Design of Fixture for Trimming of a Composite Material Shim by Abrasive Water Jet Machining

Abstract

The fixtures required in manufacturing must correctly locate workpiece in a given orientation with respect to cutting tool. The present work aims at design of fixture for trimming of a component called shim which is made of composite material. The trimming is done by abrasive water jet machine. Machining by conventional methods compromise the strength of the composite materials and/or cause delamination, making it less suitable for aerospace applications, thus Abrasive Water Jet (AWJ) technology is used for machining composite materials. In present work, the shim made of composite material is required to be cut at specified orientation at given location in a circular path. Since the shim is a thin-walled structure, excess clamping force may deform it and it may not get cut at required positions, although sufficient support and clamping is required to hold the component during trimming operation by water jet machining. The fixture needs to be designed for an abrasive water jet machine in which the water jet nozzle head is stationary and automation, e.g., rotary table is not available for maintaining circular cut at specified location and orientation. A fixture is designed to meet the above requirements. The suitable rotational speed to cut the shim is found experimentally and the shim is cut in circular path at desired location on the fixture.