Novel Clamping System for Machine Tools

Abstract

The need for higher productivity and efficiency in manufacturing of complex parts makes 5-axis machining centers preferred to a machine tool in industrial production. Along with the machine capability, 5-side accessibility of the workpiece, as well as safe and repeatable clamping is required. However, conventional clamping-technology by means of a vise gives full access on 3 sides of the workpiece only. Furthermore, it has disadvantages such as workpiece elastic and occasionally plastic deformation due to the high clamping forces, and, custom or additional chucks are required for clamping specific shapes. Alternative clamping techniques, for instance magnetic or vacuum, have a restricted use due to the requirement of ferromagnetic materials or shape constraints, respectively. In this work, a novel way of clamping workpieces was subject to research. Instead of clamping the workpiece on its surface, like conventionally carried out, pins were welded onto the workpiece, which were then used for clamping. Advantages of this innovative clamping method are amongst others the unlimited access on 5 sides of the workpiece, a lower workpiece deformation compared to traditional clamping, and clamping of workpieces with irregular surfaces. Furthermore, savings in raw material and consequently reduced power consumption, as well as wider possibilities to automate the process are additional advantages of such a clamping system. The research work focuses on the feasibility and quality issues of the stud welding process and its impact on the workpiece, the positioning and the number of studs, and qualitative and quantitative comparisons of conventional clamping with the novel pin clamping method.