Improving Precision in Aluminum Alloy Machining Due to the Application of Diamond-Like Carbon Thin Film

Abstract

Cutting precision is extremely affect by a phenomenon known as built-up edge (BUE) that occurs on tungsten carbide tools during low cutting speed of aluminum alloy. BUE is responsible for early tool breakage due to excessive material build-up from the machined part on the cutting face, leading to problems of shape irregularity and tool-tip breakage. Thus, Diamond-like Carbon was deposited and tested to verify cutting precision in aluminum alloy by using tungsten carbide tools. The characterizations of the film were: Morphology analysis through scanning electron microscopy; structural atomic analysis of chemical bond from Raman Backscatter Spectroscopy; X-ray photoelectron spectroscopy helped to identify the distribution of carbon atoms on the film surface, and the evaluation of Young's modulus and hardness using the Oliver-Pahrr method. To analyse the cutting precision, drilling tests were performed on coated/uncoated drills at two cutting speeds (340 and 430 m/min). As an evaluation parameter in the aluminum alloy, the hole diameter deviation was measured after pre determined numbers of drilling operations. Statistical comparisons between the diameter deviation as a function of the number of drilling test indicated better cutting accuracy for the DLC coated tool. The factors identified in this work, such as the reduction of the friction coefficient, and the hardness and Young's modulus of the DLC helped in the performance of the tool, mainly in the lower cutting speed.

Performance Analysis of Helical Milling and Drilling Operations While Machining Carbon Fiber-Reinforced Aluminum Laminates

“…Accordingly, the surface roughness of the hole in the FRP layer deteriorates compared to that in the metal layer. Additionally, FMLs based on aluminum alloys such as CARALL, ARALL, and GLARE tend to produce an excessive built-up edge (BUE) on the drill tool, leading to a higher rate of tool life deterioration [15]. This results in inadequate chip evacuation, and the chips left behind tend to erode the fibers and metal surface, consequently diminishing the surface finish of drilled holes [16].…”

Built-up edge formation mechanisms in orthogonal cutting of wood-plastic composite

“…Furthermore, Vilches et al (2021) found that indirect wear from adhesion to built-up edge and built-up layer are the main factors leading to the cermet tool wear in the turning of UNS A97075 Alloy. Generally, the build-up was mainly caused by the thermo-mechanical effects during machining, and greatly influenced the cutting performance in terms of surface quality, cutting force, chip formation and tool wear (Pálmai 2012, Chowdhury et al 2021, Silva et al 2021.…”