Rake Surface Research Articles

Prediction of feed force with machine learning algorithms in boring of AISI P20 plastic mold steel

Feed force plays a critical role in machining performance, including efficiency, hole quality, energy consumption, and tool life. While feed force is typically measured using dynamometers, these devices are often impractical in real-world experiments due to their complexity and cost. In particular, boring operations, which are essential for enlarging holes within tight tolerances, depend on precise feed force control to maintain high-quality hole outcomes. Achieving this precision requires reliable pre-process feed force estimation. However, traditional analytical methods for calculating feed force in boring operations often fall short, largely due to factors such as in-hole dynamics, the inclination of the rake surface, and the slenderness of the boring bar. This study aims to apply single and hybrid machine learning methods to accurately model and predict feed force in the boring process. Unlike previous research, which focused on feature selection, we propose the use of all possible combinations of input feature subsets to determine the optimal input features. The results indicate that feed force can be predicted effectively using these optimized feature combinations. Such accurate feed force prediction is crucial for effective process optimization, material selection, and process planning.

Profile Optimisation of a Solid Modular Hob in the Machining of Gears Made of Classic and Unusual, Innovative Materials.

Modular hobs are tools with very complex geometry. Regardless of the material of the gear wheels, they determine the accuracy of the gears made in the hobbing machining process. Gears are made of various, often innovative materials depending on the requirements. Sometimes, the materials are characterised by very high hardness (over 65 HRC). The mathematical basis for describing the faces of a hob presented in the article allows for modifying the rack profile shaping the gear wheel's teeth. The model's universality makes it possible to perform numerical simulations of the influence of individual parameters of the hob creation process (geometry of the grinding wheels and their setting in the shaping process) on the profile of the rake and flank surfaces. The cutting edge (rack edge) is the locus of points belonging to both of these surfaces and thus directly impacts the accuracy of the gear wheel that is shaped in the hobbing process. The article summarises the authors' long-term cooperation with the industry, resulting in a series of articles devoted to hobs. The issues presented in the article are significant to the machinery industry and hob manufacturers.

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

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

Application of 3D Imaging for Analyzing the Chip Groove Shapes of Cutting Inserts

An effective chip formation process is significant for an efficient metal-cutting process. Long continuous chips can lead to scratches on the machined surface, increasing the risk to operator safety and stability of the machining process. The use of chip grooves on cutting inserts allows for control of the chip formation and breaking process during machining. The shape of the rake surface and the design of the chip groove also affect the efficiency of the machining process. The article presents the use of 3D imaging to analyze changes in the selected chip groove shapes depending on the cutting depth ap = 0.10, 0.25, and 0.50 mm and the angular location of the cutting insert relative to the machined surface of the workpiece (i.e., major cutting-edge angle K = 60° and K = 90°). The analysis methodology was based on the use of 3D image registration and surface shape modeling. In the analysis based on the 3D imaging presented, the novelty was the adaptation of methods typically used to map and model the terrain surface, which have not been used previously in cutting processes. The evaluation of the shape of the chip groove surface was carried out using, e.g., watershed maps and 3D surface maps. The obtained results indicated a significant influence of the cutting depth and major cutting-edge angle on the surface shape, profile, and length of the chip former; chip groove volume; and the theoretical contact area of the formed chip with the cutting insert. It was observed that for small depths of cut, i.e., ap < 0.25 mm, the chip-curling process may be difficult due to the flattened shape of the rake surface. In addition, the influence of the convexity of the rake surface of the cutting insert on the chip formation process was demonstrated. The results of the experimental research that verified the conclusions are presented. The developed results may be useful in the process of selecting the parameters and conditions of the metal finishing through use of tools with a shaped rake surface.

Effects of shear thickening fluid preparation on tool performance in the milling of Ti6Al4V titanium alloy

The performance and quality of tools can directly affect the efficiency and quality of machining, and preparation methods of the cutting edge have an important impact on the machining performance and tool life. As a method that can adapt to the unique and complex geometry of the cutting edge, shear thickening passivation is an innovative application of shear thickening fluid. In this study, the effects of shear thickening passivation methods on the milling performance and tool life of cemented carbide milling cutters were investigated. The cutting force, tool wear, tool life and surface morphology were analyzed by side milling Ti6Al4V titanium alloy with cemented carbide milling cutters that were unprepared, drag finished and shear thickening passivated, respectively. The results demonstrate that shear thickening passivation can remove the micro-defects of the tool after grinding. After shear thickening passivation, the cutting edge is rounded, and the rake and flank surfaces are flat, and the defects of the cutting edge are removed. Compared with the unprepared tool, the life of the shear thickening passivated tool is improved by 50 %. Therefore, the shear thickening passivation can effectively improve the tool life and tool performance and significantly reduce the economic cost in practical machining.

Development of micro-texture patterns of cemented carbide cutting tools to improve cutting performance

Micro texture on cutting tool inserts obtained via laser micro-machining has recently emerged as an environment friendly method to reduce adhesion on the tool’s rake face and to improve friction conditions during machining. However, these benefits are strictly correlated with a correct design and behavior of the texture to be replicated on the tool surface. This paper reports an experimental study of developing an array of dimples on both rake and flank of commercial, cemented carbide cutting inserts using a picosecond laser source. Experiments of orthogonal dry cutting on E235 steel tubes were performed using textured and untextured tools to evaluate the improvements obtained. The improvements achieved were assessed in terms of cutting force and their impact on cutting performances. A predictive finite element model was developed to optimize the design of the dimples, to be replicated onto the rake surface of the tool.

Study of a Methodology for Calculating Contact Stresses during Blade Processing of Structural Steel

The article presents data about the distribution of contact stresses on the rake surface of the cutter when turning steel (Fe-0.4 C-1Cr), which were obtained by the split cutter method. The article also provides graphs of the effect of the uncut chip thickness a and the rake angle γ on the main parameters of the plots of shear τ and normal σ contact stresses. For this case, The initial data were obtained by longitudinal turning of a steel workpiece with the measurement of the technological components of the cutting force by a three-component Kistler dynamometer, followed by the calculation of the physical components of the cutting force. The rake angle varied widely, from +35 to −10°, and the uncut chip thickness a varied from 0.05 to 0.37 mm. A decrease in the rake angle from +35 to −10° leads to a significant increase in the maximum normal contact stress at the cutting edge σmax: from 400 to 1400 MPa with the uncut chip thickness a = 0.37 mm. In the area of small uncut chip thickness, a (less than 0.1 mm), the paradoxical increase in the magnitude of the greatest normal contact stress with a large positive rake angle (more than +15°) is explained by the indentation (pressing) of the being machined material under the rounded cutting edge of the cutter in the chip formation zone, and their paradoxical decrease with a negative rake angle is due to the presence of a sag (deflection) of the transient surface. According to the magnitude of the reference points obtained on the basis of experimental data, it is possible to plot the contact stresses epures on the rake surface of the cutting tools when machining steel.

Performance Evaluation of Micro-Textured Inserts Coupled With Solid Lubricants During the Sustainable Dry Machining of Inconel 825

Abstract In this research work, the turning of Inconel 825 has been carried out using uncoated and coated laser-textured hard tungsten carbide (WC) cutting inserts. The efficacy of uncoated textured inserts has been tried to improve by impregnating them with micro-sized MoS2 and nano-TiC powder paste. The results of coated and uncoated textured inserts have been compared with the plain uncoated tungsten carbide insert. The use of solid lubricant-impregnated textured tools and coated textured tools has significantly reduced the cutting forces and chip–tool interface friction as compared to plain and normal textured tools. Upon the SEM analysis, high adhesion over the rake face of the plain tool has been observed. The excessive adhesion over the rake surface has been observed over the normal textured tool due to the derivative cutting phenomena. The use of MoS2 and nano-TiC-impregnated textured tools has significantly reduced the material adhesion over the rake surface by eliminating the derivative cutting effect. The use of AlTiSiN-coated textured tools has also restricted the extent of work material adhesion over the rake surface of the cutting insert.

Wear of Carbide Plates with Diamond-like and Micro-Nano Polycrystalline Diamond Coatings during Interrupted Cutting of Composite Alloy Al/SiC

The complexity of milling metal matrix composite alloys based on aluminum like Al/SiC is due to their low melting point and high abrasive ability, which causes increased wear of carbide tools. One of the effective ways to improve its reliability and service life is to modify the surface by plasma chemical deposition of carbon-based multilayer functional layers from vapor (CVD) with high hardness and thermal conductivity: diamond-like (DLC) or polycrystalline diamond (PCD) coatings. Experiments on an indexable mill with CoroMill 200 inserts have shown that initial tool life increases up to 100% for cases with DLC and up to 300% for multilayered MCD/NCD films at a cutting speed of 800 m/min. The primary mechanism of wear of a carbide tool in this cutting mode was soft abrasion, when wear on both the rake and flank surfaces occurred due to the extrusion of cobalt binder between tungsten carbide grains, followed by their loss. Analysis of the wear pattern of plates with DLC and MCD/NCD coatings showed that abrasive wear begins to prevail against the background of soft abrasion. Adhesive wear is also present to a lesser extent, but there is no chipping of the base material from the cutting edge.

An investigation on the performance of bio-mimicked rake surface structured tool during machining of hard-to-cut materials

The current work seeks to improve the machining characteristics of tool by generation of various geometrical structures on cemented carbide tool's rake face. A total of three different structures: (a) bio-mimicked micro-crescent structure, (b) micro-dimple structure, and (c) micro-groove structure, are generated using laser micro-machining technique on rake surface of tool. Dry turning tests were performed using the structured tool and conventional tool during cutting of AISI 420 workpiece material. The effect of various geometrical textures on chip-tool contact area, surface roughness, cutting force, morphology of chip and residual stress have been compared with respect to conventional tool. Results indicate that crescent-shaped bio-mimicked structured tool indicated better cutting performance in decreasing contact area of chip-tool by 43.6%, tangential force by 15.38%, feed force by 20.22%, and average surface roughness by 8.81% relative to the conventional tool. The machined surface of structured tool also indicated lower generation of residual stress of 419.3 MPa in cutting direction and 316.9 MPa in feed direction relative to 608.3 MPa in cutting and 375.5 MPa in feed direction using conventional tool machined surface. Segmented chips were produced during all machining conditions, and crescent-shaped structured tool indicated least chip reduction coefficient of 1.08 compared to 1.57 in the case of conventional tool. The results of the current study are very essential for expanding the application of bio-mimicked structured cutting tools for cutting different hard to machine materials.

Influence of laser parameters on the machining performance of textured cutting tools

Over the past three decades, surface texturing has garnered significant interest as a method of controlling friction and wear in tribological systems. Surface textures play a significant role in reducing friction under dry machining conditions by lowering adhesion, decreasing the effective area of contact, and collecting wear particles. However, the effect of various laser parameters on the machining performance of textured tools is still unclear. In this research study, linear textures have been fabricated on the rake surface of uncoated carbide tools using the Nd:YAG laser by varying the laser parameters. The effect of the laser parameters, such as fluence and the average number of pulses per surface spot has been evaluated in terms of depth of textures, resolidified layer, and change in substrate hardness. The textured tools have been further used for turning the pH 13–8 Mo SS (UNS S13800) alloy under dry and wet conditions. The machining outcome results obtained with the textured tools have been compared with the plain tool. The turning experiments showed that textured tools helped in improving the machining performance by reducing the cutting forces, cutting temperature, surface roughness, and tool wear. In this research work, the textured tools fabricated with the combination of fluence = 31.4 J/cm2 and pulses per surface spot = 5 pulses/surface spot have outperformed the other textured tools fabricated with the combination of different laser parameters in terms of machining performance.

Research on cutting temperature distribution of carbide cutter rake face considering sticking-welding layer

In the process of cutting 2.25Cr1Mo0.25V material with carbide cutter, the cutter-chip element diffusion occurs, which will cause sticking-welding layer easily produced on rake surface. In order to study the influence of the sticking-welding layer on the temperature distribution and gradient of rake face, the thermal conductivity of sticking-welding layer on rake face was calculated by using the Maxwell-Eucken diffusion phase continuum principle. According to the heat conduction theory, the theoretical model of heat transfer with or without the sticking-welding layer on rake face was established, and combined with the finite element simulation model, the temperature distribution of rake face is studied by combining model calculation and numerical simulation. The results show that: when there is sticking-welding layer on rake face of cutter, this specified layer will play the role of heat insulation, leading to relatively low temperature of rake face. The presence of sticking-welding layer will cause the temperature fluctuation of cutter rake face, and the temperature also increases with the increase of the thickness. At the same time, the variation trend of temperature gradient in sticking-welding layer is similar with different layer thickness, whereas the larger the thickness, the greater the variation of temperature gradient due to the thermal resistance. By comparing and analyzing the average cutting temperature of rake face of the actual cutting and simulation, it is concluded that the temperature simulated by the finite element model will be closer to the actual measured temperature, and the measurement error is less than 10%, which provides a theoretical basis for delaying the tool life.

A conceptual framework for sustainability impact assessment in machining bohler tool steel under hBN-enriched nano cutting fluids environment

The term “sustainability assessment” refers to a set of practices that “guide the planning and decision-making process to realize sustainable development.” Sustainability is becoming an increasingly central notion for many businesses. However, the current sustainability assessment techniques are being heavily criticized for a number of reasons, including a lack of interdependence and consistency, the predominance of subjectivity, and financial biases. Therefore, the present study applies the fundamental conceptual framework for sustainability evaluation to enhance the process performance of machining Bohler K490 steel using minimum quantity lubrication (MQL) and hBN-enriched nano-MQL cooling/lubrication. Power consumption and machining parameters such as tool wear, surface roughness, and chip morphology were taken into account while developing the sustainability assessment model. Then, the sustainability performance indicator (SPI) was determined. This global SPI supports the claim that using nano-MQL improves both sustainability and machining performance. The findings of tool wear clearly illustrated that applying hBN-enriched nano fluids from both the rake and flank surface reduced the tool wear values by up to 26.9%.

Enhancing cutting performance of Ti(C,N)‐based cermet tools on nodular cast iron by incorporating high‐entropy carbide

AbstractIn this study, we investigated the cutting performance and wear mechanisms of Ti(C,N)‐based cutting tools containing varying weight percentages (0%, 5%, 10%, and 15%) of high‐entropy carbide (HEC) (V0.2Nb0.2 Mo0.2Ta0.2W0.2)C phase, when used for turning nodular cast iron. According to the turning test results, the cermet cutting tools containing 0 wt%, 5 wt%, 10 wt%, and 15 wt% HEC phases demonstrated effective cutting lives of 402, 720, 632, and 465 s, respectively. The tool with 5 wt% HEC phase showed the best cutting performance. When cutting nodular cast iron with cermet cutting tools, the main wear mechanisms observed were diffusion, oxidation, adhesion, and abrasion on the flank surface, along with diffusion, oxidation, and abrasion on the rake surface. The results of this study indicated that (V0.2Nb0.2Mo0.2Ta0.2W0.2)C could be adopted as an effective reinforced phase in the cermet cutting tools.

Performance investigation of cryogenic treated-double tempered cutting inserts in dry turning of Ti–6Al–4V alloy

Dry machining of Titanium alloy Grade 5 (Ti–6Al–4V) with cryogenic treated, double-tempered KC5010 cutting inserts was examined. The impact of cryogenic treatment followed by tempering of the carbide inserts was investigated using microstructure analyses. The effects of constant depth of cut, cutting speed, and feed rate on machining variables (torque, force, surface roughness, temperature, and tool wear) were investigated. According to the experimental results, the cutting speed is the most important parameter that has a direct influence on the machining characteristics. Increased cutting speed and feed rate generate larger tangential pressures, allowing for a reduction in chip contact length; a shorter contact length results in reduced surface roughness and flank wear rate, respectively. The effects of cutting speed and feed rate on chip thickness were studied. Image analysis of the segmented chip was used to investigate the form and size of the saw-tooth profile of serrated chips. It was discovered that raising the cutting speed from 73 m/min to 160 m/min enhanced the free surface lamella of the chips and improved the visibility of the saw tooth segment. As cutting speed increases, all response parameters (torque, temperature, force, tool wear, and surface roughness) increase at the same time, by nearly 300%. Deep cryogenic treatment enhanced micro-hardness, resistance to wear, and toughness. As a result, there was reduced flank wear with tiny abrasion lines. Lower cutting speeds and feed rates resulted in less rake surface wear. Finally, the current study's convergence with earlier research was presented, indicating strong agreement between the two examinations.

Turning insert with lubricating passage along the normal plane for minimization of friction, cutting force and tool wear

This article proposed a strategy of generating lubricating passage on the turning insert to minimize the friction and cutting force. The lubricating passage comprised of a micro groove on the insert along the normal plane. The passage enabled favourable flow of lubricant towards the rake surface and flushed away the chips from the insert. Therefore, a better lubricating interface has been generated at the chip-tool contact zone with ameliorated penetration of the cutting fluid. Consequently, the friction and cutting force has been reduced. Maximum 55% reduction of cutting force has been achieved using these inserts in combination with MQL supply. Additionally, the flank wear and average surface roughness have been reduced significantly. Moreover, these inserts have participated as chip breaker as well.

Novel texture pattern on WC inserts fabricated using reverse-μEDM for enhanced cutting of Ti6Al4V

Textured rake and flank surfaces of a cutting tool exhibit promising results in machining performances. This work proposes a novel texture pattern to mitigate the disadvantages of the existing textures. Experiments are performed to check the fabrication feasibility of the proposed pattern on the rake face of Tungsten Carbide (WC) inserts using Reverse-micro Electrical Discharge Machining (R-μEDM) process. In order to investigate the advantage of the proposed pattern, orthogonal machining of Titanium alloy is conducted. A significant reduction of 25.77% is obtained in the measured temperature and 11.1% in the friction coefficient compared to the plain insert.

Dry and MQL Milling of AISI 1045 Steel with Vegetable and Mineral-Based Fluids

The use of mineral-based cutting fluids in machining has the drawback of affecting the environment and industries are under pressures to reduce its use in favor of cleaner productions. In this regard, the vegetal-based cutting fluids can be a superior alternative, provided they improve the technical outcomes. In the milling process, dry cutting is commonly performed, however, the application of cutting fluids using the minimum quantity of lubricant (MQL) method has proven advantageous when compared with dry machining. Furthermore, in the midst of the availability of several cutting fluids in the market, the testing of their individual performance can ascertain their potential and effectiveness for a particular application. This study examined the performances of two vegetable-based and one mineral-based oils applied by the MQL method, followed by their comparison with dry cutting amid end milling of AISI 1045 steel with TiAlN-coated cemented carbide inserts. The cutting temperature, machining forces, power consumption, workpiece surface roughness, tool life, and tool wear mechanisms were chosen as the output parameters. The experiments were conducted using two cutting speeds (150 and 200 m/min) and feed rates (0.07 and 0.14 mm/tooth), and constant axial (1 mm) and radial depths of the cut (25 mm). The temperature was measured using a K-type thermocouple soldered to the part and an infrared camera. The power was monitored with a Fluke 435 energy analyzer, and the machining force components with a Kistler dynamometer. The worn inserts were inspected under a scanning electron microscope (SEM) to analyze the tool wear mechanism. The MQL-assisted application of the cutting fluids notably lowered the cutting temperature and increased the tools’ lives. However, the cutting fluids did not reflect any significant effect on the machining force, power consumption, or surface roughness. Among all the analyzed cutting conditions, the abrasive wear mechanism dominated, damaging the cutting edges, flank, and rake surfaces of the cutting tools. In addition, adhesive and diffusion wear mechanisms were also observed.

Thermal modelling of cutting tool under different cutting environment in turning

In most of the manufacturing industry, turning is one of the essential machining operation, due to which the study of the turning tool becomes a necessary part for most of the manufacturing researchers. During dry turning of workpiece excessive amount of heat is generated which results in a localized distribution of heat at the tool tip, thus increasing the cutting temperature, which further decreases the tool life by making the tool blunt and also decreases the surface finish of the workpiece while machining. Excessive heat generation can be controlled by the use of different cutting fluids as per convenience and availability as they carry away most of the heat away from the workpiece and thus decreasing the temperature at the tool tip. This present study deals with the thermal modelling of carbide tool that is the distribution of temperature over its rake surface due to localised heat source at its tool tip. Conjugate heat transfer approach have been established for the distribution of temperature over the rake surface using ANSYS. The present study focusses of the temperature distribution by using air and water as the cutting fluids.

Cutting Energy Consumption Modelling of End Milling Cutter Coated with AlTiCrN

As an indispensable piece of equipment in the manufacturing industry, the machine tool is low-energy-efficiency and high-energy-consumption in operation. Therefore, it is urgent to establish a cutting energy consumption model to guide production and reduce the energy consumption of the machining process. In this paper, the AlTiCrN-coated cutting tool is taken as the object of study, and the cutting energy consumption model is established. The cutting energy consumption model is composed of a machining time model and a cutting power model. The cutting power model can be divided into the shear deformation power model of the workpiece, the friction power model of the flank surface and the friction power model of the rake surface. The influence of the edge shape is taken into account in the establishment of the friction power model of the flank surface. The machining time model considering the S-type acceleration and deceleration stage is established. The accuracy of the model was verified by experiments. Experimental results show that the model has high accuracy. The Taguchi method was used to carry out the numerical experiment with the cutting energy consumption of the machine tool as the response. The influences of cutting parameters on energy consumption are analyzed. Cutting width is the most important factor, followed by cutting depth, then feed rate and spindle speed. The physical principle of the influence of cutting parameters on cutting energy consumption is revealed.