DRILLING OF SANDWICH MATERIAL USING DRILLS WITH DIFFERENT GEOMETRIES: CONSTRUCTION OF A MATHEMATICAL MODEL TO PREDICT THE FORWARD FORCE

Abstract

The sandwich materials are thus named because they combine as properties of two types of materials, acquiring a structure with a core and two outer faces. The present research used a sandwich material with aluminum faces and a polyethylene core. One of the ways to process this material is through machining, more specifically in drilling operations, which was the focus of this research. The reduction of the cutting forces is desired during the drilling operation, thus improving the quality of the holes due to the reduction of vibrations in the system. It can also increase tool life, eliminating costs due to longer tool replacement times. Based on this principle, this research allied statistical knowledge applied to engineering in order to construct mathematical models to predict the behavior of the forward force in the drilling of sandwich material using drills with different geometries, denominated twist drill with two edges, twist drill with three edges and Brad & Spur. The objective was to develop multiple linear regression equations to identify the influence of cutting speed and feed rate on the thrust force for each of the drills studied. In addition, it was investigated whether the drill geometry impacted behavior that could be modeled by mathematical equations with a certain degree of acceptable confidence.