Grinding Characteristics Research Articles

An Experimental Investigation on the Characteristics of Cylindrical Plunge Dry Grinding with Structured cBN Wheels

This paper proposes a new innovative concept approaching the optimum cylindrical plunge dry grinding. The concept is based on the individual dressing operation in order to create designed structures on the grinding wheel surface. Cylindrical plunge dry grinding experiments have been carried out by employing both structured wheels and normal wheels. The results show that dry grinding with the structured wheel leads to lower grinding forces, area-specific grinding energy, and thermal damages to the workpiece as compared to the case of grinding with the normal wheel. The relatively higher surface roughness values, although, were resulted in the case of applying the structured wheel, they may be lowered by an additional spark-out pass to the values obtained with using the normal wheel.

The Characteristics of Mechanical Grinding on Kaolinite Structure and Thermal Behavior

The relationship between kaolinite structure and the temperature of thermal transformation of phase was discussed in this paper through grinding and heating treatment. The results show that the structure of kaolinite is destroyed rapidly with increasing mechanical grinding time, and the kaolinite structure collapses completely after 1h grinding. The temperature of thermal transformation of phase decreases with the destruction of kaolinite structure. This result has a great significance for the utilization of kaolinite associated with coal measures in China.

502 ステレオ視法による砥石砥粒形状の3次元計測(OS7-1 オーガナイズドセッション《精密/微細加工と評価》)

Abrasive grain shape and its distribution in the grinding wheel have an influence on the grinding characteristic of the wheel. Therefore, we aim to develop the 3D measurement system for abrasive grain shape and its distribution in the grinding wheel by binocular stereopsis. In this paper, 3D measurement of sample object is carried out to investigate the capability of the proposed measurement method. From the comparison between the 3D shape by proposed method and laser microscope, we confirmed the capability of this proposed method.

横型ビーズミルによる炭酸カルシウムの粉砕性能の評価

横型ビーズミルによる炭酸カルシウムの粉砕性能の評価

E22 スパイラル超音波援用研削によるサファイアの基礎加工特性(OS7 研削・砥粒加工(1))

E22 スパイラル超音波援用研削によるサファイアの基礎加工特性(OS7 研削・砥粒加工(1))

Grinding characteristics of a nickel-based alloy using vitrified CBN wheels

An experimental study is reported on the grinding of a nickel-based alloy using vitrified CBN wheels. This work was motivated by switching the grinding of fir-tree root forms of jet engine blades from creep-feed grinding with conventional abrasive wheels to vitrified CBN wheels. The objective is to explore process limits and practical grinding parameters for judging the switch in terms of overall costs and productivity. Straight surface grinding experiments were conducted with water-based fluid on rectangular blocks at a fixed wheel speed vs = 45 m/s, various depths of cut a = 0.05–1.0 mm, and workspeeds vw = 2–40 mm/s. Grinding and dressing power, forces, surface roughness, and radial wheel wear were measured. Specific material removal rate of 8 mm3/(mm.s) was reached in rough grinding using a wheel dressed for achieving surface roughness Ra = 0.8 μm in finish grinding. It was found that shallow depths of cut combined with fast workspeeds, or less creep-feed modes, are more suitable for achieving high material removal rates with vitrified CBN grinding. Rough grinding is restricted by high grinding temperatures with newly dressed wheels and by chatters with worn wheels.

509 導電性ラバーボンド砥石による軟質材料の加工特性(OS7-3 オーガナイズドセッション《精密/微細加工と評価》)

509 導電性ラバーボンド砥石による軟質材料の加工特性(OS7-3 オーガナイズドセッション《精密/微細加工と評価》)

Study on the Simulation Model and Characteristics of High-Speed Grinding for Ceramics

Engineering ceramic machining would bring out several kinds of surface damage owing to its hard and brittle nature. In this paper, a simulation model of single-grit grinding for silicon carbide (Sic) was established to explore the high-speed grinding mechanism. The material behavior was described with the Johnson-Holmquist Ⅱ (JH-2) model. According to the simulation experiment results, the optimal grinding parameters to achieve ductile grinding for Sic has been analyzed, which would provide theoretical basis and take surface damage under control.

Simultaneous Optimization of Multiple Quality Characteristics in Electrical Discharge Diamond Cut-Off Grinding (EDDCG)

This paper presents the simultaneous optimization of multiple quality characteristics (Material removal rate and Average surface roughness) using Taguchi method for electrical discharge diamond cut-off grinding (EDDCG) during machining of cemented carbides material. The experiments are carried out on a self-developed electrical discharge diamond grinding setup in cut-off mode, In the present work four input parameters ( current, pulse on-time, duty factor and wheel RPM ) were selected in which each parameter was at three levels. The total degree of freedom (dof) has been calculated without considering the effects of interaction among the different control factors. Based on design of experiments (DOE), a standard L9 orthogonal array (OA) was taken for experimentation. The result shows the considerable improvement of 13.999dB in multiple S/N ratio as compared to initial condition. Also, the comparison of results from single and multi-objective optimization has been presented.

Comparing the performance of neural networks developed by using Levenberg–Marquardt and Quasi-Newton with the gradient descent algorithm for modelling a multiple response grinding process

Monitoring and control of multiple process quality characteristics (responses) in grinding plays a critical role in precision parts manufacturing industries. Precise and accurate mathematical modelling of multiple response process behaviour holds the key for a better quality product with minimum variability in the process. Artificial neural network (ANN)-based nonlinear grinding process model using backpropagation weight adjustment algorithm (BPNN) is used extensively by researchers and practitioners. However, suitability and systematic approach to implement Levenberg–Marquardt (L–M) and Boyden, Fletcher, Goldfarb and Shanno (BFGS) update Quasi-Newton (Q-N) algorithm for modelling and control of grinding process is seldom explored. This paper provides L–M and BFGS algorithm-based BPNN models for grinding process, and verified their effectiveness by using a real life industrial situation. Based on the real life data, the performance of L–M and BFGS update Q-N are compared with an adaptive learning (A-L) and gradient descent algorithm-based BPNN model. The results clearly indicate that L–M and BFGS-based networks converge faster and can predict the nonlinear behaviour of multiple response grinding process with same level of accuracy as A-L based network.

Research of High Efficiency Combined Wire Electrochemical Machining Technology and its Application

In view of major problems for the current metal cutting technology, a combined sand coated wire electrochemical machining technology is introduced. This method uses porous silicon carbide coated in metal wire electrode for grinding and electrolytic machining, which has both wire electrolytic and sand wire grinding characteristics, and greatly improves the cutting efficiency. The composite wire electrochemical cutting technology principle is analyzed. The method for determining the main process parameters is presented, and the effectiveness of its application in thin-walled metal pipe cutting is validated.

Analysis of Specific Energy of TC18 and TA19 Titanium Alloys in Surface Grinding

As two kinds of advanced titanium alloys, TC18 and TA19 were introduced in this paper. The machinabilities of TC18 and TA19 alloys were described in the grinding process. Grinding experiments were completed using green silicon carbide grinding wheel with the coarser 100 grit. Grinding forces and specific energy in surface grinding were investigated. And then, for studying the grinding characteristic, SEM images of the workpiece material were obtained. The results indicated that specific chip formation had the great effect on the mechanism of grinding TC18 and TA19 alloys, and the scratch was the main characteristic of surface grinding. TC18 alloy had the poor grinding performance compared to TA19 alloy.

The Experimental Study on Characteristics of Low-Temperature Grinding of Ceramic Hollow Ball Super-Hard Composite Abrasive

Ceramic hollow ball Super hard composite abrasive has spherical hollow Mini-bore structure, This article introduced the structure of hollow spherical super hard abrasive, grinding model and the experimental investigations were conducted, It is found that the grinding wheel with hollow ball Super hard composite abrasive has more holes in the working layer of grinding wheel and can carrying more cooling fluid into the grinding area for heat exchanges, thus reducing the grinding temperature.

Research on Micro-Grinding Method and Surface Quality

Grinding characteristics brought by the grinding speed reduction and geometrical model differences between micro-grinding and conventional grinding have been mainly researched. Influences which micro-grinding parameter and micro-grinding tool dimension parameter giving to grinding surface quality have been analyzed. The comparison experiment between micro-grinding and micro-milling has been carried out on the micro-machining test-bed developed by Northeast University. Wear of the grinding pin obtained from experiment is considered to provide the basis for the micro-machining system and fabricating of grinding pins.

Improvement of grinding characteristics of Indian coal by microwave pre-treatment

The influence of microwave pretreatment on the grindability of high-ash Indian coal was investigated. Scanning electron microscope analysis characterized the micro fractures in microwave treated coal samples, which may be due to the thermal stress cracking resulting from the microwave pretreatment. X-ray diffraction analysis showed that the microwave treated coal had a higher peak compared to the untreated coal indicates that the crystallinity increased with the microwave exposure time. The calculation of the Hardgrove grindability index indicated an increase in the ease of grinding or an increase in the grindability index of the microwave treated coal. Bond grindability tests showed that the work index decreased 15.4% after a microwave exposure time of 120 s. Grindability tests showed that the microwave treated coal ground much more rapidly initially than the untreated coal, with the specific rate of breakage (S 1) increasing by an average of 15%. The results showed that the rates of breakage of both microwave untreated and treated coal samples were dependent on particle size.

Study on the Simulation Model and High-Speed Characteristics of Cylindrical Grinding

The existing research shows that high-speed grinding is the main way to machining the common materials and difficult-to-machine materials efficiently and critically. However, the research on mechanism and high-speed characteristics of high-speed cylindrical grinding is few searched. Based on three-dimensional simulation software DEFORM-3D, the simulation model of high speed cylindrical grinding with single grit was established, and the relevant experiment of 3D simulation for high speed cylindrical grinding process was processed. In this paper, the impact of the grinding parameters, such as wheel speed and depth of cut on the grinding force and grinding temperature is explored through analyzing the variation of strain rate, grinding force and temperature, and found that the increasing strain rate can lead to the increase in grinding force and temperature. According to the simulation experiment results, the control model of grinding temperature for prediction of grinding temperature and optimization of grinding parameters, is analyzed and developed in the end. The engineering experiment, conducted on the high speed cylindrical grinder and measured grinding temperature with thermal infrared imager, has been carried out in this study. Engineering and simulation experiments results show good match, for grinding temperature would decline with the increasing wheel speed when the grinding depth keeps constant, and thus can reduce grinding burn, improve the surface quality of workpiece.

Wet grinding characteristics of soybean for soymilk extraction

Wet grinding of hydrated soybean was carried out with mixer grinder, stone grinder and colloid mill which revealed that particle size had a profound effect on the protein recovery in the extracted milk with a maximum recovery of 89.3%. Greater reduction in particle size was achieved with mixer grinder (180 μm) with 5 min of grinding while reduction was not significant beyond 18 min (233 μm) in stone grinder. Specific energy consumption in colloid mill was only one-fourth of the mixer grinder while stone grinder required twice the energy. Although Kick’s, Rittinger’s and Bond’s laws could not be applied for total grinding duration, all the three classical laws were found suitable after the initial grain break-up period (2 min). Temperature and duration of thermal treatment given during hot extraction influenced protein recovery and viscosity of soymilk. The results suggest that colloid mill is a potential device for industrial scale operation.

Dynamic Analysis of a High-Speed Grinding Spindle

This paper presents the effects of spindle system configuration on the dynamic and static characteristics of high speed grinding. A 3D physical mode of high-speed grinding motorized spindle system with rotation speed of 150m/s was provided. The motorized spindle system consists of bearings, rotor, stator, spindle housing and grinding wheel. Based on the finite element method (FEM), the static characteristics, dynamic and the transient response are analyzed based on the finite element analysis software NASTRAN. It is shown that the spindle overhanging, bearing span have a significant effort on spindle deflection. The dynamic analysis shows no resonance will happen during its speed range. The methods and solutions for the motorized spindle system design and engineering applications was given in this paper.

Research on Grinding Characteristics of Ultrasonic Aided Grinding

Experimental study of radial ultrasonic vibration aided grinding of sintered Nd-Fe-B permanent magnetic material was conducted contrasted with traditional grinding. The effect on normal grinding force of grinding parameters was analyzed respectively in the two grinding processes. Experimental results indicate that the discontinuous grinding mechanism caused by ultrasonic vibration is the main factor that reducing the normal grinding force. The process of radial ultrasonic vibration aided grinding is especially suitable for shape machining of sintered Nd-Fe-B permanent magnet.

The Experimental Study on Grinding Properties of Gas Quenching Steel Slag

A gas quenching process to deal with steel slag and its characteristics of the new technology was briefly introduced. The grinding characteristics, mineral phases of gas quenching steel slag and the potential economic benefits of using it as cement mixing material was studied by compared to heat-stew steel slag. The results indicated that the specific surface areas (S) and grinding times (t) of the gas quenching steel slag showed a first order exponential decay relationship. With the extension of time, the specific surface areas of heat-stew steel slag was tending to balance earlier than that of gas quenching steel slag; The energy consumption of gas quenching steel slag was much lower than that of heat-stew steel slag. Gas quenching steel slag was comprised of C2S, C3S, a certain amount of (Ca2(Al, Fe)2O5）and RO phase, but the content of RO phase was relatively low, which increased the grindability of the quenching steel slag, so that the grindability of gas quenching steel slag was much better than that of heat-stew steel slag. Gas quenching steel slag prepared for cement addictives would bring great economic benefits.