Carbide End Mill Research Articles

Performance of carbide end mills coated with new generation nano-composite TiAlSiN in machining of austenitic stainless steel under near-dry (MQL) and flood cooling conditions

In the present study, a new generation nano-composite TiAlSiN coating has been deposited on 2-fluted carbide end mills using High Power Impulse Magnetron Sputtering (HiPIMS) in quadra-cathode target configuration. A highly smooth coating of about 3 μm thickness was realized and coated tools were subject to high-speed milling of austenitic stainless steel, which is otherwise known to cause severe diffusive wear on uncoated carbide tools. The effectiveness of TiAlSiN coating has been investigated on austenitic stainless steel under dry, wet (flood, 25 l/h), and near-dry (MQL, 250 ml/h) conditions. TiAlSiN coated tools experienced severe diffusive adhesion of work material on its cutting edge during dry machining. The near-dry approach with a cutting fluid consumption rate of only 250 ml/h was found to be a more effective, and greener approach. There was no sign of delamination of the coating under dry, flood, and near-dry environments. A maximum of 20 % reduction in cutting force and 45 % reduction in roughness (Ra) have been recorded in a near-dry environment compared to a flood environment. Performance of the HiPIMS deposited TiAlSiN coated tools have also been compared with that of commercial TiAlN and commercial TiAlSiN tools (deposited by DC Magnetron Sputtering) and found to be potentially more effective in milling of SS304 steel.

Micro End Mill Capability Improvement Due to Processing by Fast Argon Atoms and Deposition of Wear-Resistant Coating

Micro-milling is widely used to make micro-channels in various fields. In this study, micro-milling of rectangular bronze microchannels was carried out with carbide end mills with a diameter of 1 mm, processed with fast argon atoms, and coated with anti-friction wear-resistant titanium diboride. It was shown that the removal of a 3 µm thick surface layer from a micro end mill with fast argon atoms makes it possible to reduce the cutting edge radius of the tool to 1.2 µm, which is three times lower than the minimum value of 4 µm achievable in mechanical manufacturing. The subsequent deposition of a 3 μm thick anti-friction coating results in a wear-resistant micro end mill with original geometric parameters but improved performance. The surface roughness of the machined bronze microchannel significantly decreased, and the burrs above the groove practically disappeared after micro-milling.

Comparison of Machinability Performances in Milling of Al-7Si-Mg and Al-7Si-0.6Mg Alloys

In this study, the microstructural, mechanical and machinability properties of Al-7Si-Mg and Al-7Si-0.6Mg casting alloys were experimentally researched. While the microstructures of the alloys were determined by optical microscope, the hardness values were determined by Brinell method, elongation to fracture, yield (YS) and tensile strength (TS) values were measured by tensile tests. Milling experiments were performed 6 mm diameter of uncoated carbide end mill which two flutes in CNC vertical machining center using different cutting speeds (V), feed rates (f) and a constant depth of cut (DoC). In microstructural examinations, it was observed that the microstructure of the Al-7Si-Mg alloy comprised of a-Al, primary Si, eutectic Al-Si, Mg2Si, B-Al(Fe, Mn)Si, β-Al5FeSi and π-AlSiMgFe phases. In addition to the existing phases, B-Al8Mg3FeSi6 phase was formed in the microstructure of the Al-7Si-0.6Mg alloy. Al-7Si-0.6Mg alloy exhibited higher hardness, YS and TS and lower elongation to fracture (EF) values compared to Al7Si-Mg alloy. In the milling tests, it was stated that the cutting force (CF), built-up layer (BUL) and builtup edge (BUE) reduced with the increment of the V, while it increased with the increment of the

Removal of Wear-Resistant Coatings from Cutting Tools by Fast Argon Atoms

Wear-resistant coatings improve the machining capability of cutting tools and extend their useful life. However, when a tool needs to be reused, it is mandatory to remove the existing coating to facilitate resharpening and recoating. The existing technique uses electrochemical stripping, which is hazardous to the environment. The environmentally friendly pulsed laser stripping causes the melting and mixing of tools and coating materials, which makes it difficult to separate and remove the coating. This paper presents the results of coating stripping via a beam of fast argon atoms. Due to the twentyfold compression of the beam, a 3 µm thick AlTiN coating was removed from a rotating solid carbide end mill within 25 min. A subsequent one-hour-long irradiation of the cleaned tool with the same beam led to a decrease in the radius of the tool’s cutting edges from 10.5 to 3.5 µm. This allowed us to redeposit a 3.5 µm thick AlTiN coating and obtain a coated end mill with a cutting-edge radius of 7 µm.

Analisa Keausan Mata Pahat Kardiba dan Kedalaman Potong pada Proses Milling Baja SKD 11

Not all machining processes are carried out using a CNC (Computer Numerical Control) system, but are started by using conventional machines that do not require a high level of accuracy. In accordance with the advantages it has for product accuracy, most CNC systems are intended for finishing processes. The level of surface roughness of a product is indeed adjusted to the usefulness of the product itself, but it cannot be denied that the better the quality produced, the higher the selling value of the product. This study aims to determine the effect of variations in depth of cut on the wear value of the EndMill Carbide chisel on the SKD 11 steel material used in the manufacture of Dies. This study used a literature study type method, research procedures, first material preparation, second specimen machining procedure, recorded cutting time, looked at the surface of the tool after the cutting process was carried out using a microscope, determined the condition of the tool damage and then re-cut until the tool could not be used again or wear has reached 0.3 mm, then record the cutting length every 5 minutes of cutting and finally data analysis. Based on the results of the test data obtained, it shows that the wear of the carbide endmill (VB) chisel blade from the comparison of machining time and feed rate has a graph, namely if the cutting time is longer, namely 30 minutes. The higher the cutting length, the faster the wear value occurs and vice versa the lower the cutting length value, the smaller the wear value achieved. The type of endmill carbide cutting tool wear that occurs is flank wear.

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.

티타늄 합금의 평엔드밀 가공 시 공구 방향에 따른 가공성 평가

Titanium alloys are classified as difficult-to-cut materials with poor machinability, leading to a continuous demand for the development of machining methods. For machining titanium alloys, various tool orientations can be employed based on the shape of the workpiece, such as the presence of an inclination angle. In this study, machining tests considering tool orientation were performed using a solid carbide end mill tool. The tool orientation was classified into three categories with inclination angles of 90° (Reference), 45° (Upward), and 135° (Downward). The machining tests indicated that the Reference orientation exhibits the longest tool life and best surface roughness. Conversely, the Upward orientation exhibited the shortest tool life, while the Downward orientation exhibited the poorest surface roughness. When considering the Upward and Downward cases, the contact length between the cutting edge and the material becomes longer due to the inclination angle during machining, which in turn affects cutting performance.

Influence of cutting damage on the bending strength of Ti<sub>2</sub>AlC MAX phase machinable ceramics

Ti2AlC MAX phase ceramics are excellent candidates for high-temperature heat resistant materials. In addition, they are machinable using cemented carbide tools. However, heavy machining induces many surface cracks, reducing the mechanical strength and reliability of ceramic parts. Herein, we investigated the influence of the machining process on the bending strength and microstructure of Ti2AlC ceramics. Nearly fully dense Ti2AlC ceramics with elongated grains were machined using a carbide end mill in brittle mode, producing numerous cracks; however, the roughness of the ceramic was similar to that of tool steel cut in ductile mode. Despite its rough surface, the bending strength of the machined Ti2AlC was only slightly lower than that of polished Ti2AlC. The cracks in the machined Ti2AlC ceramics were induced with a kinking structure; however, they stopped at a length equivalent to one grain. The minimum strength of the machined Ti2AlC ceramics with a fracture toughness of 6.9 MPa·m1/2 was estimated by assuming a machining through-crack shape that was as deep as the maximum grain size. Cutting damage was limited to a single grain; thus, the bending strength of the machined Ti2AlC was not significantly reduced.

Comparative analysis of tool wear in micro-milling of wrought and selective laser melted Ti6Al4V

The parts produced by additive manufacturing (AM) are not usually appropriate for direct applications and require several post-processing operations. Micro-milling, as a most common post-processing operation in micromachining, is performed considering selective laser melted (SLM) Ti6Al4V as the workpiece under dry condition. The experiments are conducted considering a constant cutting speed and axial depth using a TiAlSiN-coated tungsten carbide end mill of Ø300 μm. It employs two different feed rates considering the size effect imposed by the edge radius of the micro end mill. The micro-milling performances for the SLM Ti6Al4V are compared with the performance for wrought Ti6Al4V. The outcomes, such as tool wear and surface characteristics, are examined for both the materials. Equiaxed grains, exhibiting higher ductile nature of wrought Ti6Al4V, produces adhesive tool wear, BUE formation and poor surface topography at both feed rates. Alternatively, the lamella microstructure of SLM Ti6Al4V, exhibiting relatively high hardness, produces less adhesive tool wear and BUE formation; instead, it generates more abrasion of the tool and hence increases the surface roughness. Quantitatively, the cutting-edge radius enlarges by 18–37% and 10–34% for wrought and SLM Ti6Al4V, respectively. Moreover, the SLM Ti6Al4V shows an 8–10.6% lower average surface roughness value than wrought Ti6Al4V.

EFFECT OF THE COOLING WITH AIR AND WATER VAPOR ON MILLING PERFORMANCES

This study aims to investigate experimentally and analytically the effects of different machining parameters such as cooling methods and cutting tool materials on surface roughness and chip thickness ratio for milling of AA7075-T6 aluminum alloy. The carbide and high-speed steel (HSS) end mills were used as cutting tools and the conventional, vapor, and compressed air were used as cooling methods in the experiments. The experiment conditions for compressed air at the cutting zone were 6 bar pressure and 30[Formula: see text]m/s speed flow rate. A mixture of boron oil and water (1/20 mixture ratio) was used as cutting fluid in conventional cooling. The study was carried out using three levels of feed rates (20, 40, 80[Formula: see text]mm/min), rotational speeds (780, 1330, 2440[Formula: see text]rpm), and a constant 2[Formula: see text]mm deep cut. As a result of the experiments, the surface roughness values increased with the increasing levels of feed rate. Besides surface roughness values decreased with increasing levels of the rotational speed. In addition, a better surface quality was obtained in milling processes by using carbide cutting tools compared to HSS tools. It was concluded that the most important parameter affecting the surface roughness and chip thickness ratio is feed rate and the rotational speed, respectively. Better surface roughness and chip thickness ratio were obtained from the vapor processing than the conventional and compressed air.

Influence of Size Effect in Milling of a Single-Crystal Nickel-Based Superalloy

This paper details an experimental investigation on the influence of the size effect when slot-milling a CMSX-4 single-crystal nickel-based superalloy using 1 mm- and 4 mm-diameter TiAlN-coated tungsten carbide (WC) end-mills. With all tools having similar cutting-edge radii (re) of ~6 µm, the feed rate was varied between 25-250 mm/min while the cutting speed and axial depth of cut were kept constant at 126 m/min and 100 µm, respectively. Tests involving the Ø 4 mm end-mills exhibited a considerable elevation in specific cutting forces exceeding 500 GPa, as well as irregular chip morphology and a significant increase in burr size, when operating at the lowest feed rate of 25 mm/min. Correspondingly for the Ø 1 mm micro-end-mills, high levels of specific cutting forces up to ~1000 GPa together with severe material ploughing and grooving at the base of the machined slots were observed. This suggests the prevalence of the size effect in the chip formation mechanism as feed per tooth/uncut chip thickness decreases. The minimum uncut chip thickness (hmin) when micromilling was subsequently estimated to be less than 0.10 re, while this increased to between 0.10-0.42 re when machining with the larger Ø 4 mm tools.

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).

Tool Condition Monitoring Using Machine Tool Spindle Electric Current and Multiscale Analysis while Milling Steel Alloy

In the metal cutting process, the tool condition directly affects the quality of the machined component. To control the quality of the cutting tool and avoid equipment downtime, it is essential to monitor its condition during the machining process. The primary purpose is to send a warning before tool wear reaches a certain level, which could influence product quality. In this paper, tool condition is monitored using fractal analysis of the spindle electric current signal. The current study analyzes the monitoring of the cutting tool when milling AISI 5140 steel with a four-flute solid carbide end mill cutter to develop monitoring techniques for wear classification of metal cutting processes. The spindle electric current signal is acquired using the machine tool internal sensor, which meets industrial constraints in their operating conditions. As a new approach, the fractal theory is referred to analyze the spindle electric current signal and then assess the tool wear condition during the metal cutting process. Fractal parameters were defined to extract significant characteristic features of the signal. This research provides a proof of concept for the use of fractal analysis as a decision-making strategy in monitoring tool condition.

Effect of end milling parameters on MRR and hardness variation of AA7075

The end milling process is a bulk machining process used for machining an edge surface on the part, making slots, pockets, dies and moulds. Aluminium alloy 7075 (AA7075) is an alloy, with zinc as the principal alloying element. It shows good ductility, high strength, toughness, and fatigue resistance. It is one of the most used aluminium alloys for highly stressed structural applications and is widely applied in aircraft structural parts.By considering the application of AA7075 and uses of the milling process in product manufacturing, the present work focuses on studying the effect of End milling process parameters in the milling of AA7075 plate by varying three distinct parameters: Cutting speed (S), Feed (f) and Depth of cut (d). The output parameters measured were Material Removal Rate (MRR) and Hardness (BHN) variation on the machined surfaces. The BHN of the machined surfaces varied from 178 to 260 BHN. Similarly, the MRR varied from 1500 to 13200 mm3/sec. The down milling experiments were conducted as per Taguchi’s L9 orthogonal array on a 6 mm thick plate using a solid carbide end mill cutter of 10 mm diameter.The effect of milling process parameters on selected responses was analyzed, and the optimization of process factors for maximization of MRR and hardness was carried out to improve the machinability of AA7075 alloy.

Vibration features for indirect monitoring of end micromilling process

Monitoring a micromachining process is essential to ensure machined surface quality. Vibration signal has been used to monitor conventional process, however, to apply this signal to monitor a micromachining process is not a simple task. One of the main difficulties is to identify which signal features is correlated to changes in the micromachining process, such as roughness. This work investigates the correlation between vibration signals for an end micromilling operation. Different features were extracted from time and frequency domain aiming to analyze their correlation to the roughness and identify those better correlated to surface roughness. Six carbide end mill tools with a diameter of 0.4 mm were tested under different parameters. Vibration signals were collected, and roughness was measured for each machined channel. Through the analysis of the vibration signals and Pearson Correlation, features that are directly correlated with the roughness were identified, with emphasis on 2 x IPF (Insert Passing Frequency). The results show that the proposed features can be used for indirect monitoring of the end micromilling process, avoiding unnecessary stops and fabrication of rejected parts.

Effect of milling parameters on the surface quality of a flax fiber-reinforced polymer composite

Flax fiber-reinforced polymer composites are an interesting alternative to synthetic fiber-reinforced polymer composites for many engineering applications. When machining flax fiber-reinforced composite materials that are by definition heterogeneous, the matrix and the fibers react differently and hence many sorts of damage may occur such as poor surface roughness, delamination, and fluffing. The novelty of the current work lies in identifying the major factors that affect the quality of the milled surface of composites reinforced with flax fibers and provides recommendations and collaborative solutions to the composite machining community. In this study, the impact of cutting conditions (cutting speed, feed rate, and fiber orientation) on the cutting forces and surface roughness during milling of the flax/epoxy composite is investigated. For this purpose, slotting tests are performed on flax fiber-reinforced polymer plates using a carbide end mill tool based on a full factorial design of experiment. Furthermore, a randomization in the order in which experimental runs are done is used to reduce bias by balancing the effect of uncontrolled variables that have not been accounted for in the experimental design. It is concluded that the feed rate has the most influence on the cutting forces and roughness parameters. Moreover, the fibers orientation also has a significant effect on the outputs, and the cutting speed has less effect but it remains significant.

Single and multi-objective optimization for cutting force and surface roughness in peripheral milling of Ti6Al4V using fixed and variable helix angle tools

Ti6Al4V titanium (Ti) alloy is a frequently used engineering material in industrial applications due to its superior properties. In this work, single-objective and multi-objective methods were used to optimize control factors (cutting speed, feed rate, and cutting tool helix angle) for minimal cutting force (Fc) and surface roughness (Ra) in peripheral milling of Ti6Al4V. Machinability experiments were performed using carbide end mill cutting tools with fixed and variable helix angles. Following the machinability tests performed using the L18 orthogonal array, the Taguchi technique was used as a single-objective optimization for each of the cutting forces and surface roughness. The Entropy-weighted TOPSIS approach was used in the second step to provide the optimum levels of the control factor, which minimizes both cutting force and surface roughness. The effects of control factors and interactions on thrust force and surface roughness were determined by Analysis of Variance (ANOVA) and contour plots. As a result of this study, it was determined that the helix angle of the cutting tool (84.91 % contribution) was the most effective parameter on the cutting force and the feed rate (22.71 % contribution) on the surface roughness. The cutting force and surface roughness values decreased in peripheral milling at high cutting speed, whereas the cutting forces increased, and the surface quality of the workpiece deteriorated in machining at high feed rates. The helix angle of the cutting tool has a favorable influence on the cutting force and surface roughness when milling with fixed helix tools. Cutting forces are minimized, and workpiece surface quality is improved using cutting tools with a larger helix angle. Variable helix tools with a large helix angle performed best in cutting force and surface roughness. Variable helix end mills with large helix angle (HA = 35°/38°), high cutting speed (Vc:108 m/min), and a low feed rate (f:0.04 mm/tooth) should be used in peripheral milling of Ti6Al4V Ti alloy to achieve both minimum cutting force and best surface quality. The mean cutting force and surface roughness values were obtained as 628.69 N and 0.363 μm, respectively, in the peripheral milling process performed at different levels of control factors. The cutting force was reduced to 227.52 N (34.71 % improvement) and the surface roughness value to 0.237 μm (276.32 % improvement) using the Entropy-weighted TOPSIS multi-objective optimization approach.

Improvement of structural/tribological properties and milling performances of tungsten carbide cutting tools by bilayer TiAlN/TiSiN and monolayer AlCrSiN ceramic films

In this study, bilayer TiAlN/TiSiN and monolayer AlCrSiN ceramic films were grown on carbide cutting tool material by cathodic arc physical vapor coating (CAPVD) method to improve the structural/tribological properties and milling performances. The ceramic films were applied on cylindrical test samples and carbide end mills. The coated materials' structural, mechanical, and tribological properties were determined via scanning electron microscope (SEM), X-ray diffraction meter (XRD), tribometer, microhardness tester, and optical profilometer. DIN 40CrMnNiMo8-6-4 steel workpieces were machined by using a CNC vertical machining center to determine the actual working performance of the coated and uncoated cutting tools. The wear performance of the cutting tools after machining was determined by measuring the flank wear widths and mass losses. The hardness and adhesion results of the coated sample with bilayer TiAlN/TiSiN were higher than the coated sample with monolayer AlCrSiN. According to the scratch test results, the best adhesion results were obtained for TiAlN/TiSiN coating. The critical load value was determined as about 105 N. As a result, the wear rate value of the TiAlN/TiSiN thin film coated sample was lower. After machining, the mass loss of TiAlN/TiSiN coated tools was lower than AlCrSiN coated tools. In addition, the surface roughness value of the workpiece machined by the cutting tool coated with AlCrSiN was higher than the cutting tool coated with TiAlN/TiSiN.

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.