Papers by Keyword: Ultrasonic Machining

Abstract: In this study, the potential to monitor the high-technology nailing of carbon fiber reinforced thermoplastic material (CFRTP) under ultrasonic vibration was investigated by acoustic emission (AE) method. AE signals were detected by a piezoelectric AE sensor during high-technology nailing under ultrasonic vibration. This paper describes some experimental results on AE signal characteristics and observation of the high-technology nailing. In order to investigate the effects of machining condition, we focused on RMS voltage, which is dependent on the energy parameter of the AE signal. It was found that the AE method is a useful method of monitoring high-technology nailing.

Abstract: Milling and drilling of titanium alloys represent a key technology for the aircraft manufacturers. The balancing act between production costs and tool costs leads to the need of tests and an optimized setup of the whole process. A Styrian consortium with experts in materials, tools and machining has been formed to extend the tool life in machining of titanium alloys. A series of tests is set up to evaluate the roughing and finishing operations. For finishing operations ultrasonic assisted milling is introduced and compared with conventional milling. Force measurement and optical wear detection are used for tool characterization.

Abstract: Ultrasonic excited fluid has been researched for machining of hard-to-grind materials. Ultrasonic vibration is applied to grinding fluid by an ultrasonic oscillating comb-shape effecter with integrated nozzle. Grinding fluid discharges from a nozzle placed between the comb’s feet and passes through the vacant space between comb teeth. By this setup, flowing grinding fluid can be continuously excited by ultrasonic vibration. Based on the principle of an ultrasonic washing machine, impulsive force caused by cavitation bubble will reduce the adhesion of chips on the cutting face of grain and chip pockets. Some effects of ultrasonic excited grinding fluid have been recorded such as reducing grinding heat in the case of grinding for Titanium alloy and decreasing in grinding force, improving surface roughness in the case of grinding for Aluminum and stainless alloy. However, the reason of better grinding performance is still unknown. Therefore, experiments conducted with different type of grinding fluids with and without ultrasonic vibration are needed. Pure Titanium, which considered a hard-to-cut material, is chosen as work material. Grinding forces and grinding heat during grinding will be measured and evaluated to clarify the mechanism of ultrasonic excited grinding fluid.

Abstract: WC-Co composite materials possess a vast range of industrial applications owing to their excellent properties such as superior hardness, toughness and dimensional stability. Present article has been targeted at investigating the impact of different experimental conditions (power rating, cobalt content, tool material, thickness of work piece, tool geometry, and abrasive grit size) on penetration rate in ultrasonic drilling of WC-Co composite material. Taguchi’s L-36 orthogonal array has been employed for conducting the experiments. Significant factors have been identified using analysis of variance (ANOVA) test. The experimental results revealed that power rating, abrasive grit size, and tool profile is most significant factor for penetration rate. From the microstructure analysis, the modes of material deformation have been observed and the parameters (i.e. work material properties, grit size, and power rating) were observed as the most crucial for the deformation mode.

Abstract: Ultrasonic machining is a contemporary manufacturing method usually employed for processing materials with higher hardness/brittleness such as quartz, semiconductor materials, ceramics etc. The machined surface produced by ultrasonic machining is found to be free from any surface defects (heat affected zone, cracks, recast layer, etc.) in contrast to the thermal based machining processes like; electric discharge machining, laser beam machining etc. In this article, a review has been reported on the fundamental principle of ultrasonic machining, effect of operating parameters on material removal rate, tool wear rate, surface roughness and hole quality. It also presents a brief review on micro-USM, rotary USM and hybrid methods with other processes.

Abstract: Knowing temperatures at the tool-chip interface is extremely important to optimize the machining condition and to improve the machining performance, furthermore to design high performance materials. In order to grasp the temperature distribution at the tool-chip interface, this study has devised an indexable insert with seven pairs of built-in micro Cu/Ni thermocouples on the rake face near the cutting edge. This paper shows the performance of the indexable insert with built-in micro thermocouples developed. The thickness of each element of the micro thermocouple is approximately 15 μm. The result of unsteady heat conduction analysis employing FEM shows that the temperature difference by installing the micro thermocouples is less than 10 K or 1.2 %. The temperature measurement experiments by cutting of aluminum alloy were carried out by changing the cutting speed. The results provided the evidence that the temperature distribution at the tool-chip interface can be grasped with the indexable insert with built-in micro thermocouples developed.

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: The material removal in ultrasonic machining (USM) is based on brittle fracturing of workpiece materials. The properties and fracture behavior are different for varied materials, and they would have an influence on the machining performance of USM. The smoothed particle hydrodynamics (SPH) method was used to simulate the USM process for different workpiece materials. Three typical hard and brittle materials, i.e. silicon carbide (SiC), alumina (Al₂O₃), and glass will be used as the workpiece materials. Experiments are also conducted for comparing with the simulation results. Through this study, the material fracturing processes for different work materials are shown visually using the SPH method, which is very useful for USM study.

Abstract: In this study, drilling for nickel alloy was carried out with ultrasonic vibrating carbide drill. Micro drilling is not an easy machining process due to remarkable tool wear, lower stiffness of the tool, difficulty of chip and heat removal from cutting point. Ultrasonic vibration assisted machining has effects of decrease of cutting force, generation of fragmented small chip, extension of tool life and improvement of surface integrity. In this study, ultrasonic vibration drilling for nickel super alloy was investigated to improve the tool life and productivity. The drilling for heat-resisting nickel super alloy was performed with the drill of 0.3mm in diameter. As a result, ultrasonic vibration drilling performed 302 holes with thickness of 2.0mm by applying minimum quantity lubrication to blow off the chips on the flutes. Ultrasonic vibration improved deviation of position of drilled hole because the hammering motion of the chisel edge results in good bite of tool on work surface. The productivity is directly depends on feed rate. The increasing feed rate from 6mm/min to 60mm/min dramatically reduced the tool life one thirtieth under conventional drilling condition. On the other hand, the ultrasonic vibration drilling reduced the tool life only one half.

Abstract: Ultrasonic machining is used for machining hard and brittle materials: semiconductors, glass, quartz, ceramics, silicon, germanium, ferrites etc. Titanium and its alloys are alternative for many engineering applications due to their superior properties such as chemical inertness, high tenacity, high specific strength, excellent corrosion resistance and oxidation resistance. In the present investigation, the effect of energy input rate on the surface topography has been evaluated, under controlled experimental conditions. It has been found that the mode of material removal may change from brittle fracture to ductile failure under extremely small energy input conditions. Moreover, a mixed mode with varied proportion of brittle fracture and plastic deformation could be obtained through systematic variation of the input parameters. In comparison to an electrical energy based method such as WEDM, the titanium components processed by USM does not exhibit any appreciable surface damage in the form of recast material, heat affected zone or residual stresses.