Papers by Keyword: Material Removal Rate (MRR)

Abstract: To Acompany the novel technology advancement demands for advance materials. Beryllium copper is such solitary material which has conspicuous material properties, to be pricise good wear resistance, corrosion resistance and high fatigue strength. But the concern with this is machining by treditional machining processes. To defeat this problem Powder Mixed Electric Discharge Machining(PMEDM) is a surrogate technology, which is acquiring much importance in machining such materials. As compared to convenctional electric discharge machining the powder mixed electric discharge machining has delivered much efficiency because of the addition of fine powder particles in dielectric media. It increases the steadiness and concentrated sparking on the work piece material. This study aims at machining beryllium copper alloys using powder mixed electric discharge machining. The electric parameters namely pulse on time, pulse off time, and gap voltage are retained constant throughout the experimentation. Copper electrode of 3 mm square tip was used for machining of beryllium copper work piece. Gap current is varied as 8 A, 10 A, 12 A and 14 A whereas powder concentration is varied as 2 gm/litre, 4 gm/litre and 6 gm/litre. Material removal rate (MRR) and tool wear rate (TWR) were considered as electric discharge machining output measures for the study. It was observed that the efficiency of powder mixed electric discharge machining improved by using powder mixed dielectric. It was found that the MRR improves as the gap current is increased by the increament of 2A. One more obeservation found was the improvement in the both MRR and TWR with the increase in the powder concentration . Tool wear rate increases due to the truth that as the depth of machining increases the efficiency of flushing reduces hence leading to higher tool wear rate.

Abstract: Monel alloys are pioneering materials which have exceptional engineering properties such as corrosion resistance, high toughness and show good response to cryogenic treatment. It finds uses in ship building, nuclear aerospace, missile and valve industries. These materials shows strain hardening effect which results in tool wear and in some cases tool breakage when machined by conventional methodshence, unconventional machining such as electrical discharge machining (EDM)discoverspurpose for machining of such materials. Researchers have recognized relation between electrical input process parameters of EDM process and output parameters of EDM process. But researchers have not investigated the influence of external magnetic field and cryo-treatment of work piece on EDM performance measures namely material removal rate (MRR) and tool wear rate (TWR). In vision of this the objective of present work was to study the effect of gap current, external magnetic field and cryogenic treatment of work part on MRR and TWR. Experiments were carried out by creating a 3 mm square hole on Monel400 alloys. Based on experimental results it was found that as gap current increases the MRR and TWR increases for untreated work part. For treated work part MRR increases and TWR decreases with increasein gap current. MRR and TWR increases with constant gap current for untreated work part, as magnetic field increases. For treated work part MRR increases and TWR decreases with increase in magnetic field at constant gap current.

Abstract: NiTi alloys possess superior material properties such as high specific strength, high corrosion resistance, high wear resistance and high anti-fatigue property. Due to these properties it is difficult to machine these alloys using conventional machining process. Nowadays non-conventional machining processes are widely used for machining such adavanced materials. Electrical Discharge machining (EDM) is one such non-conventional process, which can machine electrically conductive materials of any hardness values. Present study aims at drilling mesoscale 3 mm square holes on NiTi alloy by varying the electrical parameters namely, gap current, pulse on time and pulse off time. Additional, the present work includes finding out the effect of cryogenic treatment of NiTi work material on electrical discharge machining performance measures namely material removal rate (MRR) and tool wear rate (TWR). Based on experiments conducted, it can be concluded that with increase in current both material removal rate and tool wear rate increases. It is also noted that cryo-treatment of workpiece material improves MRR with respect to gap current. Similarly there is an increase in MRR with respect to pulse on time and pulse off time for cryo-treated workpiece material. There is a slight improvement of TWR with respect to gap current, pulse on time and pulse off time for cryo-treated workpiece material.

Abstract: Electrochemical discharge machining (ECDM) is an ideal process for machining of nonconductive materials in micro-domain. The material removal takes place due to combined action of localised sparks and electrolysis in an electrolytic chamber. The electrolyte is most important process parameter for ECDM as it governs spark action as well as electrolysis. This article presents a comparison of three preferred electrolytes used in ECDM viz. NaCl, KOH and NaOH on drilling of glass workpiece material. The quality characteristics measured are material removal rate (MRR) and hole overcut. Results reveal that NaOH provides 9.7 and 3.8 times higher MRR than NaCl and KOH respectively. MRR and hole overcut are found significantly affected by spark characteristics.

Abstract: The environment issue and green machining technique have been induced intensive attention in recent years. It is urgently need to develop a new kind dielectric to meet the requirements for industrial applications. The aim of this study is to develop a novel dielectric using gas media immersed in deionized water for electrical discharge machining (EDM). The developed machining medium for EDM can fulfill the environmentally friendly issue and satisfy the demand of high machining performance. The experiments were conducted by this developed medium to investigate the effects of machining parameters on machining characteristics in terms of material removal rate (MRR) and surface roughness. The developed EDM medium revealed the potential to obtain a stabilizing progress with excellent machining performance and environmentally friendly feature.

Abstract: Electrical discharge machining (EDM) is a non-conventional machining technique which can be used to machine non-conductive ceramics. This technique removes materials from the workpiece by thermal energy exerted from series of electrical sparks. Using copper foil as assisting electrode (AE), machining of Al₂O₃ is done successfully. In this investigation, experiments were performed to study the effect of gap voltage and pulse-on time on material removal rate (MRR) for EDM of Al₂O₃. The results showed that the lowest and the highest values of gap voltage were 12 V and 14 V, respectively, with a fixed peak current of 1.1 A and pulse-on time of 8 μs. Beyond these two voltage values, material cannot be removed due to insufficient pyrolytic carbon layer generation. Similarly, pulse-on time is varied from 6 μs to 8 μs when gap voltage is fixed at 14 V and peak current at 1.1 A. MRR, in this case, is increased almost 20 times from a lowest value of 0.006 mm³/min to a highest value of 0.119 mm³/min for the specified gap voltage and pulse-on time.

Abstract: This research work describes the effect of powder concentration in dielectric fluid during electrical discharge machining (EDM) of mild steel on material removal rate (MRR), electrode wear rate (EWR) and work surface roughness (Ra). The machining parameters studied in this research are current (4.5A, 5.5A, and 6.5A) and concentration of the powder (30g/l, 60g/l, and 90g/l). It was decided to use copper (Cu) as the electrode, mild steel as the work material and tantalum carbide (TaC) as the powder to be mixed with the dielectric. Design-Expert software was used to design and analyze the experiments. The performance of machining was analyzed and it was found that powder concentration does not have much effect on MRR or work surface roughness (Ra). At low current powder concentration reduces electrode wear rate (EWR), but at higher current the situation is opposite. It was also found that in all conditions, MRR and EWR increases with increase in current. A higher current produces stronger spark with higher energy that melts more materials from the workpiece and the electrode. As a result both MRR and EWR increases and job surface becomes poor.

Abstract: This paper investigates the material removal rate (MRR) in electro discharge micromachining (micro-EDM) of zirconia. Experimental investigation is carried out with 800 μm diameter tungsten electrode with two varying parameters rotational speed and gap voltage. The MRR data are analyzed and an empirical model is developed using Design Expert software. The optimum parameters for maximum MRR are found to be 375 rpm rotational speed and 80 V gap voltage.

Abstract: Abrasive jet machining (AJM) also known as abrasive micro-blasting or Pencil blasting is an abrasive blasting machining process that uses abrasives propelled by high velocity gas to erode material from the work piece. It has been applied to rough working such as deburring and rough finishing, machining of ceramics and electronic devices. AJM has become a useful technique for micro machining. It has various distinct advantages over the other non-traditional cutting methods, which are high machining versatility, minimum stresses on the substrate. This paper deals with several experiments that have been conducted by many researchers to assess the influence of abrasive jet machining (AJM) process parameters such as type of abrasive Particle , Abrasive Particle size, Jet pressure Nozzle tip distance. Various experiments were conducted to assess the influence of abrasive jet machine.

Abstract: Abrasive waterjet machining (AWJM) is one of the non-traditional machining processes used for machining hard and difficult materials including metal matrix composites (MMCs) and ceramic matrix composites (CMCs). MMCs and CMCs are widely used in the industries such as automobile, aerospace, defense, etc. In AWJM, the material is removed by a narrow stream of high pressure water along with abrasive particles. This work, reviews the research work carried out on the machining aspects of MMCs and CMCs using AJWM. Most of the research work in MMCs is carried out on aluminum based matrix reinforced with ceramics such as silicon carbide (SiC) and aluminum oxide (Al₂O₃) in various proportions. In the case of CMCs, the research work mostly are carried out on alumina (Al₂O₃) based work specimen. Generally, it is observed that the reinforcement particles in the MMCs and CMCs greatly influence the output process parameters like depth of the cut, material removal rate (MRR), surface roughness (R_a), kerf width, etc. From the literature review, it is observed that the increase in volume percentage of reinforced abrasive particles results in decreased MRR, decreased in the depth of cut and increase in the R_a. This work also covers the future research work in the machining aspects of MMCs and CMCs.