Flank Surface Research Articles

Performance evaluation of WC, SiAlON and SiCw + Al2O3 tools in dry machining of Inconel 617

Despite the fact that Inconel 617 has prominent industrial applications, the machining characteristics of the same alloy are relatively unknown. The present study, therefore, aims at comparative evaluation of performance of WC, SiAlON and SiCw + Al2O3 tools under different cutting parameters during dry machining of Inconel 617. Solid solution strengthening due to Ni-Cr-Mo-Co phases and precipitation strengthening due to M23C6 carbide present in Inconel 617 specifically lead to rapid rate of tool wear. Finite element (FE) simulation is carried out to predict cutting zone temperature and tool wear followed by experimental validation. The results indicate that WC tool performs well in terms of cutting force, temperature and surface roughness under the condition of low cutting speed of 50 m/min due to low tool wear. The effectiveness of WC tool rapidly deteriorates under high cutting speeds of 150 and 250 m/min. Ceramic tools outperform WC under the condition of higher cutting speeds in terms of greater resistance to crater and flank wear, cutting force, temperature and surface roughness. However, depth-of-cut notch and nose chipping are the predominant modes of tool wear for ceramic tools during machining of Inconel 617.

Влияние формы тороидальной задней поверхности на углы режущего клина и механические напряжения вдоль режущей кромки сверла

Introduction. Drilling holes with standard tolerance varying from IT8 to IT12 is widely used in industrial production. However, at present time, there are neither comprehensive studies, nor scientifically justified recommendations for the rational choice of the geometry of the cutting part of drills with a toroidal flank surface. Therefore, the computer-aided design (CAD) of new drill designs with a toroidal flank surface and finite element modeling (FEM) of the stressed state of its cutting part are important tasks. The purpose of the work is reducing both the range of change in the rake angle and the wedge angle of the cutting wedge along the cutting edge from the periphery to the center and the equivalent stresses in the cutting wedge. In this paper we investigate changes in the rake and wedge angles of the cutting wedge depending on the radius of the generatrix line of the toroidal flank surface as well as changes in equivalent stresses in the cutting wedge, which depend on changes in the radius of the generatrix line of the toroidal flank surface. The research methods include the fundamentals of the theory of cutting, CAD methods, and the FEM, which was applied in this work to new drill designs. Results and discussion. It is found that the range of changes in the rake angle and the wedge angle of the cutting wedge of the drill decreases compared to the standard design with decreasing radius of the generatrix line of the flank surface. A CAD system for drills with a toroidal flank surface is developed. As a result, the range of changes in the rake angle along the cutting edge decreased by 86 % for a drill with a minimum radius of the generatrix line of the toroidal surface compared to that with the conical flank surface, the range of the wedge angle of the cutting wedge decreased by 56 %, and the maximum equivalent stresses decreased by 2.13 times. It is also important to note that in this case, the wedge angle is close to constant for half of the drill tooth. These indicators exceed those for existing designs of the twist drills that indicate the key achievement of this paper.

Analysis of turning on A286 alloy with different environmental conditions

ABSTRACT Recent research has mostly focused on replacing traditional lubricants with nanoparticle-based fluids to increase machining performance. The current work compares three distinct environmental conditions in turning of A286 alloy: oil machining (OM), nano Low Quantity Lubrication (nLQL), and LN2 (liquid nitrogen). Cutting speed (Vs), environment, and feed rate (f) were used as control parameters, with responses assessed in terms of flank wear (Vb), crater wear, surface roughness (Ra), machining temperature (Mt), and chip morphology. The L27 array was chosen for the testing runs. The experimental findings demonstrated that LN2 cooling significantly lowered Ra by 54% and 24%, Vb by 62% and 53%, and Mt by 45% and 73% when compared to the OM and nLQL settings. Under cryogenic circumstances, surface integrity was also enhanced. COPRAS, a multi-response optimization approach, was used to determine the best trials for picking the best outcomes.

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.

Non-contact flank modifications of spur gears using cathodic gear tools and mechanisms: an experimental study

ABSTRACT This paper introduces cathodic gear tools designed for non-contact modification of spur gears through pulsed electrochemical flank modification. Operating with continuous rotary motion, these tools achieve profile crowning, lead crowning, tip relieving, root relieving, and end relieving. Anodic workpiece gears experience constant or variable reciprocating velocity based on the modification type. Experimental investigations confirm that the tools not only achieve the intended flank modification but also reduce flank surface roughness, eliminating hob cutter marks and cracks from the modified spur gear surfaces. The magnitude of intended modifications increases with higher voltage and longer modification duration. Notably, root relieving requires a longer duration (20 minutes) compared to other modifications (12 minutes). Details of variation in surface roughness and surface morphology using scanning electron microscopy are also presented to validate the developed mechanism.

Identification method for unsteady friction of tool flank for high efficiency milling cutter

Under the cutting loads of high efficiency and intermittent, the friction status between the tool flank and transition surface has time-varying characteristics, which directly affects friction and wear performance of the milling cutter. The dynamic distribution of instantaneous friction on tool flank under milling vibration needs to be revealed. In this work, the effect of milling vibration on instantaneous cutting contact relationship between milling cutter and workpiece was researched, a calculation method for the instantaneous friction velocity and friction energy consumption on tool flank was proposed. The variation of instantaneous friction between tool flank and transition surface under milling vibration was identified and evaluated by power spectral entropy and cross-correlation function. A method for identifying the unsteady friction of tool flank was proposed. The response analysis and experimental verification were conducted. The results showed that the frequency domain parameter distribution of friction energy consumption on tool flank had a strong correlation with the wear depth distribution, and was obviously sensitive to the milling parameters. The above models and methods could be used to reveal the influence of key milling process variables on unsteady friction and wear process of milling cutter’s multiple tool flank.

Meshing Characteristics of Profile Shifted Cylindrical Quasi-Involute Arc-Tooth-Trace Gears. Part 2. Calculation Results

Abstract Based on the results obtained in the previous research, the values of meshing characteristics of profile shifted quasi-involute arc-tooth-trace gears is calculated. The influence of the values of profile shift coefficient and the angle of tooth trace on meshing characteristic distribution on the tooth flank surface along tooth trace is defined. The results can be used for design of profile shifted quasi-involute arc-tooth-trace gears, cut by Gleason-type cutters with different profile angle value.

Development of analytical models for tip, root, and end relieving of spur gears by pulsed electrochemical finishing process

This paper describes analytical modelling for the non-contact tip, root, and end relieving of spur gears and their associated volumetric material removal rate (MRR) by the pulsed electrochemical finishing (PECF) process. The models were developed using Faraday’s law of electrolysis and involute geometry of spur gears. The developed models are validated experimentally using the innovatively designed and developed cathode gears and experimental apparatus by varying voltage, pulse-on time, and pulse-off time at four levels each. It found that minimum prediction errors for the developed models for the amount of tip, root, and end relief are 0.8%, 0.3%, and 1.3%, respectively, and minimum prediction error for models of volumetric MRR of tip, root, and end relief are 6.9%, 0.6%, and 9.8% respectively. A study of microgeometry along the profile and lead direction of spur gear confirmed that the PECF process not only successfully imparted tip, root, and end relief but also reduced their arithmetical average roughness and maximum height by 61.1% and 62.5% for tip relief, 67.7% and 67.8% for root relief, and 63.8% and 66.6% for end relief respectively. It also removed hob cutter marks and cracks revealed from the comparison of surface morphology of spur gear flank surfaces before and after tip, root, and end relieving. Maximum values of % reductions in maximum height and arithmetical average roughness occurred for pulse-on and pulse-off times as 3 and 4 ms (i.e., 43% duty cycle). The developed models will be very useful in designing or predicting the amount of tip, root, and end relief that can be imparted for a given modification duration. Conversely, they can be used for parametric optimization of the PECF process and to compute the required duration for the PECF process to impart the desired amount of tip/root/end relief to spur gears.

Novel use of cryogenic cooling conditions in improving the machining performance of Al 8011/nano-SiC composites

The inclusion of nanoparticles makes the composite not only stronger but also lighter and highly resistant towards wear among many other positive attributes. However, the high hardness and abrasive characteristics of the composites make machining a formidable task. Hence to surmount these challenges, various coolant conditions have been entailed like dry machining, flood cooling, minimum quantity lubrication (MQL), and cryogenic (cryo) CO2 cooling. This investigation encompasses the influence of diverse coolant techniques during the machining of as casted aluminium with nano silicon carbide (Al/n-SiC) composite. This study further incites the analysis of the machining temperature, surface characteristics, flank wear, and chip morphology under each coolant techniques. The outcomes of this investigation furnish a comprehensive understanding of the impact of distinct coolant environments on the machining performance of Al/n-SiC composite. The cutting temperature under cryo-CO2 was found to be lowered by 41–47%, 15–21%, and 8–12% when compared to the usage of dry, flood, and MQL, respectively. The study unveils that cryo-CO2 cooling developed the lowest machining temperature, followed by MQL, flood cooling, and dry machining. Furthermore, cryo-CO2 cooling and MQL exhibited the best outcome in terms of flank wear and surface characteristics. The verdicts of this investigation suggest the use of cryo-CO2 cooling and MQL makes eloquent improvement in the machining performances of Al/n-SiC composites.

EFFECT OF TEXTURED CUTTING INSERTS IN MICRO-TURNING OF TI-6AL-4V ALLOYS

There is an increasing demand for higher machining quality and service life of the cutting tools used for the machining of high-strength alloys. Various studies revealed that textured cutting tools could improve the cutting performance by enhancing the tribological characteristics of the cutting regime. Advances in precision machining enabled the creation of micro/nano-textures on tool surfaces with excellent dimensional control. In this work, distinct micro designs, viz. horizontal line, vertical line and cross-hatch, are made, varying the pitch on the rake faces of coated carbide cutting inserts (CCMT060202LF KC5010). An in-house micro-turning machine was utilized to perform all the experiments in dry-cutting conditions. Micro-turning operations were performed using plain and textured inserts and varying the cutting parameters under dry conditions. The effectiveness of micro-scale textures at a contact interface was evaluated based on the cutting forces, tool flank wear and surface roughness. Compared to non-textured inserts, the machining using cross-hatch textured inserts with 100 µm pitch resulted in 50 % lower cutting forces, a 45 % improved surface finish and 37 % reduced tool flank wear. When machining with horizontal-line textured inserts with a 100 µm pitch, cutting forces are reduced by 46 %, the surface finish is enhanced by 34 % and the tool flank wear is lowered by 30 %. Similarly, when machining with vertical-line textured inserts with a 100 µm pitch, cutting forces are minimized by 38 %, the surface finish is improved by 20 % and the tool flank wear is lowered by 26 %. Additionally, a durability test was conducted for the inserts, and the results showed that the cross-hatch textured tool life improved by 80 %, the life of the horizontal-line textured tool increased by 50 % and the life of the vertical-line textured tool increased by 40 % compared to plain inserts. The heat dissipation and tool-chip friction during machining are thus significantly influenced by the texturing, namely by its design, dimensions and orientation.

Structural modification of WC-Co cutting tools by laser doping treatment

We have previously shown that sharpening the cutting edge of a cemented carbide tool by chemical-mechanical polishing (CMP) improved the cutting speed by approximately 150% and reduced the wear on the flank surface by approximately 50% compared to a commercial tool when cutting a heat-resistant alloy. In addition, the cutting edges of carbide tools treated by laser doping (LD) using boron nitride as doping material achieved approximately 100 times longer cutting distance in glass machining than the edges of carbide tools treated with CMP grinding wheels. In this study, LD was conducted on a tool base material (WC–Co) to investigate and understand the crystal structure changes of the base material upon treatment. Electron backscatter diffraction and X-ray diffraction results show that the effect of LD was observed in the region 50 nm below the surface. LD improved the strength by approximately 11.7% without destroying the surface crystal structure. Thus, doping can be performed on tool tips while maintaining the WC structure to improve the performance of WC-Co cutting tools.

AN INVESTIGATION ON MEAN ROUGHNESS DEPTH AND MATERIAL EROSION SPEED DURING MANUFACTURING OF STAINLESS-STEEL MINIATURE RATCHET GEARS BY WIRE-EDM

This paper presents the results of an investigation conducted on wire electric discharge machining (wire-EDM) of miniature ratchet gears. Effects of three important process parameters spark duration, ‘Ton’, spark-off-duration ‘Toff’, and wire tension ‘WT’ on surface quality, i.e., mean roughness depth ‘Rz’ and productivity, i.e., material erosion speed ‘MES’, have been investigated by conducting seventeen experimental trials. Both Ton and Toff have been identified as the significant parameters. Further, an optimization of wire-EDM parameters resulted in simultaneously best compromise values of Rz 5.30 µm and MES 6.75 mm/min and is achieved the following cutting regime: Ton 1.5 µs, Toff 42.5 µs, and WT 1500 g. At the end, surface quality study has been conducted to evaluate the tribological fitness of the miniature ratchet gear machined at optimum combination of wire-EDM parameter values. It was investigated that the generation of uniform and shallow craters on the flank surfaces of ratchet gear machined at optimum values of parameters, imparted smoother bearing area curve and lower coefficient of friction. The profile and flank surface of the ratchet gear also found free from cracks, burrs, and dirt.

Automated detection of gear tooth flank surface integrity: A cascade detection approach using machine vision

The surface integrity of gear tooth flanks significantly impacts the efficiency and reliability of gear transmission systems. This article proposes a cascaded detection approach using machine vision to comprehensively localize and identify thermal damages on tooth flanks following the grinding process. This method utilized an image enhancement to correct non-uniform illumination and a saliency detection based on the spectral residual algorithm to extract individual tooth flanks. Additionally, an image semantic segmentation model, GBSU-Net, was put forward to detect thermal damage regions on the tooth flank and quantify the severity of grinding burn with the area ratio. The experimental results demonstrated the efficacy of the proposed method on the gear surface image dataset, with the Dice coefficient and IoU metrics achieving 84.29 % and 73.95 %, respectively. The proposed method is applicable for real-time detection during gear machining processes because of its swift and accurate detection capability.

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.

Evaluation of CNC routed surface quality of maple (Acer pseudoplatanus) and oak (Quercus robur L.) with different milling angles as function of grain orientation

The study assessed CNC routing quality on maple and oak samples, using 90º V-Grooving router bits at various milling angles as function of grain orientation: 0°, 15°, 30°, 45°, 60°, 75°, 90°, and feed speeds of 3 and 6 m/min at spindle speed of 15,000 rpm. The routing quality was evaluated by roughness parameters for the V flank surfaces and by visual examination for the flanks’ edges. The change in the feed speed had no significant effect for the flanks surface quality of both species, but roughness values were considerable higher for maple samples at 90º and u=3 m/min (Rk = 23.7 µm compared to along the grain, Rk=9.83 µm for u=6 m/min) due to possible processing vibrations. The milling angle as function of grain orientation was significant in the case of oak, as the processing roughness increased with the cutting angle from 0° (Rk=11 to 13 µm) to 60°(Rk =28 to 30 µm). Fuzziness around the earlywood pores of oak was higher for the 6 m/min feed speed. A substantial increase in waviness coinciding with the annual growth areas was measured for crosscut oak samples (Wa = 34.0 µm, compared with Wa =7 .39 µm along the grain). The surface waviness of maple was not sensitive to the variation in the cutting angle or feed speed (Wa was around 3 to 4 µm). For the flank edges, the best visual option was found for cutting along the wood grain and the worst was for 60º, which caused biggest ruptures and especially for the 3 m/min feed speed, for both species.

Simulation Study on the Tribological Characteristics in the Meshing Contact in the Context of the Load Carrying Capacity Calculation of Internal Gears with Unbalanced Sliding Conditions

Planetary gearboxes are characterized by a high power density and a compact design with coaxial in- and output. Consequently, planetary gear units are frequently used in many practical applications, e.g. in wind energy and industrial transmission systems as well as in automotive applications such as automatic transmissions. As a result of the scaling-up of the required system power, the risk of flank damages increased during the last decade. Certain damage types, such as pitting and micropitting, occur predominantly in contact areas of negative specific sliding on the tooth flank surface. Unlike external gears, internal gears offer the possibility of positioning the pitch point C outside of the active profile. Depending on the gear design, this allows a complete avoidance of negative specific sliding either on the planet or on the ring gear. In contrast, the corresponding gear is subjected to negative specific sliding only. It can be assumed that the lifetime regarding flank damages of each meshing partner can be affected by different positions of the pitch point and the resulting differences in the specific sliding, which allows an optimization of the full gear system, taking into account e.g. the load carrying capacity reserves for different material pairings. It is to be noted that such gear designs are already part of some practical applications.However, the existing analytical approaches within standardized load carrying capacity calculation methods are typically based on investigations considering external gears with balanced sliding conditions. Systematic results on internal gear designs with pitch point positioned outside of the active profile are not available.Within this paper, extended theoretical studies on the tribological characteristics of different internal gear designs are presented. Therefore, a reference geometry with balanced sliding conditions is compared to internal gears with pitch point below respectively above the active profile. The focus of the studies is the analysis of the lubricant film thickness and the contact temperature in the meshing contact. Referring to this, a high-order TEHL contact simulation model was used. The results of the numerical analysis with the FZG calculation software TriboMesh are compared to different analytical approaches in the context of the calculation of load carrying capacity to derive recommendations for the design of internal gears.

Machinability appraisal of nitronic-50 under dry environment using uncoated carbide inserts

ABSTRACT Nitrogen strengthened austenitic stainless steels are uneasy to machine. 22-13-5 stainless steel better known as Nitronic-50 is also not an exception. The current study deals with such an investigation where Nitronic-50 has been machined under varied cutting speeds, feeds and depths of cut and its machinability has been tried to be adjudged on the basis of cutting forces, apparent coefficient of friction, tool-tip temperature, chip reduction coefficient, flank wear width, chip morphology and surface roughness. It is seen that while using higher cutting speed-lower feed-higher depth of cut combination, tangential cutting forces were 18.83% and 29.57%, apparent coefficient of friction was 9.48% and 12.90%, tool-tip temperature was 11.02% and 22.31%, flank wear was 41.25% and 29.91%, and surface roughness was 22.91% and 24.27% lesser as compared to the higher values obtained with higher cutting speed-higher feed-higher depth of cut and intermediate cutting speed-higher feed-higher depth of cut combinations, respectively.

Numerical investigation on the premature and extended contact behaviour of engineering thermoplastic gears and its effect in gear kinematics

PurposeThis research work aims to determine the maximum load a thermoplastic gear can withstand without the occurrence of extended contact. The extended contact of polymer gears is usually overlooked in basic design calculations, although it considerably affects the gear's load-carrying ability. Although various researchers highlighted the phenomenon, an extensive investigation of the extended contact behaviour is limited. Hence the work aims to investigate the premature and extended contact behaviour of thermoplastic gears and its effect in the gear kinematics, bending stiffness, stresses induced and the roll angle subtended by the gear pair.Design/methodology/approachThe work uses finite element method to perform quasi-static two-dimensional analysis of the meshing gear teeth. The FE model was developed in AutoCAD and analysed using ANSYS 19.1 simulation package. A three-dimensional gear model with all the teeth is computationally intensive for solving a static analysis problem. Hence, planar analysis with a reduced number of teeth is considered to reduce the computational time and difficulty.FindingsThe roll angle subtended at the centre by the path of approach is higher than the path of recess because of the increased load sharing. The contact stress profile followed a unique R-F-R-F pattern in the premature and extended contact regions due to the driven tip-driver flank surface contact. A non-dimensional parameter was formulated correlating the young's modulus, the load applied and deflection induced that can be utilised to predict the occurrence of premature and extended contact in thermoplastic gears.Originality/valueThe gear rating standards for polymer gears are formulated from the conventional metal gears which does not include the effect of gear tooth deflection. The work attempts to explain the gear tooth deflection for various standard thermoplastics and its effect in kinematics. Likewise, a new dimensionless number was introduced to predict the extended contact that will help in appropriate selection of load reducing the possibility of wear.

Optimization of Machining Variables of Inconel 800 Alloy in CNC Face Milling Using TiAlN and TiAlN-TiN Coated Inserts

This research work is based on the machinability of an Inconel 800 alloy using TiAlN-coating and TiAlN-TiN-coating tools. In the CNC VMC Face milling process feed, depth of cut (DoC), and cutting speed consider input variables and surface roughness, Tool wear is measured for all machining conditions. To enhance the machining conditions a Taguchi L9 Design of Experiment was created. ANOVA analysis was used to identify the important variables influencing Flank wear (tool wear) and surface roughness. The signal-to-noise ratio for the ideal cutting combination was identified by evaluating the optimum surface roughness and tool wear. for the effect of coating, a comparison was done between the findings obtained using both TiAlN-coated and TiAlN-TiN tungsten carbide-coated tools. The best optimum surface roughness and tool wear of the experiment conducted under machining with TiAlN-TiN coated carbide tool resulted in .3433 µm and 128 µm respectively.