Grinding is extensively used as surface generation process in finishing operations, which makes it imperative that the generated surface adheres closely to strict quality check norms failing which the component will be rejected incurring a loss to the industry. To ensure the intended surface quality falls within tolerances, the grinding wheel plays an important role as an abrasive tool. The finished surface is a direct outcome of grinding wheel topography and its various microscopic interactions with the surface creating a compelling need for in-depth understanding. Study and characterization of grinding wheel topography in the present paper aim to understand the behavior of forces in the contact area. Due to stochastic abrasive grain distribution and quasi-static surface wear, 3-dimensional parameters hold a better physical significance in explaining the nature of microscopic interactions and their impact on the behavior of forces. Experiments are performed in a manner to wear out grinding wheels of the same specification with varying number of passes in an attempt to highlight the influence of varying topography on tribological interactions in the grind zone. The variation in topography at a specific interval of time is captured using a confocal laser scanning microscope and further processed for surface characterization whereas forces are captured using a dynamometer. SEM micrographs are presented to understand the type of wear on the wheel surface. The outcome of present paper enables to understand and report the surface interactions quantified in terms of cutting, ploughing and rubbing whereas surface parameters are characterized as per ISO 25178. The reasoning behind variations during surface interactions was discussed and interpretations were reported.

The growing demand for ultrafine surface generation has forced the researchers to look for new methods of polishing that can guarantee both qualities as well as productivity. The existing polishing methods have several limitations such as bluntness of tool due to loading, metallurgical changes on the polished surface due to frictional heat generated at the interface, etc. These limitations have prompted the researchers to develop self-sharpening polishing tools. One such method is Ice Bonded Abrasive Polishing (IBAP) which uses frozen slurry for polishing, where ice serves as a matrix to hold the abrasives. Frictional heat produced at tool work interface causes the tool to melt and thus exposes fresh abrasives present in different layers. This paper attempts to interpret the mechanisms responsible for the ultrafine surface generation and then to develop an analytical model for estimating material removal. During polishing, the asperities on work surface experience variable force due to the changing condition of the tool with time. Initially, the first layer of rigid ice with fixed abrasives interacts with the work surface, making it as a solid-solid interaction. Molten state of ice behaves as semisolid and leads to slurry formation afterward. Therefore, the work surface will experience two-body and three-body interactions simultaneously. The proposed model implements the concepts of contact mechanics for predicting material removal from the work surface and finally, the effectiveness of the model has been validated with experimental results.

Abrasive waterjet technology is favored over solid cutting tools for cutting of multi-layered structures in view of its non-contact nature and its ability to cut a wide range of materials. However, the stochastic nature of abrasive water jet (AWJ) interacting with a multi-layered structure (MLS) produces a non-uniform kerf geometry. This non-uniformity depends on the characteristics of jet i.e. jet energy, the duration of interaction of jet with the material, and the nature of material exposed to the jet during cutting. This paper attempts to cover a study that systematically analyses the geometry of kerf generated in MLS and a stack of multiple materials with each material having different mechanical properties. It also covers a study to analyse the role of interfacial adhesive layer on kerf profile variation, and the preferential orientation of multi-layered structure and stacked materials, with its top layer, having an appropriate mechanical resistance (MR), in order to arrive at a strategy to present the structure or a stack of materials to AWJs for producing near uniform kerf profile. Hence, AWJ cutting experiments were carried out over a single- and double- layered structures (SLSs, DLSs) with two different materials such as aluminum (Al), mild steel (MS), which showed a completely different kerf geometry when these materials are stacked in different ways. Stacking of these materials in different ways produced kerf of different geometry not only in the materials but also at their interface. This systematic study enabled to suggest the correct presentation of MLS and also a stack of multiple materials with a suitable material in top layer, to AWJ, for producing near uniform kerf in them. Further, this study also suggested several hypotheses like the importance of relative MR of adjoining layers, critical jet traverse rate, pseudo focusing nozzle, and the choice of layer placement in producing near uniform kerf on MLS and a stack of materials, so as to minimize the efforts in post machining of AWJ cut surfaces. Finally, the relevance of the proposed hypotheses was validated by analyzing the kerf formed over MS-rubber-MS and rubber-MS-rubber configured three-layered structure.

Titanium alloys are prevalently used in automotive, aerospace and biomedical applications. It is identified as not easy to machine by conventional machining process because of fast tool wear. Hence, for machining of titanium alloy, non-conventional machining processes are generally recommended. In non-conventional machining, vibration assisted Wire Electrical Discharge Machining has shown promising results to improve the machining rate. The present work will focus on machining of titanium alloy workpiece by vibrating the wire in lateral direction with varied frequency of excitation to enhance the material removal rate and to obtain the required kerf width in Wire Electrical Discharge Machining. Experiments were performed on Ti-6Al-4V alloy material during a wire electrical discharging machine operation using zinc coated brass wire and brass wire electrode. Roughness with all those irregularities on machined surface, with varied vibration condition, are measured with contact stylus type surface roughness measuring instrument. Machined kerf size was measured using non-contact optical Co-ordinate Measuring Machine. White layer formed and surface integrity were examined through Scanning Electron Microscope with provision of Energy Dispersive Spectroscopy. The developed vibrating system worked effectively, improved material removal rate and their surface modification has been obtained and reported.

Biphasic calcium phosphate (BCP) ceramics are based on an optimum balance of the more stable hydroxyapatite (HAp) and more soluble tricalcium phosphate (high temperature phase of HAp). This paper describes the release profiles of doxycycline, a broad-spectrum antibiotic, by BCP ceramics. The BCP granules were prepared in-situ by microwave processing and subsequent pellets were formed by conventional sintering at 1000°C. The porosity of the pellets was varied by varying the amount of flour mixed with the ceramic before sintering. The BCP granules and pellets were characterized by X-ray powder diffraction method, thermal analysis and scanning electron microscope. The release profiles were studied by UV- Visible spectroscopy and the drug release was optimised by varying the porosity and loading pH. The amount of drug absorbed by the pellet formed with 40% flour content was about 70% and this also showed maximum release compared to the other systems which were studied.

Building information modeling (BIM) is progressively being adopted for precast construction as it facilitates efficient design, manufacturing and construction through generation and management of the virtual models incorporating both the physical attributes and functional behavior. Several studies have addressed the application of BIM for precast construction; however, these studies have focused on specific areas in the precast project lifecycle such as construction and inventory management. This study focuses on the systematic review of the potential applications of BIM through the entire precast project lifecycle. The stages in the lifecycle considered are "Concept," "Design," "Planning," "Production," "Logistics," and "Erection/Construction" which are similar to stages of a manufactured product. This study reviews past work in the domain and identifies areas for future work. The benefits and shortcomings of BIM application are evaluated based on the needs of each area and the features available in current BIM software. This paper provides a detailed review of the state-of-art of BIM application for precast construction lifecycle and potential for integrated BIM implementation in practice.

Hydroxyapatite (HA) was deposited on commercially pure titanium foils by microwave processing. Initially a coat of HA was formed on titanium foil by a simple dip-coating method. Prior to the coating, the substrate surface was etched in hydrofluoric acid to have an optimal surface morphology and thickness. The foil was subsequently exposed to microwave irradiation using a domestic microwave oven. The power and duration of the irradiation were adjusted for improving coating adhesion to the substrate: The coated implant materials have been characterised by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and adhesion test. The XRD result indicated that crystalline HA was deposited successfully on the titanium foil. The cross-section of the treated foil revealed that the deposition of HA within the surface cavities was non-uniform. The results suggest that hydroxyapatite deposits of thickness about 30 μm are formed on titanium foil by microwave processing. Copyright © 2004 by Society for Advancement of Heat Treatment & Surface Engineering (SAHTSE).

This paper covers the development of a multilayer icebonded abrasive polishing (IBAP) tool for multistage polishing of Ti-6Al-4V alloy specimens based on a systematic study that determined the number of layers, thickness of each layer, and the type, size and concentration of abrasives in each layer. Based on this study, a three-layered IBAP tool with the bottom layer consisting of soft aluminum oxide abrasives of 3 µm size with 5% concentration, the middle layer with moderately hard silicon carbide abrasives of 8 µm size with 10% concentration and the top layer with hard boron carbide abrasives of 15 µm size with 30% concentration was formulated for ultrafine finishing of Ti-6Al-4V alloy specimen in a single setup. The performance of the three-layered IBAP tool assessed in terms of finish and morphology over the work surface showed 81% improvement in surface finish, showing its effectiveness over a single-layered IBAP tool. Polishing studies have clearly demonstrated the generation of ultrafine surfaces, yielding a finish of 37 nm while the morphological studies on the polished surface have shown a nearly scratch-free surface on the Ti-6Al-4V alloy.

Grinding being a finishing process, the quality of the ground surface is one of the most important performance evaluation parameters. Grinding process being highly stochastic in nature, surface finish is affected by many factors and experimental evaluation of each factor is a tedious task. In this study, the in-process signals collected using various sensors attached to a cylindrical grinding machine such as Accelerometer and Power are processed, and their features are correlated with a surface finish parameter. This correlation is modelled using gradient boosting algorithm and surface finish obtained is predicted and validated on an industrial application.

Ice bonded abrasive polishing (IBAP) is a novel polishing method that employs a frozen slurry of water and abrasives as a polishing tool. This process is capable of producing ultra-fine finish on metallic as well as on non-metallic (ceramic) surfaces. The enhancement of productivity and efficiency of the process depends on the characteristics of the IBAP tool. During polishing, the IBAP tool melts due to frictional heat generated at the tool and workpiece interface. The melting rate influences the tool life and is one of the crucial aspects of the IBAP tool design. The present study aims to develop an analytical model to predict the melting rate of the tool as a function of abrasive properties, applied pressure, the relative velocity between the tool, and the workpiece surface. This model considered Jaeger's moving heat source method (1942) to determine the rise in temperature of tool and workpiece interface at steady-state and Blok's postulation (1963) to determine the fraction of heat conducted into the tool. The estimated melting rate of the IBAP tool is compared with the experimental data obtained from the reduction in the height of the IBAP tool at the polishing zone.

This article covers the efforts on characterising ice-bonded abrasive polishing tool in terms of the mechanical and tribological properties such as hardness, coefficient of friction, and wear rate. These studies were attempted on the tools prepared at different temperatures ranging from −10 °C to 0 °C with a view to identify the condition suitable to prepare ice-bonded abrasive polishing tool for effective polishing of Ti–6Al–4V alloy specimen. It also presents the methods adopted to determine various properties of ice-bonded abrasive polishing tool. Hardness was estimated from the measured penetration depth of cone shape indenter into the tool, coefficient of friction was determined from the change in power drawn by the motor rotating the tool mould, and wear behaviour of tool was assessed from the melting rate of the tool determined from the change in height of ice-bonded abrasive polishing tool at different stages of polishing. From the results of this study, it is clear that ice-bonded abrasive polishing tool prepared at −4 °C has possessed sufficient hardness, coefficient of friction, and reasonable wear rate suitable for polishing of Ti–6Al–4V specimens. This article also covers the details of low-temperature coolant supply unit developed to prepare the ice-bonded abrasive polishing tool at any desired temperature between 0 °C and −40 °C and thus to maintain it for a long time. Polishing studies with such ice-bonded abrasive polishing tool showed 72% improvement in finish after 90 min of polishing of Ti–6Al–4V specimen with tool, prepared at −4 °C.

Kerf profile generated by abrasive waterjet (AWJ) machining process has always been an interesting area as it dictates the quality of the part. However, due to the non-deterministic nature of the process, it is a challenging task to predict it. On the other hand, understanding and controlling the kerf profile in multi-layered structures (MLSs) is a further difficult task as various layers made of different materials respond to erosion in a different manner and results in a completely different kerf shape (barrel or x-shaped kerf profile) due to the material removal mechanisms dependency on the material property of the specific layers, jet divergence and position of specific layer. Therefore, it is important to understand and develop predictive models of resulting kerf profile in MLSs so that they can be used in controlling the accuracy of the resulting kerf which in turn dictates the final part accuracy. The attempts in this direction are very limited although some modeling efforts are reported in homogeneous materials (metals, ceramics). For the first time, an analytical model for predicting the kerf profile generated in MLS machining with AWJ was presented in this research work. Discretized form of Hashish model was used for determining depth of cut. The effect of jet divergence from the experimentally obtained values, upon passing through the upper layer has been considered. The developed predictive model was validated by the kerf shapes obtained from the experimental trials on metal-adhesive-rubber MLS. Kerf profiles obtained from the simulations have captured the resulted convergent-divergent (X-shaped) profile, while cutting metal-rubber laminate composite, effectively. Furthermore, the effectiveness of the proposed analytical model was demonstrated by generating the various kerf shapes generated at various jet traverse rates.

Abrasive waterjets can process multi-layered structures but pose difficulties in producing quality cuts since MLS comprises of layers of materials with heterogeneous/homogenous properties. Stacking sequence of layers and the interface between layers influence kerf characteristics. Kerf geometry in each layer is influenced by a nonlinear structure with non-uniform energy distribution of AWJ. This paper presents a model to predict kerf geometry in a double-layered structure by considering jet characteristics, workpiece properties, jet-workpiece interaction at the layers' interface, and AWJ process parameters. Towards determining the jet's exclusive interaction with each layer, complete kerf profile (CKP) formation is analyzed by considering homogenous materials as constituent layers of Al-MS and MS-Al configurations. The model predicted results are in good agreement with experimental results. The average root mean square error of the kerf profile is less than 0.048 mm, and the mean absolute error is about 12.63% on both configurations.

Self-excited regenerative vibration or chatter limits the primary requirements like productivity, surface finish and dimensional accuracy of high-speed machining. It is the most critical factor that severely affects the tool-life and life of the machine tool. Out of several methods followed for suppressing and avoiding chatter, machining conditions chosen with stability lobe diagram is the most reliable way. Stability lobe diagrams are typically generated by knowing specific cutting force coefficients and tool point frequency response functions (FRFs). Inaccurate use of tool point FRFs significantly affects the stable regions of stability lobe diagrams. As tool-point FRFs are influenced by gyroscopic effect, centrifugal force, thermal change in bearing dynamics, etc. during machining, it is important to consider the effect of these factors on tool point FRFs in order to generate accurate stability lobe diagrams. The present work covers a new approach for estimating tool point FRFs during machining operations, employing cutting tool vibration signals. For measuring the vibration at the tip of end mill at different spindle speeds, a non-contact laser vibrometer is used. In order to remove the tooth pass frequency and its harmonics from the measured signals, a comb filter is employed. The filtered signal is subjected to Operational Modal Analysis (OMA) in order to derive tool point FRFs. With the estimated FRFs at different spindle speeds, the stability lobe diagrams are drawn for high-speed milling machine. Comparative study of stability lobe diagrams, drawn with static modal analysis and Operational Modal Analysis, have shown that the cutting conditions chosen from stability lobe diagram derived with OMA, are found to be more realistic for avoiding chatter during high-speed milling applications.

This paper covers the efforts of developing a compact dressing attachment on a cylindrical grinding machine for on-line laser dressing of wheels used in internal grinding of SAE-52100 bearing steel parts. With this attachment, alumina wheel was dressed with different conditions of dressing and its suitability for grinding was evaluated by analysing the topography on laser dressed wheel surface with scanning electron microscope and confocal laser scanning microscope. Out of these images, confocal microscopic images were found to present 3d images of dressed wheel surface. Evaluation of these images, in terms of Spk, Sk and Svk parameters obtained from bearing area curves, and their comparison with those parameters obtained from the images over diamond dressed surface, indicated the suitability of dressing leads of 0.016 mm/rev and 0.032 mm/rev for dressing of wheels with pulsed laser radiation. Effectiveness of these conditions was further established by evaluating the performance of laser dressed wheels in terms of G-ratio values, form error and finish observed on ground parts. Further, this work suggests the application of on-line imaging and analysis of laser dressed surface for quickly identifying suitable conditions of dressing of internal grinding wheels with on-line laser dressing attachment so as to make laser dressing as an economically viable process for certain critical applications.