Rake Face Of Cutting Tool Research Articles

Predicting Cutting Force and Primary Shear Behavior in Micro-Textured Tools Assisted Machining of AISI 630: Numerical Modeling and Taguchi Analysis.

The cutting tool heats up during the cutting of high-performance super alloys and it negatively affects the life of the cutting tool. Improved tool life can enhance both the machinability and sustainability of the cutting process. To improve the tool life preferably cutting fluids are utilized. However, the majority of cutting fluids are non-biodegradable in nature and pose harmful threats to the environment. It has been established in the metal cutting literature that introducing microgrooves at the cutting tool rake face can significantly reduce the coefficient of friction (COF). Reduction in the COF promotes anti-adhesive behavior that improves the tool life. The current study numerically investigates the orthogonal cutting process of AISI 630 Stainless Steel using different micro grooved cutting tools. Results of the numerical simulations point to the positive influence of micro grooves on tool life. The results of the main effects found that the cutting temperature was decreased by approximately 10% and 7% with rectangular and triangular micro grooved tools, respectively. Over machining performance indicated that rectangular micro groove tools provided comparatively better performance.

Machining performance of protruded textured high-speed steel cutting tool under dry turning operation

AISI 316 L stainless steel is one of the difficult material to machine by traditional machining process due to its low thermal conductivity and high ductility properties which can cause high tool wear and high cutting forces. This can be addressed while using cutting fluid, however, cutting fluid causes severe environmental pollution while disposal. In recent studies, the usage of surface textures on cutting tools exhibited an improved machining performance without cutting fluids. The present work made an attempt to fabricate positive (protruded) surface textures on HSS cutting tool rake face and study its effect on the machining performance of AISI 316L stainless steel under dry machining. The surface textures are fabricated using the reverse-electro discharge machining process. In the present work, the effect of texture parameters such as texture density, texture height and diameter on the machining performance parameters like cutting forces, flank wear and machined surface quality of the machined workpiece are studied. The results indicated that a positive (protruded) surface textured cutting tool exhibits better machining performance as compared to the un-textured cutting tool. In addition, among the texture parameters, texture height has a significant effect on machining performance. Moreover, textured tool with a combination of 150 µm texture diameter, 5% texture density and 300 µm texture height shown better machining performance. It has also been observed that tool life is improved up to 110% as compared to un-textured tool.

Machining of hard materials using textured tool with minimum quantity nano-green cutting fluid

Metal cutting causes severe friction and heat generation in the machining zone. Previously, petroleum-based cutting fluids were applied for reducing friction and machining temperature at the machining zone. Nowadays, nano-cutting fluids are preferred owing to their higher thermal conductivity and better lubricating ability. However, during machining of hard materials (hardness, ≥50 HRC), the effectiveness of these nano-cutting fluids is limited, as they rarely reach to the cutting edge of cutting tool because of high normal stresses. In this regard, the combination of rake face micro-textured cutting tool with indigenously synthesized nano-green cutting fluids under in-house developed minimum quantity cutting fluid (MQCF) environment is accomplished for hard machining experiments. For comparison, hard machining experiments are also performed under dry machining, green cutting fluid and nano-green cutting fluid (NGCF) with untextured cutting tools. Detailed analysis shows significant improvement in hard machining performance using combination of micro-textured tools with NGCF corresponding to forces, chip-tool interface friction, workpiece surface roughness and chip morphology. It is attributed to better infiltration of NGCF in-between chip-tool interface by virtue of micro-textures present on the cutting tool rake face. Further, the proposed analytical model captures the effect of textures on the tool surface in the same way as reduced contact tools. It is in a good agreement with corresponding experimental cutting forces.

Experimental study on role of tool-work materials and machining conditions on Built-up Edge Formation

Built-up Edge is a well-known phenomenon in the manufacturing industry which probably a danger for the quality of the semi-finished or finished product. This unfavourable incident hampered surface finish and reduce the life f tool. During any machining operation such as turning; the tool and the performed blank stick together like welding action. Under high compressive stress, seizure keeps the material from sliding over the cutting tool rake face. The presence or non-appearance of a developed edge (BUE) is significant according to apparatus wear and surface completion. The potential systems and cycles of wear impacted by the various kinds of the built-up edge were talked about in our study. Metallographic examinations have indicated that recrystallization happens in the streamed layer. The progression of sub microscopic crystallites over the tool-face affects tool wear. From the experiment, the most positive cutting conditions, from the perspective of both wear and surface completion, happen without a developed edge. This work and moderate reports on the investigation of the BUE calculation of C30 steel machined at low rates with and without a cutting liquid.

Chamfer texturing of tungsten carbide inserts applied to turning of grey cast iron

Owing to the relevance of the turning operation to the metal working industry, intensive research is constantly undertaken in order to improve the quality of manufactured products, optimise production time, and reduce costs. Among the investigated topics, texturing of the cutting tool rake face has received increasing attention since it can affect tool life, process forces, and cutting temperature. The contribution of the present work resides in depicting the procedure for laser texturing the cutting edge chamfer of uncoated tungsten carbide inserts aiming at weakening the stability of the seizure region. Moreover, the performance of textured and non-textured tools was assessed when turning grey cast iron. Two parallel columns of dimples with an average diameter of 40 μm and variable distance between rows of dimples (60, 100, and 200 μm) were produced and the turning experiments were carried out dry and with the application of minimal quantity lubrication (MQL). The findings indicated that the lowest values for the turning force components were obtained when cutting with textured tools possessing dimples 100 μm apart and using MQL. Texturing did not affect tool life in dry turning; however, when cutting with MQL, the longest tool lives were obtained using the tools textured with dimples 60 and 100 μm apart. Finally, machined surface roughness was not affected by tool texturing and decreased slightly with the application of MQL.

3D FEM simulation of the turning process of stainless steel 17-4PH with differently texturized cutting tools

Micro-texturing techniques are applied to improve the performance of cutting tools by improving the tribological performance. However, sharp edges of linear micro-grooved tool designs may adversely affect tool-chip contact, create interlocking effects, and weaken the potential benefits. This paper investigates new designs in curvilinear micro-grooves on the cutting tool rake face to reduce the interlocking effect and further improve the performance. A modified methodology that uses an orthogonal cutting model and inverse analysis was utilized to determine the Johnson–Cook (J–C) constitutive material model parameters for stainless steel 17-4PH. The finite element method (FEM) simulation results in force predictions confirmed that this methodology is suitable to obtain J–C model parameters used in high-speed machining regimes. Then, three-dimensional (3D) simulations for rough and finish turning were developed and validated for machining with the non-textured cutting tool. The performance of cutting with curvilinear micro-grooved tools was investigated by 3D FEM simulations. These newly designed micro-grooved tools showed improved performance in tool-chip friction, chip formation, cutting force, temperature, and tool stress fields than non-textured and linear micro-grooved designs.

Thermal, rheological, wettability and hard machining performance of MoS2 and CaF2 based minimum quantity hybrid nano-green cutting fluids

Minimum quantity cutting fluids (MQCF) is an alternative for dry machining and flood cooling. However, use of MQCF is limited to mild machining conditions due to high heat generation during machining of hard materials. The applicability of MQCF can be extended in aggressive machining conditions by using vegetable-based green cutting fluids (GCF) with solid lubricant nanoparticles as potential additives. In the present study, hybrid nano-green cutting fluids (HN-GCFs) were prepared by mixing different volume concentration of calcium fluoride (CaF2) and molybdenum disulphide (MoS2) solid lubricants in indigenously developed vegetable based GCF. Dispersion stability, thermal conductivity, specific volumetric heat capacity, viscosities and wetting angle of HN-GCFs were measured. In-house fabricated MQCF setup is used to apply minimum HN-GCF across the machining region. Later, the experimentally optimised concentration of both CaF2 and MoS2 based HN-GCFs were selected for machining experiments using MQCF setup. Hard machining experiments were carried out using four different cutting fluids: commercial mineral oil (MO), GCF, 0.3% concentration of CaF2 based HN-GCF (HN-GCF-0.3C) and 0.3% concentration of MoS2 based HN-GCF (HN-GCF-0.3 M). Comparative tool wear, workpiece material adhesion and workpiece surface morphology were also investigated. Results show that 0.3% concentration of HN-GCF-0.3M performs better concerning tool-workpiece interface coefficient of friction, cutting force, feed force, and workpiece surface roughness compared to other cutting fluids. During machining with HN-GCF-0.3M, cutting tool experiences 17% and 28% lower cutting as well as feed force, respectively as compared with machining using MO. Also, 11% reduction in tool-chip interface coefficient of friction was observed during machining using HN-GCF-0.3M, and it also produces 37% better workpiece surface finish. Elemental analysis of cutting tool confirms less work material adhesion on the cutting tool rake face using HN-GCF-0.3M.

Hard machining performance of indigenously developed green cutting fluid using flood cooling and minimum quantity cutting fluid

Cutting fluids play a vital part in turning process. Basically, these cutting fluids are made up of mineral oil (MO) and performance enhancing additives that are produced chemically. However, MO has adverse environmental effects and causes health hazards. Therefore, MO is gradually replaced by green cutting fluid (GCF). Indigenously developed environmental friendly vegetable based GCF with minimum quantity cutting fluid (MQCF) application technique can serve as a viable solution to make current work a cleaner process. In this present study, vegetable-based GCF was synthesised and characterized. Emulsion stability and anti-corrosion properties of GCF were investigated. MQCF machining process parameters such as cutting fluid emulsion composition, nozzle stand-off distance and nozzle spray angle were experimentally optimized to extract better output. Hard machining experiments were performed with developed GCF using flood cooling (FC) and MQCF techniques during turning of hardened AISI H-13 steel. For comparison, dry machining experiments were also carried out. Cutting force, feed forces, centre line average (CLA) surface roughness of workpiece were measured and the coefficient of friction was calculated. After machining, cutting tool rake face morphology and wear characteristics were studied using field emission scanning electron microscope, optical microscope and non-contact 3D surface profilometer. Result shows that cutting force, feed force, coefficient of friction and CLA surface roughness of workpiece were reduced using optimized MQCF process parameters. Also, machining performance was improved with MQCF technique using GCF as compared to flood cooling and dry machining.

Environmental friendly hard machining performance of uncoated and MoS 2 coated mechanical micro-textured tungsten carbide cutting tools

Abstract Nowadays dry machining is favored due to various detrimental environmental effects and health hazards to operator by use of cutting fluids. Surface texturing on the cutting tool is one of the viable solutions to enhance tribological properties in dry hard machining. In present paper, performances of six different mechanical micro-textured (MμT) cutting tools are compared. At first, three different types of MμTs are fabricated on the cutting tool rake face using Vickers hardness and micro-scratch testers. Furthermore, a set of MμT tools are coated with molybdenum disulphide (MoS2). Dry machining experiments are carried out and found that MoS2 coated perpendicular MμT tool performs better among all. Thus, MμT tools can be a viable alternative to the cutting fluids in machining.

Mechanism of the crack propagation in the chip root in dry hard orthogonal turning of the hardened steel

Analytic model of the crack-tip field in the cutting tool tip located in the chip root in dry hard orthogonal turning (DHOT) of the hardened steel was established in this paper according to the metal cutting principle and fracture mechanics theory. The relationship between the crack inclination angle ψ to the direction of the tensile stress σ and the crack propagation angle θ0 in I-II mixed model also was proposed. The control equation, displacement function, and boundary condition of crack dynamic propagation in the chip root were derived. The mathematical model for the relationship between the shear angle ϕ and the crack propagation angle θ0 also was presented. Furthermore, formation mechanisms of the serrated chip in DHOT of the hardened steel Cr12MoV (40–60 ± 1HRC) by utilizing the Polycrystalline Cubic Boron Nitride (PCBN) inserts were experimentally investigated. The results showed that the cutting speed and quenching hardness of workpiece have great influence on the crack propagation angle θ0. The shear angles ϕ calculated by the mathematical model are basically in agreement with the experimental results. The thermal softening chip squeezed from the cutting tool rake face begins to shear and slip at high speed along the direction of the crack propagation angle θ0 in the chip root and then the serrated chip forms.

Surface textures on cemented carbide cutting tools by micro EDM assisted with high-frequency vibration

This paper demonstrates the process of micro electro-discharge machining (micro EDM) assisted with high-frequency vibration machining micro holes and linear grooves which are straight or inclined on WC/8 % Co (MA) and WC/15 % TiC/6 %Co (MB) cemented carbide cutting tool rake face or scrap reeling slot. Low-voltage sensing contact is introduced to determine the exact position of holes and grooves. Morphology of textured regions is examined and the elemental chemical composition of close proximity region to a straight hole is identified. Results show that micro holes and linear grooves with high dimension accuracy and exact position are machined as expected by micro EDM assisted with high-frequency vibration. There is no debris accumulating around the cavities. Materials of MA cutting tool adhere on the micro tool electrode slightly, while the dimension of adhesion position becomes constant after 3 μ holes are finished. However, the adhesion does not occur during machining MB cutting tools. The distance of edges of grain refinement regions and areas where elemental chemical composition varies to the contour of the hole is no more than 15 μm.

Diamond turning of small Fresnel lens array in single crystal InSb

A small Fresnel lens array was diamond turned in a single crystal (0 0 1) InSb wafer using a half-radius negative rake angle (−25°) single-point diamond tool. The machined array consisted of three concave Fresnel lenses cut under different machining sequences. The Fresnel lens profiles were designed to operate in the paraxial domain having a quadratic phase distribution. The sample was examined by scanning electron microscopy and an optical profilometer. Optical profilometry was also used to measure the surface roughness of the machined surface. Ductile ribbon-like chips were observed on the cutting tool rake face. No signs of cutting edge wear was observed on the diamond tool. The machined surface presented an amorphous phase probed by micro Raman spectroscopy. A successful heat treatment of annealing was carried out to recover the crystalline phase on the machined surface. The results indicated that it is possible to perform a ‘mechanical lithography’ process in single crystal semiconductors.

切削工具すくい面上摩擦分力の予測法に関する一試案

切削工具すくい面上摩擦分力の予測法に関する一試案

C13 切削工具一体型WC-Cr極小温度センサアレイの開発(OS5 加工計測・評価(1))

In this paper, a new temperature sensor was proposed in order to measure cutting temperature fields continuously with a quick response regardless of the conductivity of a work. It has thermocouple array constructed by a tool and sputtered metallic lines, which are embedded into a cutting tool rake face. Here is a process flow. The trenches and electrodes were milled by femto second laser. And, insulating films and metallic lines were sputtered on the rake face. Finally, unwanted films were removed selectively by polishing. The thermo electromotive force of our sensor was converted to temperature based on a calibration curve obtained by experimentally. Cutting experiment showed that cutting temperature at the rake face could be measured by our sensor.

Structure evaluation of submicrometre silicon chips removed by diamond turning

Continuous chips removed by single-point diamond turning of single crystal silicon have been investigated by means of scanning electron microscopy/transmission electron microscopy and micro-Raman spectroscopy. Three different chip structures were probed with the use of electron diffraction pattern: (i) totally amorphous lamellar structure, (ii) amorphous structure with remnant crystalline material and (iii) partially amorphous together with amorphous with remnant crystalline material. Furthermore, micro-Raman spectroscopy from the chips remained in the cutting tool rake face depicted different silicon phases. We have found, from a detailed analysis of the debris, five different structural phases of silicon in the same debris. It is proposed that material removal mechanisms may change along the cutting edge from shearing (yielding lamellar structures) to extrusion. Shearing results from structural changes related to phase transformation induced by pressure and shear deformation. Extrusion, yielding crystalline structures in the chips, may be attributed to a pressure drop (due to an increase in the contact area) from the tool tip towards the region of the cutting edge where the brittle-to-ductile transition occurs. From this region upwards, pressure (stress) would be insufficient to trigger phase transformation and therefore the amorphous phase would not form integrally along the chip width.

Multiple phase silicon in submicrometer chips removed by diamond turning

Continuous chips removed by single point diamond turning of single crystal silicon have been investigated by means of Scanning Electron Microscopy/Transmission Electron Microscopy and micro-Raman Spectroscopy. Three different chip structures were probed with the use of electron diffraction pattern: (i) totally amorphous lamellar structure, (ii) amorphous structure with remnant crystalline material and, (iii) partially amorphous together with amorphous with remnant crystalline material. Furthermore, micro-Raman spectroscopy from the chips left in the cutting tool rake face showed different silicon phases. We have found, from a detailed analysis of the debris, five different structural phases of silicon in the same debris. It is proposed that material removal mechanisms may change along the cutting edge from shearing (yielding lamellar structures) to extrusion. Shearing results from structural changes related to phase transformation induced by pressure and shear deformation. Extrusion, yielding crystalline structures in the chips, may be attributed to a pressure drop (due to an increase in the contact area) from the tool tip towards the region of the cutting edge where brittle-to-ductile transition occurs. From this region upwards, pressure(stress) would be insufficient to trigger phase transformation and therefore amorphous phase would not form integrally along the chip width.