Papers by Keyword: Material Removal Rate (MRR)

Abstract: This paper investigates the performance of brass electrode on the removal of aluminium alloys LM6 (Al-Sil2) in an electrical discharge machining (EDM) die-sinking. The machining parameters such as pulse-on time, pulse-off time and peak current were selected to find the responses on the material characteristics such as material removal rate (MRR), electrode wear rate (EWR) and surface roughness (Ra). Brass with diameter of 10mm was chosen as an electrode. Orthogonal array of Taguchi method was used to develop experimental matrix and to optimize the MRR, EWR and Ra. It is found that the current is the most significantly affected the MRR, EWR and Ra while pulse on time, pulse off time and voltage are less significant factor that affected the responses. Percentage optimum value of MRR increases to 3.99%, however EWR and Ra reduce to 3.10% and 2.48% respectively. Thus, it shows that brass having capability to cut aluminium alloys LM6.

Abstract: Chemical mechanical polishing (CMP) had been considered as the most practical and effective method of achieving an ultra-smooth and non-damage surface in manufacturing SiC crystal substrate. CMP slurry was one of the key factors of CMP technology. In this paper, through investigating the changes of several core factors to evaluate the performance of CMP, such as the material removal rate (MRR), surface roughness Ra, 3D surface profiler, etc., the influence of various slurry and its content on the polishing efficiency and surface finish quality had been studied. The research results showed that different oxidant had different chemical action mechanism, also affecting the stability of CMP slurry and surface quality of specimen; adding suitable an oxidant to slurry could effectively improve the CMP performance.

Abstract: Flexible displays will become the mainstream display of next generation, so the manufacturing technology of the flexible display substrate is one of very important technologies. In this paper, according to orthogonal design, the composition selection and optimization of chemical mechanical polishing (CMP) slurry based on alumina abrasive had been done in CMP ultra-thin stainless steel surface by a lot of tests. The CMP slurry based on alumina abrasive for ultra-thin stainless steel surface had been obtained. According to the test results, the material removal rate (MRR) is about 177 nm/min and the surface roughness (Ra) is about 0.018μm.

Abstract: In chemical mechanical polishing (CMP) of ultra-thin stainless steel, the oxidant of polishing slurry determines the material removal rate (MRR). In this paper, the influences of oxidant in slurry on MRR and surface roughness have been studied in CMP of ultra-thin 304 stainless steel based on alumina (Al₂O₃) abrasive. The research results show that, in the same conditions, the MRR increases with the increase of the oxidant C and the oxidant B, the MRR decreases with the increase of the oxidant A and the MRR is max with the oxidant C. It indicated that the oxidant C has a large effect on MRR in CMP of the 304 stainless steel. The research results can provide the reference for studying the slurry in CMP of ultra-thin stainless steel.

Abstract: In this study, according to physic-chemical characteristic of the SiC crystals, we analyzed and researched the role of pH modifier in SiC crystal substrate chemical mechanical polishing and the surface after polishing. We used different polish agents which was made up with inorganic and organic bases to experiment, and then analyzed the results. The parameters of the polishing specimen, such as the removal rate of material, surface scanning and the roughness, were analyzed and used to determine the different pH modifiers played different roles in the stability of polish agents and surface quality of the specimen.

Abstract: Ultrasonic machining is an important part of modern processing technology which is adapt to all kinds of hard brittle materials processing. This paper reviews the latest progress of the material removal mechanism on one-dimensional ultrasonic machining, two-dimensional ultrasonic machining and rotary ultrasonic machining, and expounds the development trend of establishing the material removal model of the ultrasonic machining.

Abstract: In order to clarify the material removal characteristics of Al₂O₃ engineering ceramics in ultrasonic aided high efficiency lapping, a series of ultrasonic and conventional lapping contrast experiments were carried out on precision lathe with self-made ultrasonic lapping device. The research results show that the value of material removal rate in ultrasonic aided lapping is about 2~4 times that in conventional lapping, especially in ultrasonic axial lapping. In ultrasonic aided lapping, the better removal characteristics can not be obtained by adopting too high or too low lapping parameters, and there are optimum lapping parameters from which a higher material removal rate value can be achieved.

Abstract: Stainless steels are one of the most important engineering materials widely used in the industry. This paper presents multi-objective optimization of CO₂ laser cutting of stainless steel considering different cut quality characteristics and material removal rate (MRR). Laser cutting experiment trials were conducted based on Taguchis L₂₇ experimental design by varying the laser power, cutting speed, assist gas pressure and focus position at three levels. Using obtained experimental data, six mathematical models for the prediction of surface roughness, kerf width, kerf taper angle, width of heat affected zone, dross height and MRR were developed using artificial neural network (ANN). The developed mathematical models were taken as objective functions for the multi-objective optimization using genetic algorithm based on Pareto concept. As a result of multi-objective optimization, five 2-D Pareto fronts were generated covering all combinations of cut quality characteristics and MRR. It was observed that the mathematical relationships in the Pareto fronts between MRR and cut quality characteristics are in some cases linear and in another nonlinear.

Abstract: Silicon carbide substrate has been widely used in semiconductor lighting (LED), integrated circuit and microelectronic, optoelectronic devices. According to the former study, a series of the fixed abrasive lapping platen has been developed. The material removal rate (MRR), surface roughness and surface flatness of lapping SiC single crystal substrate (0001) C surface are studied using fixed abrasive lapping. Compared with the results of the free abrasive lapping, the surface flatness of SiC single crystal substrate (0001) C surface after lapping with the fixed abrasive lapping is better than that of the free abrasive lapping, the MRR of lapping with the fixed abrasive lapping platen is higher than that of the free abrasive lapping and the surface roughness (Ra) of lapping with the fixed abrasive lapping is lower than that of the free abrasive lapping. The study results show that there are some scratches on the sample surface after lapping with the fixed abrasive lapping. There are some hills and pits on the sample surface after lapping with the free abrasive, but without scratches. The height difference of the surface profile lapping with the free abrasive is much larger than that of fixed abrasive lapping. The research results can provide a reference for studying the fixed abrasive lapping platen, the lapping process and lapping mechanism.

Abstract: The tribo-electrochemical performance of polycrystalline silicon was studied by Tafel polarization curves and electrochemical impedance spectroscopy (EIS), based on which the electrochemical mechanical planarization (ECMP) simulating test was done to investigate the effects of applied potentials on friction and material removal rate (MRR) with an ECMP simulating tester. According to the research, a suitable anode polarization potential is advantageous to promote the forming of passivation film with better corrosion inhibition in alkaline CeO₂ polishing liquid, and forming of passivation film on silicon surface can increase both the friction between polishing pad and specimen and the MRR of silicon. This result provides theoretical supports and experimental bases for ECMP of silicon wafer to increase its polishing efficiency.