The Effects of Drilling Operation on the Surface Roughness of Modified GFRP Composites

Abstract

The use of fiber reinforced composites with thermoset matrix is widespread in many areas ranging from sports products to multiple industries. This prominence, aside from the lightness of composites, can be attributed to their high mechanical resistance, good corrosion resistance, and strength density ratios that are favorable over their metal counterparts. Although their final states are approached with various single step methods, they often require secondary operations such as turning, milling or drilling. Because composite materials are not homogeneous, machining process may give rise to negative outcomes like the tearing of fibers or damages on the matrix. Composites with thermoset matrix are also brittle materials. Thus, during machining, they are processed by breaking which is not favored for production. Modified glass fiber reinforced composite (GFRP) materials, which are produced with thermoset matrix epoxy resin, are drilled in this study. Previous studies on this field had focused on the processes of turning and milling regarding the products' surface roughness. Therefore, surface roughness of holes, which were drilled according to different parameters by using L 18 matrix prepared with Taguchi's design of experiment on modified GFRP part, having 30% fiber glass, were investigated. This particular study takes on the drilling process which is also essential to manufacturing of the final products of GFRP, in the same framework. In the experiments, the influence of changing spindle speed and feed rate in different drill diameters on the inner surface of the hole, were evaluated using different cutting tools. As a result, the surface roughness of the drill, produced by the uncoated drilling bit with a diameter of 4 mm, spindle speed of 200 rpm and feed rate of 720 mm/min, was determined to be optimal.

Analyzing the surface roughness for GFRPs drilled Hole when using different tools and different methodology (A review)

“…From the experimental results, it obvious that the machining performance in the drilling process of GFRP composite can improve successfully through this method and the Taguchi-GRA method can simplify the optimization of the drilling parameters and the tool geometries with multiple-performance. I. Cavusoglua, et al [39], presented an analysis of the surface roughness of the holes, which are drilled due to the different parameters by using L 18 matrix prepared with Taguchi's design of experiment on modified GFRP part, having 30% fiberglass, are investigated. In these experiments, the influence of changing the spindle speed, the feed rate, and the different drill diameters on the inner surface of the hole, are evaluated.…”

Comparison of the Surface Roughness and its Geometric Model in Case of Z-level Milling

“…The tool path patterns cause different Rz surface roughness, but smaller than the calculated cusp height. The cutting method, and the workpiece material can modify the surface roughness too [7][8] [9]. In case of turning, the feed has the same role in the geometric model, like the width of cut (a e ) in case of ball-end milling or the depth of cut (a p ) in case of Z-level milling.…”