Numerical investigation of dimple-texturing on the turning performance of hardened AISI H-13 steel

Forming micro-dimples nearer to the cutting edge on the rack face of the tungsten carbide cutting inserts will positively influence the machinability. However, it is challenging to machine the perfect micro-dimple dimensions by utilizing the available machining techniques. Finite element analysis can be an efficient way to observe the influence of dimple-texture area density, micro-dimple size, and various micro-dimple shapes on cutting inserts' machinability. This paper numerically analyses the impact of micro-dimple-textured cutting inserts in dry machining of AISI H-13 steel using AdvantEdge (virtual machining and finite element analysis software). Micro-dimples are formed on the rack face of tungsten carbide cutting inserts to observe the effect of dimple-textured cutting inserts on machinability compared to non-textured cutting inserts in terms of micro-dimple shape, micro-dimple size, and micro-dimple area density ratio. Their outcomes are analysed in terms of chip-insert contact length, main cutting force, and thrust force. It is observed that micro-dimple textured cutting inserts exhibit minimal main cutting force and thrust force in line with increasing the cutting insert life span. The abrasive wear was reduced in dimple-textured cutting inserts due to minimal contact between the cutting insert and chip developed compared to non-textured cutting inserts.

Investigation of the effect of cutting parameters on the milling process of cryogenically treated aluminum alloy with cryogenically treated and untreated inserts, using the Taguchi and Gray Relational Analysis methods

The aluminum 6061 alloy is commonly employed in the automotive industry in the manufacture of rims, panels and even the chasses of vehicles and has excellent machinability. In this study, the surface of the cryogenically processed aluminum 6061-T651 alloy was milled using both untreated and cryogenically treated TiN-TiCN-Al2O3-coated cutting inserts. The Taguchi L18 orthogonal array was chosen as the experimental design. As the cutting parameters in the experiments, two different cutting inserts (untreated and cryogenically treated, TiN-TiCN-Al2O3-coated), three different cutting speeds (250, 350 and 450 m/min) and three different feed rates (0.15, 0.30 and 0.45 mm/rev) were used. After each experiment, the surface roughness and wear values of the cutting inserts were measured, the latter after repeating the experiment five times. Wear and roughness values were optimized using the Taguchi method. Additionally, Gray Relational Analysis (GRA) was used for the combined optimization of wear and roughness values. The optimized findings determined using Taguchi optimization for minimum surface roughness were the cryogenically treated cutting insert, 250 m/min cutting speed and 0.45 mm/rev feed rate. The optimized findings for wear were the cryogenically treated cutting insert, 350 m/min cutting speed and 0.30 mm/rev feed rate. In the optimization with GRA, the common optimum parameters for surface roughness and wear were the cryogenically treated cutting insert, 250 m/min cutting speed and 0.15 mm/rev feed rate. According to the Taguchi and GRA results, the cryogenically treated cutting inserts performed the best in terms of minimum wear and surface roughness. The Gray-based Taguchi methodology proposed in this study was found to be effective in solving the decision-making problem in multi-specific results as wear and surface roughness.

Study of the anisotropy of the properties of the ceramic cutting insert obtained by the LCM technology of 3D printing from the composite Al2O3/ZrO2 (ZTA)

The anisotropy of the properties of a ceramic cutting insert (for three faces) obtained by the lithography-based technology from the Al2O3 + ZrO2 composite has been studied. The study was carried out using the indentation method and Mayer’s law. This method, in contrast to the bending test, excludes the sample destruction. All the studies were carried out on three faces of a ceramic cutting insert made of a composite Al2O3 + ZrO2. The behavior of the Mayer index was studied in the range of loads from 2 to 20 kg and from 0.2 to 1 kg. The results of studying the density, phase composition and microstructure of each face of the sample are presented. The study of the adhesion of the printed layers were also carried out using a Knoop indenter. No anisotropy of the hardness was observed in the load range up to 10 kg. It is shown that a layered structure present in the sample, contributes to the hardness anisotropy under the load of 20 kg and more. No anisotropy of the fracture toughness is observed in the load range of 2 – 20 kg. The results of using a Knoop indenter revealed a high adhesion between 3D printed layers. Studies using a Knoop indenter have indicated high adhesion between the layers of 3D printing.

Effect of Cutting Insert Type on Surface Roughness of Hardened AISI 420 Stainless Steel

AISI 420 stainless steel is one of the alloys that can be used in various applications due to its malleability, high strength, and weldability. In this study, the effects of cutting parameters (feed rate, depth of cut, and cutting speed) on the surface roughness were investigated during the turning of AISI 420 under dry test conditions using coated carbide and ceramic cutting inserts. Response surface methodology, analysis of variance, and statistical methods of the main effect plot were applied to investigate the effects of input parameters on response values. The results of this study showed that feed rate followed by the depth of cut had the most significant effect on output parameters. According to the experimental data, as the feed rate and depth of cut increase, the surface roughness increases.

Study on model for cutting force when milling SCM440 steel

This article presents empirical study results when milling SCM440 steel. The cutting insert to be used was a TiN coated cutting insert with tool tip radius of 0.5 mm. Experimental process was carried out with 18 experiments according to Box-Behnken matrix, in which cutting speed, feed rate and cutting depth were selected as the input parameters of each experiment. In addition, cutting force was selected as the output parameter. Analysis of experimental results has determined the influence of the input parameters as well as the interaction between them on the output parameters. From the experimental results, a regression model showing the relationship between cutting force and input parameters was built. Box-Cox and Johnson data transformations were applied to construct two other models of cutting force. These three regression models were used to predict cutting force and compare with experimental results. Using parameters including coefficient of determination (R-Sq), adjusted coefficient of determination (R-Sq(adj)) and percentage mean absolute error (% MAE) between the results predicted by the models and the experimental results are the criteria to compare the accuracy of the cutting force models. The results have determined that the two models using two data transformations have higher accuracy than model not using two data transformations. A comparison of the model using the Box-Cox transformation and the model using the Johnson transformation was made with a t-test. The results confirmed that these two models have equal accuracy. Finally, the development direction for the next study is mentioned in this article

An Experimental and Finite Element Approach for a Better Understanding of Ti-6Al-4V Behavior When Machining under Cryogenic Environment

Due to increasing demand in manufacturing industries, process optimization has become a major area of focus for researchers. This research optimizes the cryogenic machining of aerospace titanium alloy Ti-6Al-4V for industrial applications by studying the effect of varying the nozzle position using two parameters: the nozzle’s separation distance from the tool–chip interface and its inclination angle with respect to the tool rake face. A finite element model (FEM) and computational fluid dynamics (CFD) model are used to simulate the cryogenic impingement of cryogenic carbon dioxide on the tool–workpiece geometry. Experiments are conducted to evaluate cutting forces, tool wear, and surface roughness of the workpiece, and the results are related to the CFD and FEM analyses. The nozzle location is shown to have a significant impact on the cutting temperatures and forces, reducing them by up to 45% and 46%, respectively, while the dominant parameter affecting the results is shown to be the separation distance. Cryogenic machining is shown to decrease adhesion-diffusion wear as well as macroscopic brittle chipping of the cutting insert compared to dry turning, while the workpiece surface roughness is found to decrease by 44% in the case of cryogenic machining.

Microwave sinteringof duplex α/β-SiAlON ceramic cutting inserts: modifying m, n, z values, sintering temperature and excess Y2O3 sintering additive

Duplex α/β-SiAlON ceramic cutting inserts (30α: 70β) were fabricated by microwave sintering. The effects of solid solution parameters (m, n, z), sintering temperature and amount of excess Y2O3 sintering additive on phase assemblage, microstructure, mechanical properties and cutting performance were investigated. It was found that increasing m value could improve the formation of α phase while high z value over 1.0 would lead to the dissolution of α phase into β phase and intergranular phase. Increasing amount of excess Y2O3 could promote densification and elongated β grain growth, but the excess Y2O3 over 4 wt.% would result in substantial crystallization of M'SS phase thus declining the mechanical properties and wear resistance. The microwave-sintered α/β-SiAlON cutting insert with modified parameters (m = 1.7, n = 1.0, z = 0.7 and 3 wt.% excess Y2O3) was obtained with optimal comprehensive properties, whose tool life was increased by approximately 75% in high-speed milling of Inconel718 superalloy as compared with commercial α/β-SiAlON cutting insert.