Parameter optimization for machining of carbon fiber-reinforced polymer-aluminum composite laminates

The use of composite laminates, such as carbon fiber-reinforced polymer (CFRP) and fiber metal laminates (FML), is widespread in the aerospace and aircraft industries due to their superior qualities. FML, a hybrid material comprising thin metal sheets and fiber-reinforced adhesive layers, offer significant advantages over traditional metallic materials for aircraft structures due to their lightweight and high-performance nature. However, shaping composite materials often requires machining processes, with milling being a common method to achieve precise shapes and finishes. This study delves into the machining of CFRP and aluminum composite laminates, aiming to investigate how machining parameters affect surface roughness and machining force. Numerical control (NC) code is generated using MASTERCAM software to operate a CNC milling machine for experiments conducted with varying machining parameters. Spindle speed, feed rate, and depth of cut are key parameters, with three levels each, reflecting industry norms. A polycrystalline diamond (PCD) end mill is chosen as the cutting tool, while a dynamometer measures force and MarSurf PS1 gauges surface roughness. The optimal machining parameters are determined through Taguchi analysis, supplemented by ANOVA and regression analysis, revealing that feed rate primarily affects machinability outcomes of surface roughness and machining force. Lower feed rates, higher cutting speeds, and depth of cut result in improved surface finish, while higher cutting speeds with lower feed rates, and depth of cut reduce machining force. Validation testing confirms the recommended parameters from Taguchi analysis for achieving desired outcomes. Ultimately, the study highlights the significance of optimizing machining parameters to enhance material machinability, particularly in the aerospace industry, where high-performance components with precise finishes are crucial.