A Comparative Experimental Study on Machining Performance of Aluminium against Advanced Diamond Coated Cutting Tool Inserts

Carbide tools with mono/multilayer coating such as TiN, TiC, TiAIN, TiB2 and Al2O3 on inserts of WC-Co generated key success for machining of ferrous materials without coolant/lubrication. So far dry machining of aluminium, manufacturing industries such as automobile and aerospace engineering are facing considerable challenges. Exploration of correct cutting tool for machining of aluminium still persists in the present day context. This paper experimentally investigated the affinity and performance of different cutting tool materials available in local tool shopping center along with the diamond coated tool insert prepared and developed in our own HFCVD reactor for machining of aluminium in dry condition. Finally it is revealed that, due to the low chemical affinity, small magnitude of cutting force, chemical inertness and remarkable anti-welding characteristics, diamond coated tool displayed improved performance as compared to other tools.

Method for assessing the thermophysical properties of the contact pair ‘tool – steel workpiece’

To The analysis of methods for evaluating the properties of contact pairs “hard -alloy coated tool-steel billet” is carried out in order to use them to increase the reliability of the choice of turning modes in the generations of CNC systems equipped with technological intelligence. It is proposed to use the value of the thermo-emf of the test pass as an indirect indicator of the properties of contact pairs composed of a coated carbide tool and a processed steel billet. Models for calculating the cutting speed based on a given tool durability period of a coated carbide tool and predicting the actual cutting tool durability period for given processing conditions are proposed by introducing into their structure an additional informative value about the properties of each contact pair - the thermo-EMF of the test pass. The conducted resistance tests of various carbide plates during the processing of P-group steels showed sufficient reliability of the proposed dependences.

Effects of dry turning parameters of Incoloy 800H superalloy using Taguchi-based Grey relational analysis and modeling by response surface methodology

Incoloy 800H is an austenitic Fe-Ni-Cr based superalloy and used in many applications due to their high corrosion resistance and creep-strength. However, this alloy is difficult to machine or cut material because of their eminent characteristics such as rapid-work hardening, lesser thermal conductivity and easy to tool-material attraction. Hence, the necessary experimental investigation is required to study and optimize the turning parameters of this alloy. This work presents the investigation of turning parameter effects on the Incoloy 800H superalloy with cryogenically treated cutting tool. The dry turning experiments were conducted based on Taguchi L9 Orthogonal array (OA) with the input parameters of cutting speed, feed rate and depth of cut. The outputs such as material removal rate, surface roughness, cutting force and tool-tip temperature were considered as the responses. The measured output responses were optimized and modeled using Taguchi-based Grey relational analysis (GRA) and response surface methodology (RSM), respectively. The tool flank wear and tool life were examined on coated insert with cryogenically treated, coated insert (without cryogenic treatment) and uncoated insert for comparison. The results revealed that greater amount of tool-wear reduction was observed in the case of coated tool with-cryogenically treated about 47.88%, coated tool without-cryogenically treated about 27.51% when compared with an uncoated tool. Besides, analysis of variance (ANOVA) was performed to find the most significant parameter over the obtained responses. The obtained mathematical model through RSM was agreed with the experimental result. Further, the machined surface topography was examined using White Light Interferometer (WLI).

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.

Development of High-Performance Polycrystalline CVD Diamond-Coated Cutting Tools Using Femtosecond Lasers

Pulse laser grinding (PLG), an edge-shaping process, was developed previously to implement high-performance cutting tools. In this study, two femtosecond (fs) lasers with wavelengths of 1045 nm and 257 nm were used to conduct PLG on chemical vapor deposited (CVD) diamond-coated tool edges, as the fs laser is reported to have less thermal impact and the potential to improve the material crystallinity. We investigated the effects of the laser parameters on the tool edge formation and microstructural changes. The results show that although the infrared fs laser could – compared to the conventional nanosecond (ns)-laser PLG – naturally suppress surface thermal damage, the roughness of the processed surface remained relatively high with an Rz of 0.21 μm. However, under the optimal laser parameters proposed in this paper, an ultraviolet fs-laser PLG was used to obtain a much smoother edge, reducing Rz to approximately 0.08 μm. Moreover, scanning electron microscopy images indicated that the longitudinal machining marks on the ns-laser-processed surface were significantly reduced, with virtually no attached debris on the surface. Furthermore, from the Raman spectra, a significant increase in the diamond peak intensity was observed, indicating that the crystallinity of the CVD diamond (CVDD) was improved following ultraviolet-fs-laser PLG. These results demonstrate that edge shaping and structural modification of polycrystalline CVDDs can be integrated into ultraviolet-fs-laser PLG.