Advanced Materials Research Vol. 1136

Abstract: Inconel 718 has high yield strength, corrosion resistance, heat resistance and fatigue resistance, and possesses a lower thermal conductivity, leading to high grinding force and heavy wheel damage in grinding of this material. Against these problems, ultrasonic assisted grinding (UAG) can be the potential candidate for high efficiency processing of Inconel 718. The current work is, hence, to clarify the fundamental UAG characteristics of Inconel 718 by experimentally investigating the effect of vibration amplitude on grinding force, actual material removal and work-surface roughness under different process parameters such as the wheel rotational speed, wheel depth of cut and vibration amplitude. Summarizing the obtained results revealed that the grinding forces and the actual material removal in UAG are significantly smaller and larger, respectively, than those in conventional grinding. It is also found that ultrasonic vibration can improve the work-surface finish even at deep wheel depth of cut.

Abstract: The machining technology of ultrasonic assisted ductile mode grinding for the silicon carbide (SiC) wafer carrier. The machining tool is designed and analyzed by ANASYS 14.0 and the machining technology is studied for the 6-inch SiC wafer carrier. The ultrasonic tool holder with the resonance frequency 26 kHz is designed and fabricated. The advantageous machining parameters are proposed that spindle rotation rate is 3000 rpm, feed speed is 200 mm/min, and ultrasonic output power is 250 W. The measurement results show that the average roughness (Ra) of the SiC is 0.18 μm, the MRR is over 2.4 mm³/min, the tool tips are only minor abrasion, and the cutting temperature are reduced. Obvious, the machining technology has the advantage of high surface quality, high machining efficiency and long tool life.

Abstract: This study describes the effects of machining parameters on the thermal affected zone (heat-affected zone; HAZ) of carbon fiber reinforced plastic using fiber laser. The HAZ described in this study was defined as the area where only resin was removed. In three experiments, the HAZ area and the removal shape of carbon fiber were investigated. The study revealed that pulsed laser reduces the HAZ more than continuous-wave laser does, but it causes the swelling of the carbon fiber tip. Furthermore, the HAZ decreased as the scan speed increased, even if the number of scans was increased. In addition, it was found that nitrogen could restrain the HAZ and the swelling of carbon fiber.

Abstract: Whirling electrical discharge texturing (WEDT) was developed to process microstructures on the inner surface of cylindrical parts made of high hardness materials. However, the minimum processable diameter of the cylindrical parts was φ 5 mm and the equipment could not feed the new tool electrodes. Therefore, the authors devised a novel method of WEDT using a straight wire tool electrode for a cylindrical surfaces with a small diameter. It was confirmed that microstructures could be created on the inner surface of a cylinder of φ 1.1 mm diameter, and that the texture-area ratio could be controlled by the workpiece feed speed. Moreover, new EDT equipment with a feeding system for a wire tool electrode and a bending system for the tip of a wire tool electrode was developed. As a result, the equipment that can process microstructures on the inner surface of a cylinder with a small diameter and feed a wire tool electrode during texturing was successfully developed.

Abstract: Ultrasonic cutting is a technique that can improve machinability such as fine surface, reduce tool worn out and etc. To improve processing speed of ultrasonic cutting is difficult due to the effects of tool oscillation are invalidated when cutting speed exceeds maximum tool oscillating velocity. In this study, high speed principal direction ultrasonic turning experiments for soft magnetic stainless steel were carried out to investigate effects of cutting speed and products quality. Surface roughness, chip worn out and built up edge were investigated in this study. In case of ultrasonic turning, tool worn out and built up edge generation were reduced compare with ordinary turning. High speed ultrasonic cutting can improve cutting performances in phase of turned surface quality, cutting force and processing speed.

Abstract: Ultrasonic vibration improved the machining performance of a variety of brittle materials, and achieved good results in brittle materials machining applications. In this paper, the experiment about precision sawing engineering ceramic by using a thin diamond blade with and without ultrasonic vibration conditions was investigated. It is aimed to explore the effect of ultrasonic vibration on specific energy. The results show that ultrasonic vibration makes specific sawing energy having a significant reduction during material removal process. Under the ultrasonic vibration condition, the engineering ceramic’s materials removal way is changed. It changed from plastic removal to the removal of brittle fracture, which reduced the energy consumption of material removal.

Abstract: Abrasive waterjet machining is considered as a promising technique in hard-brittle material polishing. In this paper, The ultrasonic torsional vibration is considered to apply on the workpiece to improve the abrasive waterjet polishing quality and efficiency. The process parameters in the ultrasonic torsional vibration-assisted abrasive waterjet polishing are optimized. The ultrasonic torsional vibration in the role of the abrasive waterjet polishing is investigated. The results show that the application of ultrasonic torsional vibration can effect of abrasive particle movement and increase the critical depth of the ceramic materials.

Abstract: The purpose of the paper is to investigate the influence of the processing parameters on the surface roughness in rotary ultrasonic burnishing of titanium alloy Ti-6Al-4V plane. A Taguchi orthogonal array for three levels and four factors, which include burnishing depth, feed fate, spindle speed and ultrasonic frequency, are designed. The optimal combination of ultrasonic burnishing process parameters is obtained. Analysis of variance (ANOVA) is applied to determine the most significant processing parameter and to obtain the optimal combination level of processing parameters for the lowest surface roughness. The results show that burnishing depth has the most predominant effect on surface roughness, and spindle speed is the secondary one. Feed rate and ultrasonic frequency are then followed and have no distinct effect on surface roughness in rotary burnishing of Ti-6Al-4V.

Abstract: Metal bonded diamond grinding wheels are very important for precision grinding operations of hard and brittle materials especially like ceramics or cemented carbides. But the trueing and dressing problem has affected its wide use. In this paper, a new EDD (Electrical discharge dressing) device was developed for the dressing of metal bonded diamond arc grinding wheels. The EDD experiments were carried out with the new dressing device. The influence of dressing parameters on the dressing efficiency and precision was studied. Experimental results shown that the increase of pulse period and duty period helped improve the dressing efficiency in a certain range. The higher electrical parameters could get better dressing efficiency. The detection results revealed that the error of the arc profile after EDD could reach to around 3μm. mazhaokai2014

Abstract: For the purpose of improving the electric discharge machinability of PCD, the authors have proposed a method using an electrode made of a specific transition metal which is easy to react with diamond. As a result, Ti, Nb, Ta, Mo, and W among various reactive metals brought very high efficiency, higher than 3 times of existing electrode materials (Cu, CuW) in the EDM of PCD. It was thought that the higher removal efficiency was due to the material properties such as mixing enthalpy between transition metal atom and carbon atom and a crystal structure of body centered cubic (bcc) lattice.