Vibration Grinding Research Articles

Study on Grinding Force of High Volume Fraction SiCp/Al Composites with Rotary Ultrasonic Vibration Grinding

High volume fraction SiCp/Al composites were grinded in rotary ultrasonic vibration aided grinding in this experiment, exploring the effects of different grinding parameters (grinding depth, grinding wheel speed, feed rate) on grinding force and the material removal mechanism with ultrasonic grinding. The results showed that grinding force of ultrasonic grinding is lower than the ordinary grinding in the same grinding parameters. Studying on material removal mechanism of ultrasonic vibration grinding is bound to have important theoretical and practical significance for the improvement of grinding processes and the development of mechanical according to the advantages of grinding and ultrasonic machining. Keywords: High volume fraction SiCp/Al composites; ultrasonic grinding; grinding force

Research on Ceramics Crack Propagation under the Ultrasonic Vibration Grinding Based on the Nonlocal Theory

This paper researched the crack propagation and the variation of microstructure for ZTA ceramics under ultrasonic vibration grinding. To interpret the phenomenon, the nonlocal theory was introduced to establish the constitutive model under the ultrasonic vibration. Grinding experiments on surface quality of nanoZrO2 ceramic are carried out using diamond grinding in different condition, both with and without ultrasonic vibration. Experimental results show the surface quality after two-dimensional ultrasonic assisted grinding is superior to that after common grinding. Meanwhile, the effects of amplitudes and frequencies on ZrO2 ceramics crack propagation were analyzed by SEM. The results show that the crack propagation rate decrease with the amplitudes and frequencies increasing, this is because that the nonlocal attenuation ratio reduced and the nonlocal effects also the strongest. The results of experiments are in accordance with the theoretical conclusions drawn from the nonlocal theory, which verifies that the act ion of ultrasonic vibration can actually postpone the ceramic crack propagation rate.

A Processing Predictive Model of Ultrasonic Vibration Grinding Assisted Electric Discharge Machining Based on Support Vector Machines

To predict the machining results of ultrasonic vibration grinding assisted electric discharge machining (UVGAEDM) in the condition of building predictive model with a few samples but fluctuant values, a predictive model based on SVM was proposed in this paper. Taking machining SiCp/Al as an example, the samples for modeling were obtained through orthogonal test, and then the predictive model was established utilizing MATLAB. Finally, the model was optimized to further improve the prediction accuracy about the processing indicatorssurface roughness and processing velocity. It shows that the predictive results are in good accord with the test results, with the maximum relative error being less than 12%, meaning the predictive model is reliable and effective.

Preparation of a Novel Cementitious Material from Hydrothermally Synthesized C–S–H Phases

New cementitious materials based on calcium hydrosilicate hydrates were recently developed as potential substitutes for ordinary portland cement, but with a reduced CO2 footprint. The materials are produced by hydrothermal processing of SiO2 and Ca(OH)2, giving rise to calcium silicate hydrates, followed by mechanical activation of the latter via cogrinding with various siliceous materials. Thus, the chemical composition in terms of C/S ratio could be adjusted over a broad range (1–3). In this study the synthesis of a previously unknown cementitious material produced via the combination of mechanical activation in a laboratory mill and thermal treatment of a mixture of quartz and hydrothermally synthesized calcium silicate hydrates: α‐Ca2[HSiO4](OH) (α‐C2SH) and Ca6[Si2O7](OH)6 (jaffeite) are reported. It forms independently of the type of mill used (eccentric vibrating mill, vibration grinding mill) after thermal treatment of the ground materials at 360°C–420°C. The new material is X‐ray amorphous and possesses a CaO/SiO2 ratio of 2. A characteristic feature in regards to the silicate anionic structure is the increased silicate polymerization (up to 27% Si2O7 dimers) as revealed by the trimethylsilylation method. Infrared (IR) spectra show a very broad absorption band centered at about 935 cm−1. Another characteristic feature is the presence of ~2.5 wt% H2O as shown by thermogravimetry (TG) coupled with IR spectroscopy. As this water is bound mostly as hydroxyl to Ca, we refer to this new cementitious material as calcium‐oxide–hydroxide–silicate (C–CH–S). Calorimetric measurements point to a very high hydraulic reactivity which is beyond that for typical C2S materials. The influence of the type of grinding on the thermal behavior of α‐C2SH upon its transformation into water‐free Ca2SiO4 modifications is discussed.

Study on Effects of Ultrasonic Vibration on Grinding Force

The mathematical models of the dynamic grinding force and the average grinding force were established by introducing the unit grinding force Fu. And the formula of the average grinding force in the grinding zone was derived. The experiments were conducted in the traditional grinding (TG) mode and tangential ultrasonic vibration grinding (TUAG) mode. The results show that the unit grinding force in TUAG is lower than that in TG in the same machining condition; the grinding force ratio is decreased due to the tangential ultrasonic vibration of the workpiece. It is helpful to improve the machinablity of the hard-brittle material.

Sustainability Indicators for Finishing Operations based on Process Performance and Part Quality

Production engineers need to focus increasingly on the sustainability of manufacturing processes. Unfortunately, there are a confusingly high number of sustainability indicators available and they mostly focus on energy and material efficiency. These indicators are, however, not all appropriate for finishing operations. For example, many efficiency indicators relate to the material volume processed, but since the volume is very small in finishing operations, the material removal rarely is the best indicator. This paper discusses more appropriate efficiency indicators for finishing operations which are calculated as ratio of change in process performance or part quality divided by the needed resources. Three efficiency indicators based on average roughness, average peak-to-valley height and subjective part quality are then used in a case study on vibratory grinding. This study provides a starting point to apply more diverse performance and quality-oriented indicators for finishing processes.

Synthetic Topographical Characterization Analysis of Oxygen Free Copper Surface Prepared by UVG on the Basis of Wavelet

To study the synthetic topographical characterization of oxygen free copper surface created by ultrasonic vibration grinding(UVG) and carry out a detailed research to indicate the removal mechanisms of ultrasonic vibration grinding and its technological process of surface creating, this paper researches the surface signals obtained by contact profiler and utilizes a new wavelet based method. Through wavelet decomposition and re-construction of surface signal, surface features, such as form error, waviness and roughness are separated rationally. Synthetic topographical characterization of oxygen free copper surface prepared by ultrasonic vibration grinding has been summarized in detail.

Detent Force Analysis of Permanent Magnet Linear Synchronous Motor for Bearing Grinding Machine Application

The detent force of permanent magnet linear synchronous motor (PMLSM) leads to the thrust ripple, vibration and noise inbearing grinding machines, In order to overcome the negative effect, detent force needs to be decreased. Through theanalytical andfinite element methods, two main components of detent force are investigated in this paper. Firstly, finite element analysis (FEA) and fast Fourier transform (FFT) are employed to analyze the end force. Then athree dimensional (3-D) FEA model of a short secondary PMLSM with skewed poles is erected and the cogging force is studied.Compared with the two dimensional (2-D) model of PMLSM without skewed poles, the detent force is remarkably reduced.

Experimental Investigations of Grinding Forces in Elliptical Ultrasonic Assisted Grinding (EUAG) of Monocrystal Sapphire

Grinding forces characteristics in elliptical ultrasonic assisted grinding (EUAG) of sapphire are investigated experimentally. The EUAG is a new grinding method proposed by the present authors in which an elliptical ultrasonic vibration is imposed on the workpiece by using an elliptical ultrasonic vibrator. In this paper, grinding experiments under the presence/absence of ultrasonic vibration assistance are performed. The effects of the vibration amplitude and grinding parameters such as the depth of cut, the grinding wheel speed on the grinding forces, grinding force ratioFn/Ftare clarified. The obtained conclusions are as follows: the grinding forces during EUAG lowers to 50% and grinding forces ratio becomes reduced by 33% compared that during conventional grinding (CG); the grinding forces during EUAG have the less variation rate than those during CG as grinding parameters change; higher grinding wheel speed causes the larger grinding forces in CG, but has little effect on the variation of grinding forces in EUAG. By using EUAG method, the grinding forces and force ratio are greatly decreased, and surface quality is better, meaning that grindability of sapphire material is improved.

Establishment of the Prediction Model for Ferrite Surface Roughness in Ultrasonic Vibration Grinding

In this paper, the author performed orthogonal tests of ultrasonic vibration grinding on ferrite in the DMG machining center, and established a prediction model of ferrite surface roughness in ultrasonic vibration grinding with multiple linear regression analysis method based on the test results, and carried out significance tests on regression equation and regression coefficient, showing that the prediction model had high credibility, the effect of spindle speed and amplitude of ultrasonic vibration on surface roughness was significant, but of grinding depth and feed rate was not obvious.

Study on the Surface Quality of Silicon Nitride Ceramics in Ultrasonic Vibration Grinding

The conventional machining method for silicon nitride ceramics has low machining efficiency, prone to cracking, chipping and other defects. In this paper, the author carried out a study on the influence of ultrasonic vibration grinding on surface quality of silicon nitride ceramic, and carried out ultrasonic vibration grinding process test for silicon nitride ceramic and conducted the analysis of influence of this machining process on surface quality with orthogonal test. The test results showed that the influence on surface roughness decreased in the order of spindle speed, feed rate, cutting depth, and amplitude of vibration.

Effects of Ultrasonic Frequencies on Grinding Force of Nano-Composite Ceramics Based on Nonlocal Theory

Based on nonlocal theory, The effects of ultrasonic frequencies on the grinding force and nonlocal decay rate are obtained through the experimental study of material properties under ultrasonic vibration grinding test. The results of experiments showed that grinding force is attenuated in the ultrasonic vibration frequency ranges and this attenuation phenomenon becomes more and more evident by the increase of the ultrasonic frequencies. Through analysis of the grinding surface morphology and phase structure, it showed that ultrasonic vibration greatly reduces the average grinding force, and the surface quality are improved, and that it is much easier to achieve ductile-mode machining under ultrasonic vibration. The results of experiments are in accordance with the analysis of nonlocal theory.

Optimized laser processing of calibration blocks for grinding burn detection with Barkhausen noise

Calibration samples for the Barkhausen noise (BN) method were produced with laser processing. A planet gear wheel used for production quality control was subjected to laser irradiation to verify the BN sensor output. Different samples were found to respond similarly to the laser processing although the laser parameters needed to be adjusted for different surface qualities separately. The surface optimization for laser processing was studied with different surface qualities of samples. The ground surface was compared with a sandblasted and vibratory ground surface. The ground and sandblasted surfaces were both amenable to the laser processing whereas the vibratory grinding process created inhomogeneous surfaces for laser beam absorption. Laser processing was found to produce uniform changes in the residual stress values in two perpendicular measuring directions. The root mean square value of the BN voltage signal exhibited linear correlations with the values of the residual stress and surface hardness.

Research on Surface Residual Stress of Nano-ZrO<SUB>2</SUB> Ceramic After Ultrasonic Vibration Grinding

Research on Surface Residual Stress of Nano-ZrO<SUB>2</SUB> Ceramic After Ultrasonic Vibration Grinding

Research on Surface Residual Stress of Nano-ZrO<SUB>2</SUB> Ceramic After Ultrasonic Vibration Grinding

Research on Surface Residual Stress of Nano-ZrO<SUB>2</SUB> Ceramic After Ultrasonic Vibration Grinding

Experimental characterization of binary and ternary blended-cement concretes containing ultrafine residual rice husk and sugar cane bagasse ashes

In the present work an experimental program was carried out to investigate the influence of residual sugar cane bagasse and rice husk ashes (SCBA and RHA, respectively) in the properties of concretes. SCBA and RHA were produced using vibratory grinding in dry open circuit and conventional and high-performance concretes were produced with 0% and 20% of both ashes as cement replacement (by mass). Ternary mixtures containing cement, SCBA and RHA (0.6–0.2–0.2) were also produced in order to study the benefits of the simultaneous use of both ultrafine ashes on concrete properties. Experiments were performed to investigate the rheology (yield stress and plastic viscosity), compressive strength (at 7, 28, 90, and 180days), Young’s modulus (at 28days) and rapid chloride-ion penetrability. The pore size distribution and adiabatic temperature rise of the reference and ternary mixtures were also evaluated. The joint influence of both ashes allowed reaching positive effects in rheology and kept constant or increased the compressive strength when compared to the reference mixtures. Moreover, the ternary concretes presented lower electric charges and the replacement of cement by 40% SCBA and RHA decreased significantly the maximum adiabatic temperature rise of conventional concrete.

Ultrasonic Characteristics of the Ultrasonic Grinding Process about the Nano-Ceramic Plate

In this paper, the sand vibration test of the ultrasonic wave is done under ultrasonic vibration grinding. In this test, the "skin effect"is observed when the ultrasonic waves pass to the nano-ceramic plate, which is amplified by the ultrasonic horn. This phenomenon is analyzed by the second-order surface wave theory and the waves which pass to the workpiece are surface waves generated. These explain the good grinding surface quality and high efficiency under the two-dimensional ultrasonic grinding in the same conditions.

Effect of Ultrasonic Vibration Grinding for Mechanical Properties of Al2O3/ZrO2 Ceramics

The effect of ultrasonic vibration grinding for mechanical properties of Al2O3/ZrO2 ceramics composite was studied in this work. The phase compositions and the microstructures of Al2O3/ZrO2 ceramics were investigated by XRD, SEM and TEM. Results indicated that the hardness and fracture toughness of Al2O3/ZrO2 ceramics could reach 1496Mpa and 9.44 MPa.m1/2 respectively, which increase 60% and 12% compared to that without ultrasonic vibration grinding.

Surface topography of fine-grained ZrO2 ceramic by two-dimensional ultrasonic vibration grinding

The surface quality of fine-grained ZrO2 engineering ceramic were researched using 270# diamond wheel both with and without work-piece two-dimension ultrasonic vibration grinding(WTDUVG). By AFM images, the surface topography and the micro structure of the two-dimensional ultrasonic vibration grinding ceramics were especially analyzed. The experimental results indicate that the surface roughness is related to grinding vibration mode and the material removal mechanism. Surface quality of WTDUVG is superior to that of conventional grinding, and it is easy for two-dimensional ultrasonic vibration grinding that material removal mechanism is ductile mode grinding.

Research on Vibration Grinding Finishing Technology

In mechanical manufacturing, the traditional methods adopted for finishing is not only high labor intensity, but also difficult to reach the surface roughness and requirements. The vibration grinding finishing process method is put forward, and the surface finishing experiments for spiral nozzle which is one of the important parts for aeroengine are carried. It can be seen from the experimental results that the vibration grinding process method can reach the finishing effect. Compared with the common grinding method, the vibration grinding has the features of high efficiency and high quality, etc. The vibration grinding new process method has high practical value.