Analytical Design and Manufacturing of Expanding Workholding Collet for Fixture

Abstract

Background: The function of a Fixture is to clamp, locate and orient a part without causing deformation in the part geometry. Clamping has a major role to play to achieve this function most of the times. One of the categories of clamping elements clamps the part by either inner or outer diameter. Collets fall in this category, which clamps the components either by expanding or collapsing according to diameter. Whenever the component has a circular feature in the form of inner or outer diameter, fixture designer has a good choice to clamp using collets. newlineNeed: Thus, to achieve high accuracy and close tolerances, perfect design of collet is required which gives maximum clamping force without deforming. Calculation and measurement of deflection and clamping force are a major focus of this research. newlineMaterials and Methods: This research work is on Analytical design and Manufacturing of expanding workholding collet. In this research, deflection and clamping force is mathematically modelled. MATLAB is used to solve second order differential equation. The results are validated using Ansys and Creo. One set of collet and mandrel is manufactured. An experimental setup to measure clamping force and deflection of the collet is also designed and manufactured. Analytical values are also validated using FEA with Ansys and Creo. AutoCAD and Microsoft Excel is also used in subsequent stages. Results and Discussion: Analytical result, Experimental data and Finite Element method s result have an overall difference of 4.2 %. The percentage difference for the deflection is the 4.9 and value difference is 8 microns. The percentage difference for force is 3.9 and value difference is 7 N. This difference is within an acceptable range. newline