Asif Equbal

This research investigates the performance of ABS P400 parts under compressive loading. These ABS P400 parts are fabricated by fused deposition modeling (FDM) process using omnidirectional printing. The effects of three critical parameters, raster angle (A), air gap (B), and raster width (C), each at three different levels, were analyzed on three different performance measures, i.e. total deformation up to failure ([ ]) measured in %, maximum energy ([ ]) in MJ/m ³ and break energy ([ ]) in MJ/m ³ . Results of experimentations were analyzed using analysis of variance (ANOVA), perturbation curve and 3D surface plots. The research established the anisotropic nature, durability and less brittleness of the FDM fabricated ABSP400 part, which leads to lower strength and also influence the energy absorbing behavior while deformation under compression. Complex relationships were exhibited between the chosen parameters and studied measures. It was also observed that [ ] is noticeable due to less brittleness of ABS P400 however, [ ] and [ ] vary in a contradictory fashion with changes in process parameters. The models were validated using normality plots. Multi-objective optimization was done using the desirability approach to determine the optimal combination of FDM process parameters for optimum responses. The desirability result showed that the optimized input parameter is [ ][ ]mm, and [ ][ ]mm which yield maximized optimum responses as [ ]%, [ ][ ]MJ/m ³ , and [ ][ ]MJ/m ³ . The work not only reflects the effect of three FDM parameters on the total deformation up to failure ([ ] in %) but, in addition, energy absorption behavior of FDM parts under compression is also investigated. The study on the behavior of energy at ultimate stress or ultimate load and breaking stress or breaking load were rarely investigated in earlier research which reflects the novelty of our research.

Fused deposition modeling (FDM) fabricated components have gained significant attention and widespread adoption across modern industries due to their versatility, serving as both prototypes and final products. FDM offers rapid and cost-effective prototyping and production capabilities; however, utilizing directly manufactured FDM parts is not practical. Secondary operations like post-processing, testing, and validation are typically required to ensure that the fabricated parts meet the necessary standards for their intended applications. Desired repeatability, reproducibility, reliability, and preciseness should be the main prerequisites of the part fabricated. It is desirable that additive manufacturing (AM) products should be produced with advanced control processes which should possess acceptable quality characteristics. Ensuring the dimensional accuracy of FDM parts is very crucial, and hence it is important to emphasize the key factors that influence the dimensional precision during their fabrication. Sharing insights into these critical factors is essential to steer scholars, researchers, and the AM industry towards informed decisions and future advancements in AM. We aimed to outline the significant factors influencing the dimensional accuracy of the FDM part. These research papers are collected from Scopus and web of science data using "FDM" and "dimensional accuracy" as the keywords. We include the latest papers published especially during 2020 to 2024, which were lacking in earlier research.

The present study investigates the CNC milling performance of the machining of AISI 316 stainless steel using a carbide cutting tool insert. Three critical machining parameters, namely cutting speed (v), feed rate (f) and depth of cut (d), each at three levels, are chosen as input machining parameters. The face-centred central composite design (FCCCD) of the experiment is based on response surface methodology (RSM), and machining performances are measured in terms of material removal rate (MRR) and surface roughness (SR). Analysis of variance, response graphs, and three-dimensional surface plots are used to analyse experimental results. Multi-response optimization using the data envelopment analysis based ranking (DEAR) approach is used to find the ideal configuration of the machining parameters for milling AISI 316 SS. The variables v = 220 m/min, f = 0.20 mm/rev and d = 1.2 mm were obtained as the optimal machine parameter setting. Study reveals that MRR is affected dominantly by d followed by v. For SR, f is the dominating factor followed by d. SR is found to be almost unaffected by v. Finally, it is important to state that this work made an attempt to successfully machine AISI 316 SS with a carbide cutting tool insert, to investigate the effect of important machining parameters on MRR and SR and also to optimize the multiple output response using DEAR method.

Electrical discharge machining (EDM) is a precise machining technique where machining is done by a series of repetitive sparks between electrode and workpiece. EDM not only results in finishing of workpieces, but also the wearing of electrode also occurs in addition. Since the performance of electrodes is important in EDM, it is necessary to understand the complex wearing behaviour of electrodes obtained during machining. It was observed that the wear of electrode is affected by a number of factors. While it is difficult to avoid or control the factors affecting the electrode wear, it is more appropriate to control the machining factors used in EDM. In the present study, wear of copper electrode (tool wear ratio, TWR) was investigated during machining of AISI 1035 steel. Experiments were designed using a full factorial design (FFD) of experiments and undertaking three critical EDM factors i.e. current (I), spark on time (T _on), and spark off time (T _off). ANOVA (analysis of variance) is used to determine the significant EDM factors affecting the wear of electrode and its performance. The impact of individual factors on TWR is demonstrated using main effect plot, and to minimize the wearing of electrode, the optimal setting of EDM factors that produces the minimum electrode wear is proposed using the desirability function approach.

In this study, compacted hematite (Fe₂O₃) preforms were made and sintered at various temperatures, such as 1250 °C and 1300 °C, using both conventional and microwave sintering methods. The density, porosity, microhardness, cold crushing strength, microphotographs, and X-ray diffraction (XRD) analysis of the sintered preforms were used to evaluate the performance of the two sintering methods. It was found that microwave sintered preforms possessed lesser porosity and higher density than conventionally sintered preforms owing to uniform heating of the powdered ore in microwave sintering method. Furthermore, it was also observed that microwave sintered preforms exhibited relatively higher cold crushing strength and hardness than conventionally sintered preforms. Thus, the overall results revealed that microwave sintering yielded better properties considered in the present study.

In the present study, cylindrical ABS P400 polymer parts (diameter 6.5 mm) to be used as die-sinking EDM (electric discharge machining) novel electrodes were fabricated using a fused deposition modeling (FDM) process. To meet the conductivity requirement in EDM, ABS parts were metallized using an innovative method that comprised putting aluminum–charcoal (Al–C) on them followed by their copper electroplating. Real-time EDM of the mild steel workpiece was performed using novel electrodes, and machining performance of the electrodes, measured in terms of dimensional accuracy, i.e., change in diameter (ΔD) and change in depth (ΔH) of the cavity, under varying levels of three EDM factors, i.e., current (I), pulse on time (T_on), and pulse off time (T_off), was investigated. Machining results were analyzed using analysis of variance (ANOVA), perturbation graphs, and 3D surface plots. The optimal setting of the EDM parameters for minimizing ΔD and ΔH was determined using the desirability function approach. The suitability of the novel electrodes for EDM was ascertained by comparing their machining results with those of solid copper (SC) electrodes and electrodes fabricated by FDM and metallized using the electro-deposition method (FDM-EM), already reported in the literature, under similar machining conditions. From the results, it was found that ΔD and ΔH were less when EDM was performed using novel electrodes.