PERFORMANCE STUDY OF TREPANNING TOOL FOR DEEP ANNULAR GROOVING

Abstract

Drilling is one of the most commonly used machining process in manufacturing industry. In drilling, the entire volume of hole is converted to chips. If the holes produced have diameter larger than 30 mm, a lot of material is converted into chips and wasted. The present study focuses on design and development of a trepanning tool for drilling of 40 mm diameter holes in stainless steel 304 steel, by cutting material in annular ring form and saving solid central disk shaped core. Literature review available in the field of trepanning and drilling reveals that, most of the researchers studied the effect of various process parameters on the thrust force and torque developed while machining and surface roughness and material removal rate of the holes produced. A few researchers made attempt to design and develop a trepanning tool for machine composite materials to reduce the delamination of fibers. However, not much work is available on design of trepanning tool for stainless steel machining. The need for designing dynamometer for measurement of cutting forces and a new tool for trepanning of stainless steel 304 has been achieved by using finite element analysis of octagonal rings of dynamometer and trepanning tool. Finite element analysis using ANSYS software was used to increase the sensitivity of the dynamometer by finding the accurate positioning of the strain gauges on octagonal rings of the dynamometer. A new design for two insert trepanning tool with 4 mm insert thickness was proposed. Simulation of the trepanning operation of 40 mm thick stainless steel 304 plate with this new tool was carried out using smoothed particle hydrodynamics (SPH) – a mesh free method in LS DYNA software. The structural analysis of the tool body was carried out using ANSYS software for validating the design. Three different insert coating grades were used in experimentation. Statically designed experimentation was carried out using three insert grades and three levels of cutting sped and feed rate. Further experimentation can be conducted by choosing insert coating grades suitable for other difficult to cut materials like aerospace materials to analyze the performance of this new trepanning tool. Also insert mounting arrangement can be modified to make it more rigid. In future, the tool can be modified to incorporate a provision of finishing the drilled hole further to avoid need of any subsequent finishing processes.