Good Surface Finish Research Articles

Micro injection moulding process with high-temperature resistance resin insert produced with material jetting technology: Effect of part orientation

Material jetting is an additive manufacturing technology used to produce resin parts with high accuracy and good surface finish. It is often used for visual prototypes or for rapid tooling applications to realise moulds for the standard injection moulding process because of the mechanical properties of the material. However, owing to the poor thermal properties of the resin, this technology is limited by the melting temperature of the material and the production rate. Currently, newer resins are able to withstand temperatures up to 250 °C. To enhance the potential of this technology, in this study the authors tested the performance of a mould insert for microinjection moulding application, produced with a high-temperature resin. In particular, it has been analysed how the orientation of the mould insert on the build plate significantly affects the insert resistance and surface roughness and consequently the quality of the moulded part. The results obtained open up new possibilities for testing a series of small batches and highlight new challenges to improve the process performance.

Comparative Analysis and Optimization of Thermoelectric Machining of Alumina and Silicon Carbide-Reinforced Aluminum Metal Matrix Composites Using Different Electrodes

In this paper, a comparative experimental analysis of die-sinking electric discharge machining (EDM) to two most exhaustively used aluminum metal matrix composites (AMMCs) has been performed using Copper and Tungsten as tool electrodes. AMMCs containing silicon carbide (SiC) and alumina (Al2O[Formula: see text] as reinforcement (10[Formula: see text]wt%) were fabricated by stir casting method. The Box–Behnken Design (BBD) approach of response surface methodology was used to develop experimental models for material removal rate (MRR) and surface roughness (SR). Effect of input parameters such as current ([Formula: see text]–12[Formula: see text]A), gap voltage ([Formula: see text][Formula: see text]V), pulse-on time ([Formula: see text]s), and duty factor ([Formula: see text]–6) on the output responses has been investigated with response surface plots. Effectiveness of design of experiment (DoE) and evolutionary algorithm-based multi-objective optimization (MOO) technique have been compared to find the best feasible optimal solution. ANOVA analysis reveals that for alumina reinforced AMMC interaction between [Formula: see text] has significant effect on both MRR and SR using Cu electrode. But for tungsten, electrode interaction between [Formula: see text], [Formula: see text], and [Formula: see text] have major role on MRR whereas SR is mostly influenced by interaction between [Formula: see text] and [Formula: see text]. The parametric analysis reveals that an increase of current from 4[Formula: see text]A to 12[Formula: see text]A at a higher pulse-ontime increases the MRR more significantly, and higher MRR occurs in cases of alumina-reinforced AMMC. Increase of pulse-ontime at low current (4[Formula: see text]A) reduces the MRR in AMMC/Al2O3. Good surface finish can be obtained by combining high voltage (60[Formula: see text]V) with either small current (4[Formula: see text]A) or small duty factor (4) for both AMMCs. Both DoE and metaheuristic-based MOO technique reveals that copper electrode should be preferred for die-sinking EDM of AMMC/SiC. Metaheuristic approach should be preferred for optimization of die-sinking EDM of AMMCs using different electrodes because it requires low current for effective machining of different AMMCs.

Optimization of Process Parameters in Wire-EDM of AL6063-T6 Alloy Using Taguchi DOE

Abstract: Wire-EDM is a controlled machining process used to produce geometrically intricate shapes with great accuracy and good surface finish that are difficult to machine with the help of conventional machining processes. Work has been done to study parametric optimization in wire-EDM machining of AL6063-T6 alloy. The input process parameters such as pulse on time (Ton), pulse off time (Toff), wire tension (WT), wire feed (WF) and dielectric flushing pressure (WP) with the performance parameters as surface roughness (Ra) and material removal rate (MRR). L8 orthogonal array (OA) of matrix developed by Taguchi was used for design of experiment and data analysis by implementing S/N ratios, ANOVA, and response optimization to predict values of control factors at optimum conditions of Ra and MRR.

Parametric Optimization of Wire Electrical Discharge Machining in AA7075 Metal Matrix Composite

Aluminium 7075 metal matrix composite reinforced with silicon nitride was fabricated using the stir casting technique. Composite fabricated was machined and subjected to wire electrical discharge machining to study the significant process parameter. Taguchi design of experiment using L9 orthogonal array was selected with three factors, current, pulse ON time, and wire feed at three levels. Influencing process parameters were identified using analysis of variance. Pulse ON time of 130 μs, current of 20 A, and wire feed of 1 mm/min were identified as optimized parameters for higher material removal rate. For a good surface finish, the optimized parameter was identified as 130 μs pulse ON time, 20 A current, and wire feed rate of 2 mm/min. Pulse ON time was identified as an influencing parameter followed by the current in achieving better material removal rate with good surface finish, whereas wire feed has no influence on the output parameters. Results of experimentation showed improved machining characteristics for higher pulse ON time and current for machining the synthesized composite through the Taguchi design of the experiment.

Machining parameter optimization and experimental investigations of nano-graphene mixed electrical discharge machining of nitinol shape memory alloy

Excellent characteristics of Nitinol shape memory alloys (SMAs) makes them favourable for use in industrial applications. Precision machining of such advanced alloys becomes a key requirement for industrial applications. Conventional machining processes imposes many difficulties for nitinol SMAs. Electrical discharge machining (EDM) process is appropriate for fabricating intricate and complex profile geometries and also provides a better alternative for difficult-to-cut materials. Addition of nano-particles in an appropriate amount in the dielectric fluid improves the machining by producing good dimensional accuracy, higher productivity, and good surface finish for machining of newly developed advanced alloys. The current study investigated the performance of powder-mixed EDM of nitinol SMA with the considerations of design variables of current, pulse-on-time (Ton), nano-graphene powder concentration (PC), and pulse-off-time (Toff) on surface roughness, dimensional deviation (DD), and material removal rate (MRR). Taguchi's L9 (3ˆ4) design was employed to perform the experiments and Minitab 17 software was used for statistical analysis of design variables using ANOVA, residual plots, and main effect plots. ANOVA results depicted that PC, Ton, and Toff were identified to be the highest contributing parameters with 75.18%, 29.37%, and 45.72% to affect MRR, SR, and DD, respectively. Obtained results has depicted a preferred combined positive trend of increase in MRR with a simultaneous drop in SR and DD after the addition of nano-graphene PC. HST algorithm was used to optimize single and multiple responses. Validation trials were also conducted to reveal the ability and suitability of the HTS technique. Field emission scanning electron microscopy revealed the minor occurrence of resolidified debris particles, globules, micro-pores, and micro-cracks after the addition of nano-graphene PC at 2 g/L.

Analysis of Turning Performance on AISI O1 Steel Using VO+nMoS2 as Coolant

AISI O1 cold work steel is a hard-to-machine material as a reason of its good temperature resistance, superficial hardness, and lesser response to wear. Hence, material removal from such hard materials is both cost- and time-consuming. Conventional cutting fluids fail to lessen the hotness at the tool-work junction. This research work explores the effects of a uniquely prepared and eco-friendly cutting fluid on the cutting performance of AISI O1 steel using tool inserts of three different materials. The prepared cutting fluid, molybdenum disulfide nanoparticle (MoS2) blended in biodegradable vegetable oil (VO) was distributed into the cutting zone with the help of the minimum quantity lubricant (MQL) technique. The integrated approach of Taguchi’s average normalized S/N ratio-based RSM method was employed to model the parameters for better responses. The optimal condition predicted by the approach (the type of insert – CBN, Vc – 110.12 m/min, f – 0.08 mm/rev, and DOC – 0.20076 mm) was observed to produce noteworthy improvements in tool wear and lessen the cutting force in addition to a good surface finish. The study will offer the required guidance for tool and die industries handling AISI O1 steel and help researchers work towards sustainable machining.

Parametric Optimization for Quality of Electric Discharge Machined Profile by Using Multi-Shape Electrode.

The electrical discharge machining (EDM) process is one of the most efficient non-conventional precise material removal processes. It is a smart process used to intricately shape hard metals by creating spark erosion in electroconductive materials. Sparking occurs in the gap between the tool and workpiece. This erosion removes the material from the workpiece by melting and vaporizing the metal in the presence of dielectric fluid. In recent years, EDM has evolved widely on the basis of its electrical and non-electrical parameters. Recent research has sought to investigate the optimal machining parameters for EDM in order to make intricate shapes with greater accuracy and better finishes. Every method employed in the EDM process has intended to enhance the capability of machining performance by adopting better working conditions and developing techniques to machine new materials with more refinement. This new research aims to optimize EDM’s electrical parameters on the basis of multi-shaped electrodes in order to obtain a good surface finish and high dimensional accuracy and to improve the post-machining hardness in order to improve the overall quality of the machined profile. The optimization of electrical parameters, i.e., spark voltage, current, pulse-on time and depth of cut, has been achieved by conducting the experimentation on die steel D2 with a specifically designed multi-shaped copper electrode. An experimental design is generated using a statistical tool, and actual machining is performed to observe the surface roughness, variations on the surface hardness and dimensional stability. A full factorial design of experiment (DOE) approach has been followed (as there are more than two process parameters) to prepare the samples via EDM. Regression analysis and analysis of variance (ANOVA) for the interpretation and optimization of results has been carried out using Minitab as a statistical tool. The validation of experimental findings with statistical ones confirms the significance of each operating parameter on the output parameters. Hence, the most optimized relationships were found and presented in the current study.

Development of Zinc and Low Carbon Steel Coatings on ABS Plastic by Electric ARC Spraying

<div class="section abstract"><div class="htmlview paragraph">Acrylonitrile Butadiene Styrene (ABS) is a highly sought-after engineering plastic for industrial applications, particularly in modern aircrafts. It offers better balance of impact strength, tensile strength, thermal resistance, dimensional stability, processing ability and affordability, the aircraft interior parts are made up of ABS plastic. However, ABS plastic is not a good choice for heavy-duty industrial applications that require corrosion resistance, abrasion resistance and durability. Several studies have been published on surface metallization of ABS plastic using conventional electroplating and electroless methods, but there is little information is available on the use of thermal spray technique. This opens up a huge opportunity for research in this area to be conducted using most commonly used materials like zinc and low carbon steel. In the light of the above, the current work employs an electric arc spray technique to coat zinc and low carbon steel on ABS plastic. Prior to coating the alumina grit blasting was carried on tensile and bending samples which were prepared as per ASTM D638 and ASTM D790 standards respectively. Comparative studies showed that the zinc coated ABS samples showed better tensile strength, flexural strength and flexural modulus than that of low carbon steel coated ABS specimen. Visual examination showed good surface finish with no surface damage for zinc coated ABS component.</div></div>

Optimization of Machining Parameters for Wire EDM of AMCs (LM5/ZrO2) using Taguchi Technique

Aluminium alloy with high toughness, hardness, and impact resistance, is increasingly in demand in the aerospace and mechanical industries. Machine tools have seen rapid growth over the past two decades, but they are still not commonly used to their maximum potential. The inability to use machine tools at their peak output thresholds is at the core of the problem. Practicing engineers and researchers were intrigued by the difficulty of reaching a meticulous analysis of effective parameters. AMCs-LM5/3,6,9% ZrO2 fabricated by stir casting process are machined in Wire EDM to choose the optimum parameters by changing the Pulse on Time, Pulse off Time, Gap Voltage and Wire Feed. Achieving a good surface finish, as well as a better MRR and less kerf in the WEDM machining is of paramount importance. The experiments were conceded using the Taguchi’s L27 OA to obtain the desired effects. ANOVA determines the parameters that affect the Wire EDM, and also the relative contribution of machining parameters. The optimum levels of process parameters, for maximum MRR, minimum SR and minimum kerf were calculated. S/N ratio analysis determines the parameter that has the most impact on the response. A confirmation experiment was done for the best combination of parameters.

Formability and surface quality of non-conventional material sheets for the manufacture of highly customized components

In this work, incremental forming of pure niobium planar isotropic sheets was studied; in particular, two different types of test were conducted by varying the tool/sheet contact conditions, in order to understand the complex phenomena interesting this hard-to-form non-conventional material and to focus the attention on its formability and the finishing of the worked surfaces. From the tests, the formability limits were determined, the forming forces were acquired and analysed, the quality of the worked surfaces was evaluated with measures of roughness and high-magnification visual inspection, as well as the failures of the sheets were observed and interpreted. The results highlight that a proper choice of the contact conditions can avoid the occurrence of galling while preserving an optimal carrying out of the process. In any case, very good surface finishing and workability of niobium sheets, despite their brittle nature, is found when incrementally formed. As a consequence, incremental sheet forming of this non-conventional material can be considered a faisible way of manufacturing highly customized components.

INFLUENCE OF THE BRUSHING PROCESS ON THE ROUGHNESS OF INCLINED SURFACES OF PIECES MANUFACTURED IN X40CrMoV5

The purpose of the burnishing process is to achieve a good surface finish, improve mechanical properties and increase the useful life of parts with different geometries. This paper analyzes the effect of this process on the surface topology of parts made of X40CrMoV5 steel tempered to 40-42 HRC, used for the manufacture of molds. The starting surfaces are prepared by applying a standard milling process for their subsequent ball-burnishing process. This is done with a new burnishing tool designed for this purpose. Subsequently, the surface roughness values are evaluated, depending on the feed and the force, to obtain the best parameters to apply the burnishing. These roughness values will be measured parallel and perpendicular to the burnishing direction. It starts from a previous experience to take the best values found to decide the force and feed values to use. Each condition is tested 3 times to validate the repeatability of the obtained results. Burnishing has been demonstrating to improve the surface properties of the material, and a technological recommendation resulting on the best parameters to apply this process on this type of surface.

Investigation of pulse current densities and temperatures on electrodeposition of tin-copper alloys

The tin-copper alloys are widely used in various applications, such as jewelry, antiques, bearings, and electronics due to their superior advantages in several aspects such as corrosion resistance, lubrication, and visual appearance, etc. One of the dominant coating processes to fabricate such an alloy is the electrodeposition since it helps to improve several advantages, such as low processing cost, good surface finish, and flexible method. However, the electrodeposition in a solution containing tin often causes whisker growth, which results in rough and poor surface finish. Therefore, this study aims to investigate the effect of electrodeposition's pulsing current densities (33%, 50%, 67%, and 100%) and electrodeposition's temperatures (25 °C, 45 °C, and 60 °C) on tin-copper alloys' electrodeposits. The electrodeposits are all characterized for microstructures, chemical compositions, crystalline phases, corrosion resistance, and adhesivity. The information regarding those characterizations is discussed in this study.

Multiresponse Optimization of Wire Electrical Discharge Machining Parameters for Ti-6Al-2Sn-4Zr-2Mo (α-β) Alloy Using Taguchi-Grey Relational Approach

The Ti-6Al-2Sn-4Zr-2Mo alloy was machined using the wire electrical discharge machining (WEDM) method in this research. The consequences of input values like pulse on duration, wire tension, and wire feed on metal removal rate (MRR) and surface roughness (SR) have indeed been observed. After conducting 27 experiments using Taguchi’s L27 type of research technique, empirical designing and analysis of variance (ANOVA) were performed. For process optimization, the Taguchi technique, which is based on the grey relational analysis approach, is used. The results show that a material removal rate of 0.293 mm3/min was obtained with factors of 10 µs pulse on duration, 7 m/min of wire feed, and 12 g of wire tension (the higher the better), and surface roughness of 2.129 µm was obtained with factors of 6 µs pulse on duration, 3 m/min of wire feed, and 8 g of wire tension (the lower the better). The percentage of errors between results obtained and grey relational analysis (GRA) predicted results varies around 6%. Wire electrical discharge machining with Ti-6242 alloy to optimum conditions resulted in better MRR and surface integrity with good surface finish and integrity as evidenced by a substantial reduction in the crack formation, lumps, and accumulated surfaces.

Machinability Study on CNC Turning of Stainless Steel 303 with CVD Multi-Layer (TiN/Al2O3/TiCN) Coated Carbide Insert by using Grey-Fuzzy Logic Approach

Manufacturing requires reliable models and methods for the prediction of output performance of machining processes as the demand for highly automated machine tools in the industry has been increased. The prediction of optimal machining conditions for good surface finish and dimensional accuracy plays a very important role in process planning. In the present work, dry turning of austenitic Stainless Steel (SS303) using CVD multi-layer (TiN/Al2O3/TiCN) coated carbide insert has been investigated. Cutting speed, feed rate, and depth of cut have been considered as the input process variables for the dry turning process. Taguchi's L9 orthogonal array has been utilized for designing the experiments. A Grey-Fuzzy logic approach has been employed to investigate the multi-objective optimization of turning process parametric combination to provide minimum Surface Roughness (SR) with the maximum Material Removal Rate (MRR). Analysis of Variance (ANOVA) technique has been employed to identify the most influencing input process variable for achieving minimum SR and maximum MRR. Morphology analysis has been performed on the machined surfaces and the chips generated during the machining processes using a Scanning Electron Microscope (SEM) in order to relate the surface quality with the input factor setting.

Ceramic Stereolithography of Bioactive Glasses: Influence of Resin Composition on Curing Behavior and Green Body Properties.

Herein we report on the preparation of a bioactive glass (BAG)-based photocurable resin for the additive manufacturing of BAG scaffolds with high filler loadings. The preparation of glass/ceramics resins for stereolithography with high filler loading is always a challenge, especially for fillers with a high refractive index variance. Various photocurable resin compositions with and without bioactive glass fillers have been investigated to see the influence of bioactive glass on physical properties of the resin and resulting green body. The effect of concentration of monomers, reactive diluent, light absorber (Sudan orange G dye), photoinitiator (PI), non-reactive diluent, and fillers (BAG) on rheology and photocuring behavior of the resin and tomography of the resulting 3D structures have been investigated. The BAG contents affect the rheology of resin and influence the rate of the polymerization reaction. The resin compositions with 55–60% BAG, 10% PEG-200 (diluent), 1% of PI and 0.015% of the dye were found to be suitable compositions for the stereolithographic fabrication. A higher percentage of PI caused over-curing, while a higher amount of dye decreased the cure depth of the resin. The micro-computed tomography (µ-CT) and scanning electron microscopic (SEM) images of the resulting green bodies display a relatively dense glass scaffold without any visible cracks and good interlayer connection and surface finishing. These properties play an important role in the mechanical behavior of 3D scaffolds. This study will be helpful to prepare high density glass/ceramic slurries and optimize their printing properties.

Additive manufacturing of three-dimensional intricate microfeatures by electrolyte-column localized electrochemical deposition

Electrochemical additive manufacturing (ECAM) based on electrochemical deposition (ECD) has been increasingly used, owing to its inspiring capacities of fabricating void-free and crack-free three-dimensional (3D) complex dense nano-and micro-sized metal geometries. In this study, a unique electrolyte-column localized electrochemical deposition (ECL-ECD) was initially proposed to manufacture 3D intricate precision micro-and mesoscale solid objects. In ECL-ECD, a dynamically stable electrolyte column is maintained between the electrolyte nozzle (anode) and cathodic surface, and metal electrodeposition is localized and guided by the electrolyte column, which is moved controllably. Its working mechanisms were determined from simulations and experimental findings, and some intricate structures such as curved columnar structures, U-shaped, Z-shaped, and spiral structures were successfully manufactured via the proposed technique using different path planning and control strategies. It was indicated that ECL-ECD has an excellent capacity in additively manufacturing micrometer-to-millimeter-scale freestanding metal geometries simultaneously with relatively high geometrical accuracy, good surface finish, and material compactness. ECL-ECD, as a novel metal additive manufacturing (AM), is significantly competitive in micro and mesoscale metal manufacturing, filling the gap in mesoscale ECAM technology.

Performance Evaluation of Blended Vegetable Oils as a Cutting Fluid under MQL in Turning

Abstract: Cutting fluids has been extensively uses over the years for the higher productivity and making good quality products. But, Cutting fluid related high costs and health problems are associated with exposure to operator and this lead to environmental pollution increasing. Therefore to maintain free pollution environmental sustainability in manufacturing various vegetable oils has been widely use in various machining process as a cutting fluid. Therefore in this work various vegetable oils were selected due to their wide usage. However compared to bare vegetable oils, vegetable based nanofluids are showed better performance due to their enhanced thermo-physical properties but, they are not suitable for economical machining. Hence, in this work the performance of the widely used three blended bare vegetable oils with their different combinations were evaluated under the turning of AISI 304 austenitic stainless steel by using Carbide tool through Minimum quantity lubrication (MQL) technique by the measurements of Surface roughness, maximum generated temperature at specified location and formation chips. All the measured parameters were in agreement, confirming that produces good surface finish, low temperature generated at specified location and better chip formation. It is suggested that considerable cost reduction by using blended vegetable oils as compared to commercial oils. Keywords: Vegetable oils, Blending, MQL, Machining performance, Turning, Carbide Insert

RSM Modelling for Laser Cutting of Shore Wood to Replace Traditional Manufacturing Method

A study on the dimensional tolerance for CO2 laser wood cutting is focused on the Meranti (Shorea) wood with the thickness of 19 mm. The results on kerf width for two surfaces which are top surface (Kt) and bottom surface (Kb) are investigated. It is interested to find out the optimum cutting parameters to achieve the smallest variance on top and bottom kerf to improve dimensional quality. Laser power, cutting speed, and gas pressure had been selected as investigate parameters and the cut kerf had been analysed. The investigations revealed that laser power and cutting speed are the significant parameters not only in producing a good surface finish, but also in yielding much narrower kerf with to ensure there will be no dimensional errors of the shore wood products. Besides quality, the laser processing approach has overcome most of the challenges faced by conventional production method.

Process optimization and removal of phenol formaldehyde resin coating using mechanical erosion process

Consumption of coated abrasive discs in various automobile and pipe fitting application is increasing, due to its good surface finish. Coated abrasive disc consists of single layer of abrasive grain bonded to a fibre backing. The major portion of the disc is comprised of fibre backing. But the sustainability of the fibre backing is low and is dumped as waste after usage. The present work deals with the removal of resin coating and recovery of fibre backing from the spent coated abrasive discs using physical separation process such as sand blasting technique. Initially, the recovery experiment was carried out based on L16 orthogonal array. The factors and levels chosen for the experiments were erodent pressure (0.2, 0.4, 0.6 and 0.8 MPa), erodent size (36, 60, 80 and 120 grit), disc orientation (30, 45, 60 and 75°) and number of times flexing (5, 10, 15 and 20). The experimental result shows that erodent size and erodent pressure have a major impact on recovery of the fibre backing. The surface structure of the recovered backing was analysed using scanning electron microscopy and optical microscopy. The recovered backing was very much useful for the coated abrasive industry as the flexible backing and support material for abrasive grain coating.

Optimization of WEDM Process Parameters in Al2024‐Li‐Si3N4 MMC

The present study focuses on optimization of operating parameters in wire electric discharge machining of AA2024 aluminium alloy reinforced with lithium and silicon nitride particles. Aluminium composite was produced through the two‐step stir casting route with the combination of 2% lithium and 10% silicon nitride reinforcements. Experiments were performed using the Taguchi design of experiments to optimize the selected input parameters such as pulse on time, pulse off time, current and wire feed for the response parameter, material removal rate, and surface roughness. An ANOVA‐based regression equation with genetic algorithm was used to optimize the input variables. The gray relational grade was also performed to optimize multiple performance characteristics. Taguchi‐based optimization analysis results in wire feed as the domination factor for material removal rate and surface roughness. Increased wire feed increases the material removal rate with good surface finish as confirmed from gray relational grade analysis. Regression equation generated results with minimum error (<2%) proving the accuracy of the investigation. A genetic algorithm‐based study also confirms the analysis of Taguchi and gray relational grade. The wire feed rate at 3 m/min and pulse on time of 120 microseconds were found to be similar for material removal rate and surface finish. Current at 50 A increases the material removal rate and current at 30 A results in good surface finish.