Statistical Modelling to Study the Implications of Coated Tools for Machining AA 2014 Using Grey Taguchi-Based Response Surface Methodology

Milling is the surface machining process by removing material from the raw stock using revolving cutters. This process accounts for a major stake in most of the Original Equipment Manufacturing (OEM) industries. This paper discusses optimizing process parameters for machining the AA 2014 T 651 using a vertical milling machine with coated cutting tools. The process parameters such as cutting speed, depth of cut, and type of the cutting tool with all its levels are identified from the previous literature study and several trial experiments. The Taguchi L9 Orthogonal Array (OA) is used for the experimental order with the chosen input parameters. The commonly used cutting tools in the machining industry, such as High-Speed Steel (HSS) and its coated tools, are considered in this study. These tools are coated with Titanium Nitride (TiN) and Titanium Aluminum Nitride (TiAlN) by Physical Vapor Deposition (PVD) technique. The output responses such as cutting forces along the three-axis are measured using a milling tool dynamometer for the corresponding input factors. The input process parameters are optimized by considering the output responses such as MRR, machining torque, and thrust force. Grey Taguchi-based Response Surface Methodology (GTRSM) is used for multiobjective multiresponse optimization problems to find the optimum input process parameter combination for the desired response. Polynomial regression equations are generated to understand the mathematical relation between the input factor and output responses as well as Grey Relational Grade (GRG) values. The optimum process parameter combination from the desirability analysis is the HSS tool coated with TiAlN at a cutting speed of 270 rpm and a depth of cut value of 0.2 mm.

CVD Diamond Coated Tungsten Carbide (WC) Tool Inserts

In this paper a self-developed polycrystalline diamond coating was done on tungsten carbide (WC) tool insets by using simple thermal chemical vapor deposition technique. The growth of these diamond films has been carried out at ~900 ºC temperature. The as-grown polycrystalline diamond films on the surface of tungsten carbide tool inserts have been characterized using Raman spectrometer and scanning electron microscope (SEM). The morphological studies reveal that the as-grown diamond films are of high crystalline quality. The as-grown diamond films possess compressive stress. The micro-hardness indentation test of the as-grown diamond films on WC tool inserts and bare have also been done and it has been found that the Vicker’s hardness of the as-grown diamond WC tool inserts is found to be 1423.32 HV which is 29% better than the un-coated tools.

Experimental study and multi-objective optimization of process parameters during turning of 100Cr6 using C-type advanced coated tools

The drive of this research is to examine the machinability of 100Cr6 bearing steel using advanced C-type cutting tools. Experimental studies investigated the effects of machining variables on the surface quality, chip reduction coefficient and cutting force. Seven advanced coated tools were checked for characterization by micro hardness (VHN), adhesion quality, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS). The experimental trials were planned by Taguchi’s L18 orthogonal array using a mixed-level design. Two numerical machining variables feed rate and cutting speed, and one categorical machining variable tool type was taken into consideration while a constant depth of cut was kept for all trails. A combined Taguchi-Satisfaction function distance measure approach was implemented for multi-response optimization. The most promising machining parameter setting for minimization of surface roughness, cutting force, and chip reduction coefficient was identified. The most important process parameter was found to be tool-type. Ceramics tools are found to be best trailed by WC coated tools under most of the conditions. Lower tool wear was observed in the CBN tool as compared to others.

Wear Behavior of Uncoated and Coated Tools in Milling Operations of AMPCO (Cu-Be) Alloy

Copper-Beryllium alloys have excellent wear resistance and high mechanical properties, they also possess good electrical and thermal conductivity, making these alloys very popular in a wide variety of industries, such as aerospace, in the fabrication of tools for hazardous environments and to produce injection molds and mold inserts. However, there are some problems in the processing of these alloys, particularly when these are subject to machining processes, causing tools to deteriorate quite rapidly, due to material adhesion to the tool’s surface, caused by the material’s ductile nature. An assessment of tool-wear after machining Cu-Be alloy AMPCOLOY 83 using coated and uncoated tools was performed, offering a comparison of the machining performance and wear behavior of solid-carbide uncoated and DLC/CrN multilayered coated end-mills with the same geometry. Multiple machining tests were conducted, varying the values for feed and cutting length. In the initial tests, cutting force values were registered. The material’s surface roughness was also evaluated and the cutting tools’ edges were subsequently analyzed, identifying the main wear mechanisms and how these developed during machining. The coated tools exhibited a better performance for shorter cutting lengths, producing a lower degree of roughness on the surface on the machined material. The wear registered for these tools was less intense than that of uncoated tools, which suffered more adhesive and abrasive damage. However, it was observed that, for greater cutting lengths, the uncoated tool performed better in terms of surface roughness and sustained wear.

Effect of Volcano-like Textured Coated Tools on Machining of Ti6Al4V: An Experimental and Simulative Investigation

In this work, the main aim is to reduce the adhesion and wear that happened during machining of the Ti6Al4V alloy by employing volcano-like texture on the rake face of coated tool. A combination of experimental and simulative investigation was adopted. DEFORM-3D software with updated Lagrangian formulation was used for numerical simulation, and the thermo-mechanical analysis was performed using Johnson-Cook material model to predict the cutting temperature, cutting forces, chip morphology and tool wear. In cutting experiments, volcano-like textures with different area densities (10%, 20%, 30%) were fabricated by fiber laser on the rake face of cemented carbide tools close to the main cutting edge. Then, these textured tools were deposited with CrAlN coating through cathodic vacuum arc ion plating technique. Experiments in cutting Ti6Al4V alloy were carried out with the textured coated tools and non-textured coated tool under dry and wet cutting conditions. Then, the chip morphology, chip size and tool wear were investigated. The results showed that textured coated tools were superior to conventional tool. Especially in wet cutting, compared with those of non-textured coated tool, the adhesion area and the chip curling radius of the coated tool with texture area density of 20% (VCT2) were reduced by 31.2% and 49.7%, respectively. Therefore, VCT2 tool showed a better cutting performance. Finally, the mechanisms of textured coated tools under dry and wet cutting conditions were proposed.

Influence of Micro Sandblasting on the Surface Integrity of the AlTiN Coated Tool Material

Due to the high-efficiency, environmental protection the low cost, the micro sandblasting technology is used in the surface treatment of the coated tools. The simulation and application of micro sandblasting of the coated tool are carried out to reveal the surface treatment mechanism and analyze the influence of sandblasting parameters on the tool surface integrity. The flow field erosion simulation model of abrasive-water-air three-phase flow is established. The results show that the maximum velocity and pressure are obtained at the center of jet flow. The pressure distribution on the target surface has little correlation with the distance to the nozzle. The surface morphology of the AlTiN coated tool changes obviously after micro sandblasting. Moreover, the low surface roughness Ra of the blasted tool can be obtained at the small sandblasting pressure and time. Additionally, the residual compressive stress on the surface of the AlTiN coated tool is enhanced after micro sandblasting. This work has practical significance for optimizing micro sandblasting process and improving the surface integrity of coated tools.