Shailendra Kumar

Bio: Shailendra Kumar is an academic researcher from Sardar Vallabhbhai National Institute of Technology, Surat. The author has contributed to research in topics: AutoLISP & Machining. The author has an hindex of 17, co-authored 105 publications receiving 795 citations. Previous affiliations of Shailendra Kumar include Hindu College, University of Delhi & Techno India.

Fused deposition modelling: a review

Abstract: Fused deposition modelling (FDM) is the most economical additive manufacturing technique. The purpose of this paper is to describe a detailed review of this technique. Total 211 research papers published during the past 26 years, that is, from the year 1994 to 2019 are critically reviewed. Based on the literature review, research gaps are identified and the scope for future work is discussed.,Literature review in the domain of FDM is categorized into five sections – (i) process parameter optimization, (ii) environmental factors affecting the quality of printed parts, (iii) post-production finishing techniques to improve quality of parts, (iv) numerical simulation of process and (iv) recent advances in FDM. Summary of major research work in FDM is presented in tabular form.,Based on literature review, research gaps are identified and scope of future work in FDM along with roadmap is discussed.,In the present paper, literature related to chemical, electric and magnetic properties of FDM parts made up of various filament feedstock materials is not reviewed.,This is a comprehensive literature review in the domain of FDM focused on identifying the direction for future work to enhance the acceptability of FDM printed parts in industries.

Experimental study of delamination and kerf geometry of carbon epoxy composite machined by abrasive water jet

Abstract: The present article focuses on mechanism of delamination and kerf geometry in abrasive water jet machining of carbon epoxy composite. In the present study, four process parameters of abrasive water...

A knowledge based system for automated design of deep drawing die for axisymmetric parts

Abstract: This paper presents the research work involved in the development of a knowledge based system (KBS) for automated design of deep drawing die for axisymmetric parts. The production rule based KBS approach of artificial intelligence (AI) is utilized for development of the proposed system. The overall system is organized in 27 modules. System modules are coded in AutoLISP language and user interface is created using Visual Basic 6.0 and AutoCAD software. The proposed system is capable to automate all major activities of design of deep drawing die such as manufacturability assessment of deep drawn parts, design of strip-layout, process planning, selection of die components, and modeling of die components and die assembly. The system is user interactive, flexible and has low cost of implementation.

Experimental study of surface roughness, dimensional accuracy and time of fabrication of parts produced by fused deposition modelling

Abstract: This paper aims to focus on an experimental study of surface roughness, dimensional accuracy and time of fabrication of parts produced by fused deposition modelling (FDM) technique of additive manufacturing. The fabricated parts of acrylonitrile butadiene styrene (ABS) material have pyramidal and conical features. Influence of five process parameters of FDM, namely, layer thickness, wall print speed, build orientation, wall thickness and extrusion temperature is studied on response characteristics. Furthermore, regression models for responses are developed and significant process parameters are optimized.,Comprehensive experimental study is performed using response surface methodology. Analysis of variance is used to investigate the influence of process parameters on surface roughness, dimensional accuracy and time of fabrication in both outer pyramidal and inner conical regions of part. Furthermore, a multi-response optimization using desirability function is performed to minimize surface roughness, improve dimensional accuracy and minimize time of fabrication of parts.,It is found that layer thickness and build orientation are significant process parameters for surface roughness of parts. Surface roughness increases with increase in layer thickness, while it decreases initially and then increases with increase in build orientation. Layer thickness, wall print speed and build orientation are significant process parameters for dimensional accuracy of FDM parts. For the time of fabrication, layer thickness and build orientation are found as significant process parameters. Based on the analysis, statistical non-linear quadratic models are developed to predict surface roughness, dimensional accuracy and time of fabrication. Optimization of process parameters is also performed using desirability function.,The present study is restricted to the parts of ABS material with pyramidal and conical features only fabricated on FDM machine with delta configuration.,From the critical review of literature it is found that some researchers have made to study the influence of few process parameters on surface roughness, dimensional accuracy and time of fabrication of simple geometrical parts. Also, regression models and optimization of process parameters has been performed for simple parts. The present work is focussed on studying all these aspects in complicated geometrical parts with pyramidal and conical features.

The Design and Analysis of Experiments

Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

Information Behavior on Social Live Streaming Services

Abstract: In the last few years, a new type of synchronous social networking services (SNSs) has emerged—social live streaming services (SLSSs). Studying SLSSs is a new and exciting research field in information science. What information behaviors do users of live streaming platforms exhibit? In our empirical study we analyzed information production behavior (i.e., broadcasting) as well as information reception behavior (watching streams and commenting on them). We conducted two quantitative investigations, namely an online survey with YouNow users (N

Fused filament fabrication of polymer materials: A review of interlayer bond

Abstract: Fused filament fabrication (FFF), one of the most promising additive manufacturing (AM) methods has attracted considerable attention to date. Although FFF is evolving into a manufacturing tool with significant technological and material advancements, there remains a challenge to transfer FFF-printed parts into functional objects for practical applications. Polymer components fabricated by FFF technique exhibit weak and anisotropic mechanical properties compared to their counterparts by conventional processing. The limited mechanical property for the FFF-printed parts is a result of weak interlayer bond interface that develops during the layer-wise deposition process. This review documents recent advances on the bond interface in FFF-printed parts in aspects of its mechanisms, characterization and enhancement methods. The main objective is to provide a comprehensive understanding of the process-structure-properties of interlayer bond in FFF technique.

Use of ANP weighted crisp and fuzzy QFD for product development

Abstract: Quality Function Deployment (QFD) is a popular planning method often used to transform customer demands/requirements into the technical characteristics of a new or improved product or service. In order to better capture (and represent) the multifarious relationships between customer requirements and technical characteristics, and the relative weights among customer requirements, in this study a hybrid analytic network process (ANP)-weighted fuzzy methodology is proposed. The goal is to synthesize renowned capabilities of ANP and fuzzy logic to better rank technical characteristics of a product (or a service) while implementing QFD. To demonstrate the viability of the proposed methodology a real-world scenario, where a new equipment to squeeze the polyethylene pipes to stop the gas flow without damaging the pipes, is developed. The ranking of technical characteristics of the product is calculated using both crisp and fuzzy weights for illustration and comparison purposes.