Journal of Advanced Manufacturing Systems

This work aims to develop a mathematical model and predict the machining performance characteristics of electric discharge machining (EDM) process using response surface methodology (RSM) coupled with desirability function approach (DFA). The effect of various factors, such as electrode material, pulse current, pulse ON time and pulse OFF time were selected as input process parameters with an objective to maximize the material removal rate (MRR), minimize the surface roughness (SR) and electrode wear ratio (EWR). The machining was conducted on Al-Zn-Mg-Cu (AA7075) alloy composite reinforced with 10wt.% TiO₂ particulates produced by stir casting route. The experimental work was planned as per L27 orthogonal array using design of experiments through RSM. Experimental results show that, pulse current and pulse ON time are the most significant factors for MRR and SR while electrode materials and pulse current have notable effect on EWR. Finally, multi-response optimization was performed to predict the EDM parameters by using DFA. The optimum combination of parameters were identified as electrode material (Br), pulse current (15 amps), pulse ON time (900$\mu$s) and pulse OFF time (30$\mu$s).

Maskless electrochemical micromachining (EMM) is an alternative method to fabricate microsurface textures on conductive substances, but it is still very challenging issue to create microsurface textures by this method. This paper proposes a new issue that maskless EMM process generates micro rectangular patterns using various pulse waveforms i.e. triangular, sine and square of pulsed DC power supply at constant voltage mode on stainless steel (SS-304) workpiece. A novel concept of maskless EMM setup consisting of EMM cell, electrode holding devices, electrical connections and vertical cross flow electrolyte system is introduced for the generation of high-quality micro rectangular patterns using various pulse waveforms. Another important finding is that SU-8 2150 negative photoresist can fabricate more than 28 micro rectangular patterned samples with higher dimensional accuracy and surface quality. The influence of machining voltage, inter electrode gap, pulse frequency, duty ratio and flow rate is investigated on machining performance such as length overcut, width overcut, machining depth and surface roughness ($R_a)$ of micro rectangular pattern using three pulse waveforms. One mathematical model is developed to show the effectiveness of three pulse waveforms by the estimation of current efficiencies. From the experimental investigation, it is observed that higher frequency with square waveform at constant duty ratio is suitable to generate high-quality micro rectangular patterns under pulsed DC power supply.

Surface finish is the most desired properties of any sophisticated machinery parts for its proper functioning and long endurance. The surface finish must be in the order of micrometer to nanometer for most of the machinery parts. The nontraditional surface finish processes prepare these parts; in these processes, the uses of electromagnet play a vital role in the surface finishing mechanism. Magnetic abrasive flow finishing (MAFF) is such a hybrid process, which gives a combined effect of abrasive flow finishing (AFF) and magnetic abrasive finishing (MAF). In this method, a pair of electromagnets are attached to the AFF setup. By using electromagnet in the AFF process, it enhanced material removal and surface finishing. The main process parameters selected in the MAFF process were magnetic flux density, number of cycles, percentage abrasive content, piston speed, and corresponding responses selected were material removal, percentage improvement in surface finish. In this research paper, the responses were optimized by a combination of utility theory and meta-heuristic firefly’s algorithm. The utility theory based-firefly algorithm’s predicted global optimum parameters set, which was more suitable for reducing the finishing time and required surface finish. The confirmatory test validated this optimized parameter set and it was revealed that the meta-heuristic firefly algorithm embedded with utility theory had given optimized results in the MAFF process.

Nowadays, industrialists, especially those in the automobile and aeronautical transport fields, seek to lighten the weight of different product components by developing new materials lighter than those usually used or by replacing some massive parts with thin-walled hollow parts. This lightening operation is carried out in order to reduce the energy consumption of the manufactured products while guaranteeing optimal mechanical properties of the components and increasing quality and productivity. To achieve these objectives, some research centers have focused their work on the development and characterization of new light materials and some other centers have focused their work on the analysis and understanding of the encountered problems during the machining operation of thin-walled parts. Indeed, various studies have shown that the machining process of thin-walled parts differs from that of rigid parts. This difference comes from the dynamic behavior of the thin-walled parts which is different from that of the massive parts. Therefore, the purpose of this paper is to first highlight some of these problems through the measurement and analysis of the cutting forces and vibrations of tubular parts with different thicknesses in AU4G1T351 aluminum alloy during the turning process. The experimental results highlight that the dynamic behavior of turning process is governed by large radial deformations of the thin-walled workpieces and the influence of this behavior on the variations of the chip thickness and cutting forces is assumed to be preponderant. The second objective is to provide manufacturers with a practical solution to the encountered vibration problems by improving the structural damping of thin-walled parts by additional damping. It is found that the additional structural damping increases the stability of the cutting process and reduces considerably the vibrations amplitudes.

New superalloys are potential materials in aircraft and power plant industries because of their properties like high-temperature strength, creep life and resistance to corrosion and oxidation at elevated temperatures. Because of the superior properties of superalloys, machining them using the conventional processes is a difficult task that is associated with high cost and poor accuracy. In this study, an attempt has been made to machine NIMONIC 75 superalloy by the electro discharge machining (EDM) process, using the Taguchi-based Gray Relational Analysis method for multi-objective optimization of material removal rate (MRR), tool electrode wear rate (TEWR) and surface finish (SF). The experiments conducted were based on $L_{18}$ (2${}^1\times 3^5$) orthogonal array. Six input parameters namely tool material, peak current, gap voltage, pulse on-time, pulse off-time and tool lift time were considered in this study. The validation results proved that the parametric setting of tool material as copper, peak current as 12A, gap voltage as 50V, pulse on-time as 200$\mu$s, pulse off-time as 15$\mu$s and tool lift time as 2s, yields optimized values of the performance characteristics. SEM images indicate the presence of numerous surface irregularities, whereas the XRD test shows the formation of various carbides on the EDMed surface.

Perforation pipes are widely used in oil&gas exploration. Aligning a perforated pipe in different workstations is very important for quality control. Typically, a keyway in a perforated pipe is machined as the alignment feature. Once the angle of a keyway is measured, an industrial robot is used to rotate the perforated pipe to the desired location. However, due to various errors, the industrial robot cannot rotate the perforated pipe to the desired location using the measured angle once. In this paper, a method based on generalized regression neural network (GRNN) is proposed to predict the rotation angle such that an industrial robot can rotate a perforated pipe to the desired location. Training datasets are collected first to train a GRNN model. The model is then deployed to predict the rotation angle. Experiments were performed to validate the proposed method and the results show that the final keyway angle satisfies the requirement of keyway alignment.

The outstanding characteristics of titanium alloy (Ti–6Al–4V) have made this material applicable in aerospace and medical components. However, due to its poor machinability characteristics, researchers are forced to understand the machinability behavior of Ti–6Al–4V. In this paper, $L_{16}$ orthogonal array-based three-dimensional finite element modeling for the cutting force and chip formation analysis during the machining of Ti–6Al–4V using cubic boron nitride tool in dry turning environment has been investigated. The finite element simulation was performed using ANSYS Workbench, version 19.0. Cutting force and chip formation were investigated using the results obtained from $L_{16}$ orthogonal array-based three-dimensional finite element modeling. This research would help to identify the optimum cutting conditions and minimize the cutting force followed by analyzing the types of chips formed during machining under the selected set of cutting conditions.

In this paper, a new mathematical model is presented for a cellular manufacturing system into tactical planning of a closed-loop supply chain to build a sustainable manufacturing enterprise. On the manufacturing side of the model, a comprehensive cellular manufacturing system is designed considering dynamic cell configuration, alternative process routings, lot splitting, sequence of operations, multiple units of identical machines, machine capacity, machine adjacency requirements, and cell size limits. On the closed-loop supply chain side of the model, different activities are considered including acquiring returned products, setting up the system for the implementation of disassembly operations, inventory holding of the returned products, remanufacturing the parts having high quality, and disposing of the returned products that cannot be economically recovered. The mathematical model in this paper, to the best of our knowledge, is the first model reducing the total costs of the cellular manufacturing system while considering the alternative process routings and subcontracting of the part demands. A detailed economic analysis is done on the large-sized example problem of the mathematical model to investigate the impacts of adopting different production policies such as internal production, inventory holding, and subcontracting as well as different manufacturing attributes such as dynamic reconfiguration and alternative process routings. The mathematical model is also solved for different instances to investigate the effects of incorporating subcontracting, alternative process routings, and dynamic reconfigurations in the model. Sensitivity analyses are also conducted to investigate the effects of the recovery rate of returned products on the objective function value and the number of returned products to be acquired. The effect of taking alternative process routings into consideration on the objective function value is also investigated.

The reduction of wastes, improved industrial performance, and the SME environment are very important topics for the image of the organization. Recently, several business managers have implemented lean manufacturing in order to improve and optimize productivity and quality of production, some of them have achieved significant results while others have not yet succeeded in setting up lean manufacturing. The purpose of this paper is to provide an in-depth analysis of the implementation of lean manufacturing in SMEs worldwide, to identify and present the critical difficulties and obstacles that impact the implementation, and to highlight the success factors of manufacturing firms. The bibliographic study findings allowed us to collect a list of the difficulties that we classified according to the amount of occurrences which showed that five difficulties represent 77, 78% of the discontent causes, from what we note: the lack of leadership and the lack of commitment of top management; lack of financial resources; resistance to change; lack of training and knowledge about lean tools; and lack of know-how, skills and expertise. We noticed that these difficulties are extremely identical whether in Morocco or elsewhere in the world. In the same way, we have pointed out that the commitment of top management is a key factor that determines the success of the implementation and the success of the company. Finally, the novelty of our paper lies in the preliminary proposal of a model that explains the impact of the management commitment on the performance of the company, and on its customers and employees.

Ultrasonic tube forming is an innovative and promising technology that could replace the conventional thermoforming process for plastic automotive tubes. This process allows for the forming of extruded tubes four times faster, with a substantial increase in energy efficiency. This research focuses on the experimental study of this innovative process and its comparison to the conventional thermoforming in a hot air table. A prototype has been designed and assembled to study the main process variables that are significant to the forming result. A complete design of experiments (DOE) has been applied to quantify the effect of each process parameter, thereby obtaining a mathematical model that allows for the prediction of the curvature angle for a specific parameter combination. It has been concluded that the application of ultrasonic cycles, with short cooling cycles in between, is the best option, in comparison to a continuous application. The amplitude of vibration, ultrasonic time for the cycle, and number of cycles have proven to be the most significant variables of the process. Furthermore, the cooling time between cycles and the position of the squares for the initial bending angle are also important parameters that can be set up to refine the result. Quality control tests related to material degradation and geometry have been passed successfully, showing a high stability of the results. Consequently, this new process has a promising place in the future of plastic tube forming.

The paper discusses a unique technique developed initially at Nation Institute of Technology, Surat that is remodeled in real-world applications. The concept consists primarily of a user-friendly software facilitating direct communication with any intelligent or learning system/robot operating under known parameters of motor specifications. Any software base permitting high level PC interface without ASCII interrupt can be used for easy programming. This allows for a learning operation mode where a prevention of time lag is enabled by stored machine data, captured through movements such movements can be physically made or taught via programs to the device and such learning aspects make the machine more efficient where the robot can either perform individual actions as needed or learn new methods for the same results and can perform a series of actions continuously. Using the stored data, the machine is also capable of autonomous movements based on the path of least resistance as calculated by the time it takes to perform an act.

Interfacing Technique Tool Machining Robot (ITTMR) was developed as robotic tool holder that can determine the shape and size of different OCTG pipes utilized in the downhole industry and enable it to machine appropriate threads on the pipe with no manual intervention.

The process thereby completely negates any possibility of human error which can otherwise cause heavy loss on finished equipment that are rendered unusable because of threading errors on almost nearly finished complex milled parts or assemblies that are pending threads as the final operation. The purpose of the software codes is to provide a user-friendly GUI that can communicate with any machine by pulling in appropriate ACNC programs and performing the required tasks associated with the operating system and specifications of the motors/mobilization equipment’s used. For the purpose of this paper, the software code is not provided.

Any firmware base that permits the usage of an ASCII interrupt can be used and for the purpose of this operation, an RS323 equivalent board will also suffice for basic operations, however a complex ITTMR system has been utilized. This paper solely addresses the technique of how the threading operation is performed and does not address the process of how the pipe is bought to the machine or other associated aspects of the software to retain any possible patent applications on the same.