Research on Diamond Wheel’s Specialties during ELID Ulterprecision Grinding of Silicon Nitride

2011 ◽  
Vol 295-297 ◽  
pp. 51-55
Author(s):  
Wei Dong Jin
Keyword(s):  
Silicon Nitride ◽  
Surface Profile ◽  
Grinding Wheel ◽  
Cutting Depth ◽  
Insulator Layer ◽  
Silicon Nitride Ceramic ◽  
Workpiece Surface ◽  
Abrasive Grain ◽  
Materials Research ◽  
Hard And Brittle Materials

Taking ultraprecision grinding of silicon nitride ceramic as an example, this paper mostly introduces some influences of diamond wheel’s specialties on the grinding process and surface quality during ELID (electrolytic in-process dressing) grinding of hard and brittle materials. Research indicates that grain size and concentration of abrasive material should be reasonably selected based on the surface roughness. And Inhomogeneity of concentration distribution along wheel circumference will result in heterogeneity of insulator layer state, which will bring difference in the number of abrasive grain in the grinding area, thereby changing the actual cutting depth of every abrasive grain. Dynamic balancing of grinding wheel should be accurately adopted to reduce eccentric mass, furtherly to avoid generating waveness on the workpiece surface. For the purpose of reflecting rightly compositive effect from eccentricity of wheel shape, roundness of the wheel and periodical vibration derived from eccentric mass, actual radial runout of grinding wheel should be well and truly measured and controlled based on the wheel’s surface profile during wheel is rotating at working speed.

Study on Material Removal Mechanism of Silicon Nitride during ELID Ultraprecision Grinding

2011 ◽  
Vol 314-316 ◽  
pp. 1740-1745
Author(s):  
Wei Dong Jin
Keyword(s):  
Silicon Nitride ◽  
Material Removal ◽  
Dynamic Balance ◽  
Grinding Process ◽  
Silicon Nitride Ceramic ◽  
Elid Grinding ◽  
Hard And Brittle Materials ◽  
Plastic Shearing ◽  
Material Removal Mode ◽  
Passivating Films

Based on the analyzing ultraprecision grinding process of hard and brittle materials, taking ELID grinding of silicon nitride ceramic as an example, active control technology of passivating films state was introduced in this paper. ELID ultraprecision grinding process respectively at adaptive dynamic balance mode, discontinuous electrolyzing mode and discontinuous grinding mode had been comparatively studied. By means of AFM used for analyzing surface topography of parts, studies show that material removal method for ELID grinding is always a combination of micro brittle fracture, plastic shearing, lapping and polishing action, and which is the main material removal mode depends on the actual grinding contact state. Finally, finishing surface generating mechanism for silicon nitride in ELID ultraprecision grinding was summed up.

Experimental Research on High Speed Grinding of Silicon Nitride Ceramic Spindle

2016 ◽  
Vol 874 ◽  
pp. 253-258
Author(s):  
Ke Zhang ◽  
Jian Sun ◽  
He Wang ◽  
Yu Hou Wu
Keyword(s):  
Silicon Nitride ◽  
High Speed ◽  
Linear Velocity ◽  
Grinding Wheel ◽  
Feed Speed ◽  
Silicon Nitride Ceramic ◽  
Technical Parameters ◽  
Internal Grinding ◽  
Brittle Rupture ◽  
High Speed Grinding

Grinding is a main method of silicon nitride ceramic in finish machining stage. The technical parameters had an important influence on the surface quality of silicon nitride ceramic. The silicon nitride ceramic spindle was ground by the high-speed cylindrical grinder MGKS1432-H. The relations between different speed parameters and surface roughness were researched. The cylindrical and internal high speed grinding experiments of silicon nitride ceramics spindle were carried out. The S-4800 scanning electron microscope was used to explore the roughness change rule of the grinded surface under the condition of only changed grinding wheel’s velocity. In the process of cylindrical and internal grinding on silicon nitride ceramic spindle, the roughness tended to decrease with the linear velocity increasing, and increased with the radial feed speed increasing and decreased with the wheel shaft’s oscillation speed increasing. The result indicated that the linear velocity of grinding wheel influenced the sample’s roughness most. The effect of radial feed speed on the roughness is next only to the effect from linear velocity. The effect of shaft’s oscillation speed on the roughness is the lowest of the three factors. In the process of internal grinding, with the linear velocity increasing, the ceramic material transformed from brittle rupture to plastic deformation and the roughness appeared one peak. These results were very helpful to optimize the grinding parameters and improve grinding efficiency.

Research of the Grinding Mode Applied by the Cranfield BoX Ultra Precision Grinding Machine

2013 ◽  
Vol 712-715 ◽  
pp. 553-558
Author(s):  
Zhuang De Jiang ◽  
Shu Ming Yang ◽  
Jin Long Wang ◽  
Guang Tao Yuan ◽  
Xing Yuan Long
Keyword(s):  
Grinding Wheel ◽  
Precision Grinding ◽  
Wheel Surface ◽  
Cutting Depth ◽  
Workpiece Surface ◽  
Ultra Precision ◽  
Simulation Results ◽  
Grinding Machine

In this paper an efficient grinding mode which is employed by the Cranfield BoX ultra precision grinding machine is discussed. The equations of workpiece surface and grinding wheel surface are proposed and the grinding motion is simulated via Matlab. The trajectory of the changing cutting region is discussed. The simulation results show that this grinding mode is suit to manufacture low slope surfaces. Generally, the workpiece surface is steeper, and the cutting range of the machine is smaller. The angle of the spindle inclination, the grinding wheel width and the cutting depth should be chose properly for different manufacturing capacity.

scholarly journals Cavitation Effect in Ultrasonic-Assisted Electrolytic In-Process Dressing Grinding of Nanocomposite Ceramics

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5611
Author(s):  
Guangxi Li ◽  
Fan Chen ◽  
Wenbo Bie ◽  
Bo Zhao ◽  
Zongxia Fu ◽  
...  
Keyword(s):  
Ultrasonic Cavitation ◽  
Grinding Wheel ◽  
Workpiece Surface ◽  
Elid Grinding ◽  
Cavitation Effect ◽  
Ultrasonic Assisted ◽  
Hard And Brittle Materials ◽  
Cavitation Threshold ◽  
Grain Distribution ◽  
Experimental Substantiation

Ultrasonic-assisted electrolytic in-process dressing (UA-ELID) grinding is a promising technology that uses a metal-bonded diamond grinding wheel to achieve a mirror surface finish on hard and brittle materials. In this paper, the UA-ELID grinding was applied to nanocomposite ceramic for investigating the cavitation effect on the processing performance. Firstly, the ultrasonic cavitation theory was utilized to define the cavitation threshold, collapse of cavitation bubbles, and variation of their radii. Next, the online monitoring system was designed to observe the ultrasonic cavitation under different ultrasonic amplitude for the actual UA-ELID grinding test. A strong effect of ultrasonic cavitation on the grinding wheel surface and the formed oxide film was experimentally proved. Besides, under the action of ultrasonic vibration, the dressing effect of the grinding wheel was improved, and the sharpness of grain increased by 43.2%, and the grain distribution was dramatically changed with the increase of ultrasonic amplitude. Compared with the conventional ELID (C-ELID) grinding, the average protrusion height increased by 14.2%, while the average grain spacing dropped by 21.2%. The UA-ELID grinding reduced the workpiece surface roughness Rz and Ra by 54.2% and 46.5%, respectively, and increased the surface residual compressive stress by 44.5%. The surface morphology observation revealed a change in the material removal mechanism and improvement of the surface quality by ultrasonic cavitation effect. These findings are considered instrumental in theoretical and experimental substantiation of the optimal UA-ELID grinding parameters for the processing of nanocomposite ceramics.

Analysis on the Factors of Surface Morphologies on Si3N4 Ceramic Internal Grinding

2017 ◽  
Vol 31 ◽  
pp. 44-52
Author(s):  
Jian Sun ◽  
Peng Zhou ◽  
Yu Hou Wu ◽  
Ke Zhang ◽  
Li Xiu Zhang
Keyword(s):  
Silicon Nitride ◽  
Grinding Wheel ◽  
Axial Vibration ◽  
Machined Surface ◽  
Silicon Nitride Ceramic ◽  
Linear Speed ◽  
Internal Grinding ◽  
Grinding Parameters ◽  
Feeding Speed ◽  
Surface Morphologies

Different grinding parameters of silicon nitride ceramic are researched at the process of internal grinding. The influences on the roughness of surface by the linear speed of grinding wheel (vs), radial feeding speed (f) and axial vibration speed (fa) are studied in the uniformity testing. The experimental equation of silicon nitride ceramic internal grinding is optimized. The machined surface morphologies of the ceramic specimen are measured by roughness instrument of Taylor-Hobson Surtroni-25 and scanning electron microscope of S-4800. The results show that with the increasing of the linear speed of grinding wheel the roughness of surface get reduced, and with the increasing of radial feeding speed the roughness of surface get raised. It is also inversely proportional to the axial vibration speed. The linear speed of grinding wheel has the biggest impact on the roughness of surface of the silicon nitride ceramic internal grinding among the three grinding parameters. With the increasing of linear speed of grinding wheel, the value of roughness of surface declines from 0.4095μm to 0.1726μm. The influences on the roughness of surface of the silicon nitride ceramic internal grinding by different factors are found out in the research, and its removal mechanisms are cleared up under different linear speeds of grinding wheel.

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

2013 ◽  
Vol 579-580 ◽  
pp. 144-147 ◽  
Author(s):  
Guo Jun Dong ◽  
Ming Zhou ◽  
Shao Nan Huang
Keyword(s):  
Silicon Nitride ◽  
Surface Quality ◽  
Ultrasonic Vibration ◽  
Machining Process ◽  
Test Results ◽  
Cutting Depth ◽  
Silicon Nitride Ceramic ◽  
Nitride Ceramics ◽  
Conventional Machining

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.

Measuring Method of Distribution of Abrasive Grain Cutting Edge by Means of AE Sensors

2016 ◽  
Vol 1136 ◽  
pp. 601-605
Author(s):  
Takazo Yamada ◽  
Hwa Soo Lee ◽  
Kohichi Miura
Keyword(s):  
Measuring Method ◽  
Cutting Edge ◽  
Experimental Results ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Wheel Surface ◽  
Workpiece Surface ◽  
Abrasive Grain

In grinding process, the grinding wheel profiles are copied to workpiece surface. Therefore, the finished workpiece surface can be estimated by the grinding wheel surfaces. In this paper, new measuring method of the distribution of cutting edge in grinding wheel surface by two AE sensors is proposed. From experimental results, it is confirmed that the distribution of cutting edges in wheel surface can be measured easily by the proposed method compared to another measuring method.

scholarly journals Experiment on Foreign Object Damage of Gas Turbine-Grade Silicon Nitride Ceramic

1998 ◽  
Author(s):  
Hiro Yoshida ◽  
Takashi Nakashima ◽  
Makoto Yoshida ◽  
Yasushi Hara ◽  
Toru Shimamori
Keyword(s):  
Elevated Temperature ◽  
Silicon Nitride ◽  
Elevated Temperatures ◽  
Tensile Load ◽  
Strength Degradation ◽  
Spall Fracture ◽  
Silicon Nitride Ceramic ◽  
Impact Tests ◽  
The Impact ◽  
Bending Fracture

A new high quality turbine system using monolithic silicon-nitride ceramic is under development. In this study particle impact tests of the silicon-nitride have been tried at room and elevated temperatures with and without tensile load, which simulates centrifugal force of blade rotation. In the experiment 1 mm diameter particle is impacted at velocities up to 900 m s−1. In this paper, critical velocities for bending fracture and Hertzian cracks are examined. Moreover, strength degradation at elevated temperature and spall fracture of the blade are discussed. The main results are: 1) The bending fracture mode critical impact velocity for soft particles is higher than that for hard particles. 2)The impact parameter ϕ for initiation of Hertzian cracks ranges 1.08×10−5 – 1.56×10−5 for the materials tested. 3)Strength degradation at elevated temperature was clearly observed. 4) In the impact tests on blades spall fracture, which was caused by interaction of stress waves, appeared.

Computer-Aided Simulation of Dressing Using Diamond Rotary Dresser and Visualization of Dressing Process

2014 ◽  
Vol 1017 ◽  
pp. 592-597 ◽  
Author(s):  
Akihiko Kubo ◽  
A.M.M. Sharif Ullah ◽  
Jun’ichi Tamaki
Keyword(s):  
Solid Body ◽  
Surface Profile ◽  
Depth Of Cut ◽  
Grinding Wheel ◽  
Wheel Surface ◽  
Contour Map ◽  
Removal Process ◽  
Computer Aided ◽  
Actual Depth

The surface of a grinding wheel dressed by a diamond rotary dresser was generated by computer-aided simulation for the case of multipass dressing on the assumption that the grinding wheel is a homogeneous solid body and the dressing trajectories of the diamond grits are perfectly copied on the grinding wheel surface. The dressing process was visualized as a contour map of the dressed surface profile and the effects of the dressing strategy, i.e., down-cut dressing or up-cut dressing, on the grinding wheel removal process were investigated. It was found that the diamond grits remain the residual depth of cut on the surface of the grinding wheel, resulting in an actual depth of cut larger than that given by the rotary dresser.

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