Cemented Carbide End Mills Research Articles

Investigation on the performance of spark plasma sintered ultrafine WC-Co cemented carbide end mills during high-speed precision milling of Ti-6Al-4V alloy

In this study, ultrafine WC-Co and WC-(Ti,W)C-Co cemented carbide end mills were fabricated via spark plasma sintering. The performance of those tools in the high-speed precision machining of Ti-6Al-4V alloy was investigated, focusing on the analysis of tool wear mechanisms, cutting performance, and machined surface roughness. The results reveal that adhesive wear emerges as the predominant wear mechanism influencing the performance of both tools. The addition of (Ti,W) C leads to high workpiece element enrichment on the flank face of the tool, increasing subsequently severe adhesive wear. WC-(Ti,W)C-Co displays a greater propensity for crack propagation and material chipping, culminating in premature tool failure with the formation of significant wear craters and cutting edge breakage. Conversely, WC-Co exhibits comparatively milder wear patterns and a reduced incidence of cutting edge chipping due to its inherent resistance to adhesive wear. Additionally, the comparison of the developed ultrafine cemented carbide tools with similar commercial tools demonstrates that WC-Co has superior cutting performance in terms of tool life, 1.5–1.8 times longer than the commercial tools. These findings provide guidance for optimizing machining strategies and developing advanced tool materials for high-speed milling titanium alloy.

Wear behavior of ultrafine WC-Co cemented carbide end mills during milling of Inconel 718

Two innovative ultrafine cemented carbide end mills, denoted C1 and C2, were synthesized through spark plasma sintering, featuring compositions of WC-8Co-0.4VC-0.4Cr3C2 and WC-40(Ti,W)–8Co-0.4VC-0.4Cr3C2, respectively. Their wear behaviors were delved into during the precision machining of Inconel 718, and distinct disparities in wear evolution and tool longevity were unveiled. C1 exhibits exceptional wear resistance, surpassing C2 by a striking margin of 7.4–9.5, depending on the cutting speed employed. The sharp cutting edge of C1, characterized by a single hard phase of WC, minimal grain size, and high hardness, demonstrates excellent wear resistance and deformation resistance, thereby minimizing the onset of notch wear. In contrast, C2 experiences severe adhesive and diffusive wear phenomena, which culminate in substantial flank wear and cutting edge chipping. The addition of 40 wt% of (Ti,W)C exacerbates adhesion, flaking, and notch wear during machining. The prolonged and intensified adhesive wear witnessed in C2 leads to the deterioration of the tool surface and the formation of deep wear craters on the flank face. A comparison evaluation involving the prepared novel tools and commercially available end mills reveals that C1 boasts a longer tool life that outstrip those of its commercial counterparts by approximately 1.7–3.5 times under identical cutting conditions.

High Efficiency Milling of Inconel 625 Alloy (Effect of Cutting Condition on Tool Life)

Inconel 625 alloy consisting of Ni and Cr and others has advantageous properties such as heat resistance and corrosion resistance, which make it a suitable material for application in aerospace, energy, and marine industries. However, it is also a difficult-to-machine material because of factors such as work hardening, low thermal conductivity, and high tool affinity. Therefore, the problems of the tool wear, chipping, and adhesion often occur in milling of Inconel 625 alloy using end mills. In this study, the milling of Inconel 625 was conducted using coated cemented carbide end mills, and the cutting conditions with the high efficiency were investigated under three rotational speeds and four feed rates. The results showed that increasing the feed rate increased the surface roughness, but did not increase the tool life. In addition, the results also showed that increasing the rotational speed did not increase the tool life, but reduced the surface roughness. As a result, the effects of the rotational speeds and feed rates on the tool life were clarified.

Ultrafine WC–Co cemented carbide end mills prepared by spark plasma sintering and wear mechanism in milling of AISI H13

AbstractUltrafine tungsten carbide (WC)–cobalt (Co) and WC–(Ti,W)C–Co end mills were produced via spark plasma sintering. The wear mechanism of these end mills during machining of AISI H13 steel was investigated. WC–Co exhibits good mechanical properties (HV30: 2110 kg/mm2, KIC: 10.4 MPa/m1/2, TRS: 1990 MPa). Although the high hardness of WC–Co makes it show excellent resistance to abrasive wear, it suffers from a significant adhesion problem. As the cutting temperature increases, the oxidation of the WC–Co causes damage to the microstructure of tool materials, which deteriorates the grain boundary strength and promotes adhesive wear. This phenomenon causes large areas of tool materials to chip off and eventually results in cutting‐edge breakage. The high brittleness of (Ti,W)C causes cracks to propagate at low‐stress levels, reducing the mechanical properties of WC–(Ti,W)C–Co (KIC: 8.8 MPa/m1/2, TRS: 1090 MPa). However, (Ti,W)C addition enhances the resistance to oxidation and workpiece adhesion, which reduces the tool material loss caused by adhesive wear. The tool life of WC–(Ti,W)C–Co is three times longer than that of WC–Co in milling of AISI H13 at the same cutting speed. The key to maximizing the mechanical properties of ultrafine cemented carbide tools when machining AISI H13 is the modification of anti‐adhesive wear of surface.

Chatter failure comparison for high-speed milling of aerospace GH4099 with silicon nitride ceramic end mills: A laboratory scale investigation

Chatter generated in the high-speed cutting process can seriously limit the machining efficiency and affect the surface machining quality, which urgently needs to be controlled. Aiming at brittle ceramic end mills that are very sensitive to vibration, a strategy based on the modal experimental method is proposed to construct effective and accurate stability lobe diagram (SLD) for chatter prediction and failure analysis in this work. Firstly, the tool tip frequency response function (FRF) of four kinds of self-developed ceramic end mills and commercial cemented carbide end mills with the same structure are established by means of hammering modal experiments, and the modal parameters are solved and identified. Then, based on our established high-speed milling chatter prediction model, the milling force coefficients are obtained by linear regression analysis and calculation, thereby the milling SLDs of five end milling tools are developed. Finally, a series of high-speed side milling experiments are carried out using consistent cutting conditions. The results show that the constructed SLDs can effectively predict the chatter failure region and milling stability for five kinds of end mills, and four ceramic milling tools exhibit more excellent chatter suppression performance according to frequency domain analysis of vibration signals and the observation of workpiece surface vibration marks, in which the S4 ceramic milling tool presents the most significant high-speed milling stability.

Sharpening of graded diamond grinding wheels

Grinding the flutes of cemented carbide end mill cutters results in high and uneven radial wear of the grinding wheel. This is a consequence of the varying geometrical contact conditions over the grinding wheel width. Decreased manufacturing accuracy regarding the tool target geometry is the consequence. To compensate for this, the dressing intervals must be shortened. High non-productive times and an additionally reduction of the grinding layer results from this. The higher non-productive times reduce the productivity of the grinding process and, in conjunction with the shorter lifetime of the grinding tool, thus increase the costs per work piece. It has already been shown that load-adapted grinding wheels can reduce uneven radial wear up to 50%. The adaptation of the wear behaviour to non-uniform engagement conditions causes non-uniform radial wear to occur again under uniform engagement conditions. Uniform engagement conditions occur during grinding wheel sharpening. Therefore, the present study investigates the influence of sharpening on the grinding tool topography. For this purpose, sharpening tests are carried out on four differently graded grinding wheels. For comparability, the tests are also carried out on two non-graded grinding wheels. In the present work, the surface parameters are evaluated with regard to their suitability for analysing the sharpening condition of graded grinding wheels. The grain protrusion derived from this is subsequently used for evaluation. For this, a dependency on the grain concentration is proven and the grain protrusions are shown over the grinding wheel widths. From this, sharpening parameters are determined that enable reproducible sharpening of graded grinding wheels.

High-Speed Machining of Ti–6Al–4V: RSM-GA based Optimization of Surface Roughness and MRR

This article offers experimental research into getting the lowest possible roughness on the surface profile of Ti–6Al–4V produced by High-Speed Machining (HSM) in conjunction with the highest feasible material removal rate (MRR). All three machining variables—cutting speed (mm/min), feed rate (mm/min), and depth of cut (μm)—are investigated in this experiment. The combined optimization of Response Surface Methodology (RSM) and Genetic Algorithm (GA) are used to optimize the cutting parameters for a high-speed end milling operation. For the 20 distinct runs that CCD (Central Composite Designs) offers, employing uncoated cemented carbide end mill cutters is a more affordable choice for cutting the alloy Ti–6Al–4V. Machining data are analyzed with Design Expert software and MATLAB, respectively, utilizing RSM and GA. It has been shown that speeding up the cutting speed (105.56–138.86 mm/min) while decreasing the feed rates (25–37 mm/min) improves surface roughness. The minimum achievable surface roughness predicted by GA and RSM are 0.063 μm and 0.093 μm, respectively. This study presents that the desirability of getting the optimum result would reduce sharply (26.39%) by sacrificing the surface roughness for only 0.1 μm. The cutting edge will be ready for machining with optimum machining combination (cutting speeds of 105.56 and 138.86 m/min and feed rates of 25 and 37 mm/min). The findings illustrate that lowering the surface roughness by only 0.1 μm will increase the MRR rapidly (50.83%). A comparative study on the MRR is also conducted within the investigated input parameters range. The morphology of tool wear and the texture of the machined surface are examined using scanning electron microscopy (SEM) pictures.

Life Cycle Assessment for Rough Machining of Inconel 718 Comparing Ceramic to Cemented Carbide End Mills

Abstract Nickel-based alloys such as Inconel 718 belong to the group of heat-resistant super alloys. Combined with good mechanical properties over a wide range of temperatures, nickel alloys are used extensively in the aero engine sections exposed to elevated temperatures. Besides turbine blades and disks, integrally designed compressor rotors (Blisks) in the high-pressure compressor are increasingly made of Ni alloys. This is the result of an efficiency-driven increase in temperature levels in the rear compressor stages. The machining of these hard-to-machine materials is characterized by low productivity and high tool wear. Compared to the machining with conventional cemented carbide end mills, innovative SiAlON ceramics offer a significant potential to increase the performance of these machining processes while saving cooling-lubricants. Besides an increase in productivity, the evaluation of the overall environmental impact of specific manufacturing processes is gaining importance in the context of more sustainable product life cycles. This paper focuses on the comparison of different milling strategies in the production of high-pressure compressor rotors made from Inconel 718 in a cradle-to-gate assessment based on DIN EN ISO 14040/44. Thus, the ecological impact of both the state-of-the-art and the novel SiAlON roughing strategy are evaluated considering the consumption of energy, water and compressed air as well as the tool wear. The life cycle impact analysis (LCIA) will be performed as a midpoint analysis taking multiple indicators into account such as the global warming potential (GWP).

Pulsed magnetic field treatment of TiAlSiN-coated milling tools for improved cutting performances

In this study, a pulsed magnetic treatment was attempted to improve the cutting performance of the TiAlSiN-coated WC-12wt%Co cemented carbide end mills, and the effects of the strength of the pulsed magnetic field on the cutting forces, the cutting vibrations, the tool wear, the machined surface roughness, and mechanical properties were investigated. It is found that the cutting performances of the coated tools are successfully improved with a relatively lower cutting force and less wear area. The average resultant cutting force \({Fxy}_{ave}\) decrease by 14.53% in the last machining process when the optimum processing parameters of 0.5 T magnetic field are used, accompanying a maximum decrease of 46.8% in the cutting vibration. The maximum reductions of 57.65% and 25.4% in the flank wear and the average surface roughness of the workpiece are obtained respectively after the treatment. Both the hardness and toughness of the cemented carbides are slightly improved with the imposition of the field. The improvements in the cutting performance of the tool are attributed to the enhanced adhesion strength between the coating and matrix, which is caused by the increased compressive residual stress induced by the PMT.

Operational behaviour of graded diamond grinding wheels for end mill cutter machining

The varying related material removal rate during deep grinding of cemented carbide end mill cutters results in an unevenly wear of the grinding wheel. This study therefore presents a simulation-based model for the load-adjusted design of grinding wheels to achieve balanced radial wear, as well as an evaluation of this model. The related material removal rate along the width of the grinding wheel is determined by a Dexel based material removal simulation for different end mill geometries. Based on these results an equation is derived to adapt the abrasive layer properties to the local load differences. Three grinding wheels with different types of gradients are then manufactured by a grinding tool manufacturer based on this equation. These and two grinding wheels with constant abrasive layer properties are used for deep grinding of ten end mills each. Afterwards the radial wear of each grinding wheel is measured by a confocal microscope. An analysis of the cutting edge chipping is done to evaluate the influence on the graded grinding wheels on the cutting edge quality. It was found that a reduction of the wear difference over the grinding wheel width of 52% and an improved cutting edge quality can be achieved by using graded grinding tools. This allows the time intervals between dressing steps to be increased without compromising the accuracy of the grinding process, thus also increasing its productivity. Finally, this article shows that the presented model allows for a more balanced wear behaviour, but has to be extended by considering further factors influencing radial wear.

Experimental Study on High Speed Cutting of 7075 Aluminum Alloy

A 4-edge cemented carbide end mill with a diameter of 6 mm was used to mill a single factor groove of 7075 aluminum alloy. The results show that the surface roughness of the bottom surface of the narrow groove decreases with the increase of the cutting speed in the range of variable cutting speed. Moreover, when the cutting speed is the highest, the burr on the edge of the narrow groove is not completely eliminated, and there are more burr and curling. When the feed rate is selected as a variable, the surface roughness of the bottom surface of the milling narrow groove increases with the increase of the feed rate. When the cutting depth is selected as a variable, the surface roughness of the bottom surface of the milling narrow groove increases with the increase of the cutting depth. There are obvious extrusion bulge marks between the two intersecting steps on the bottom surface of the milling narrow groove. The reason of extrusion bulge on the bottom surface of milling may be due to the large width and elastic deformation of 7075 aluminum alloy material, which results in large plastic flow under the cutting extrusion of milling tool.

Tailoring Surface Integrity of Biomedical Mg Alloy AZ31B Using Distinct End Mill Treatment Conditions and Machining Environments

Magnesium alloys are identified as the new generation degradable biomaterials in the biomedical industry. They can prevent secondary operation for the removal of the inserted implant. Nowadays, sustainable manufacturing is promoting the use of low-temperature machining environments over the traditional means. Surface integrity characteristics of the machined surface and tool wear have always been some of the key interests of the researchers. In this research, aluminum titanium nitride-coated cemented carbide end mills were employed in an untreated and cryo-treated condition to machine the biomedical magnesium alloy AZ31B. The experiments were designed using one-factor-at-a-time (OFAT) approach, and milling operations were conducted under three different machining environments, namely wet, cryogenic, and hybrid. Spindle speed, feed rate, and depth of cut were chosen as the input control variables for a comparative study to achieve lowest surface roughness and highest surface microhardness. The results displayed an improvement in the outcome at higher spindle speed (2800 rpm) and lower feed rate (80 mm/rev) and depth of cut (0.5 mm) produced by untreated end mill during cryo-milling. However, the treated end mill performed best with hybrid machining environment (simultaneous application of LN2 and cutting fluid) during milling. Moreover, in this case, the accumulated oxides were found to form the most uniform and thinnest passivation layer over the milled surface. Higher spindle speed in cryo-milling achieved 27.45 and 19.56% better surface finish than wet and hybrid-milling, respectively. Moreover, higher spindle speed in cryo-milling achieved 14.46 and 8.72% higher surface microhardness than wet and hybrid-milling, respectively. Higher spindle speed in hybrid-milling achieved 14.89 and 6.97% better surface finish than wet and cryo-milling, respectively. Furthermore, higher spindle speed in cryo-milling achieved 7.69 and 4.10% higher surface microhardness than wet and cryo-milling, respectively.

A comparative analysis of ceramic and cemented carbide end mills

Milling of ferrous metals is usually performed by applying cemented carbide tools due to their high hardness, temperature and wear resistance. Recently, ceramic tool materials have been on the rise and enhanced the efficiency in machining. As ceramics are brittle-hard materials, tool manufacturing requires a sound knowledge in order to meet the tool requirements such as sharp cutting edges and wear resistance. In this study, milling tools made of the high performance ceramic SiAlON were compared to tools made from cemented carbide. For both tool materials, the influence of a prepared cutting edge was investigated. Both the tool manufacturing process and the cutting edge preparation processes are presented, followed by the application of those tools within milling experiments. In order to evaluate the efficiency of both tool types, the cutting forces and the cumulative process energy demand were analyzed. Additionally, surface roughness of the machined workpieces and tool wear were examined. It was found that the ceramic tools, although process forces were higher than for cemented carbide tools, exhibited by far lower energy consumption, less tool wear and finally generated lower surface roughness.

Influence of machining parameters on the polymer concrete milling process

The paper examines the wear of end mill cutters, the parameters of a workpiece’s surface layer and the values of cutting forces during the machining of polymer concrete, which is one of the most difficult-to-cut materials. Increased abrasive wear of the active cutting edges is a result of the heterogeneous structure of this material, and it has a negative effect on the cutting process, the durability of the cutting tools as well as the roughness of the workpiece. It is very important to determine the machining parameters for this material from a tool durability and quality of machining point of view. The research was divided into two stages. In the first stage, the appropriate machining parameters were determined based on the measurement of the components of the cutting force. In the second stage, durability tests of four end mill cutters were carried out. During the tests, the component cutting forces, tool wear and surface roughness were measured. The highest tool durability was recorded for the monolithic cemented carbide cutter with coating NC Mill G9F42120N 4F. Tools made of high-speed steel should not be used for machining polymer concrete, as they exhibited the highest intensity of tool wear. The rapid loss of machinability of these tools leads to a rapid increase in cutting force and the roughness of the machined surface. From an economic point of view, cemented carbide end mill cutters with coatings seem to be the appropriate choice for machining polymer concrete.

Damaging of cemented carbide end mill with different grain sizes: experimental and simulation

The main purpose of the current study was to investigate the effects of the size of WC grains on the damage evolution of WC–Co junk mills. The finite element method (FEM) simulation results showed that the fine-grain (FG) tool retained its cutting edges radii longer than the coarse-grain (CG) tool. This event leads to the larger wear rate in the CG tool. Moreover, FEM analysis indicated that through increasing the feeding rate, the wear rate and the cutting forces increased as well. The observation of worn tool surface revealed that the formation of micro-pits, micro-cracks, scratching grooves and broken WC grains was among the common signs of the damage for both CG and FG tools. However, it was found that the defects are more intensive in the CG tool. This can be due to the lower boundary strength and less WC connectivity in the CG milling tool. The finer grains also decreased the mean free path in the Co binder and impeded the micro-cracks propagation in the material.

Study on tool wear for mircomilling of 6061 aluminium alloy

Tool wear is one of the key points of studies onmicromilling, which affects tool durability and milling efficiency. In this paper, the two-flute cemented carbide end mills with coating TiAlN are used to conduct the experimental studies on the tool wear inmicromilling process for 6061 aluminium alloy material. The wear form and wear mechanism of tools are analyzed. The influence sequence of key parameters on tool wear and the optimized parameters combination are obtained by the orthogonal experiment results analyses. The results show that whenmicromilling 6061 aluminium alloy, the main wear forms of the tools are coating peeling and tip breakage, and the wear mechanism is adhesive wear. The significance order of key milling parameters for the wear band width of the side edge from large to s mall is radial depth of cut ae, feed per tooth fz and axial depth of cut ap. The optimized parameters combination which can obtain the minimize tool wear is ae = 300 μm, fz = 1 μm and ap = 150 μm. In actual machining, the tool life can be improved by selecting suitable processing parameters. The results of this study can be used as a reference for the selection of parameters inmicromilling.

Performance analysis of AlTiN/AlCrN coating on cemented carbide cutting tool using fuzzy logic analysis

The main aim of this research work is to investigate and optimise the performance of coated and uncoated cemented carbide end mill cutting tool while dry machining high hardness EN-8 grade steel. Three different end mill tools: one uncoated and the other two with 2–4 μm thickness of AlTiN coating and AlCrN coating, respectively, are used to process the EN-8 steel using a three-axis CNC milling machine. The coatings are applied using arc-PVD process. Pocket milling operation is performed on the workpiece. The effect of varying cutting parameters of cutting speed, depth of cut and feed rate, which influence the output parameters of surface roughness, temperature and material removal rate are studied. Optimisation of the output parameters is done using Taguchi Design of Experiments method with L9 orthogonal array of experiments for single-objective function of surface roughness. Fuzzy logic analysis method is used to predict the best optimal solution, and to find out the most influential parameter to determine the output characteristics. SEM and XRD analysis are studied to characterise the coated cutting tool and analyse the workpiece surface finish.

Tool Wear of Aluminum/Chromium/Tungsten/Silicon-Based-Coated End Mill Cutters in Milling Hardened Steel

In turning hardened steel, polycrystalline cubic boron nitride (cBN) compacts are widely used, due to their high hardness and high thermal conductivity. However, in milling hardened steel, fracture of cBN cutting tools readily occurs because they have poor fracture toughness. Therefore, coated cemented carbide tools, which have good fracture toughness and wear resistance, are generally and widely used. In this study, hardened steel (ASTM D2, JIS SKD11, 60HRC) was milled with three physical vapor deposition coated cemented carbide end mill cutters in order to determine effective tool materials for milling hardened steel. The coating films used were two types of aluminum/chromium/tungsten/silicon-based-coating films and (Ti,Al)N-coating film. The two types of aluminum/chromium/tungsten/silicon-based-coating films are a new type of coating film, and the Type I and Type II coating film was a two-layered and multi-layered structure, respectively. The following results were obtained: (1) In milling hardened steel at a cutting speed of 2.5 m/s, Type II coating film was the best coating material among the three types of coated film. Type I coating film was superior to (Ti,Al)N-coating film. (2) The critical scratch load of both Type I and Type II of over 130 N became larger than that of the (Ti,Al)N-coating film of 65 N. (3) The multi-layered structure is expected to improve the tool life.

Roughness Model for Helical Flute of Cemented Carbide End Mill under Grinding

Roughness Model for Helical Flute of Cemented Carbide End Mill under Grinding

Structural design of groove and micro-blade of the end mill in aluminum alloys machining based on bionics

In aerospace manufacture industry, cutting vibration is a key factor for surface quality and tool life during milling of thin-walled aluminum alloy parts, and the high-efficiency machining is limited seriously for this reason. In this research, the cutting layer’s deformation was inhibited to reduce cutting vibration by optimal design of cutting edge structure. Base on the observation and imitation of corn leaf’s teeth, the structure of groove and micro-blade of peripheral cutting edge was designed. The orthogonal cutting models were developed to analyze the cutting process by ABAQUS. Furthermore, comparative experiments of milling aluminum alloy 7050-T7451 were carried out to analyze the cutting force, vibration, surface roughness, and residual stress. The test and simulation results showed that the designed solid cemented carbide end mill based on bionics had a good effect for inhibiting the cutting layer’s deformation. The fluctuations of cutting force, cutting vibration, surface residual stress, and surface roughness were reduced effectively.