Modeling of Surface Roughness in Drilling of MDF Panels

Abstract

Medium density fiberboard wood composite panels are preferred for many domestic and industrial applications over the natural wood because of their high-quality properties. The aesthetic appearance of wood composites makes them suitable for interior and exterior construction works. Among various machining process, drilling is the most frequently used machining operation in the furniture industry in assembly of panel products. During drilling process the drill exhibits cutting forces such as thrust force and torque. The surface quality of the drilled holes are mainly affected by the cutting forces developed during drilling process which causes surface roughness, delamination like damages which leads to the rejection of the final product. Hence the reduction of the drilling defects, the control of the cutting forces is very much essential. The drilling parameters play an important role in controlling the cutting forces. The objective of this work is to study the influence of input control parameters such as spindle speed, feed rate and point angle on surface roughness in drilling of MDF panels to obtain the optimal cutting conditions. In the present study the drilling experiments are conducted using Taguchi design of experiments on wood composite panels with high speed steel (HSS) twist drills with different point angles on vertical machining center using at dry condition. Three levels and three factors are considered. Taguchi L27 orthogonal array is used. Response surface methodology is used to develop a mathematical model to predict the influence of input control parameters on cutting forces. Analysis of variance is used to check the adequacy of the model. Surface roughness is increased with an increase of feed rate and drill point angle and decreased with an increase in the spindle speed. It is revealed that high spindle speed with low feed rate and smaller point angle combination gives better results in drilling of wood composite panels.