Machinability evaluation of dies steel H-11 with CNC Milling using digraph and matrix method

Abstract

Machinability aspect is of considerable importance for efficient process planning in manufacturing. Machinability of work materials is an imperative aspect which may affect the different manufacturing phases including product design, process planning and machining operation. Machinability of engineering materials may be evaluated in terms of process output variables like surface roughness (SR), material removal rate, cutting forces etc. In this paper, graph theoretic approach is proposed to assess the performance of die steel H-11 using titanium coated carbide cutter, together with spiral type cutter path strategy. SR is considered as machinability attribute to evaluate the effect of several factors and sub-factors. Factors affecting machinability and their interactions are analyzed by developing a mathematical model using digraph and matrix method. Permanent function is obtained from the matrix model and the function value aids in quantifying the influence of considered factors on machinability. Factors affecting SR are grouped into five factors namely work-piece, tool coating, tool geometry, cutter path strategy and machine tool. The results reveals that machine tool has the highest index value and hence the most influencing factor and feed rate is the most significant sub-factor influencing SR of H-11 using titanium coated carbide cutter on CNC Milling.