International Journal of Additive and Subtractive Materials Manufacturing (15 papers in press)
Optimization for Geometrical Dimension of a Product Using 3 D Printer based on Fused Deposition Modeling
by Ganesh Chate, Anand Deshpande
Abstract: The product development and the modification of the existing product are fundamental aspects of innovation and competitiveness of organizations, supported by concurrent engineering approaches. In the present work, an attempt has been made to establish a set of the process parameters for fused deposition modeling type rapid prototyping machine using Taguchi method (L8orthogonal array) to gain better geometrical dimensions of products. The product, viz., rapid prototyping machine, thus manufactured was used as a pattern for casting. Literature review, brainstorming sessions, cause and effect diagrams, and pilot experiments demonstrated that geometrical dimensions are influenced by four major input parameters, namely, shrinkage allowance, Acrylonitrile Butadiene Styrene (ABS) temperature at nozzle, raster angle, and bed temperature. Taguchi method was utilized to study and analyze the influence of input parameters on geometric dimensions. Further, Taguchi method was used to optimize the level of process parameters of rapid prototyping three-dimensional (3D) printers. The confirmation experiments are conducted by using the rapid prototyping 3D printer, for the determined optimum process parameter set helped to obtain the desired geometrical dimensions of patterns meant for casting applications.
Keywords: 3D printers; L8 orthogonal array; ABS plastics; Taguchi method; ABS material; Additive manufacturing.
DEVELOPING FRICTION STIR SPOT WELDING WINDOWS FOR DISSIMILAR AL5083 AND C10100 JOINTS
by Siddharth Sampath Kumar, Senthilkumar Thamilkolundu
Abstract: In this investigation, process operation limit diagrams in the form of friction stir spot welding windows for obtaining good quality friction stir spot joints were attempted using dissimilar combinations of aluminum Al 5083 and Copper C10100. Effect of the changes in three important friction stir spot welding process parameters such as rotational speed of the non-consumable tool in rpm, plunge depth in mm and dwell time in seconds were considered. Two sets of friction stir spot welding windows were constructed. First, the variation of tool rotational speed with dwell time at constant plunge depths were analyzed and secondly, the variation of tool rotational speed with plunge depth at constant dwell times were considered. The process operating diagrams were made considering the joint quality, aspect, extent of flash formation, width and depth of keyhole, its tensile strength and the micro hardness at the interface. Tensile properties of the dissimilar Al/Cu joints were evaluated in the form of tensile shear failure load values in kN using lap shear tensile tests. The interface micro hardness was measured using Vickers hardness testing equipment. Validation experiments proved that the joints fabricated with process parameter values within the friction stir spot welding windows had higher tensile shear failure load and reduced interface hardness. These windows would act as reference maps for selection of appropriate parameters for good quality and strong joints.
Keywords: Friction stir spot welding; dissimilar joints; aluminum; copper; process operation limit diagrams; Friction stir spot welding windows.
Assessing the Use of Binary Blends of Acrylonitrile Butadiene Styrene and Post-Consumer High Density Polyethylene in Fused Filament Fabrication
by Nathan Decker, Albert Yee
Abstract: Several experiments were conducted to assess the suitability of binary blends of recycled high-density polyethylene and virgin acrylonitrile butadiene styrene for use in fused filament fabrication. Binary blends of the two plastics were extruded into feedstock for a 3D printer in varying proportions. Filament extrusion consistency, dimensional accuracy of 3D printed benchmarking objects, and tensile strength were each assessed. When compared against commercial acrylonitrile butadiene styrene filament, binary blends of recycled high-density polyethylene and acrylonitrile butadiene styrene were found to have inferior filament extrusion consistency and tensile strength. They also produced less accurate benchmarking objects. Despite this, binary blends were shown to produce objects with dimensional accuracy and tensile strength that would render them suitable for many applications.
Keywords: fused deposition modeling; high density polyethylene; acrylonitrile butadiene styrene; additive manufacturing; recycled materials; fused filament fabrication; binary blends.
Powder based additive manufacturing - A review of types of defects, generation mechanisms, detection, property evaluation and metrology
by Hossein Taheri, Mohammad Rashid Mohammad Shoaib, Lucas W. Koester, Timothy A. Bigelow, Peter C. Collins, Leonard J. Bond
Abstract: Powder-based Additive Manufacturing (AM) technologies have been evaluated for use in different fields of application. AM is already being utilized for part production in the aerospace and medical industries. For an AM part to replace a conventionally manufactured component, the material properties, mechanical characteristics and quality of the product should be at least the same as, or preferably better than the conventionally produced material. Manufacturing defects and their effects on the quality and performance of AM parts are a major concern. It is necessary to understand the defect types and their generation mechanisms, as well as the detection and evaluation methodologies necessary for mechanical properties evaluation and prediction and component quality control. Such knowledge becomes crucially important when considering low production volumes and high value components seen in aerospace applications as well as new developments associated with the rapidly evolving AM space. While the manufacturing processes and mechanical properties of AM parts have been reported in many articles, there is a relative dearth of papers which consider the various types of microstructural features or defects, their generation mechanisms, their effect on bulk properties and the capability of existing characterization methodologies. The current work provides an overview of the different types of defects and their generation mechanisms found in powder based AM parts. Defect detection and characterization techniques using in-situ nondestructive evaluation and their influence on mechanical properties and design considerations are also reviewed. Together, these provide a framework to understand the relevant machine and material parameters, optimize the process and production, and select appropriate characterization method.
Keywords: Additive Manufacturing; Process Evaluation; Quality Control; Defects; Inspection; In-line monitoring; Nondestructive Testing; Design Standards; Mechanical Properties.
Additive Manufacturing of High Value Ti Components: Opportunities and Challenges
by Jing Chen, Chaoli Ma, James Case Williams
Abstract: This paper describes and discusses additive manufacturing (AM) and compares it with conventional subtractive manufacturing (SM). AM creates a new way to make high values components and some resulting opportunities are described. However, like any game changing technology, there also are supporting capabilities that need to developed or at least adapted to support implementation of the new technology. These needs also have been discussed as challenges. The availability of these will necessarily occur on varying time scales and this also is discussed. The paper ends with a simple, but optimistic long term vision for AM.
Keywords: Ti alloys; Additive manufacturing; AM; 3D printing; subtractive manufacturing; SM; design synthesis; residual stress; cost; mechanical properties; tooling; risk.
Mechanical and Microstructural Characterization on Direct Metal Laser Sintered Inconel 718
by Jinoop A.N., Kanmani Subbu S., R. Arockia Kumar
Abstract: Direct metal laser sintering (DMLS) is one of the additive manufacturing technologies which al-lows the fabrication of complex components in layer by layer technique with melting and solidifica-tion of powder raw material by laser heat source. This paper investigates about the mechanical and microstructural characteristics such as bulk density, porosity, micro hardness and surface roughness on Inconel 718, a nickel super alloy made by using DMLS. Bulk density and porosity finds good agreement with the components fabricated by casting. Micro hardness and surface roughness along the surface of the component was investigated and also surface roughness along the build direction was inspected. The phases present in the processed Inconel 718 was found by using X- ray diffrac-tometer. Optical microscopy and scanning electron microscopy was used to examine and understand the microstructure of as-built Inconel 718 without post-processing effects.
Keywords: Laser; DMLS; Inconel 718; characterization; mechanical; microstructure;additive man-ufacturing.
Special Issue on: CPIE-2016 Present and Futuristic Manufacturing
AN EXPERIMENTAL STUDY OF SURFACE ROUGHNESS IN DOUBLE TOOL TURNING PROCESS
by Rathinam Kalidasan, Selvaraj Senthilvelan, U.S. Dixit
Abstract: The objective of this investigation was to determine the influence of machining parameters on the surface roughness of AISI 1050 steel and grey cast iron workpieces. It was observed that the surface roughness decreases with the increase in cutting speed. On increasing the feed for AISI 1050 steel, initially the surface roughness decreased up to 0.12 mm/rev feed and thereafter it increased, but for grey cast iron it increased with feed for all cutting conditions. The surface roughness was not affected significantly by tool separation distance. Compared to single tool turning process, the double tool turning produced much better surface finish. As a consequence, it is possible to reduce the cost of machining by suitably targeting the process parameters. An approximate cost analysis has been done to support this claim.
Keywords: double tool turning; surface roughness; cutting speed; infra-red camera; cutting temperature; profilometer; cast iron; steel; cost analysis; spanzipfel.
Experimental Study and Empirical Modelling of Laser Surface Finishing of Silicon Carbide
by Ketema Bobe Bonsa, Woldetinsay Jiru, Mamilla Ravi Sankar, U.S. Dixit
Abstract: Laser surface modification is an innovative method of polishing hard to machine ceramics for industrial applications. Laser has wide applications in industries due to a wide range of available and easily controllable power. It modifies any surface for high surface finishing applications. Silicon carbide is composed of carbon and silicon atoms forming a strong bond. It can be used in different applications like turbine components, ball valve parts, heat exchangers and semi-conductors. In this work, silicon carbide substrate material was irradiated using CO2 laser at different parameters (laser power 50─500 W and scan speed of 300─800 mm/min). After laser surface irradiation, surface roughness and its morphology were investigated. Laser irradiation improved the surface finish. The morphology of improved surface is free from any cracks. The Rockwell hardness test results show that the hardness of laser polished surface is about twice the original hardness.
Keywords: laser; ceramic; surface finishing; silicon carbide; surface roughness; hardness; CO2 laser; design of experiments; energy dispersive X-ray spectroscopy; morphology.
Estimation of Cutting Forces in Conventional and Ultrasonic-Vibration Assisted Turning Using Inverse Modelling
by U.S. Dixit, Vinod Yadav, Varun Sharma, Pulak Pandey, Anish Roy, Vadim Silberschmidt
Abstract: In this work, cutting forces in conventional and ultrasonic-vibration assisted turning are estimated using an inverse method to evaluate the velocity-dependent friction and fracture toughness based on a few tests in conventional turning. The inverse methodology requires the data on cutting and feed forces at two specified cutting speeds. Analytical expressions are employed to estimate the cutting forces in conventional as well as ultrasonic-vibration assisted turning. The suggested method was verified with experimental data. The validation of the direct model with the finite-element results available in the literature was also carried out. A sensitivity analysis revealed a significant effect of friction on cutting forces. Thanks to its simplicity, the proposed procedure may find a good application in industrial practice.
Keywords: cutting forces; ultrasonic-vibration assisted turning; friction; inverse method; fracture toughness; machining; Johnson-Cook model; Ti-6246; 4340 hardened steel; orthogonal cutting.
Parametric Optimization for Micro Electric Discharge Drilling Process
by Ravinder Kumar, Inderdeep Singh
Abstract: Electric discharge machining (EDM) is gaining significant industrial consideration due to its characteristic of machining difficult to machine materials, irrespective of their hardness. Growing product miniaturization further extends the application of EDM for the production of components featured with micro cavities. In the present experimental investigation, micro holes were drilled in the copper workpiece using tungsten electrode of diameter 120
Keywords: Micro electric discharge machining; micro holes; material removal rate; tool wear rate.
Machining of Hardened AISI H-13 Steel using Minimum Quantity Eco-Friendly Cutting Fluid
by Kishor Kumar Gajrani, Dhanna Ram, Ravi Sankar Mamilla, Uday Shanker Dixit, P.S. Suvin, Satish Vasu Kailas
Abstract: Conventionally cutting fluids are applied in the form of flood to improve machining performance and tool life. However, the use of cutting fluid has detrimental effect in the form of environmental pollution and occupational health hazard. Researchers are trying to develop alternate methodologies to reduce or eliminate cutting fluids during machining. In this study, indegenously developed eco-friendly green cutting fluid (GCF) is used with minimum quantity cutting fluid (MQCF) technique during machining of hardend AISI H-13 steel. Cutting force, feed force and centre line average (CLA) surface roughness were measured at different cutting conditions. Performance of MQCF was compared with flood coolant using GCF and dry machining. The morphology of the rake face of the tool was examined with optical microscope and surface profilometer. Cutting force, feed force, coefficient of friction and CLA surface roughness was reduced with MQCF using GCF as compared to flood coolant and dry machining.
Keywords: green cutting fluid; hard machining; minimum quantity cutting fluid; mist; hardened AISI H-13 steel; tool-chip contact length; minimum quantity lubrication; turning; surface roughness; cutting tool.
EFFECTS OF PARAMETERS ON BURR HEIGHTS & DIAMETRAL ERROR IN DRY DRILLING
by Anuj Vats
Abstract: Burr formation similar to chip genesis is a common caution in conventional metal cutting operations in which material removal by direct tool-workpiece contact cause chip generation, variation in hole quality & post cutting finishing. In the present work effects of various process parameters on burr type, entry, exit burr heights, roundness & diametral error obtained while drilling Aluminium alloy 6082 has been investigated. Equations to predict the burr heights to be obtained for different values of machining parameters were also formulated such that a tradeoff between MRR and deburring costs can be drawn for subsequent stages of machining.
Keywords: Burr; Burr height prediction; Drilling; Burr types; Roundness; Diametral error; Burr height minimization.
Experimental Investigation on Drilling of Borosilicate Glass using Micro-USM with and without Tool Rotation: A Comparative Study
by Sandeep Kumar, Akshay Dvivedi
Abstract: The application of microproducts is increasing rapidly in various fields such as automobiles, electronics, microfluidics, bio-MEMS etc. These micro products are generally made of hard and brittle materials e.g. glass, quartz, ceramics and silicon etc. The machining of these materials in micro-domain is a difficult task. Micro-ultrasonic machining (micro-USM) is a preferred process for machining of hard and brittle materials. But high tool wear and low aspect ratios limits its industrial use. This investigation compares the effect of tool rotation on material removal rate and hole overcut. Additionally aspect ratio was measured. The variable process parameters for the investigation were power rating, static load, slurry concentration and abrasive size. Imaging was used for qualitative analysis of tool wear. The experimental results reveal that micro-USM with tool rotation resulted in higher material removal rate, lesser hole overcut, high aspect ratios and lesser tool wear in compared with micro-USM without tool rotation.
Keywords: Micro-USM; Tool rotation; Microholes; Microfluidics; Hole overcut; Glass.
Influence of Glycerin-air Dielectric Medium on Near-dry EDM of Titanium Alloy
by Krishnakant Dhakar, Akshay Dvivedi
Abstract: Ti-6Al-4V is one of the most commonly used titanium alloy. The applications involve in the area of aerospace, chemical engineering, biomedical implants, marine industries etc. The electrical discharge machining (EDM) is an unconventional machining process. It is widely used to produce complex profiles on electrically conductive materials. Near-dry EDM is a process variant of the EDM process. Generally, it uses water-air mixture as a dielectric medium. Near-dry EDM is an environment friendly process. In this investigation near-dry EDM of Ti-6AL-4V was investigated with glycerin-air dielectric medium. The one-factor-at-a-time approach was used for experimentation. The process parameters selected for experimentation were current, duty factor, lift setting, sensitivity setting, flushing pressure, liquid flow rate and gap control. The responses measured were material removal rate and surface roughness. The experimental results revealed that glycerin-air dielectric medium produced higher MRR with fine surface finish even at higher current and wear ratio of the process was also less than one percent.
Keywords: Near-dry electric discharge machining; Dielectric medium; Material removal rate; Surface roughness.
Fabrication of Micro-features on 304 Stainless Steel (SS-304) using Nd:YAG Laser Beam Micro-Machining
by Rasmi Ranjan Behera, P.M. Babu, Kishor Kumar Gajrani, Ravi Sankar Mamilla
Abstract: In the present study, micro-channels and micro-dimples are fabricated with different dimensions on the surface of SS-304 alloy by pulsed Nd:YAG laser beam micro-machining. The effect of various laser parameters on the machining performance characteristics are evaluated. The effect of process parameters viz. laser scanning speed, current, laser pulse frequency and pulse duration are studied using argon gas. The width or diameter and depth of micro-features are considered as the output responses. 3-D laser surface profilometer is used to study and measure the dimensions of fabricated micro-features. The results showed that the selection of micro-feature size is critical to achieve desired machining results. All the processing parameters have noticeable effect on the geometry and quality of micro-features. The dimensions (diameter, width and depth) of micro-features are decreased with higher scanning speed and increased with increase in pulse frequency, pulse duration as well as current. The appropriate combination of parameters can yield the better results for quality and size of micro-features. Lower scanning speed with higher pulse frequency with a proper set of current and pulse duration can be used in order to fabricate micro-channel whereas higher scanning speed and lower pulse frequency can be used to obtain micro-dimples.
Keywords: Laser beam micro-machining; Millisecond pulsed Nd:YAG laser; Stainless steel SS-304; Micro-features; Micro-channels; Micro-dimples; Laser energy density; Surface topography; Spatter deposition.