Coated Carbide End Mills Research Articles

Understanding the effects of cutting conditions on vibrations, surface integrity, machining temperature and tool wear mechanisms in end milling of AISI D2 Steel

The study explores vibrations, and thermal and tool wear (TW) mechanisms during dry end milling of AISI D2 steel employing two-, four-, and six- flute designs of TiAlN-PVD coated carbide end mill cutting tools. Because of multi-physics interactions in machining zone, supervised machine learning is used to understand TW, machining vibrations (MV), surface roughness (Ra) and the temperature of machining zone (TMZ), and to correlate the surface characteristics. A dedicated full factorial design of experiments campaign involving flutes (Fn), feed rate (Fr), and depth of cut (Doc) as variables is carried out to learn tool-workpiece interfacial characteristics. Results revealed that MV, Ra, TMZ and TW improved 57.82 %, 87.11 %, 79.22 % and 79.40 %, respectively at Fn = 6, Fr = 300 mm/min and Doc = 0.5 mm. Supervised machine learning (neural networks) and non-dominated sorting genetic algorithm (NSGA-II) based results showed reduction in vibrations by 89.84 %, Ra 97.39 %, tool-workpiece interaction temperature by 56.86 % and TW by 57.07 % by understanding mechanistic correlations of machining parameters with performance metrics.

Experimental research and optimization based on response surface methodology on machining characteristics of cast Al-7Si-0.6 Mg alloy: Effects of cutting parameters and heat treatment

In this study, structural, mechanical and machining features of Al-7Si-0.6 Mg alloy manufactured by permanent mold casting (PMC) in both as-cast (AC) and T6 heat-treated (HT) conditions were investigated. Structural and mechanical properties were determined using conventional methods. Milling experiments were conducted with titanium aluminum nitride (TiAlN) coated carbide end mills in CNC milling machine under conditions of three different cutting speeds (V: 50, 80 and 110 m/min), feed rate (f: 0.08; 0.16 and 0.24 mm/rev) and constant depth of cut (DoC) (1.5 mm). It was seen that structure of AC Al-7Si-0.6 Mg comprised of aluminum-rich α-Al, coral-like eutectic Al-Si, primary Si, Mg2Si, Fe-rich plate, acicular β-Fe (β-Al5FeSi) and script-like π-Fe (π-AlSiMgFe) intermetallic phases. Eutectic Al-Si, primary Si, β-Fe and π-Fe phases in the structure of the alloy in the HT condition were partially dissolved and turned into an agglomerated and spherical state. While the hardness (HB), yield (YS) and tensile strength (TS) of the alloy raised with HT, the elongation to fracture (EF) reduced. While cutting force (CF), surface roughness (SR), built-up layer (BUL) and built-up edge (BUE) decreased with increasing V, they increased with increasing f in the milling of both cast and HT alloys. Adhered layers and feed marks were consisted of the cutted surfaces of the alloys. While the most adhered layer was observed in AC alloys at a low V (50 m/min) and high f (0.24 mm/rev) combination, the least adhered layer formation was observed at the highest V and the lowest f value in HT alloys. Optimum parameters with Response Surface Methodology (RSM) were determined as V: 125 m/min and f: 0.04 mm/rev in AC and HT cases. The statistical significance of V and f on CF and SR was revealed by analysis of variance (ANOVA), while mathematical models were improved to predict CF and SR.

Workpiece temperature investigation in micromilling of titanium alloy

The study of the micromachining process of titanium alloys has intensified due to a greater need to develop micro components for the medical sciences. However, the investigation of the behavior of process variables is still incipient, complex and challenging. Heat and temperature distributions are important aspects for any machining process, so the main objective of this work is to investigate temperature distributions during the micro-milling of the Ti-6Al-4 V alloy combined experimentally with numerical simulations. To carry out the experiments, AlCrN coated carbide end mill tools were used for machining micro slots. During machining, the workpiece temperature is measured using T-type thermocouples welded to the workpiece surface aligned with the tool path. The temperature distribution was also obtained by numerical simulation using the commercial software Third Wave AdvantEdge (version 7.4015). The experimental results showed that the temperature on the surface of the specimen increases from the up-milling side to the down-milling side and that it tends to increase with tool wear. However, the simulated data showed that the temperature is higher in the center of the slot, which is the point with the highest undeformed chip thickness.

Tool Wear and Surface Roughness Characteristics in the High-Speed Milling of Pure Ti and Ti Alloy Using TiAlN Coated Carbide Radius End Mill

The workpiece materials used in the experiment were pure Ti and Ti alloy, which are commonly applied in the biomedical and aircraft industries. Although they are attracting increasing interest due to their superior mechanical properties, they are also known to be difficult-to-machine. This study investigated the cutting conditions for realizing minimum tool wear and optimum surface roughness using a TiAlN coated carbide end mill with a diameter of 6 mm, corner radius of 0.5 mm, and four blades in high-speed milling experiments based on the dry cutting process. In this case, peripheral speed was set as the main parameter. Cutting resistance and cutting temperature are also important parameters, but they are difficult to use as indicators for setting cutting conditions directly from the obtained data. Therefore, changing the rotational speed is a practical way to change the peripheral speed, while changing the machining conditions directly from the cutting resistance and temperature is difficult and impractical.

Comparative assessments of machining forces in 3D printed polymer composite during milling operation using two coated carbide end mills

The composites of carbon fiber reinforced polymer (CFRP) are rapidly turning into the most extensively used material in aerospace and automotive applications due to their superior corrosion-resistant exterior and ratio of strength-to-weight. The flexibility to fabricate complex shapes and alter the fiber orientation of CFRP composites via three-dimensional (3D) printing or additive manufacturing is gaining prominence. However, because of their anisotropic and heterogeneous structure these composites were regarded as the difficult-to-cut materials. The parts made out of these composites are often made to near-net shape in astronautic and aerospace industry. However, part finishing typically necessitates post-process machining such as milling, in order to satisfy dimensional accuracy prior to assembly. The aim of this thesis is to explore the machinability aspects in terms of machining forces 3D printed CFRP composites by milling CFRP employing TiAlCrN and hard carbon coated solid carbide end mills in dry cutting environments. A 3D printed multidirectional CFRP workpiece was fabricated using a Mark forged industrial printer and milling operations were carried on additively manufactured workpiece with two distinct coated tools according to the experimental design created on Taguchi’s L16 orthogonal array in which three variables namely feed rate, depth of cut, spindle speed were altered at four distinct levels. With TiAlCrN coated carbide tool, least machining forces observed compared to hard carbon coated carbide tool.

Wear behavior of Ni-B coated-hard anodized Al7Si alloy and machining performance with ZrN ceramic film coated carbide tool

In this study, it is aimed to increase the wear resistance of Al7Si alloy, which is widely used in the manufacturing industry, with different surface treatments and to propose an effective and economical cutting tool coating for machining process of the alloy. Accordingly, precipitation hardening heat treatment, Hard Anodizing and Ni-B coating processes were applied to cast Al7Si alloy samples. The structural, mechanical and tribological properties of the samples were characterized after the surface treatments. Also, the machining performance of Al7Si alloy with uncoated and ZrN ceramic film coated carbide end mills was investigated. The milling processes were performed to determine the actual working performance of the tools. SolidCAM i-machining module, which has become widespread recently, was used as intelligent machining instead of the tool paths used in traditional methods. After the precipitation hardening heat treatment, Hard Anodizing and Ni-B coating process were applied to the alloy, the wear volumes were greatly reduced. The lowest wear volume was obtained for the Ni-B coated Al7Si alloy, which also achieved the lowest coefficient of friction. After machining studies, it was determined that the ZrN coating reduced the wear on the WC tool approximately 4 times and increased the workpiece surface quality compared to the uncoated tool.

Experimental investigation on surface roughness in CNC end milling process by uncoated and TiAlN coated carbide end mill under dry conditions

Abstract In this study, the effect of machining parameters on surface roughness is investigated during CNC end milling process of Al6061 – T6 Alloy by Taguchi’s method. The work material was machined with uncoated carbide tool and TiAlN coated carbide tool and comparative analysis have made between coated and uncoated tool for identifying the better surface finish. ANOVA analyses were carried out to identify the significant factors affecting surface roughness, and the optimal cutting combination was determined by seeking the best surface roughness and signal-to-noise ratio. Finally, confirmation tests verified that the Taguchi design was successful in optimizing milling parameters for surface roughness.

Experimental Investigation on Machining Characteristics of EN19 Alloy Steel Using CNC Vertical Machining Center

In this research work, the detailed experimentation investigation was performed for EN19 steel using milling process on CNC VMC. The experimentation strategy has been planned using Taguchi’s L9 orthogonal array, consisting of three process parameters such as cutting speed, feed rate and depth of cut on material removal rate (MRR) and surface roughness (SR). Two different types of end mill cutters (solid carbide and titanium nitride coated carbide end mill) were used to find out the best performance. The level of significance of the machining parameters for their effect on the MRR and SR was determined by using analysis of variance (ANOVA). The comparative study was also performed to access the best tool for this experimental work. Finally, confirmation experiment was performed to validate the effectiveness of the proposed optimal condition.

Application of neural network in determination of parameters for milling AZ91HP magnesium alloy with surface roughness constraint

This paper presents the model for milling AZ91HP magnesium alloy with TiAlN coated carbide end mill. The model was developed on the basis of experimental data from the neural network training data set. The milling process was conducted at constant parameters of tool geometry, workpiece strength properties, technological machine properties, radial and axial depth of cut. The range of changeable machining parameters specified in this study included cutting speed, feed per tooth, and the output variable: the arithmetical mean roughness parameter (Ra). The process was modelled by means of MatLab software and its Neural Network Toolbox. The developed model was implemented in the algorithm designed to determine optimal milling conditions, exploring the space of acceptable parameters in search of those which would meet the specified roughness parameter at maximum efficiency.

The wear performance of carbide tools coated with TiAlSiN, AlCrN and TiAlN ceramic films in intelligent machining process

Nitride-based coatings are applied by cathodic arc physical vapor deposition (CAPVD) to improve the tribological properties of cutting tools. The present study examines the tool life of carbide tools coated with TiAlSiN, AlCrN and TiAlN films in intelligent machining process. Coating process was applied on both prismatic carbide test specimens and solid carbide end mills. Coating characterization was carried out on the test specimens. The structural, mechanical and tribological properties of different nitride-based coatings were investigated by means of field emission scanning electron microscope (FEG-SEM), X-ray diffractometer (XRD), scratch tester, reciprocating tribometer, calotester, microhardness device and optical profilometer. Impax steel was machined in CNC vertical machining center with uncoated and coated carbide end mills in order to determine the actual operating performance of the coatings. The g codes and toolpaths were created in the SolidCAM iMachining software. The cutting speed, feeds and overlap values are selected automatically and variably depending on geometry, tool and workpiece materials. The flank wear widths of tools were determined by SEM. In addition, the surface roughness values of the impax steel were measured from the finish surfaces. According to the scratch test results, the best adhesion results were obtained for TiAlN coating and the Lc1 critical load value was determined as about 30 N. The reciprocating sliding test results showed that the highest wear rate was obtained for the TiAlSiN coated specimen and the lowest wear rate was obtained for the uncoated specimen. Flank wear was observed on the tools after the milling process and the highest wear resistance was obtained TiAlN coated end mill. The lowest surface roughness value was obtained from the surface of impax steel workpiece which was milled with carbide end mill coated with TiAlN ceramic film.

Optimization of cutting for surface finish obtained using uncoated and diamond coated carbide end mills

Aim of this paper is to optimize the machining parameters for surface finish during end milling of Al 6061 using Taguchi method. Uncoated and Diamond Coated carbide end mills were used for conducting machining experiment. Preliminary experiments were conducted to decide the range of speed, feed & depth of cut. Stylus profilometer was used to measure the surface roughness of the machined surface. A Taguchi orthogonal array was designed with three levels of machining parameters and analysis of main effect plot for means, ANOVA, response table and regression equations were developed with the help of Minitab.

Milling of Inconel 718 block supports fabricated using laser powder bed fusion

There is significant interest in using laser powder bed fusion (L-PBF) to print metallic parts from super-alloys such as Inconel 718. L-PBF frequently requires the printing of support structures for overhanging regions of the solid part in order to mitigate warping and distortion. After the part is printed, machining processes are often employed to remove the supports from the solid part. Surprisingly, little is known regarding the machining behavior and machinability of these support structures. In this study, the milling behavior of Inconel 718 block type supports was investigated. Standard block supports of varying height were fabricated and peripherally end milled to study deformation and fracture behavior, specific cutting energy, the influence of tooth-support wall interactions on milling forces, and tool wear. The investigation revealed that supports do not uproot from the base or generally collapse when milled. Instead, they maintain their structure and support localized chip formation, despite the fact that they are designed to break away from the base using hand tools. The specific cutting energy of milling blocks supports is 12% of that of full density metal when considered on a swept volume basis. If metal volume removal is considered, the density normalized specific cutting energy is 43% of that of full density metal. Water fall FFT analysis of the forces measured during the milling of block supports revealed stronger relative contributions at higher frequencies and greater time sensitivity than the forces measured during the milling of full density metal. These are due to tooth-support wall interactions. Finally a preliminary tool wear study showed that a TiAlN coated carbide end mill is more prone to pre-mature failure when machining block supports than fully dense metal. This failure is due to fracture at the corner radius, and is possibly due to tooth-support wall interactions.

A Performance Comparison Study of Uncoated and TiAlN Coated Carbide End Mill on Machining of the Al-35Zn Alloy

In this study, Al-35Zn alloy was produced by permanent mold casting. To investigate the cutting performance of uncoated and TiAlN coated carbide end mills on this alloy, a series of tests were carried out in the CNC vertical machining center at a constant cutting speed, feed rate and depth of cut. The results obtained from the tests showed that uncoated carbide end mill have lower cutting force and surface roughness than TiAlN coated carbide end mill. These observations are discussed in terms of the alloys properties, cutting tool surfaces, and friction and wear behavior between the cutting tool and the material.

Influence of helix angle on tool performances of TiAlN- and DLC-coated carbide end mills for dry side milling of stainless steel

This work reports the influences of helix angle on tool performances of titanium aluminum nitride (TiAlN)- and diamond-like carbon (DLC)-coated carbide end mills for dry side milling of 304L stainless steel. The study results revealed that the number of axis contact points and effective cutting length increased with increasing helix angle, leading to less tool wear and thinner milled chips but higher workpiece temperature. In addition, DLC-coated tools exhibited relatively high workpiece temperature, rapid chipping wear due to thermally induced graphitization, and chip-built-up on side edge while TiAlN-coated end mills displayed less severe abrasive wear on cutting and side edges. Moreover, the DLC-coated end mill with a high helix angle of 60° gave the lowest surface roughness of 0.26 μm within the cutting length of 20 m while the corresponding TiAlN-coated tools offered longer tool cutting length of more than 50 m with comparable surface finish. Consequently, the TiAlN-coated end mill with a high helix angle of 60° offered high-quality surface finish with long tool life time and would be more useful for dry milling of stainless steels.

Optimum surface roughness evaluation of dies steel H-11 with CNC milling using RSM with desirability function

Machinability aspect is of paramount importance for efficient process planning in manufacturing. Machinability of work materials is an imperative aspect which may affect the different manufacturing phases including product design, process planning and machining operation. Machinability of engineering materials may be evaluated in terms of process output variables like surface roughness (SR), material removal rate, cutting forces etc. CNC milling has become one of the most competent, productive and flexible manufacturing methods, for complicated or sculptured surfaces. With the more precise demands of modern engineering products, the control of surface texture has become more important. This paper reports mathematical model for correlating the milling machining parameters such as spindle speed, table feed rate, depth of cut, step over and coolant pressure, with the response characteristic, SR, while machining hot die steel, H-11 with titanium coated carbide end mill cutter. The response surface methodology in conjunction with face centered central composite rotatable design has been used to develop the empirical model for the response. The significance of the mathematical model developed was ascertained using desirability functions and confirmation experiments. The results obtained depict that the mathematical model is useful not only for predicting optimal process parameters for achieving the desired quality but also for achieving the process optimization.

ダイヤモンドコーテッド超硬工具を用いた超硬合金のエンドミル加工

The cutting characteristics of tungsten carbide using a diamond coated carbide end mill was investigated. The influence of tool feed rate on the finished surface properties and cutting force was experimentally investigated. The tungsten carbide (CIS VC-70) with mean grain size of 5 Pm was used as a workpiece material. The tungsten carbide grain on the workpiece surface detached with ultrasmall tool feed rate (0.5 Pm/tooth) cutting, and the finished surface integrity was deteriorated. The difference of the cutting force in the feed rate of 0.5 and 10.0 Pm/tooth was not so significant. The appropriate tool feed rate existed to obtain the satisfactory finished surface and high cutting efficiency.

Surface Defects in Groove Milling of Hastelloy-C276 Under Fluid Coolant

This study aims to investigate surface integrity in groove milling of Hastelloy-C276 using coated carbide end mills under the application of water-based fluid coolant using different cutting parameters. Surface integrity was assessed by measuring surface roughness, using focus variation microscope, and investigating surface defects, using scanning electron microscope. Micro-chips re-deposition and long grooves dominated the machined surface at low cutting speed (24–50 m/min). While cracked and fractured re-deposited materials, grooves, large debris, and plastic flow dominated the machined surface at high cutting speed (70–120 m/min), consequently surface roughness increased with cutting speed. Nucleated cavities appeared at all cutting speeds but with different densities. Shallow depth of cut at low cutting speed gave negative effect on surface roughness due to the effect of the hardened layer. Overall, the best surface finish, with average roughness below 50 nm and minimum surface abuse, was obtained in the speed range of 24–50 m/min at feed rate of 1 µm/tooth and depth of cut deeper than 0.1 mm.

High-quality machining of CFRP with high helix end mill

Side milling tests of CFRP (Carbon Fiber Reinforced Plastics) without coolant are carried out by DLC (Diamond-Like Carbon)-coated carbide end mills. Four types of DLC-coated end mills are chosen: UBMS (UnBalanced Magnetron Sputtered) and AIP (Arc Ion Plated) coatings having different helix angles, respectively. The surface integrity is evaluated in terms of 3D profiles of the machined surface, generation of fluffing, delamination and pull-out of the carbon fiber. The cutting force and tool wear with respect to the fiber orientation are also examined. The inclination milling with high helix angle end mill is proposed in which the end mill is tilted in such a way that the resultant cutting force acts parallel to the work surface. This unique approach enables to reduce tool wear and to improve surface integrity of machined surface of CFRP.

ダイヤコート超硬エンドミルによる超硬合金の切削加工

This paper deals with the cutting mechanism against cemented carbide by using a diamond coated carbide end mill. The influence of tool wear, cutting force, and machined groove integrity on the cutting of cemented carbide was investigated experimentally. The ball end mill with a diameter of 6mm was applied under the condition of air-blow supply. As results, the coated diamond film on the rake face was immediately flaked when the grooving length was less than 20mm. However, the cutting force was decreased by flaking the coated film, and the stable cutting was achieved without any damage to the base material of ball end mill until the grooving length was 800mm.

Dry Machining of AA7075 by H-DLC Coated Carbide End Mill

Present investigation evaluates the performance of a hydrogenated diamond like carbon (H-DLC) coating on carbide end mills during machining of an Al-Zn-Mg based alloy i.e. AA7075. Although diamond is known to be the most potential hard coating on carbide tools to deal with the challenges of machining aluminium, DLC coating offers economic solution in dealing with this material at medium cutting speeds. Present study explores the feasibility of using a H-DLC coating, which is eventually softer than non-hydrogenated DLC, in machining this alloy and compares its performance with that of uncoated carbide tools under dry environment. In terms of surface finish and cutting force this H-DLC coated tool substantially outperformed uncoated carbide one in the cutting speed range of 60 to 180 m/min. The coating was able to substantially arrest built up edge (BUE) formation, however, found to be with minor trace of built up layer (BUL).