Development of a computer numerical control (CNC) modular fixture - Machine design of a standard multifinger module

This paper presents the first phase of our ongoing development of a computer numerical control (CNC) modular fixture involving the machine design of a standard multifinger module. The aim is to develop a modular fixture which consists of only one type of standard multifinger CNC module which can provide locating, supporting and clamping functions. The module consists of four fingers with eight degrees of freedom to conform to any arbitrary workpiece surfaces. The eight motions of the four fingers are controlled by one motor through the use of two transmission and clutch systems. Different fixture layouts or reconfigurations can be made by different combinations of a multiplicity of such modules for major product family changes; while adjustments to finger positions of individual modules can be made by direct computer numerical control for minor product changes within a product family. The machine design and operation of the module are presented in the paper. A prototype was built and tested and satisfactory performance was achieved. Finally, two examples are provided to illustrate the flexibility and use of the standard multifinger module.