applying the particulate bed fixture methodology to environments requiring tight indexing tolerances, such as machining or surface inspection.