Increase Tool Life Research Articles

Effect of the drag-finishing of cutting blades made of sintered carbides on tool life in particleboard machining

ABSTRACT It is currently known that in certain circumstances pre-rounding of cutting blades can significantly increase tool life. Despite many data on the beneficial effect of drag-finishing on the durability of metalworking tools, it is not entirely clear whether similar benefits appear when machining wood-based panels. The results of some pilot study are quite promising but the real impact of cutting blades pre-rounding (it is about blades made of various standard cemented carbides), on tool life in particleboard milling are very rarely studied. The study aims to fill this gap in the knowledge system. The experimental research was carried out using a CNC milling machine equipped with a single-blade milling head with replaceable blades. It turned out that the positive effect of the drag-finishing of cutting blades on tool life in particleboard machining depends on the structure and hardness of carbide. A significant extension of the tool life (about 50%) was observed only in the case of particularly hard carbide (2240 HV10). There was no significant advantage for the softer type of carbide (1800 HV10).

On the formation of Ti2AlN MAX phase coatings and improvement in tool life by superimposing on tungsten carbide cutting tool for machining Ti-6Al-4V alloys

This paper presents the development of (002) textured Ti2AlN coated wear resistant tool utilizing reactive magnetron co - sputtering. The Ti2AlN coating was developed in two different Argon, Nitrogen ratios such as 64:3 and 64:4, the influence of these parameters was identified using crystallographic, microstructural, mechanical and tribological studies. Experimental studies were performed to compare the cutting force as well as the tool life of superimposed Ti2AlN tool with a commercial tool by turning titanium alloy (Ti-6Al-4V). Results from the experimental analysis revealed an 80–85 % increase in hardness, a 13–20 % decrease in wear rate and a 27 % increase in tool life for Ti2AlN coated cutting tool. According to chip morphology, there is a 12 % increase in shear angle, 43 % and 51 % decrease in friction angle and coefficient of friction respectively. The nanomechanical studies were performed which show a maximum hardness of 29.12 ± 5.4 GPa and minimum wear rate of 10.078 × 10−9 mm3/mN.m−1 for superimposed Ti2AlN.

Tribological Analysis and Operation Issues of SiO<sub>2</sub> Nanolubricants for MQL Machining Operations

Minimum Quantity Lubrication (MQL) has been proved to be an efficient lubricant technique in machining that increases tool life, improves surface roughness, facilitates the recycling of the resulting chips, brings more sustainable practices in terms of minimum use of lubricants, and reduces the operators’ exposures to toxic particles with respect to conventional cooling practices. In order to increase the performance of MQL, nanoparticles of Al2O3, MoS2, SiO2 graphite and graphene among others have been recently introduced into MQL lubricants. This new approach, called nanoMinimum Quantity Lubrication (NMQL), has been proved to provide better thermal conductivity and lower friction coefficients during cutting, which in turns means higher cutting tool life and lower cutting forces. In this paper, a stable SiO2 -based nanolubricant was produced and characterized. A tribological analysis was conducted on SiO2 nanolubricants to be used on MQL operations. Operational issues related to particles deposition along time, loss of nanolubricant properties when it comes from the MQL system and mist generation were also analyzed.

Metal-Containing Diamond-Like Carbon Coatings with Increased Temperature Stability for Wear Protection of Nitrided Hot Forging Dies

In cold forging processes, diamond-like carbon (DLC) coatings have become established as a wear protection for forging dies, featuring high hardness and advantageous friction properties. This counteracts the particular critical abrasive tool wear and increases tool life. A major disadvantage of DLC coatings is their low thermal stability. In this study, the influence of metallic elements (niobium, tungsten and chromium) in the treatment atmosphere of the coating process is investigated with the aim of increasing the temperature resistance of the DLC coating and enabling its application as a wear-protection measure for hot forging dies. Preliminary studies were carried out to investigate the influence of different treatment atmospheres on wear-reducing properties such as high hardness and coating adhesion depending on prior nitriding processes. The most promising metal-doped DLC coating, with 30 % tungsten in the treatment atmosphere, was used in serial forging tests. At a blank temperature of 1,200 °C and a moderate count of 100 forging cycles, wear was reduced by up to 60 % compared to the nitrided reference tool.

Testing for Abrasion Resistance of WC-Co Composites for Blades Used in Wood-Based Material Processing.

Commonly used tool materials for machining wood-based materials are WC-Co carbides. Although they have been known for a long time, there is still much development in the field of sintered tool materials, especially WC-Co carbides and superhard materials. The use of new manufacturing methods (such as FAST-field-assisted sintering technology), which use pulses of electric current for heating, can improve the properties of the materials used for cutting tools, thereby increasing the cost-effectiveness of machining. The ability to increase tool life without the downtime associated with tool wear allows significant cost savings, particularly in mass production. This paper presents the results of a study of the effect of grain size and cobalt content of carbide tool sinters on the tribological properties of the materials studied. The powders used for consolidation were characterised by irregular shape and formed agglomerates of different sizes. Tribological tests were carried out using the T-01 (ball-on-disc) method. In order to determine the wear kinetics, the entire friction path was divided into 15 cycles of 200 m and the weight loss was measured after each stage. In order to determine the mechanism and intensity of wear of the tested materials under technically dry friction conditions, the surface of the tested sinters was observed before the test and after 5, 10, and 15 cycles. The conclusions of the study indicate that the predominant effect of surface cooperation at the friction node is abrasion due to the material chipping that occurs during the process. The results confirm the influence of sintered grain size and cobalt content on durability. In the context of the application of the materials in question for cutting tools, it can be pointed out that sintered WC(0.4)_4 has the highest potential for use in the manufacture of cutting tools.

Evaluation of chemical–mechanical polishing of processed WC-Co surface structure

The cutting edges of commercial cutting tools have severe surface irregularities caused by the diamond grinding wheels that are used to form the cutting edges, which result in the introduction of lattice defects to the interior of the tungsten carbide (WC) crystal. In this study, we applied semiconductor polishing technology to finish the tool edge using a chemical–mechanical polishing grinding wheel. Microstructural analysis by backscattered electron imaging and electron backscattered diffraction revealed that WC crystal structures without any processing strain were obtained at a depth of ∼ 50 nm from the surface. We believe that this study will lead to the development of improved tool polishing technology that will prevent machining strain, and therefore, increase tool life.

Optimization and prediction of CBN tool life sustainability during AA1100 CNC turning by response surface methodology

The aluminium alloy (AA1100) was familiar with automotive flexible shaft coupling applications due to its high strength, good machinability, and superior thermal and resistance to corrosion characteristics. Machining tool life drives the prominent role for deciding the product quality (machining) act aims to productivity target with zero interruptions. The novelty of this present investigation is the focus on increasing tool life during the complexity of CNC turning operation for AA1100 alloy by using CBN coated insert tool with varied input parameters of spindle speed (SS), feed rate (f), and depth of cut (DOC). Design of experiment (L16), analysis of variance (ANOVA) statistical system adopted with response surface methodology (RSM) is implemented for experimental analysis. The turning input parameters of SS, f and DOC are considered as factors and its SS (900, 1100, 1300, and 1500 rpm), f (0.1, 0.15, 0.2, and 0.25), and DOC (0.1, 0.2, 0.3, and 0.4 mm) values are treated as levels. The investigational analysis was made with the ANOVA technique and the desirability of high tool life with input turning parameters was optimized by RSM, and sample no 11/16 was predicted as high tool life and performed with extended working hours compared to other samples. The RSM optimized best turning parameter combinations are 0.1 mm DOC, 0.2mm/rev to 0.25mm/rev f, and 1300 rpm–1500 rpm SS, facilitating a higher tool life of more than 20min.

Wear suppression and interface properties of diamond tool in micro-milling of TC4 alloy under graphene nanofluid MQL environment

The sustainable micro-milling process of TC4 alloy has garnered significant attention in aerospace engineering. However, the poor machinability of TC4 alloy results in particularly severe tool wear. Tool wear directly affects the machining quality of the parts, and traditional cutting fluids of suppressing tool wear indirectly increase production costs and pollute the environment. Therefore, to suppress the negative effects caused by tool wear, this paper proposes the application of water-based graphene nanofluid in the micro-milling of TC4 alloy in diamond tools. Firstly, micro-milling experiments and molecular dynamics simulations were conducted in different environments, including dry and water-based graphene nanofluid environments. Finally, tool surface wear morphology, milling forces, surface elements and structural phase changes were compared in detail. The results show that tool wear, including adhesive wear, abrasive wear, and edge chipping, was suppressed by graphene nanofluids compared to dry conditions, thereby increasing tool life. The graphene nanofluid improved the contact state between the tool and workpiece interface, reducing the milling forces. In addition, molecular dynamics indicates that the catalytic effect of the transition elements in the workpiece on the diamond tool was also weakened, and the carbon atoms of graphene were used as a sacrificial source to balance the catalytic effect. Graphitization and diffuse wear of the diamond were suppressed. More importantly, the water-based graphene nanofluid not only improves the wear resistance of the tool, but the LCA results show its potential for sustainability. Consequently, it holds promise for advancing the sustainable processing of challenging materials.

Experimental investigation of ultrasonic vibration-assisted cryogenic minimum quantity lubrication for milling of Ti-6Al-4V and grinding of Zerodur

Increasing demands on component properties are leading to the development of high-performance materials for which conventional production methods are reaching their limits from an economic and ecological point of view. In recent years, two technologies have been developed that show great potential compared to conventional machining processes, particularly in machining high-performance materials such as the titanium alloy Ti-6Al-4V. Ultrasonic-assisted machining leads to reduced cutting forces and increased tool life. Cryogenic minimum quantity lubrication prevents the occurrence of high machining temperatures and allows higher material removal rates without a negative impact on tool life. This paper shows the influence of ultrasonic-assisted milling and grinding processes in combination with cryogenic minimum quantity lubrication on the machinability of the high-strength materials Ti-6Al-4V and Zerodur. The investigation addressed cutting forces, tool wear, and surface roughness. The superposition of the technologies resulted in longer tool life and lower tool wear for both milling and grinding. However, the surface roughness was consistently higher due to the ultrasonic superposition. Nevertheless, machining with ultrasonic vibration-assisted cryogenic minimum quantity lubrication has great potential for difficult-to-machine materials, especially due to the reduction in tool wear.

Optimization of milling tool parameters and experimental study of cryogenic minimum quantity lubrication (CMQL) for SiCp/Al composites

Silicon carbide-reinforced aluminum matrix composites (SiCp/Al) have excellent physical properties, but the presence of SiC particles in the reinforcing phase causes severe tool wear and more serious surface defects during cutting, which seriously hinders the machining efficiency of SiCp/Al composites. To improve the surface quality of SiCp/Al composites and improve the tool wear problem, it were carried out that simulation and experimental verification of the milling tool parameters of SiCp/Al composites and experimental study of CMQL with the selected tool parameters. The results show that the cutting tool with rake angle of 4° and relief angle of 10° can achieve efficient cutting of SiCp/Al composites. The CMQL condition can effectively reduce the surface roughness, improve the surface microstructure, reduce tool wear and increase tool life; The increase of cutting speed can reduce the machined surface roughness, while the increase of feed and cutting depth will lead to the increase of surface roughness.

Progress in grinding performance by additive manufacturing of grinding wheels integrated with internal venturi cooling channels and surface slots

Among the most promising features of additive manufacturing are tool or form-free manufacturing and the ability to create intricate geometries that are difficult or even impossible to fabricate with traditional methods. These advantages can be employed to produce enhanced grinding tools. Efficient coolant fluid delivery into the cutting zone of the grinding operation has been a challenging problem since high frictional contact in the arc zone deteriorates the resin bond and lessens the grinding performance. This research study was dedicated to assessing the influence of internal cooling along with surface structures on the grinding performance of resin-bonded grinding wheels fabricated via additive manufacturing. This research introduced a novel structure that benefits from internal venturi shape cooling channels to provide exceptional fluid velocity in the tool and workpiece interaction zone. The grinding wheels have been produced employing vat photopolymerization. Grinding experiments with and without internal cooling were conducted on an aluminium plate to study the impact of introduced structures on the main aspects of grinding performance, such as cutting forces, surface roughness, tool wear, and dimensional accuracy. Two different grinding scenarios comprising shallow (10 μm depth of cut) and deep grinding (100 μm depth of cut) were carried out to reveal the influence of the material removal rate on the grinding experiments. The measured grinding forces revealed that integrating internal cooling channels and surface slots in a grinding tool could significantly reduce the grinding forces, which was more pronounced in the case of using venturi channels. Measured tool wear and dimensional accuracy together with calculated grinding ratio revealed that using cooling channels could participate in a notable increase in tool life and material removal ability, especially for venturi channels, due to improved cutting conditions, by which higher dimensional accuracy was obtained as well for the ground parts. Besides, it was discovered that the cooling channels could improve the surface quality of the ground part, which was less noticeable with the venturi channel grinding wheel. Furthermore, the optical and confocal microscopy detection confirmed that internal cooling channels could reduce chip loading on the grinding wheel surface, decrease the required number of dressing intervals, and cause effective promotion of tool life.

Increasing tool life and machining performance by dynamic spindle speed control along toolpaths for milling complex shape parts

This paper focuses on dynamic spindle speed and feed rate control to increase tool life and reduce machining time during milling of complex shaped parts. Machining of complex shaped surfaces is one of the most demanding machining applications, especially if the workpiece is made of difficult-to-cut material. Tool life needs to be considered during selection of cutting conditions. Both feed rate and cutting speed also have a direct effect on the resulting roughness and accuracy. When machining with tools with a circular cutting edge, such as ball or toroidal mills, the real cutting diameter of the tool changes continuously and as a result the cutting speed along the toolpath also changes continuously. Therefore a new method to compute the required spindle speed and feed rate was proposed based on the implemented kinematic parameters of a real spindle controller. In addition, a method to calculate the effective cutting radius of the tool based on the actual height of the remaining material was proposed to achieve a constant cutting speed through dynamic spindle speed control. The benefits of using the new optimization method were verified when machining a duplex stainless steel (1.4462) part. This test confirmed that the new optimization method results in a significant increase in tool life as well as a significant saving of machining time, while achieving the desired surface quality.

Minimum Quantity Lubrication An emerging technology for sustainable development

The machining of metals has traditionally involved the use of large quantities of water and oils for dissipating the cutting tool temperature, improving the surface finish of parts and increasing tool life. Invariably, the cutting fluid has become contaminated with use, has required being environmentally disposed and has accounted for approximately 17% of the total production cost of parts. The purpose of this article is to review the relevant literature in machining using minimum quantity lubrication particularly as it pertains to environmental and health issues and outline future potential research in this technology. The findings of this study show that MQL may be an economical and environmentally compatible lubricationtechnique. Keywords—MQL, cutting fluid, sustainability.

Influence of Friction Coefficient on the Performance of Cold Forming Tools

The automotive industry has undergone significant advancements and changes over time, resulting in the use of more complex parts in modern vehicles. As a consequence, the parts used in the manufacturing process are subject to higher stress levels, which reduce their service life. To mitigate this issue, surface treatments can be applied to improve the mechanical properties of the tools. In this study, we examined the impact of surface treatments on reducing tool stress during a cold forming process. The process involved reducing the thickness of a sheet from 6 mm to 2.5 mm, which generated high stresses in the tooling. We used finite element stress calculations to analyze the process and found that by reducing the friction coefficient to 0.1, tool stresses can be reduced by 20%, leading to an increase in tool life. Moreover, the press force and tool wear were also reduced by 18%. To validate the theoretical calculations, we performed field tests in a real manufacturing process.

A new trochoidal toolpath in milling operations

The milling is a widely used method in the manufacturing industry, especially in the production of complex engravings such as die&molds. Rough milling often requires a large material removal rate in a short time. This purpose also requires the selection and use of the best milling tool path. Today, trochoidal milling is receiving more attention than conventional milling, especially as it significantly increases tool life. In this study, a new toolpath model for trochoidal milling is suggested and this proposed toolpath model is examined in terms of cutting temperature, cutting force, surface quality, tool wear. In this new trochoidal toolpath model proposed for the milling method, the cutting force did not change much compared to the standard trochoidal tool path, but better surface quality and less tool wear were observed.

Towards energy efficient milling of variable curved geometries

Development of energy efficient machining is the present focus to industries for reduction of energy consumption and making the manufacturing system more sustainable. The continuous fluctuation in force profile during machining of variable curved components creates a barrier in stable machining and in cutting power consumption. The fluctuation in force profile happens due to alteration in chip load in the presence of workpiece curvature. The current research work intends to develop an energy efficient machining strategy for milling of variable curved components where more uniform cutting force and power profiles are accomplished due to constant chip load along the peripheral length of curved geometry. The proposed strategy is compared with conventional cutting in order to confirm the acceptability of the present algorithm. The proposed algorithm involves mechanics of milling, cutting forces and cutting power consumption. It is formulated based on constant chip load by regulating entry angle of milling cutter according to workpiece curvature along the peripheral length. Thus, the cutting power fluctuation occurred due to variation of workpiece curvature is reduced by regulating tool-workpiece engagement. The energy consumption during machining is reduced almost 22 % using the proposed approach. It results into developing an energy efficient machining strategy for milling of variable curved geometry. It also provides stable machining process and increased tool life by reducing tool wear due to reduction of force fluctuation during metal removal process.

The Effects of Lubricooling Ecosustainable Techniques on Tool Wear in Carbon Steel Milling

This research analyses the viability of using cryogenic cooling combined with MQL (minimum quantity lubrication) lubrication, under CryoMQL technology, as a cutting fluid in the industrial environment to justify the increase in the environmental footprint generated by its use compared to MQL in stand-alone mode. For this analysis, a set of milling tests were carried out on carbon steel AISI 1045, which is one of the most commonly used materials in the business day-to-day. In this set of tests, the evolution of cutting edge wear and energy consumption of both technologies were recorded to check their tool life through technological and environmental analysis. Thus, we sought to discern whether the energy savings derived from the machining process make up for the greater environmental footprint initially generated by the use of CryoMQL technology itself. The results obtained show how the use of CryoMQL not only increased tool life, but also allowed an increase in productivity by increasing cutting speeds by 18%; in other words, thanks to this technology, a more technologically advanced and environmentally friendly process is obtained. By increasing tool life by 30%, a reduction in energy consumption is achieved together with cost savings, which implies that ECO2 machining has economic and ecological benefits.

Fabrication of Large-Area Micro-Hexagonal Cube Corner Retroreflectors on Three-Linear-Axis Ultraprecision Lathes

Hexagonal cube corner retroreflectors (HCCRs) are the micro-optics arrays with the highest reflectivity. However, these are composed of prismatic micro-cavities with sharp edges, and conventional diamond cutting is considered unmachinable. Besides, 3-linear-axis ultraprecision lathes were considered unfeasible to fabricate HCCRs due to the lack of a rotation axis. Therefore, a new machining method is proposed as a viable option to manufacture HCCRs on the 3-linear-axis ultraprecision lathes in this paper. For the mass production of HCCRs, the dedicated diamond tool is designed and optimized. The toolpaths are proposed and optimized to further increase tool life and machining efficiency. The Diamond Shifting Cutting (DSC) method is analyzed in-depth both theoretically and experimentally. By using the optimized methods, the large-area HCCRs with a structure size of 300 µm covering an area of 10 × 12 mm2 are successfully machined on 3-linear-axis ultraprecision lathes. The experimental results show that the whole array is highly uniform, and the surface roughness Sa of three cube corner facets is all less than 10 nm. More importantly, the machining time is reduced to 19 h, which is far less than the previous processing methods (95 h). This work will significantly reduce the production threshold and costs, which is important to promote the industrial application of HCCRs.

Role of CO2 cooling strategies in managing tool wear during the shoulder milling of grade 2 commercially pure titanium

As a result of their high hardness, osseointegration and low chemical reactivity titanium alloys have become an invaluable material species for use in medical applications. Unfortunately, many of the material properties which make titanium alloys desirable biomedical materials, also contribute towards difficulties in tool wear and surface quality during machining. Historically, this has been met via the application of robust metalworking fluid (MWF) strategies, e.g. flood, or high-pressure (HP) soluble oil coolant (emulsion). However, this brings with it its own challenges, not least of which the problem of coolant residue contamination. This study describes efforts to minimise and characterise tool wear during the shoulder milling of grade 2 commercially pure titanium (CP–Ti) by using a novel external supercritical CO2 (scCO2) coolant strategy. Whilst the results imply that the sole use of scCO2 coolant contributes to increased tool wear (relative to emulsion), an optimised strategy of combining scCO2 with minimum quantity lubrication (MQL) is shown to support up to a 245% increase in tool life. Despite this, machinability outcomes are found to be highly contingent upon proper selection of trial process variables such as scCO2 mass flow rate and cutting speed, wherein cutting speeds at or below 115 m/min, and 35 kg/h of scCO2 is generally shown to be the most efficacious parameters for this material/operation. Ultimately, scCO2 + MQL is found to be an effective compromise between the cleanliness of scCO2 and the improved function of emulsion.

Case Study of Large Three-Dimensional-Printed Slider with Conformal Cooling for High-Pressure Die Casting.

Metal three-dimensional (3D) printing technology brings several benefits to the field of high-pressure die casting of aluminum, which enhances its development. The associated conformal cooling application is already commonly used where there is a need to improve the quality of castings, increase tool life, or reduce the production cycle. However, will this technology withstand the production of a large part (∼270 × 270 × 200 mm), which will be used directly in the serial production of engine blocks? This article describes a slider with a conformal cooling case study, which was redesigned and manufactured using the laser powder bed fusion (L-PBF) method. After the slider was put into serial production of 1.0 TSI three-cylinder engine blocks, this tool was thoroughly monitored based on the temperature field by comparing the results of a simulation in SW ProCAST with reality, and furthermore examining the influence of the tool on the quality of castings. There was also an evaluation of repairs performed on the tool in the ŠKODA AUTO tool shop and the foundry. These data were compared with a serial tool. Finally, the costs to produce the slider in conventional and 3D-printed variants are compared with an outline of other possible steps for optimizing these costs. The study results show that relatively large parts can be printed and used in serial production even today. It was also confirmed that conformal cooling influenced improving tool life, and the number of repairs in ŠKODA AUTO production also decreased.