Papers by Keyword: Ultrasonic Lapping

Abstract: Lapping is widely applied to hole surface finishing. However, for small holes of high hardness material, low efficiency and unstable hole surface quality of traditional lapping cannot be ignored. In this paper, the ultrasonic transducer and horn–tool were designed by the analytical method and the finite element method (FEM). An equipment of ultrasonic lapping for small holes was developed. Vibration performance tests of developed equipment were conducted by using microscope and laser displacement sensor. The result showed that the amplitude of ultrasonic lapping equipment can meet manufacturing demand. The machining performance of the developed ultrasonic lapping equipment was also investigated by comparing the surface quality and material removal rate with traditional lapping. The result showed that the higher material removal rate and better hole surface quality can be obtained by ultrasonic lapping.

Abstract: Ultrasonic lapping can effectively improve machining efficiency and obtain higher machining precision, which can be as the final process. This paper discusses the ultrasonic lapping mechanism through simulating the lapping tracks. Based on the contrast experiments between common and ultrasonic lapping, the influence of different lapping parameters on material removal rate and surface roughness were studied and the surface microstructure of workpiece was analyzed. The experimental results show that material removal rate of ultrasonic lapping is nearly two times that of the common lapping, especially in ultrasonic axial lapping, and the better surface quality can be obtained during ultrasonic lapping. Meanwhile, the reasons for material removal rate increasing and surface quality improving were analyzed.

Abstract: Hard brittle materials have been popular used in manufacture experience because of the excellent performances. However the low plasticity, frangibility and non-conduction make the machining very difficult. Therefore, ultrasonic vibration was introduced to common lapping for the purpose of higher removal rate and fine surface quality. The acoustic model of ultrasonic lapping was proposed, the track equations of ultrasonic lapping with different vibration modes were deduced, the influencing factors of lapping tracks were obtained, and the lapping tracks with different lapping parameters had been emulated. It can be concluded that ultrasonic lapping is a high efficient processing method adapting to ceramic materials.

Abstract: In order to resolve precision machining problem for SiC single crystal, a new ultrasonic lapping method is proposed. According to the brittle and hardness character of SiC single crystal, the principle of ultrasonic lapping is firstly introduced, and then parameters of experimental for ultrasonic lapping, such as wheel speed, grit size, vibration amplitude, frequency are given. Lastly, experimental result is analyzed by comparing ultrasonic lapping process with the conventional lapping process in the MRR and surface quality.

Abstract: Based on non-smooth impact theory, the dynamic model of spiral bevel gear is constructed by considering of input shaft angle excitation. The Maximal Lyapunov Exponents (MLEs) curves for backlash 0.10mm and 0.14mm caused by exciting amplitude are given. The simulation results indicate that gear backlash, excited amplitude and retard torque have influence on the dynamics behavior of spiral bevel gear system. The experiments show that the vibration noise is deduced after ultrasonic gear lapping.

Abstract: Surface phase structure has an important effect on the surface machining quality. The surface phase transition characteristics of ZrO2 and ZTA ceramics under different machining methods were tested by X-ray diffraction in the paper. Through the qualitative and quantitative phase analyses, the influences of several different precision machining methods on the phase transitions in the machined surface were studied. Research results show that there are more transitions from tetragonal phase ZrO2 to monoclinic phase ZrO2 in the high speed grinding surface; because of the high-frequency vibration of lapping tool in ultrasonic lapping, the stress condition in the grinding area can be improved and the stable tetragonal phase ZrO2 in the ultrasonic lapped surface is easy to get. The research conclusions have important significance on analyzing the surface residual stress and improving the surface machining quality of engineering ceramics.

Abstract: Lower machining efficiency of traditional lapping with free abrasive restricts the enhancement of the precision parts’ production efficiency. It is necessary to improve lapping efficiency on the premise of guarantee of lapping quality. In this paper, a new ultrasonic aided lapping technology was developed by combining lapping technology and ultrasonic machining technology and a series of lapping experiments of ZTA engineering ceramic with and without ultrasonic assistance were carried out. The results of theoretical analysis and experimental study show that it is the ultrasonic assistance of the lapping tool that promotes the enhancement of lapping efficiency and the ultrasonic aided lapping technique with fixed abrasive can be regarded as a high efficiency processing method of the precision engineering ceramic part.

Abstract: Aimed at the precision machining characteristics of nano ZTA engineering ceramics external cylindrical components, ultrasonic aided lapping experiments were carried out adopting inhouse developed ultrasonic external cylindrical lapping device with solid abrasive material. To obtain minimum surface roughness with constraint of the material removal rate, response surface methodology (RSM) was adopted to analyze the experimental data, and suitable experiment design was chosen to fit the response surface in this research. Second-order surface response models of surface roughness and material removal rate were developed respectively, and the influence laws of lapping parameters on surface roughness and material removal rate were clarified according to the built models. Finally, parameters optimization of the ultrasonic external cylindrical lapping process for nano ZTA engineering ceramics was realized using surface response methodology.

Abstract: Ultrasonic aided high speed lapping with solid abrasive material was put forward aimed at the precision finishing of nano ZTA engineering ceramic. Through theoretical analysis and contrast lapping experiments, the influences of ultrasonic assistance on the surface machining quality were clarified. Research results show that the maximum undeformed chip thickness in ultrasonic aided lapping is smaller than that in conventional lapping under the same conditions; ultrasonic assistance is beneficial to enlarging the range of ductile lapping regime and improving the surface quality of nano ZTA ceramic; with the application of ultrasonic vibration, smaller surface roughness and more regular surface profile can be obtained.

Abstract: Experimental researches on material removal rate and surface roughness of Al2O3 engineering ceramic guide-pulley lapping were carried out using W20 and W5 fixed oilstones by self-developed ultrasonic lapping tool both with and without ultrasonic assistance. Experimental results show that lapping speed, lapping pressure and grain size produce different effects on the lapped surface roughness and material removal rate. The material removal rate in ultrasonic lapping process is two times as large as that in traditional lapping, and the ground surface roughness is superior to that in common machining method. The material removal rate increases along with the average diameter of grains and the lapping speed both in ultrasonic lapping and traditional lapping. In traditional lapping process the material removal rate becomes bigger along with the lapping force, while in ultrasonic lapping it gets the optimal value with the lapping force 450N. The value of lapped surface roughness increases along with the lapping speed in traditional lapping, on the contrary it decreases contrast to the lapping speed until 250rpm in the ultrasonic lapping. The value of traditionally lapped surface roughness decreases contrast to the lapping force, whereas it achieves the minimum with the lapping force 450N with ultrasonic assistance.