Forthcoming articles

International Journal of Precision Technology

International Journal of Precision Technology (IJPTech)

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International Journal of Precision Technology (24 papers in press)

Regular Issues

  • Computer aided tool design for micro-ECM   Order a copy of this article
    by Pratik Shah, S.S. Pande 
    Abstract: This paper reports the development of a computer aided system for micro-ECM process to design tools to produce accurate internal features on workpiece. Mathematical model has been developed to compute the inter-electrode gap (IEG) for chosen shape of tool and process conditions. Axi-symmetric tools of different profiles such as cylindrical, conical, hemispherical have been analyzed to predict the shapes of work cavities. Model is validated with the reported results and some experiments conducted by us on typical tool shapes. Parametric studies have been carried out to study influence of various process variables on the accuracy of cavity shapes. Based on these studies, guidelines for improving profile accuracy in micro-ECM have been suggested.
    Keywords: Micro-ECM; computer aided design system; inter-electrode gap; tool design; process model; parametric studies.

  • Carbon Nanofiber (CNF) Assisted Micro-Electro Discharge Machining (   Order a copy of this article
    by Prasanna Chougule, Rakesh Mote, Uday Dabade 
    Abstract: Titanium alloys have found growing applications in aerospace, biomedical and marine industry. However, extreme hardness and strength cause difficulty in machining of titanium alloys. This is further complicated by the requirements of micro features on hard to machine alloys. Micro Electro discharge machining (micro EDM) is being investigated to match the requirement. However, slower removal rates and thermal effects are the issues in thermal erosion based EDM process. In this work, we have investigated the efficacy of using carbon nanofibers (CNFs) mixed with the dielectric fluid for micro machining of Ti6Al4V using micro EDM. It is observed that the addition of CNFs not only improves electro-discharge frequency, material removal rate but also improves the surface roughness. Added nanofibers lowered the material migration and increased spark gap. We noted a significant influence of mixing CNFs in the dielectric fluid for enhancing machining performance characteristics in
    Keywords: Micromachining; Micro-EDM; Titanium alloys; Carbon nanofibers (CNFs); Additives; Surface integrity.

  • Micro-Faraday cup array structures fabrication in Silicon using Deep Reactive Ion Etching   Order a copy of this article
    by JULFEKAR ARAB, Pradeep Dixit, Prakash Brahmankar, Raju Pawade, Arvind Kumar Srivastava 
    Abstract: Micro-faraday cup array (MFCA) detectors are used for the detection and analysis of incident ion particles. Over the years, MFCA played the vital role in the field ion detection with greater stability and precision. New and simple Micro FCA structures have been designed and fabricated considering the application of ion detection in devices such as Mass spectrometry and laser plasma techniques. MFCA structures were fabricated in n-type Silicon substrate with MEMS fabrication processes such as UV lithography followed by DRIE (Deep reactive ion etching). The UV lithography process was utilized for fabrication of Micro-Faraday cup array structure in photoresist (AZ4903) deposited on silicon substrate. After that DRIE process was used for creating array pattern in Silicon. Ultimately 1x16 arrays having 25
    Keywords: Faraday Cups; micro-fabrication; characterization; UV-LED; DRIE.

  • Modelling of static surface error in end-milling of thin-walled geometries   Order a copy of this article
    by Neha Arora, Ankit Agarwal, K.A. Desai 
    Abstract: End milling is commonly employed during fabrication of thin-walled components as it can produce complex shapes in a variety of materials with higher accuracy and productivity. The static deflections of thin-walled components under periodically varying cutting forces are inevitable resulting into surface error and violation of tolerances. This paper presents finite element analysis (FEA) based approach to predict static deflections and resultant surface error during machining of thin-walled components. It has been realised that the axial variation of deflection induced surface error can be linked with cutting conditions. The paper conceptualises various shapes of surface error profile based on similarities of axial and radial engagement. The proposed methodology is implemented in the form of computational models and series of machining experiments are conducted to demonstrate efficacy of the proposed approach. The outcomes of the present study will help process planners in devising strategies to control surface error during milling of thin-walled components.
    Keywords: end milling; workpiece deflections; surface error; thin-walled components.
    DOI: 10.1504/IJPTECH.2019.10021795
     
  • High aspects ratio micro-drilling of super-alloys using ultra short pulsed laser   Order a copy of this article
    by Ganesh G. Dongre, Avadhoot Rajurkar, Ramesh Gondil, Jacob Philip 
    Abstract: The demand for high aspect ratio micro holes is growing day by day. Functional micro-holes are necessary for application areas in aeronautic, automobile, semiconductor and biomedical industries. It requires holes with high contour accuracy and minimum thermal damage. Further, the materials used in these applications are alloys, super alloys and composite materials, which are difficult to cut. Laser-machining has demonstrated outstanding capability to generate high precision micro features. The development of femto, pico-second lasers has provided a precise method for micro-fabrication. In this paper, micro-hole drilling was carried out using a 12 W, Ti-sapphire 50-100 fs laser. Holes are analysed for size and shape. It analyses the effect of pulse duration for SS-316L, Inconel-718 and Ti6Al4V. It also investigates effect of laser drilling techniques like percussion, trepanning and helical. Study concludes that with proper control on beam positioning, beam energy and pulse width one can achieve quality holes using ultrafast lasers.
    Keywords: ultra short pulse; aspect ratio; femto and pico-second laser; micro drilling.
    DOI: 10.1504/IJPTECH.2019.10021803
     
  • Development of an ultrasonic vibration assisted minimum quantity lubrication system for Ti-6Al-4V grinding   Order a copy of this article
    by Rajeshkumar Madarkar, Sahaj Agarwal, Sudarsan Ghosh, P. Venkateswara Rao 
    Abstract: Minimum quantity lubrication (MQL) is widely used in machining/grinding as a competent cooling-lubrication technique owing to its advantages in terms of better cooling, lubrication, and lower coolant consumption. Ultrasonic vibration can be used to enhance the efficiency of MQL system by atomising the cutting fluid into fine and uniform droplets. In this study, an ultrasonic vibration assisted MQL (UAV-MQL) system is indigenously developed to effectively atomise the cutting fluid using the ultrasonic vibration of a suitably designed horn. To check the effectiveness of the developed UAV-MQL system, a set of experiments have been conducted on Ti-6Al-4V alloy during surface grinding operation, and the results have been compared with dry, flood and air-assisted conventional MQL grinding process using soluble oil as a cutting fluid.
    Keywords: minimum quantity lubrication; MQL; ultrasonic; vibration; atomisation; Ti-6Al-4V; grinding force; surface finish.
    DOI: 10.1504/IJPTECH.2019.10020928
     
  • Contact behaviour of elastic abrasive spheres during self-centring type magneto-mechanical deployment for internal bore finishing   Order a copy of this article
    by V.S. Sooraj 
    Abstract: Elastic abrasive finishing, in its various forms, has been demonstrated for micro-finishing of engineering surfaces in the recent past. Conceiving the advantages of elastically controlled abrasion, a deployable type-internal bore finishing tool with self centring magnetic pads to hold elastic abrasive spheres has been introduced in this paper. Contact of such magnetically held elastic abrasives on target surfaces has been simulated, analysed with various contact hypotheses, and supplemented by experimental results. Spring-Dashpot analogy of elastic abrasive contact and characteristics of magnetically controlled abrasive deployment for surface finishing are discussed in detail. Reduced penetration depth of embedded grains due to significant reduction in elastic modulus at contact interface, through the action of elastomeric medium, is illustrated through simulations. With a significantly lower depth of cut under the action of controlled cutting velocity, elastic abrasive spheres are capable of generating fine finish without altering the surface form.
    Keywords: elastic; abrasives; magnetic; deployable; surface; finishing; roughness; contact.
    DOI: 10.1504/IJPTECH.2019.10022598
     
  • Micro-EDM performance of Inconel 718 superalloy with and without ultrasonic vibration   Order a copy of this article
    by Param Singh, Vinod Yadava, Audhesh Narayan 
    Abstract: Inconel 718 superalloy is an extremely difficult-to-machine aerospace material due to its work hardening nature and poor thermal conductivity. Drilling of cooling holes in this material is much difficult by conventional drilling processes because it has high chemical affinity with cutting tool materials, high welding action of chips at rake face, high strength at high temperature and work hardening nature. In consideration of all these problems, a self-developed setup of drilling ultrasonic assisted micro-EDM (drilling-UA-micro-EDM) has been used to create microholes in this material. A comparative study of machining characteristics of Inconel 718 in terms of material removal rate (MRR), tool wear rate (TWR), hole taper (Ta), and radial overcut (ROC) has been investigated due to drilling-micro-EDM without and with the ultrasonic vibration (UV). Comparative results show that the application of UV in drilling-micro-EDM increases MRR and decreases TWR, Ta and ROC, and gives microholes of good quality and accuracy.
    Keywords: drilling-UA-micro-EDM; hole taper; Ta; Inconel 718 superalloy; drilling-micro-EDM; material removal rate; MRR; radial overcut; ROC; tool wear rate; TWR.
    DOI: 10.1504/IJPTECH.2019.10021797
     
  • Force analysis during spot finishing of titanium alloy using novel tool in magnetic field assisted finishing process   Order a copy of this article
    by Anwesa Barman, Manas Das 
    Abstract: Magnetic field assisted finishing process is a nanofinishing process which uses magnetic field for precise control of finishing forces. Magnetorheological fluid mixed with diamond abrasive particles in base medium of glycerol, hydrofluoric acid, nitric acid, and deionised water is used as the polishing medium. The novel tool is a magnet fixture made of mu-metal which is used to hold the magnet during finishing. In the present experimental study, finishing at a spot on flat titanium alloy is carried out to analyse the forces involved in the finishing. Normal force is the main force responsible for the indentation by the abrasive particles on the workpiece surface. Tangential force helps in removing indented material. The measured normal force and tangential force during the spot finishing are 3.285 N and 0.43 N, respectively. The final surface roughness achieved after spot finishing is 10 nm from initial surface roughness of 200 nm. The percentage improvement in surface roughness is 95%.
    Keywords: nanofinishing process; MR fluid; magnetic field assisted finishing; MFAF; finishing force.
    DOI: 10.1504/IJPTECH.2019.10022606
     
  • Fabrication of high aspect ratio cylindrical tungsten micro tool by reverse micro-ECM process   Order a copy of this article
    by Abhijeet Sethi, Biswesh Ranjan Acharya, Partha Saha 
    Abstract: The present study was aimed at fabricating high aspect ratio tungsten micro tool using reverse micro-ECM process and studying the effect of different shapes of the brass cathode used on the geometry of fabricated cylindrical tungsten anode. The different shapes of cathode considered were a rectangular block, a wire and a disc. Tungsten rod of 1 mm diameter was first machined to 500 μm and diameter was further reduced below 100 μm by reverse micro-ECM process. The output parameters considered here were the average diameter, aspect ratio, tool diameter at 100 μm from the tip and total tool length. Micro tool with an average diameter of 74.57 μm with an aspect ratio of 26.8 was successfully fabricated using a block cathode in reverse micro-ECM process. Finally, experiments were conducted to study the effect of process parameters like applied voltage and electrolyte concentration with the block-shaped cathode in the machining process.
    Keywords: micro electrochemical machining; micro-ECM; micro machining; tungsten micro tool; high aspect ratio; tool geometry; cathode shape.
    DOI: 10.1504/IJPTECH.2019.10022607
     
  • Electrochemical discharge machining of soda lime glass for MEMS applications   Order a copy of this article
    by Julfekar Arab, Harshit Singh Chauhan, Pradeep Dixit 
    Abstract: Electrochemical discharge machining (ECDM) is a process to fabricate micro-features in electrically non-conductive materials like glass, ceramics, etc. These micro-features are useful in the field of microfluidics and micro-electromechanical system (MEMS) packaging. The present study includes the experimental analysis of effects of process parameters such as applied voltage and duty ratio on the machining process. Top and bottom holes diameters are the primary focus in this analysis. Structural characterisation of drilled micro-holes was performed using optical microscopes and scanning electron microscope (SEM) to analyse the surface quality. Energy dispersive X-ray spectroscopic (EDS) analysis of machined glass and needle tool after machining has been performed. An increase in hole diameter was obtained with increment in duty ratio and applied voltage. However, machining results were found to be random at extreme value of 70% duty ratio. Heat affected zone was found to be severe in higher applied voltage and duty ratio. EDS analysis of tool shown the different constituents of debris deposited on it.
    Keywords: electrochemical discharge machining; ECDM; MEMS packaging; hole diameter; applied voltage; duty ratio; surface quality; thermal damage.
    DOI: 10.1504/IJPTECH.2019.10021798
     
  • Influence of wire feed rate on microslit width fabricated by wire ECM process   Order a copy of this article
    by S. Debnath, J. Kundu, B. Bhattacharyya 
    Abstract: Miniaturisation of metallic structures has become a prime issue and to meet high demand, modern fabricators extensively use different micro machining techniques. Wire electrochemical machining (wire ECM) is such a process of removing excess material electrochemically. However, the process is still new and further research is needed. Hence, the present work aims in developing suitable wire ECM setup to find out the influence of wire feed rate at varying voltage settings on corresponding width of the generated microslits. For this, experimentations have been carried out with 50 μm dia tungsten wire and machined micro features have been carefully observed under optical microscope. Additionally, the experimental results have been represented graphically where the minimum average width of the microslit is found to be 83.117 μm with an aspect ratio of 1.2. Moreover, complex microfeature with varying width has been fabricated by changing corresponding feed values in a single run.
    Keywords: wire electrochemical machining (wire ECM) process; wire feed rate; applied voltage; microslits; slit width.
    DOI: 10.1504/IJPTECH.2019.10022597
     
  • Localised electrochemical co-deposition of copper-nickel using liquid marbles   Order a copy of this article
    by S. Shailendar, M. Sundaram 
    Abstract: A liquid marble is a droplet of liquid coated with microparticles or nanoparticles. A novel method of localised electrochemical co-deposition using liquid marbles and the feasibility of application of this method in additive manufacturing/micro-repair is discussed. Controllability of the transportation of liquid marbles to any desired location by pick and place technique has been demonstrated by depositing a 3 × 3 grid pattern with 1mm period using an in-house built CNC setup. An experimental study was conducted to study the effect of three process parameters viz. duty factor, reaction time and volume of electrolyte on the height of the deposit and ANOVA was performed at 95% confidence level. It was found that the duty factor was the most significant process parameter.
    Keywords: co-deposition; design of experiments; electrochemical additive manufacturing; liquid marble.
    DOI: 10.1504/IJPTECH.2019.10021799
     
  • Femtosecond laser assisted generation of micro-dimples on moly-chrome film for improving its tribology   Order a copy of this article
    by V. Ezhilmaran, N.J. Vasa, L. Vijayaraghavan, Sivarama Krishnan 
    Abstract: Femtosecond laser ablation of the moly-chrome deposited piston ring and the influence of laser fluence and number of laser pulses on dimple morphology and geometry were analysed. The increase of laser fluence and pulse numbers beyond 8.4 J/cm2 affected the dimple surface by inducing severe cracks due to heat accumulation. Based on the experimental investigation, the ablation threshold for moly-chrome film was found to be 0.36 J/cm2. Textured surface was formed on the moly-chrome film with laser fluence near the ablation threshold and the tribological characteristics were studied. The piston ring surface was textured with dimple diameter of 100 μm and dimple aspect ratio of 0.2. Effect of different dimple area ratios, such as 2%, 16% and 38% were analysed by reciprocating type tribology testing. The textured surface with 16% dimple area ratio showed a reduction in friction compared to the plain and the remaining textured piston rings.
    Keywords: surface texturing; micro-dimple; tribology; friction; femtosecond laser.
    DOI: 10.1504/IJPTECH.2019.10022595
     
  • Fibre laser cutting of thick closed cell aluminium foam: morphological analysis and its parametric optimisation   Order a copy of this article
    by Mohammad Shahid Raza, Susmita Datta, Jogender Singh, Partha Saha 
    Abstract: Laser cutting of 10 mm thick closed cell aluminium foam was performed using a 2 kW fibre laser. The parameters selected were laser power (1,350 W-1,750 W), scan speed (400 mm/min-1,000 mm/min) and gas pressure (6-8 bar). The kerf quality (kerf width and taper percentage) was assessed by SEM and optical microscopic images. Laser power and scan speed were found to be the most influencing parameters for good kerf quality. SEM images indicate that the dross attachment is higher at the bottom surface than that at the top surface. Parametric optimisation of the kerf width and taper percentage was carried out using response surface methodology (RSM) technique. Regression analysis was performed to correlate input and output parameters in order to apprehend the significance of these parameters. Finally, it was observed that the model was adequate to predict the variability in the response variables at a confidence level of 95%.
    Keywords: fibre laser cutting; closed cell aluminium foam; kerf quality; laser parameters; response surface methodology; parametric optimisation.
    DOI: 10.1504/IJPTECH.2019.10022603
     
  • Nickel stamp fabrication using SU-8 lithography for micro hot-embossing serpentine microfluidic channels   Order a copy of this article
    by Yugandhar Arcot, G.L. Samuel, Lingxue Kong 
    Abstract: Mass production of microfluidic devices is the need of the hour considering several applications. Among the various applications, particle inertial focusing is a prospective technique for separation of the particles using microfluidic devices. Serpentine channels have a great potential to utilise particle inertial focusing mechanism, owing to its capability of parallelisation compared to spiral channels. The devices for inertial focusing consist of different features like pillars, channels, and reservoirs where the features are ranging from micro to macro scale. Currently, the devices are fabricated using lithography techniques whose rate of production depends upon the lifespan of the silicon (Si)-master. This paper demonstrates a novel method for fabrication of nickel master used for the micro hot-embossing process on polymethyl methacrylate (PMMA) sheets with micro features. The key parameters of hot-embossing in this study include temperature and pressure which are optimised accordingly.
    Keywords: nickel master; hot-embossing; polymethyl methacrylate; PMMA; serpentine microfluidic channels; micro and macro features.
    DOI: 10.1504/IJPTECH.2019.10021800
     
  • The influence of deep cryogenic treatment and in-situ cryogenic micro turning of Ti-6Al-4V on cutting forces, surface integrity and chip morphology   Order a copy of this article
    by T. Jagadesh, G.L. Samuel 
    Abstract: The demand for sustainable manufacturing of axi-symmetric, micro turned titanium based neurosurgical implants are increasing. However, dry micro-turning of titanium alloy at higher cutting speeds, results in poor surface integrity, because of continuous saw-tooth chip formation, chip adhesion, and micro-scratch initiation on the machined surface. To overcome these issues in micro-turning, two techniques were attempted in this paper. First, Ti-6Al-4V is cryogenically cooled for 72 hours and then subsequently heat treated for four hours at 170°C before machining. Second, in-situ cryogenic experiments, liquid nitrogen is fed in the cutting zone. It is observed that, in-situ cryogenic micro-turning assists in ease of chip fracture resulting in good surface finish. It inhibits the formation of saw-tooth chip and thereby a fluctuation of forces with time is limited. Micro-scratch and adhesion of machined chips were present in non-treated and deep-cryogenic treated surfaces whereas, in-situ cryogenically micro-turned surfaces were free from the above defects.
    Keywords: micro turning; Ti-6Al-4V; cryogenic treatment; cutting forces; chip morphology; surface finish.
    DOI: 10.1504/IJPTECH.2019.10021804
     
  • Molecular dynamics simulation of mechanical polishing   Order a copy of this article
    by Prabhat Ranjan, Anuj Sharma, Tribeni Roy, R. Balasubramaniam, V.K. Jain 
    Abstract: Mechanical polishing, a nano-finishing process is extensively used for generating smooth surfaces on engineering materials. The mechanism of mechanical polishing is extremely complex due to its random nature of material removal at atomic scale. The need for a better understanding of the process at atomic scale is therefore necessary. Hence, molecular dynamics simulation (MDS) was carried out to understand the behaviour of material removal on two different types of engineering materials viz. aluminium and silicon. In the present work, material removal of rough asperities was modelled and simulated by abrading them with abrasive particles. It was observed that the nanometric abrasion occurs through adhesion de-bonding principle, recoverable phase transformation occurs during the nanometric abrasion on aluminium, and the non-crystalline debris formation during polishing of silicon as brittle crystalline structures. In addition, other attributes are also discussed such as force, stress, chemical stability, effect of abrasive particle, and temperature.
    Keywords: molecular dynamics simulation; MDS; mechanical polishing; nano-finishing; TERSOFF; EAM.
    DOI: 10.1504/IJPTECH.2019.10022599
     
  • Experimental investigations on the effect of relative particle sizes of abrasive and iron powder in polishing fluid composition for ball end MR finishing of copper   Order a copy of this article
    by Dilshad Ahmad Khan, Zafar Alam, Faiz Iqbal, Sunil Jha 
    Abstract: Demand for ultra-finished copper mirrors is very high in defence and laser optics industries due to their high heat conductivity and durability. In ultra-finishing, soft materials require gentle finishing for scratch free highest degree of surface quality. Ball end magnetorheological finishing is an advanced finishing process that confirms both the requirements of optical industries, i.e., finishing of complex surfaces and up to nanometre level of surface finish. In this study it is explored that the relative particle sizes of the abrasive and the ferromagnetic substance in magnetorheological fluid affect the chain structure and in turn the quality of the finished surface. The study has been carried out over magnetorheological polishing fluids composed of different sizes of iron particles and abrasives. The results show that magnetorheological polishing fluid having iron particles of 300 mesh size and alumina powder of 1,000 mesh size is most suitable combination for best surface finishing on copper samples.
    Keywords: ball end; magnetorheological; surface; roughness; force; iron powder; polishing fluid; normal finishing force; nanofinishing; benzotriazole; magnetic flux density.
    DOI: 10.1504/IJPTECH.2019.10021801
     
  • Effect of polishing fluid composition on forces in ball end magnetorheological finishing process   Order a copy of this article
    by Zafar Alam, Dilshad Ahmad Khan, Faiz Iqbal, Sunil Jha 
    Abstract: Ball end magnetorheological finishing is a nanofinishing process that uses magnetorheological polishing (MRP) fluid containing carbonyl iron particles (CIPs) and polishing grade abrasives to remove materials from the workpiece surface. The composition of the MRP fluid greatly influences the finishing forces. Using a dynamometer both normal and shear forces applied by the MRP are recorded on-line. A central composite design of experiments is used to plan the experiments and ANOVA to correlate these forces and process parameters. The process parameters selected here are vol.% of CIPs and vol.% of abrasives which are varied from 5% to 25% and 5% to 20% respectively to measure the forces during experimentation. Both normal and shear forces increase with increase in the CIPs content in the fluid. In case of abrasive concentration, it is observed that the forces initially increase with increase in abrasive content but begins to decline after a certain point.
    Keywords: magnetorheological; polishing fluid; smart fluid; nanofinishing; finishing forces; ball end; abrasives; carbonyl iron particles; CIPs; fluid composition; ball end magnetorheological finishing; BEMRF.
    DOI: 10.1504/IJPTECH.2019.10021101
     
  • Investigation into suitability of electrolytes during surface micro-texturing by electrochemical micromachining   Order a copy of this article
    by S. Kunar, S. Mahata, B. Bhattacharyya 
    Abstract: This article highlights the methodical investigation of suitability of various electrolytes on stainless steel by maskless electrochemical micromachining for generation of micro circular pattern. A well planned experimental setup consisting of maskless electrochemical micromachining (EMM) cell with other accessories has been designed and developed for conducting the experiments. A single masked tool with SU-8 2150 mask can generate many high quality textured samples economically. Influences of machining voltage, inter electrode gap, duty ratio and pulse frequency are investigated on material removal rate (MRR) and machining depth of micro circular pattern using three different electrolytes, i.e., NaCl, NaNO3 and NaCl+NaNO3. Out of these three electrolytes, only mixed electrolyte of NaCl+NaNO3 has been preferred as a best electrolyte based on uniform geometrical shape and controlled depth. The minimum size of the texture is 622.45 μm in mean diameter and 50.2 μm in mean depth.
    Keywords: maskless EMM; micro circular pattern; reused masked tool; material removal rate; MRR; depth.
    DOI: 10.1504/IJPTECH.2019.10021802
     
  • Constant work gap perpetuation in ball end magnetorheological finishing process   Order a copy of this article
    by Faiz Iqbal, Zafar Alam, Dilshad Ahmad Khan, Sunil Jha 
    Abstract: Ball end magnetorheological finishing (BEMRF) is an advanced finishing method employed for super finishing of flat, curved, intricate and complex surfaces. The surface finish achieved in BEMRF process is governed by machining parameters and fluid parameters. A main contributor towards super finishing by BEMRF process is the work gap. A constant work gap ensures a uniform finishing operation throughout the entire surface; however, there are many cases wherein the work gap between tool tip and workpiece varies over the surface due to geometric form deviations induced by preceding manufacturing process or linear positioner having a tilt error. This paper describes a method to keep a constant work gap for finishing in BEMRF process. A confocal sensor is used to scan the surface in order to detect any height deviations that prevent a constant work gap. Experimental results show a considerable improvement in the surface quality while finishing with perpetuated work gap.
    Keywords: work gap; perpetuation; nano finishing; non-contact measurement; confocal sensor; ball end; BEMRF; automated finishing; surface roughness; surface metrology.
    DOI: 10.1504/IJPTECH.2019.10022608
     
  • Investigation of tool-workpiece interaction in nanoscale cutting: a molecular dynamics study   Order a copy of this article
    by Anuj Sharma, Tribeni Roy, Prabhat Ranjan, Debabrata Datta, R. Balasubramaniam 
    Abstract: Ductile and brittle materials differ in their physical and mechanical properties and pose distinct interaction with the cutting tool while nano-machining. It is thus imperative to analyse the mechanism of material removal and tool-workpiece interaction. Towards this, molecular dynamics simulation (MDS) is carried out to study the diamond tool and workpiece interaction in the nanoscale cutting of Cu (ductile material) and Si (brittle material). Results show that material removal in Cu takes place through shear deformation by dislocations formation and their propagation while in case of Si, it takes place through phase transformation of the material in cutting zone. Force analysis of both the materials shows that machinability of Cu in nanoscale cutting is better compared to Si. Furthermore, tool wear while machining of Si with sharp edge tool is due to chipping whereas radial distribution function reveals that graphitisation of the round edge tool occurs during machining of Si.
    Keywords: cutting mechanism; tool wear; molecular dynamics simulation; MDS; diamond turning; nanoscale cutting; subsurface damage; deformation; dislocation; silicon; copper.
    DOI: 10.1504/IJPTECH.2019.10022605
     
  • In situ geometric measurement of microchannels on EN31 steel by laser micromachining using confocal sensor   Order a copy of this article
    by Ashish Kumar Sahu, Faiz Iqbal, Aman Kumar, Sunil Jha 
    Abstract: Laser micromachining is a prominent method of fabricating microchannels on a wide range of metals, non-metals, and polymers for biomedical, chemical, fuel-cell applications for flow of liquids and gases in predefined path for microfluidic systems. In situ measurement of precise geometrical features on fabricated channels is required to avoid systematic errors. The geometrical parameters such as width, depth, aspect ratio of microchannels are the most important attributes which greatly influence quality of microchannels. This paper proposes in situ measurement of fabricated microchannels on EN-31 steel using LMM by integrating confocal sensor with micromachining system. Geometrical features have been measured with confocal sensor which is further employed to evaluate aspect ratio (AR). Obtained results are compared with microscopic images of the samples for geometrical features. Confocal sensor used to measure surface roughness. 3D profilometer is used to analyse MRR (based on measured cross section area) and oxidised zone width surrounded to microchannel.
    Keywords: laser micromachining; LMM; microchannel; in-situ measurement; confocal sensor; aspect ratio; metal removal rate; MRR; oxidation zone.
    DOI: 10.1504/IJPTECH.2019.10021796