Turning Tool Inserts Research Articles

Optimizing machining efficiency: a comprehensive study on PVD cathodic arc evaporation coated turning tool inserts with TiAlN/AlCrN multilayer coatings

The effectiveness of turning processes in manufacturing depends on the efficiency of cutting tool inserts. Coating these inserts is one common method that has been used to prolong their life span, reduce friction and increase wear resistance. The main purpose of the present study was to enhance the efficiency of turning tool inserts by exploring different combinations of coating substances such as TiAlN, AlCrN, and TiAlN/AlCrN. Cutting speed, feed rate, cutting depth and type of coating material were important input parameters for optimization. It was observed that tools with coatings like TiAIN and AlCrN had higher performance than those with single-layered ones. The use of multilayer coated inserts comprising TiAlN/AlCrN increased the hardness but reduced the wear thereby enhancing machining effectiveness. For Taguchi Grey Relation Analysis (GRA) optimization technique with L27 array for hardness and flank wear output parameters aimed at enhancement of input process parameters in turning operations. The coatings crystalline structure, phase composition and other crucial details for their performance were analyzed using Energy Dispersive (EDS) Spectroscopy and Scanning Electron (SEM) Microscopy techniques. The TiAlN/AlCrN coatings showed greater machinability than those with only TiAlN or AlCrN, even at high spindle speeds. The best processes were identified using the Taguchi and Grey relational optimization techniques. Some of these parameters include a speed of 600 m min−1, a feed rate of 0.10 mm rev−1, a depth of 1.5 mm, and a TiAlN/AlCrN coating. This meant that the hardness was at 3772 HV while flank wear is 6.45 mm for optimum parameters among others obtained from experiments. The Grey relation analysis results demonstrated significant improvement in grade indicating the good performance of selected parameters. Various relationships can be displayed using contour plots which are usually visual representation between several factors in an experiment such as hardness and wear resistance which is shown by multilayer coating compared to single-layer coatings.

Sustainable approach for machining of Ti6Al4V using micro-pillar textured turning tool insert

The use of cutting fluids (CF) in metal cutting is questioned due to environmental and biological impacts, encouraging the adoption of dry machining to minimize these effects. However, dry machining accelerates tool wear, particularly in difficult-to-machine materials like Titanium and Nickel alloys. Approaches, such as rake surface texturing, address this challenge and promote sustainability in metal cutting. This study explored the impact of an innovative micro-pillar texture pattern fabricated using a combination of Laser Beam Micro Machining (LBμM) and Reverse Micro Electrical Discharge Machining (RμEDM) for the dry machining of Ti6Al4V. The investigation considers various parameters, including tool wear, contact length, titanium adhesion, cutting forces, cutting temperature, and chip morphology. An indirect approach was adopted to estimate the temperature of the tool tip using the temperature measured at a distant location. Implementing the textured tool with 15 μm deep micro-pillars in the dry machining of Ti6Al4V exhibited the best overall performance for various responses. A notable reduction of more than 40% for both tool-chip contact length and titanium adhesion, compared to a plain tool, indicated a perceptible decrease in the seizure zone at the interface. Moreover, the textured tools demonstrated a remarkable maximum reduction of 56.4% in flank wear, ensuring the prolonged retention of a sharp cutting edge. The responses for contact length, adhesion, and flank wear contributed to an 18.8% decrease in cutting force and a substantial 45.7% reduction in thrust force. Force analysis further confirmed the directional independence of the texture pattern. Under the influence of surface texturing, chip morphology changed to shorter, untangled, and tightly curled, with a 30.8% reduction in curl radius. A theoretical estimation based on the minimum energy approach was also performed to demonstrate an increment in the shear plane angle.

Experimental Investigation and Optimization of WEDM Process Parameters for the Development of Ni-Based Hardfaced Turning Tool Insert Using Hybrid GA-CoCoSo Technique

Experimental Investigation and Optimization of WEDM Process Parameters for the Development of Ni-Based Hardfaced Turning Tool Insert Using Hybrid GA-CoCoSo Technique

Tribomechanical investigation and parametric optimisation of the cutting performance of Ni-based hardfaced turning tool insert

Tribomechanical investigation and parametric optimisation of the cutting performance of Ni-based hardfaced turning tool insert

CFD based study of fluid flow and heat transfer effect for novel turning tool configured with internal cooling channel

Internal-cooling method due to its numerous advantages has been used during the machining of hard to cut and difficult to machine materials. Cooling channels developed in the cutting inserts, drills, end mills and grinding wheels are used for the heat removal which is concentrated at a smaller region during machining process. So, these cooling channels play a vital role in decreasing the temperature and wear rate of the tools. The heat generation and transfer rate depend upon the physical configuration of the cooling channel. This research work presents novelty in the concept of developing internal cooling channel cutting inserts with different profiles. Three different profiles have been developed to investigate cooling effect on the turning tool insert with different shapes. The results have been compared with the standard tool having no cooling channel. Computational Fluid Dynamics (CFD) has been used to simulate temperature rise for all profiles. A temperature drop of 188 K has been found for internally cooled cutting insert in comparison to the standard tool having no channel. It has also been found that the temperature difference of range 20 K–88 K can be achieved by varying the profile of the channel. Besides this, an increase in the inlet pressure of the cutting fluid has been found to make the coolant profile more efficient in terms of heat removal. Through the velocity vector results, it has been found that with more flow velocity of coolant inside the channel more heat transfer takes place. Turbulence Kinetic Energy (TKE) results showed that the heat transfer rate can be increased with an increase in the TKE value which in turn depends upon the profile of the coolant flow channel. This CFD study in turn has laid the platform for setting the optimum parameters during the turning of Titanium alloy with internal cooling channels.

Cutting Forces, Surface Roughness and Tool Wear Quality Assessment Using ANN and PSO Approach During Machining of MDN431 with TiN/AlN-Coated Cutting Tool

The aim of this study was to improve the life and performance of tungsten carbide turning tool inserts coated with TiN/AlN multilayer thin films using physical vapor deposition technique. Quality characteristics of the coating are evaluated using Calo and VDI 3198 tests. Thickness of the coating is found to be $$3.651 \,\upmu \hbox {m}$$ with adhesion quality of HF1. The performance of coated tool inserts is evaluated using cutting speed (59–118 m/min), feed rate (0.062–0.125 mm/rev) and depth of cut (0.2–0.4 mm) as process parameters in turning MDN431 steel. Experimental investigation has been carried out based on full factorial design, and regression analysis was used to analyze and build the mathematical models for cutting force and surface roughness. Multi-objective optimization of the process parameters has been done with the combination of desirability approach and MOPSO technique. Optimum machining condition for least cutting force and optimum surface roughness is found to be $${V}_{\mathrm{c}} =59\, \hbox {m/min}$$, $${f}=0.063\,\hbox {mm/rev}$$ and $${a}_{{p}} =0.2\,\hbox {mm}$$. Cutting force and surface roughness are reduced by 9% in TiN/AlN-coated tools compared with the uncoated tool. To improve the CoD and capability of predictive regression models, ANN modeling has been adopted. ANN trained model and mathematical regression models are used to predict the results and predict the responses, which follow the experimental data with minimum absolute error. The predicted results are validated using ANN and regression analysis found with minimum error, and developed models are adequate for further usage. Tool wear was reduced by 105% in TiN/AlN-coated tools compared with the uncoated tool.

Using the Machine Vision Method to Develop an On-machine Insert Condition Monitoring System for Computer Numerical Control Turning Machine Tools.

This study uses the machine vision method to develop an on-machine turning tool insert condition monitoring system for tool condition monitoring in the cutting processes of computer numerical control (CNC) machines. The system can identify four external turning tool insert conditions, namely fracture, built-up edge (BUE), chipping, and flank wear. This study also designs a visual inspection system for the tip of an insert using the surrounding light source and fill-light, which can be mounted on the turning machine tool, to overcome the environmental effect on the captured insert image for subsequent image processing. During image capture, the intensity of the light source changes to ensure that the test insert has appropriate surface and tip features. This study implements outer profile construction, insert status region capture, insert wear region judgment, and calculation to monitor and classify insert conditions. The insert image is then trimmed according to the vertical flank, horizontal blade, and vertical blade lines. The image of the insert-wear region is captured to monitor flank or chipping wear using grayscale value histogram. The amount of wear is calculated using the wear region image as the evaluation index to judge normal wear or over-wear conditions. On-machine insert condition monitoring is tested to confirm that the proposed system can judge insert fracture, BUE, chipping, and wear. The results demonstrate that the standard deviation of the chipping and amount of wear accounts for 0.67% and 0.62%, of the average value, respectively, thus confirming the stability of system operation.

Experimental investigation and modelling of WEDM process for machining nano-structured hardfacing material

In recent years, nano-structured hardfacing alloy constituting fine carbides, borides and boro-carbides have become pioneered in modern manufacturing industries due to their superior properties (excellent hardness, toughness and wear resistance) even at elevated temperatures. A nano-structured hardfacing alloy component was produced using manual metal arc welding process for making turning tool insert. The present paper investigates the effect of wire electrical discharge machining (WEDM) parameters such as discharge pulse time, discharge stop time, servo voltage, wire tension and wire feed rate on machining performances viz. material removal rate, machining time and surface roughness after proof-machining of welded nano-structured hardfacing material. Taguchi’s (L25) orthogonal array has been used to perform the experimental runs using conventional brass wire and zinc-coated wire electrodes, respectively. A combination of Taguchi’s robust design concept with principal component analysis has been applied to optimize the process parameters. For brass wire, the optimal settings of the input process parameters corresponds to discharge pulse time 0.45 µs, discharge stop time 8 µs, servo voltage 35 V, wire tension 800 g and wire feed rate 7 m/min, respectively. Similarly, for zinc-coated brass wire, the corresponding settings are discharge pulse time 0.5 µs, discharge stop time 11 µs, servo voltage 41 V, wire tension 600 g and wire feed rate 7 m/min. This paper also establishes the inter-relationships of various WEDM machining parameters and performances by employing response surface methodology-based approach. A confirmation test has also been carried out with the optimal process parameters to conform to the experimental result.

Multi-objective optimization in WEDM process of nanostructured hardfacing materials through hybrid techniques

Abstract Hardfacing is one of the most efficient and cost-effective ways to scale down operating expense leading to improved performance and reliability of the equipment. Presence of nano-particles in hard facing metal matrix dramatically enhanced surface area to volume ratio resulting in magnificent improvement in conductivity, hardness, heat and wear resistant properties. This paper presents an application of nanostructured hardfacing material for the development of turning tool insert through welding and machining by WEDM process. In order to simultaneously optimize performance characteristics (MRR, machining time and surface roughness), a novel hybrid approach combining grey relational analysis with principal component analysis has been proposed to identify the optimal combination of process parameters in WEDM for machining nanostructured hardfacing materials. The grey relational analysis manifests discharge pulse time a most important parameter for both brass and zinc coated brass wires. Further, mathematical models are developed using response surface methodology to investigate the effects of the WEDM parameters on grey relational grade. As subsequent comparison made in terms of performance characteristics amongst brass and zinc coated brass wire, it is observed that zinc coated brass wire is highly worthy of being chosen especially for machining of nanostructured hardfacing material.

Impact of Tool Inserts in High Speed Machining of GFRP Composite Material

Composite materials are in-homogenous, anisotropic and cause high tool wear at high cutting speeds in machining. Industrial practices worldwide reveal a need to use high speed machining to achieve the desired material removal rate, surface finish and to reduce cost cutting. In this research work, impact of turning glass fibre reinforced polymer tube with two contrasting turning tool inserts such as titanium aluminium nitride and tungsten carbide have been analysed. The turning was conducted at low to high cutting conditions up to spindle speeds of 2000 rpm and feed rate of 0.446mm/rev. The cutting force, feed force were acquired with a strain gauge based dynamometer, the chip cross section was observed using scanning electron microscopy and the temperature was sensed with a infra red thermo sensor. The advanced titanium aluminium nitride insert shows better machining characteristics across cutting speeds.

The Correlation of the Volumetric Wear Rate of Turning Tool Inserts With Carbide Grain Sizes

The objective of this paper is to analyze the effect of different carbide grain sizes on the tool material volume worn away from straight tungsten–carbide–cobalt (WC–Co) turning inserts. A previously developed metrology method for assessing the tool material volume worn away from milling inserts is adapted for quantifying the volumetric tool wear (VTW) of turning inserts. Controlled turning experiments are conducted at suitable points in the feed-speed design space for two sets of uncoated inserts having different carbide grain sizes. Three levels of Ti–6Al–4V stock removal volumes (10-cm3 each) are analyzed. For each insert, the tool material volume worn away (in mm3) as well as the three-dimensional (3D) wear profile evolution is quantified after each run. Further, the specific volumetric wear rate and the M-ratio (volume of stock removed to VTW) are related to the material removal rate (MRR). The effect of carbide grain size on VTW is examined using scanning electron microscopy and elemental analysis. Finally, the inverse dependence of the M-ratio on MRR enables the definition of actual usable tool life in terms of its efficiency in removing stock, rather than being based on a tool geometry related metric.

Investigation of the machinability characteristics of GFRP/vinyl ester composite using design of experiments

Many glass fibre reinforced polymer (GFRP) composite components made from primary melt processes require additional machining to meet the requirements of assembly and accurate dimensional tolerances. Despite the wide applications of reinforced vinyl ester resin in electrical components, automotive structural applications, mining and chemical process industries, high performance marine applications and sporting goods, very little is known about its machining aspects. Cutting force is treated as one of the primary measures of machinability of materials. In this study, the effect of cutting parameters and tool nose radius on the main cutting force in the turning of vinyl ester and woven fabric-based GFRP composites manufactured by hand lay-up process is investigated. Polycrystalline diamond turning tool inserts are used for machining. The force was measured through longitudinal turning, according to the experimental plan developed based on Taguchi methodology. The signal to noise ratio and analysis of variance were applied to the experimental data in order to determine the effect of the process variables on cutting force.

Cryogenic Turning of AISI 304 Stainless Steel with Modified Tungsten Carbide Tool Inserts

The machining of stainless steel inherently generates high cutting temperature, which not only reduces tool life but also impairs the workpiece surface quality. Conventional cooling methods are ineffective in controlling the high cutting temperature and rapid tool wear. In the present research work, the effect of liquid nitrogen as a coolant applied through holes made on the rake and flank surfaces of the PVD TiAlN coated tungsten carbide turning tool inserts of ISO CNMG 120412 MP–KC5010 on the turning of AISI 304 stainless steel is studied. The influence of cryogenic cooling on the cutting temperature, cutting force, surface roughness, and tool wear, has been compared with those of wet machining. It has been observed that in the cryogenic cooling method, the cutting temperature was reduced by 44–51%, the cutting force was decreased to a maximum of 16%, and the surface roughness was reduced by 22–34% over that of wet machining. Cryogenic cooling using liquid nitrogen reduced tool wear through the control of temperature-dependant wear mechanisms.

Machinability of C45 steel with deep cryogenic treated tungsten carbide cutting tool inserts

Abstract In the present investigation, coated tungsten carbide ISO P-30 turning tool inserts were subjected to deep cryogenic treatment (−176 °C). Machining studies were conducted on C45 workpiece using both untreated and deep cryogenic treated tungsten carbide cutting tool inserts. The machinability of the C45 steel workpiece is evaluated in terms of flank wear of the cutting tool inserts, main cutting force and surface finish of the machined workpieces. The flank wear of deep cryogenic treated carbide tools is lower than that of untreated carbide tools on machining of C45 steel. The cutting force during machining of C45 steel is lower with the deep cryogenic treated carbide tools when compared with the untreated carbide tools. The surface finish produced on machining the C45 steel workpiece is better with the deep cryogenic treated carbide tools than when compared with the untreated carbide tools.

Chip analysis for the determination of flank wear in dry turning

The performance assessment of a cemented carbide turning tool insert during dry turning of steel of hardness value ranging from 25 to 40 HRC is presented in this analysis. This work includes chip study and experimental flank wear measurement at different test conditions for optimising the process and product parameters to minimise the flank wear by using Taguchi's Design of Experiments. A validation experiment is conducted and the validated results are confirmed by calculating the values of Confidence Interval (CI) based on error degrees of freedom and error variance. The required empirical models for flank wear are also developed. The developed empirical models show a goodness of fit with the experimental values. In this work, it is proved that the flank wear of cutting insert is possible to be calculated from the various models developed based on chip characteristics.

Solving an inverse heat conduction problem using a non-integer identified model

An inverse heat conduction problem in a system is solved using a non-integer identified model as the direct model for the estimation procedure. This method is efficient when some governing parameters of the heat transfer equations, such as thermal conductivity or thermal resistance, are not known precisely. Reliability of the inversion depends on the precision of the identified model. From considerations on the analytical solutions in simple cases and on the definition of non-integer (or fractional) derivative, the non-integer model appears to be the most adapted. However, some experiments do need to be carried out on the physical thermal system before it can be identified. An application that consists in estimating the heat flux in a turning tool insert during machining is presented. First, identification is performed using a specific apparatus that permits a simultaneous measurement of temperature and heat flux in the insert. Then, during machining, heat flux can be estimated from temperature using this identified model.

Temperature effects on the mechanism of time independent hydrogen assisted fatigue crack propagation in steels: Marrow, T.J., King, J.E. and Cotterill, P.J. Acta Metall. Mater. Aug. 1992 40, (8), 2059–2068

An inverse heat conduction problem in a system is solved using a non-integer identified model as the direct model for the estimation procedure. This method is efficient when some governing parameters of the heat transfer equations, such as thermal conductivity or thermal resistance, are not known precisely. Reliability of the inversion depends on the precision of the identified model. From considerations on the analytical solutions in simple cases and on the definition of non-integer (or fractional) derivative, the non-integer model appears to be the most adapted. However, some experiments do need to be carried out on the physical thermal system before it can be identified. An application that consists in estimating the heat flux in a turning tool insert during machining is presented. First, identification is performed using a specific apparatus that permits a simultaneous measurement of temperature and heat flux in the insert. Then, during machining, heat flux can be estimated from temperature using this identified model.