Trends in Manufacturing Processes

Friction stir welding technique is one of the most emerging, environmental-friendly and rapid-growing solid-state joining technique based on heat generated due to friction and application of pressure. This technique is generally used to join materials that have wide range of industrial applications and that are difficult to weld by fusion welding process, like aluminum, copper, nickel. In the past, researchers have searched a number of approaches to improve joint properties by analyzing process parameters that affect the mechanical and microstructural characteristics of the joint. The experimental and theoretical studies show that the weld joint properties can be improved considerably by proper selection of process parameters. This article shows an overview of various optimization techniques that can be used to find the optimum welding operational parameters during the joining of similar and dissimilar materials.

Electrical and automobile industries have high demands for an effective joining of dissimilar materials because of their enormous use. In the present research, numerical and experimental investigations have been conducted to study the effect of parameters of ultrasonic spot weld on metal joints for electronic components. Copper and brass alloy sheets have been welded using ultrasonic spot welding in the lap configuration. Regression analysis in combination with analysis of variance has been applied to formulate the models. Based on the optimum condition determined for the input parameters, mechanical and microstructural analysis is performed using tensile testing and SEM analysis, respectively. Finite-element modelling (FEM) simulation is conducted for the temperature near heat-affected zone (HAZ) and fusion zone (FZ). The results obtained from experiments are compared with the simulation results obtained from FEM modelling. Slight variations in tensile properties of the weldments that are free from defects have been observed with increase in welding time and frequency. A close agreement between the experimental and simulated values of FEM has been observed, which establishes the validity of reasonable accuracy of the model.

It is very challenging to machine high aspect ratio and complex-shaped holes with micro-electrical discharge machining process. Micro-hole drilling plays a vital role in the production of various aspect ratio (length/depth) micro-holes. This work presents an attempt to fabricate high aspect ratio micro-holes using micro-EDM process on a brass workpiece with tungsten carbide electrode. In the present study, the effect of different machining and operating parameters, namely, spindle speed, feed, input voltage and capacitance on the performance of micro-EDM process is studied. The performance of micro-EDM process is evaluated on the basis of material removal rate (MRR) and the tool wear rate (TWR). It was found that there is significant effect of capacitance and feed on the MRR. The MRR improved with increasing values of capacitance and feed rates, while the TWR decreases with increasing discharge energy (capacitance and voltage).

The present research manages through transmission laser welding (TTLW) of polycarbonate and acrylic, both being transparent, have been directed framing a lap joint. A 12-W Nd:YVO₄ laser with 1064 nm wavelength has been used for the welding procedure. The effect of welding parameters, to be specific, scanning speed, laser power and laser frequency, has been analysed. The weld quality has been assessed by an ultimate load (UL). Response surface methodology (CCD) has been embraced for the experimental procedure. To correlate the welding parameters with a response, a quadratic model has been created. The analysis of variance method is used to find out the important parameter/s on specific response. A mathematical model has been used to optimize the ideal welding conditions to achieve the improved ultimate load. To validate the applied optimization technique, confirmatory tests have been performed.

A finite-element-based three-dimensional thermo-mechanical model was investigated to predict the temperature distribution in tool and workpiece during friction stir welding (FSW) of AA7075 T651. ANSYS APDL had been used for this simulation. It was defined by four different load steps: plunge, dwell, traverse, and pull out of tool. Temperature-dependent friction coefficient between tool and workpiece was considered. The cooling effect caused by the free convection in ambient air, backing plate, and clamping bar has been taken into account. It was observed that the peak temperature of outside the shoulder region sharply reached its peak point and then decreased slowly, whereas the peak temperature within the shoulder region was dependent on shoulder diameter and welding speed. In addition, it is also observed that peak temperature during welding is not uniform due to temperature-dependent material properties.

The present study is concerned with the design of an automotive suspension system that leads to better dynamic performance in uncertain operating conditions. The analysis is being carried out on a half-car suspension system model subjected to the random road excitations. Full-factorial design approach has been applied at the deliberated range of different speed levels using MINITAB^® V17 tool. The major design parameters have been optimized to obtain the maximum level of comfort and vehicle body stability. A half-car structure has been modeled in Matlab Simulink to examine the dynamic behavior through the parametric variations in the ISO 2631-1:1997 recommended ranges of body acceleration. The reliable results for better dynamic performance of the proposed model have been obtained. A dynamic model of the double-wishbone suspension model generated at ADAMS^® successfully validates the results.

Green-machining is an environment-friendly and cost-effective metal-cutting process because it does not use cutting fluids. This paper focusses on the study of green-machining characteristics and comparison of AISI-1055 and AISI-4340 steels in meso-scale end-milling. All the experiments were conducted with four-flute solid-carbide end-mill tool of 2 mm diameter under dry cutting condition using Taguchi L9 orthogonal array (OA) design. Machining parameters were optimized using S/N-ratio of Taguchi design technique. Analysis of variance was used for investigating the effect of cutting parameters on the burr width (BW) and surface roughness (Ra). All the experimental data obtained for “Ra” and “BW” were used to develop their regression models. The developed regression models for “Ra” and “BW” could be used for predicting the responses in meso-scale end-milling of AISI-1055 and AISI-4340 steels with minute error. At last, a comparison between AISI-1055 and AISI-4340 steels with respect to “Ra” and “BW” obtained in meso-scale end-milling was carried out. The comparative analysis between the two materials in meso-scale end-milling depicts that the machining performance of steel AISI-4340 is more effective than the machining performance of steel AISI-1055 on the basis of obtained “Ra” and “BW”.

Stainless steel exposes high intensity of rigidity and strength. Electrical discharge machine (EDM) has the ability to machine such materials. Optimization of machining parameters is absolutely crucial for effective results of machining. The present work addresses the influence of process parameters, such as current (I_p), pulse duration (T_on), and voltage (V) on recital quantity material removal rate (MRR) on sinker electrical discharge machining of steel s-32670. Taguchi design approach has been used for planning the experiment and to establish the optimal setting level of controllable factors using signal-to-noise (S/N) ratio, and the significant contribution of these factors on output responses is analyzed with the assistance of analysis of variance (ANOVA). Minitab18 software is used to analyze the experimental design with 16 treatment condition of controllable parameters arrangement called L₁₆ orthogonal array. Recital quantity MRR is calculated and amended for different set of experiments. The result of the present work reveals the optimal level of input factors for maximum MRR, while factors such as current and pulse duration play the most considerable role in EDM machining process. The findings from this study will be valuable for engineers to opt for optimal level of EDM machining factors to appliance s-32670 steel, which curtail the losses for the period of machining and directly elevate outlay and time.

Accurate flow measurement has fiscal consequences and also necessitates fulfillment of stipulated requirement of upstream and downstream straight length at flow metering section. Many times, the site constraints do not permit to fulfill this requirement at metering sections. The present paper addresses to simulate an alternate by-pass flow meter to identify and measure the flow through the sloped pipelines of larger one for various flow rates. The alternate by-pass flow meter will be effectively useful in maintaining process accuracy by reducing downtime and improving the operational cycle of units at large. Based on the flow performance of the by-pass secondary pipes, the flow through the sloped pipe can be established by using the equation arrived by the standards flow simulation at site. The experiment reveals that by establishing by-pass arrangement, the head loss across the combined piping is minimized, The modified by-pass arrangement will be more useful for sloped pipes in terms of site constraints and operational difficulties encountered in the process industries.

An experimental study has been conducted for natural convection heat transfer over the outer surface of circular finned and unfinned helical coil heat exchanger. Hot water flowing in the range of 1–3 l/min has been taken as working fluid and is cooled by ambient air at 32.5 ± 0.1 °C. The volume flow rate of hot water covers the Reynolds number from 4230 to 12,720 and Prandtl number around 3.7. The temperature of hot water at the inlet of test section is maintained at 50 ± 0.1 °C. The heat transfer rate of hot water has been investigated. Better outside heat transfer coefficient has been found for circular finned helical coil heat exchanger than unfinned one. It is also observed that the temperature drop decreases with increase in hot water flowing through test section.

The micro, small and medium enterprises (MSMEs) have a sizeable role to play in the growth of any nation. In spite of its essence in the socioeconomic progress of the nation, Indian MSMEs have to encounter big challenges in their endeavor to be competitive. Low productivity is also a challenge for the management for Indian MSMEs to sustain competition in the world market. Productivity improvement of MSMEs depends on different factors. Responsiveness of a production system is one of the major factors among them. In this paper an attempt has been made to investigate the order fulfillment strategies of Indian MSMEs with an objective to determine whether responsiveness aspects of the firms practices would affect their productivity and hence performance in terms of profits and being competitive. This investigation is based on the study of production practices adopted by North Indian MSMEs in different manufacturing sectors, like automobile components, leather products and electrical goods. In the current competitive environment enterprises must become more responsive to acquire advantages or to avoid being driven out of the market.

In this paper, the structural and mechanical properties of IS:2062 mild steel after single-pass gas tungsten arc welding (GTAW) were investigated and evaluated, to reveal the weld strength and microhardness of welded joints. The properties of the welded joint are affected by various welding parameters, such as welding current, welding speed, gas flow rate and groove angle. This work concerns with mild steel plate joining with bevel angle (30°–50°) and also using filler material same as the base metal. The quality of welds will depend on the modeling of weld bead shape.

Application of multi-criteria decision-making to resolve industrial problems is well-known. The present research is related to the use of fuzzy-AHP in selection of a supplier in the presence of conflicting criteria. There is always an uncertainty present if the crisp values are used. To avoid uncertainty, in this study linguistic variables have been used. An integrated model of DEMATEL and FAHP has been presented here. The weights obtained from the DEMATAL have been used to calculate the ranking of suppliers through FAHP. The rankings obtained through FAHP have also been compared with the rankings calculated through FTOPSIS [13] for the purpose of validation.

This paper presents the evaluation of the mechanical properties and microstructure of the butt joint of AA 8011 produced by friction stir welding (FSW). The effect of the important FSW parameters on ultimate tensile strength (UTS) was determined using Taguchi L9 orthogonal arrays (OA) for analyzing the main effects and variance. From the results of the study, it was found that the most dominating factor affecting the UTS is welding speed, contributing 61.87%, followed by shoulder diameter with 18.02% and lastly tool rotational speed with 13.38%. The maximum UTS of 142.1 MPa higher than the base metal (BM) strength was attained at ideal settings of rotational speed at 560 rpm, welding speed of 100 mm/min and tool shoulder of 16 mm. The microstructure revealed dynamically recrystallized fine and equiaxed grains in SZ. The microhardness in SZ was found to be greater than the BM/TMAZ/HAZ.

Springback effect is the most sensitive feature in sheet metal forming. There are many input process parameters of die and press, which affect the springback/go. In the present study, three different aluminium alloys (AA), namely AA6082-T6, 5083-O and 5052-H32, are used. The objective of this work is to compare the effect of process parameters of V-bending die on springback by using Taguchi method. Bending angle (BA), punch load (PL) and punch velocity (PV) were taken as input process parameters. Taguchi approach and ANOVA (analysis of variance) were applied to find the most significant parameter(s) which affects the output response, that is, springback/go in V-bending process. The experiments were performed on V-bending die using a blank size 40 × 100 × 2.0 mm³ and the springback/go value was calculated using optical microscope. Taguchi L₉ orthogonal array design of experiment was applied to all aluminium alloys AA6082-T6, AA5052-H32 and AA5083-O and the experiments were performed separately. The result shows that the bending angle is the most significant parameter affecting the springback/go value with a contribution of approximate 99% for all aluminium alloys. The optimal values obtained for springback/go for AA6082-T6 at 120° BA, 4 KN PL and 8 mm/s PV, for AA5083-O at 120° BA, 2 KN PL and 24 mm/s PV and for AA5052-H32 are 120° BA, 4 KN PL and 8 mm/s PV.

In offshore oil and gas operations, sand particles with the crude oil causes drastic particulate erosion of transporting pipes, especially during bending of flow, which results in higher economic losses in terms of replacement of pipe fittings. Sand particles having critical velocity strike the wall surface of pipe-elbow, which causes pitting phenomena of material from the erosion zone on the basis of brittleness or ductile nature of pipe fitting material. This problem is countered by using target tee or cushion tee, which is generally a 90° elbow with a blind-end branch. The blind branch is filled with soft materials to accommodate the excessive erosion caused by sand particles. The blind end of target tee is filled with soft material, which provides the cushion effect to the impinging solid particles of fluid at the bend surface. This cushion effect reduces the probability of erosion in target tee and prevents the flow process from the economic losses caused by erosion.