International Journal of Machining and Machinability of Materials (17 papers in press)
Metrological changes in surface profile, chip, and temperature on End Milling of M2HSS die steel
by Balamurugan Karnan
Abstract: The effect of the thermal energy generated during end milling on the surface profile and chip morphology with a change in the spindle speed and feed rate is studied and reported. Steels with 5% Molybdenum have found an amicable application as Molybdenum based high speed die steel (M2HSS). It is used as the machining material. Taguchys L9 orthogonal array machining condition is performed for two different tool diameters of 10 mm and 12 mm. High machining temperatures initiate a local welding zone, creates a weldment between the chip and tool surface, and progress to excess tool wear. This experimental study reveals that the details of increased thermal interaction that allows an excessive deformation of the sample through chip removal. With an increase in the high level of spindle speed and low feed rate, it is possible to get an acceptable level of surface profile roughness with a less tool wear rate. Further, the chip morphological analysis was performed and reported.
Keywords: End Milling; Die steel; Wear; thermal integration; chip formation; chatter growth.
Experimental study of orthogonal cutting of unidirectional CFRP laminates
by BLANCHET Florent, LACHAUD Frederic, PIQUET Robert, LANDON Yann
Abstract: This article relates to the study of orthogonal cutting of unidirectional carbon epoxy composite laminates T800S/M21 with tool angle influences. Many positive and negative values of the cutting angle () and of the angle 2 defined by the direction of the cutting speed and the fibers direction of the workpiece are used. Then this papers focus on the study of the cutting mechanisms, the morphology of the chip (its mode of formation and its shape), and the surface quality obtained according to the cutting forces evolution. Finally, study explains angle influence of surface roughness.
Keywords: Orthogonal cutting; Unidirectional carbon epoxy laminates; cutting forces; surface quality after machinning; cutting mechanisms.
Innovations in Electro Chemical Discharge Machining process through Electrolyte Stirring and Tool Rotations
by Chandrashekhar Jawalkar, Apurbba Kumar Sharma, Pradeep Kumar
Abstract: Electro chemical discharge machining (ECDM) process is gaining considerable importance in micro-machining of non-conductive and brittle materials like glass and ceramics. Recently it has undergone some innovations in the form of hybrid and variant processes, which have been reviewed and discussed in this paper. To further aid developments, an innovative hybrid process combining electrolyte-stirring and tool-rotation effect has been experimented and reported in this paper. The study was carried out in a phased manner on an in-house fabricated set-up using Taguchis orthogonal array L18. The experimental results illustrate an improvement in the process as compared to normal ECDM (without using electrolyte stirring and tool rotations). The optimum value for material removal was 1.282 mg/min and surface finish (Ra) was 0.4
Keywords: Tool Rotations; Electrolyte Stirring; Material Removal; Surface Finish.
Experimental investigation of surface characteristics and dynamic effects at micro milling of hardened hot-work tool steel
by Barnabas Zoltan Balazs, Barnabas Zoltan Balazs, Marton Takacs, Marton Takacs
Abstract: One of the main trends in modern manufacturing technology is miniaturization. In this field, micro milling offers the most flexible machining method. Size reduction results in special and unique characteristics with respect to the machining process. The current paper addresses the investigation of the dynamic effects and surface characteristics of micro milled structures. Experiments were carried out on AISI H13 hot-work tool steel with 50 HRC hardness using a 5-axis micro milling centre: cutting force components and the vibration signal were recorded and analysed. By means of Fast Fourier Transform, the dominant frequencies of the process were identified. Time-frequency diagrams were prepared by Short-Time Fourier Transform for studying process changes during cutting time. Also, correlations between surface roughness, burr formation and cutting parameters were investigated. The results of this research provide a deeper understanding of the micro milling process, which ensures well-controlled and reproducible machining of up-to-date materials.
Keywords: micro milling; hot-work tool steel; vibration; signal analysis; burr formation; surface quality.
Mechanistic Modelling of Dynamic Cutting Forces in Micro End Milling of Zr-based Bulk Metallic Glass
by Debajyoti Ray, Asit Baran Puri, Naga Hanumaiah, Saurav Halder
Abstract: This paper presents the mechanistic modelling of dynamic cutting forces in micro end milling of Zr-based bulk metallic glass using empirically determined cutting force coefficients. The cutting force coefficients are determined for the ploughing and shearing dominant regimes from the average cutting forces in full immersion micro milling experiments at different feed rates. The ploughing forces are modelled as proportional to the interactive area between the bottom segment of the rounded cutting edge and the in-flowing work material. The influence of the edge radius of the cutting tool and the effects of minimum uncut chip thickness, elastic recovery, overlapping tooth engagement etc. are considered in the modelling of the cutting forces. The cutting force model uses separate edge coefficients for the ploughing and shearing dominant regimes of cutting. The paper also analyses the effect of low uncut chip thickness on effective rake angle for different edge radii. The proposed model is compared with the results of several micro milling experiments carried on Zr-based bulk metallic glass. The study reveals that the radial ploughing coefficient is larger than the tangential ploughing coefficient. However, the tangential cutting coefficient is found to be larger than the radial cutting coefficient. At lower feed rates, edge radius of the cutting tool influences the cutting forces due to increased ploughing and rubbing effects. The absolute percentage deviation of the prediction from the experimental values of the average peak cutting force components in X-, Y- and Z- directions are in the range of 4.26-6.16%, 3.24-10.44% and 14.67-28.01% respectively for the feed rate range of 0.5-6
Keywords: Micro end milling; Cutting forces; Mechanistic model; Cutting force coefficients; Cutting edge radius; Ploughing; Elastic recovery; Bulk metallic glass.
Optimal cutting state predictions in internal turning operation with Nano-SiC/GFRE composite layered boring tools
by Bonda Atchuta Ganesh Yuvaraju, Bijoy Kumar Nanda, Jonnalagadda Srinivas
Abstract: This paper presents a passive vibration control methodology in internal turning process with the use of hybrid nanocomposite coatings (nano-SiC/GFRE) on the surface of boring bar. Natural frequencies and damping ratio of different composition tool-holders are obtained experimentally using impact hammer test. Three different configuration considered are: (i) conventional (tool-holder 1), (ii) nano-SiC/GFRE with 1% SiC (tool-holder 2) and (iii) nano-SiC/GFRE with 2% SiC (tool-holder 3). A better damping ability is noticed in third configuration of tool-holder compared to others. Furthermore, using single mode data, analytical stability lobe diagrams are constructed for all three tool-holders. Moreover, Box-Behnken design (BBD) is adopted and a set of fifteen experiments are performed with each tool-holder. For third configuration of tool holder, effect of input variables on the surface roughness and tool vibration amplitudes is studied using neural network model. Finally, the neural network regression model is employed as a function estimation tool in simulated annealing for obtaining optimal cutting conditions.
Keywords: boring bar; passive damping; nanocomposites; tool vibration; surface roughness; modal parameters; stability lobes; design of experiments; analysis of variance; neural network; optimization.
An Application of Fuzzy logic with Grey Relational Technique in Grinding Process using Nano Al2O3 Grinding Wheel on Ti-6Al-4V alloy
by PRABHU SETHURAMALINGAM, Stephen Deborah Serenade
Abstract: This investigation is focused on studying grinding of Titanium alloys (Ti-6Al-4V) by using nano Al2O3 grinding wheel as an alternative approach to existing methods of grinding. To evaluate optimum conditions of grinding process output, a full factorial technique has been used. L27 orthogonal array was chosen to arrive at an optimized permutation of grinding depth of cut, speed and feed. Consequently, the optimal combination of parameters was tested and results were compared with those of a conventional grinding wheel. The results show superior surface finish on Ti alloy when ground with nano Al2O3 grinding wheel. Confirmatory tests assured that a great improvement in Grey Relational Grade with fuzzy logic, from 0.551 to 0.749 was observed, which substantiates the progress in the performance at best possible levels of nano grinding parameters. Improvement of 21.47% in surface finish of the ground material using combinations of Fuzzy grey relational analysis have been achieved.
Keywords: Abrasive grinding; MRR; Nano Al2O3 Grinding Wheel; Surface roughness; Grey Relational Analysis (GRA); Fuzzy logic analysis;.
The problem of determining the ploughing forces
by Alexey Popov, Iuliia Krasnikova
Abstract: Currently, two methods are most often used to determine the ploughing forces: the extrapolation on zero uncut chip thickness and the comparison of total forces at different flank wears. These methods assume that the processes occurring on the front surface of the tool cause no effect on the processes transpiring on the rear surface. This study attempted to prove that the processes on the front surface of the tool affect the processes on the rear surface, and both extrapolation and comparison methods cannot be used to find the ploughing forces. This paper presents the experimental measurement results of the ploughing forces obtained in turn by different methods. The comparison of the measurement results was carried out in turning of aluminum alloys and structural steels in orthogonal cutting. The results of experimental studies showed that the increase in the uncut chip thickness causes the increase in the ploughing forces. This finding proves the connection between the processes occurring on the front and rear surfaces. Thus, the extrapolation method on zero uncut chip thickness and the comparison method of total forces at different flank wears cannot be used to determine the ploughing forces. To accurately reveal the ploughing forces, we suggest using the third method, the comparison method of the total forces for different contact areas, which is based on the dependence of the processes on the rear surface on the processes on the front surface.
Keywords: cutting speed; ploughing forces; turning; uncut chip thickness; wear.
Machinability studies on Al7075 based hybrid composites reinforced with SiC, Graphene and CNT
by Ajithkumar J P, Anthony Xavior M
Abstract: This experimental study analyses the machinability of Graphene-based and Multi Wall Carbon Nano Tubes (MWCNT)-based hybrid metal matrix nano-composites by dry turning process using uncoated and Diamond-Like Carbon (DLC) coated carbide inserts. Al7075 matrix was used along with reinforcements such as Silicon Carbide (SiC), Graphene and CNT. Two composites with different weight fraction namely (i) Al7075 - 10%SiC - 0.1% Graphene, and (ii) Al7075 - 10%SiC - 0.1%CNT were fabricated through the united stir and squeeze casting process with ultra-sonification. The effect of Graphene and CNT on cutting force, surface roughness, flank wear, crater wear and chip morphology were quantified and presented. ISO 3685 (1993) tool life testing standards were followed to conduct the experimental study. Graphene-based composite, recorded the highest cutting force (383.4 N) followed by CNT-based (318.6 N) composite at the considered machining parameters. Higher surface roughness of 0.8519
Keywords: Hybrid Composites; Graphene; MWCNT; Surface Roughness; Wear;.
Study on characteristics of AlTiN and TiCN coating layers deposited on carbide cutting tools in hard turning of steel: experimental, simulation, and optimisation
by Armansyah Ginting, Che Hassan Che Haron, Issam Bencheikh, Mohammed Nouari
Abstract: Objective of the present work is focused to study the characteristics of monolayer PVD-coated carbide AlTiN and TiCN cutting tools. Some features related to machinability such as tool wear, tool life, and surface roughness were adopted to study the tools characteristics. Moreover, effort was also paid to determine the cutting condition for both cutting tools that subjected to another feature, namely volume of material removal (VMR). The results of experiment showed that AlTiN gained higher cutting condition than TiCN due to higher usage temperature of its coating material. However, TiCN produced higher VMR than AlTiN and longer tool life. Flank wear and chipping were observed as the wear modes of both cutting tools. Surface roughness was resulted at the quality of medium finish. The finite element method was utilised to provide an orthogonal cutting simulation for resulting the map of cutting temperature distribution at the tool-chip interface. Finally, multi-objective genetic algorithm optimisation was employed for obtaining the optimum yield of VMR.
Keywords: volume of material removal; orthogonal cutting; cutting temperature; finite element method; multi-objective genetic algorithm.
Surface morphology and effect of cutting force and temperature in formation of the white layer during hard machining
by Sanjib Kr Rajbongshi, Deba Kumar Sarma
Abstract: In hard machining, different tribological phenomenon occur, out of which white layer formation and surface characterization are an important aspect. The white layer is found to be harder and fragile. It may cause a crack and may lead to failure in machined parts. Here, an experimental work is conducted in machining hardened AISI D2 steel. Cutting speed, feed, and depth of cut are taken as the input parameters. The level of each parameter is two. The white layer development process considering the impact of cutting force, temperature and morphology of hardened surfaces, etc. are covered in the study. The study of white layer morphology and hardness are carried out with FESEM and Micro-Vickers tester. The parametric study reveals occurrence of white layer due to the cutting force and temperature. Temperature has an important effect in increasing the surface hardness due to which the thickness of white layer changes. ANOVA analysis showed that cutting speed is the influencing variable for white layer thickness and microhardness, whereas depth of cut is influential for temperature, flank wear and cutting force.
Keywords: White layer; microhardness; cutting force; temperature.
Effect of rake surface textures spacing and width on the cutting performance of inserts in dry machining of Titanium alloy
by Amal Siju, Sachin Waigaonkar
Abstract: One of the crucial parameters that can be altered to improve machining efficiency in metal cutting is reducing the friction between tool and chip, especially along the rake surface of the tool. Studies have shown that many parameters of the micro or nanoscale texturing on the tool surface may influence its competence in reducing friction. However, the influence of texture parameters like width, spacing, etc. are not well understood, especially in the dry machining of hard alloys. In this experimental investigation, uncoated single point cutting tool inserts with different texture geometries on their rake surface were tested for adequacy in the typical turning operation of Titanium alloy. The novelty of the study involves identifying the influence of texture spacing and width on the cutting parameters at different feeds in the dry machining of the Ti-6Al-4V alloy. The surface characterization of the inserts shows how the textured surface was damaged under the machining regime. Chip morphology analysis was conducted to study the effect on chip thickness and shear plane angle. Inferences were made on the effect of texture dimensions on the frictional forces during machining.
Keywords: surface texturing; single-point cutting tool; chip-morphology; coefficient of friction; machinability; Ti alloy.
Diamond turning of optical materials: A review
by Bhaskar Goel, Sehijpal Singh, RamaGopal V. Sarepaka, Vinod Mishra, Neha Khatri, Vivek Aggarwal, Keshva Nand, Raj Kumar
Abstract: Single point diamond turning SPDT is key technology to overcome the shortcomings of conventional machining of optical components. In last decade, researchers explored various factors of SPDT to improve the machinability of optical materials. Collection of these studies in the form of detail review is missing. In this paper, existing literature has been studied in three categories of optical materials i.e. ductile, polymers and brittle materials keeping in view of their usage for lenses and molds. Most of the authors have analysed the effect of three input variables namely depth of cut, spindle speed and tool feed rate on surface roughness. This paper emphasizes on review of effect of all the input variables i.e. nose radius, depth of cut, rake angle, feed rate, tool overhang, spindle speed etc. Effect of all these process variables are reviewed not only on surface roughness but also on profile error and waviness error.
Keywords: Single point diamond turning; grey relational analysis; profile error; ductile regime machining; surface roughness; sub-surface damage; waviness error;.
Improving the Micro-Electrical-Discharge Drilling Performance of Carbon Fiber-Reinforced Polymer: Role of Assisting-Electrode and Shaped Tool
by Hrishikesh Dutta, Kishore Debnath, Deba Kumar Sarma
Abstract: This paper presents the investigation on the fabrication of though micro-holes in carbon fiber-reinforced polymer composites using micro-electrical-discharge drilling method coupled with assisting-electrode and rotary tools of copper and brass. Bisphenol-A based epoxy resin LY 556 having medium viscosity and hardener HY 951 were used for the fabrication of composites. The sizes of the fabricated micro-holes were in the range of 600-830
Keywords: Micro-electrical-discharge drilling; carbon fiber-reinforced polymer; machining time; surface morphology; regression analysis.
Estimation of surface roughness in a turning operation using industrial big data
by Kaustabh Chatterjee, Jian Zhang, Uday Shanker Dixit
Abstract: Surface roughness prediction in a turning process is of paramount importance. However, there is hardly any physics-based model that can predict it accurately. Recently, thanks to advancements in information technology, there are an ample amount of data in the industry. This article proposes a methodology to estimate surface roughness in turning based on industrial big data. An attempt has been made to extract and preserve the concise, useful information to reduce the burden on data storage. The proposed methodology predicts the lower, upper and most likely estimates of the surface roughness. A case study containing 35000 datasets is simulated using a virtual lathe to demonstrate the efficacy of the methodology. The whole region of data is divided into 81 cells, and model fitting is carried out in each cell. The developed model based on industrial big data provides reasonable prediction of surface roughness.
Keywords: Surface roughness; Data analytics; Multiple-linear regression; Turning; Outliers; Machining; Cook’s distance.
Study of tool wear progression and optimization while machining mono and hybrid zinc – aluminium based MMCs
by Rajaneesh Marigoudar, Shashidhar P S, Sadashivappa Kanakuppi, Dharmendra B V, Manjunatha T S
Abstract: \r\nThe effect of graphite addition to conventional composites and making it hybrid for better machinability is the motto behind this work. Here ZA43+SiC mono composite and ZA43+SiC+Graphite hybrid composite are machined under dry condition. Machining is executed using commercially available coated carbide SNMG 090308 tool. Cutting variables viz. machining speed, feed rate and depth of machining are varied and for each machining trial fresh cutting edge is used. Tool damage is measured while machining both the categories of materials and are compared. It is noticed that the hybrid composite causes less damage in comparison with mono composite. The reason may be due to powdered graphite present in the composite which is responsible for reduction in the friction. Graphite being solid lubricant prevents tool getting abraded by the hard workpiece and promotes easy machinability. Statistical analysis done on the results gives the details about most influencing variable to the machining process. The tool wear during composite machining is greatly influenced by machining speed and feed. Optimum machining parameters can be drawn considering material composition for less tool wear condition.\r\n
Keywords: Hybrid MMC; Stir Casting; Coated carbide; Tool Wear; Abrasion; Graphite; Self Lubrication
Machining austempered ductile iron – Impact of the cutting edge geometry on tool wear and surface quality
by Jörg Hartig, Benjamin Kirsch, Jan C. Aurich
Abstract: In general, the performance of cutting tools are determined by its cutting material specification, macrogeometrical shape, cutting edge design and coating. The cutting edge geometry can be considered as one of the most important factors for optimizing cutting tools. By using cutting edge preparation, tools can be tailored to the machining task. A homogeneous preparation is either applied to resist high loads in the machining process or to optimize the resulting surface. Inhomogeneous cutting edge preparations can individually be designed to the machining task to match both target criteria simultaneously. In the following article, the cutting edges of tungsten carbide indexable inserts were prepared homogeneously and inhomogeneously. Tool wear and machining results during turning and drilling austempered ductile iron (ADI) 900 were investigated.
Keywords: cutting edge design, tungsten carbide, austempered ductile iron, turning, drilling, tool wear, surface roughness, machining, machinability, PVD coating, optimization