Papers by Keyword: Material Removal Rate (MRR)

Abstract: In the previous many years, several attempts have been made to enhance the effectiveness of the Spark erosion machining process. This review clearly mentioned all the work outputs of Vibration Assisted Electric Discharge Machining at a glance. One of these non-traditional machining techniques, called electric discharge machining (EDM), produces higher surface finishes, high levels of precision, and machinability. Ultrasonic vibrations are used in many industrial processes, such as material removal operations for form generation on material surfaces. Lately, there has been an increasing trend toward using ultrasonic vibration to enhance process performance. Ultrasonic vibration finds noteworthy application in industrial processes such as spark erosion machining, where vibration is enhanced by using ultrasonic waves as a medium. The electrode's ultrasonic vibration modifies the discharge gap and improves the chip removal capability, making it a very effective technique for raising EDM efficiency. An overview of the literature on the application of ultrasonic vibrations in electric discharge machining is presented in this article. Review work has been done on how ultrasonic vibrations can be applied, their ability to affect performance metrics, how to predict and optimise processes, and how to use them with advanced materials that can be difficult to cut. Future requirements for research have been highlighted to increase the ability and potential for the technique of electric discharge machining based on an evaluation of the present state of ultrasonic-assisted electric discharge machining.

Abstract: Currently, one of the most used electrodes are brass wire electrodes, which, thanks to their good electrical conductivity, suitable mechanical properties and acceptable performance, can meet the high demands placed on the cutting tool. A special type are coated wire electrodes, which include a range of specifics regarding machining efficiency and the quality of the machined surface. Therefore, the aim of the research was to identify these parameters based on the experiments carried out in connection with the quality of the machined surface and the productivity of the electro-erosive process in the machining of high-speed steels. The influence of a standard brass multipurpose wire electrode and two brass wire electrodes coated with a double layer of gamma diffuse zinc and zinc alloy on the quality of the machined surface and the productivity of the EDM process was investigated.

Abstract: The modified SiC slurry for CMP process was proposed in order to obtain high-quality surface of 150 mm SiC wafer and then tried to explain the mechanism of the effect of added transition metal ion to improve polishing characteristics of SiC crystal substrate. SiC substrate with using modified slurry exhibited slightly higher MRR value and lower platen temperature than those with using commercial slurries. The addition of transition metal ion into the slurry enhanced oxidation efficiency of SiC crystal surface and improved MRR and the quality of SiC surface.

Abstract: A material with exceptional levels of abrasion resistance, compressive strength, and hardness is known as bearing steel, also known as EN-31 high-grade carbon alloy steel. It has several uses, including the bulk manufacturing of roller bearings, taps, gauges, ejector pins, swaging dies, etc. The lowest surface roughness (Ra) and highest material removal rate (MRR) are sought for this alloy steel in order for it to be used successfully in a range of applications. In the experiment, a L9 Taguchi orthogonal array design was used to CNC end mill EN-31 steel using a bullnose end mill carbide tool with inserts. This study presents a way for enhancing process factors such as cutting speed, depth of cut, feed rate, and tool corner radius that result in desirable output responses. Taguchi and Taguchi-Grey analyses are used to show the best input values that reduce surface roughness and increase MRR. The lowest level of surface roughness could be attained using the operating parameters of 3000 rpm cutting speed, 500 mm/min feed rate, 0.25 mm depth of cut, and 1.00 mm tool corner radius, while the highest level of material removal rate could be attained using 3000 rpm cutting speed, 2500 mm/min feed rate, 0.25 mm depth of cut, and 1.00 mm tool corner radius.

Abstract: Wire Electrical Discharge Machining (WEDM) is a modern machining technique. WEDM is electro-thermal non-conventional machining processes follow to cut very hard materials. WEDM is non-traditional material cutting operation employed to machine complex geometries and shapes. The present paper attempts to study surface and sub-surface variations during WEDM of titanium grade 7 alloy with Brass wire coated with Zn. This paper presents experimental studies with varying three key process parameters viz. pulse ON time (TON), pulse OFF time (TOFF), peak current (IP). The investigation is focused on assessment of material removal rate, surface roughness as well as recast layer. Scanning electron Microscope (SEM) examinations are carried out on surface textures and are discussed in the article. The obtained results indicated that the stretched pulse time discharges more energy causes rough surface finish. The MRR is also strongly influenced by T_ON.

Abstract: Silicon Carbide (SiC) provides excellent characteristics such as superior thermal conductivity, high carrier mobility and extreme chemical stability in comparison with those of Silicon (Si). SiC is already showing significant device performance benefits in power devices, high performance communication, and LED lighting. However, SiC presents many challenges for wafer surface treatment because of its high hardness and remarkable chemical inertness. Today, mechanical polishing techniques on industrial batch CMP tools are the predominant methods for SiC wafer surface treatment, but material removal rate (MRR), surface defects and wafer flatness control are reaching fundamental limits with increasing wafer diameter. Batch processing typically results in a higher amount of surface scratches and defects, higher wafer to wafer variability, and higher wafer breakage rates. A unique single wafer chemical mechanical polishing (CMP) technique on 150mm n-doped, 4° off-axis, single crystal, 4H-SiC wafers was developed to create a virtually defect-free surface. A polishing head has been designed to manipulate polishing pressures at various zones of the wafer. This capability can modulate the removal thickness at each region on the wafer surface, resulting in a highly uniform wafer profile. Additionally, a CMP slurry has been formulated to maximize MRR from 2μm/hr to over 8.5μm/hr. Potassium permanganate has been selected as an oxidant and aluminum oxide particles as the abrasive. The oxidant concentration and abrasive content along with slurry pH level have also been optimized for ideal chemical and mechanical activity. Scratch-free wafer surfaces are observed with atomic force microscopy (AFM) and bright field (BF) and dark field (DF) inspection techniques. Roughness on the Si face is reduced to below 0.08nm. Total length of surface scratches was reduced to 10mm or less. Industrial metrics of wafer flatness, including total thickness variation (TTV) and local thickness variation (LTV) are modulated and improved. A test run completed on 25-wafers shows an overall 31% improvement of TTV post CMP process.

Abstract: Micro-electrochemical discharge machining is hybrid machining process which is based on combined principle of electro discharge machining and electro chemical machining. It is suitable for machining of both conductive as well as non-conductive materials. In this study a micro hole drilled on Ti-6Al-4V as work piece by varying machining parameters like electrolyte concentration, voltage and duty factor at three different levels. Orthogonal array L9 considered for design and performing experiments. The Grey relation analysis (GRA) was performed to optimize the output parameters i.e. material removal rate (MRR) and hole tapper angle (HTA). The result reveals that voltage was the most significant factor for both MRR and HTA followed by electrolyte concentration and duty factor. The maximum MRR and minimum taper angle are 1.50 mg/min and 0.98 ° obtained respectively. The GRA show optimal machining parameters at electrolyte concentration 3M, voltage 40 V and duty factor 25% respectively.

Abstract: The present work reports the influence of various Electric-Discharge Machining (EDM) process parameters on the surface morphology and EDM characteristics of thixoformed A356-5TiB₂ in-situ composites. The important EDM parameters such as pulse current, pulse-on time, Duty Cycle, etc. on Surface morphology and Material removal rate of the thixoformed A356-5TiB₂ in-situ composites have been investigated. Further, the machining parameters were optimized using Fuzzy-logic and grey relational analysis approach. The effect of EDM parameters and their interactions on the erosion behavior of A356-5TiB₂ in-situ composites on various aspects of surface integrity and Material Removal rate (MRR) is reported. The surface integrity during EDM was characterized by Scanning Electron Microscope and analyzed from the machinability point of view. Thus, this work is an attempt to study the machinability behavior of thixoformed A356-5TiB₂ in-situ composites.

Abstract: The choice of abrasive particle size is crucial to improve the lapping efficiency and surface quality in lapping of sapphire wafer by fixed abrasive (FA) pad. A model for the penetration depth of a single abrasive is developed with fixed abrasive pad. A serious of lapping tests were carried out using FA pads embedded with different size of diamond particles to verify the validity of the developed model. Results show that the penetration depth of abrasive is related not only to the particle size, but to the hardness ratio of the work-piece to the pad as well. The material removal rate of sapphire is proportional to the square of abrasive particle size, while the average surface roughness is proportional to the abrasive particle size.

Abstract: To improve the material removal rate (MRR), the effects of electrode rotational speed, gap voltage and pulse width on the MRR of PCD EDM grinding process were studied. By adding pre-experiments, the optimization process is more rapid. A second-order regression model of MRR is established by using response surface method based on Composite Circumscribed design (CCC). And the influence of each parameter on the response is analyzed. The results show that the optimal removal rate is after optimized, which is 11.8% higher than that of the pre-experiment.