A Study on Electrolytic In-Process Dressing (ELID) Grinding of Sapphire With Acoustic Emission

2009 ◽  
Author(s):  
Peidong Han ◽  
Ioan D. Marinescu ◽  
Anil Srivastava
Keyword(s):  
Acoustic Emission ◽  
Surface Finish ◽  
High Efficiency ◽  
High Hardness ◽  
Processing Parameters ◽  
Great Promise ◽  
Grinding Wheel ◽  
Wheel Wear ◽  
Elid Grinding ◽  
Wheel Loading

Single crystal sapphire is of significant interest due to its combination of excellent optical, electrical, and mechanical properties. However, fine grinding of sapphire is quite challenging because of its high hardness and low fracture toughness, making it sensitive to cracking. Wheel loading is a common problem in conventional grinding of hard and brittle materials. ELID grinding shows great promise in achieving a mirror surface finish at a relatively high efficiency. ELID grinding of sapphire was investigated using acoustic emission. The effects of processing parameters on surface finish and acoustic emission signals were evaluated. Correlations were found among the dressing current intensity, surface finish and acoustic emission signals. A smoother surface was obtained using a higher dressing current at the cost of a higher wheel wear rate. The wheel wear mechanism in ELID grinding of sapphire was dominated by bond fracture because the bond strength is reduced by electrolysis. Results indicate that the acoustic emission technique has the potential to be used for monitoring ELID grinding process, detecting the condition of the grinding wheel, and investigating the mechanisms of ELID grinding.

Effect of Complex Electrodischarge Grinding for Electrically Conductive PCD

2011 ◽  
Vol 325 ◽  
pp. 276-281 ◽  
Author(s):  
Manabu Iwai ◽  
Shinichi Ninomiya ◽  
Kiyoshi Suzuki
Keyword(s):  
High Efficiency ◽  
Low Cost ◽  
Surface Condition ◽  
High Hardness ◽  
Grinding Wheel ◽  
Wheel Wear ◽  
Electrically Conductive ◽  
Grinding Method ◽  
Conventional Grinding ◽  
Composite Diamond

Polycrystalline Composite Diamond (PCD) is excellent in chipping resistance despite its very high hardness. However, it is not easy to EDM or grind PCD. To realize high efficiency and high quality processing of PCD simply and at low cost, the authors devised new PCD (EC-PCD) by using electrically conductive diamond particles and applied a complex electrodischarge grinding method. In this study, investigation is made on effective grinding condition to realize high efficiency, low and stable grinding force and low wheel wear in complex electrodischarge grinding. As a result, superior grinding property was obtained when the grinding wheel was set at minus polarity, and set peak current of iP = 4 and 6 A was applied. Furthermore it also became clear that additional conventional grinding process followed after complex electrodischarge grinding improved the surface condition.

Development on Micro Precision Truing Method of ELID-Grinding Wheel (1st Report: Principle & Fundamental Experiments)

2005 ◽  
Vol 291-292 ◽  
pp. 207-212 ◽  
Author(s):  
Hitoshi Ohmori ◽  
Shao Hui Yin ◽  
Wei Min Lin ◽  
Yoshihiro Uehara ◽  
Shinya MORITA ◽  
...  
Keyword(s):  
High Precision ◽  
High Efficiency ◽  
High Hardness ◽  
Experimental Results ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Grinding Wheels ◽  
Elid Grinding ◽  
High Toughness ◽  
Diamond Grinding

Metal bonded diamond grinding wheels are widely used in the grinding process, especial in ELID grinding. However, truing is difficult owing to the high toughness of metal bond materials and high hardness of diamond abrasives. To realize high precision and high-efficiency truing, we propose a new micro-truing method consisting of electro-discharge truing and electrolysis-assisted mechanical truing in this paper. The process principle and fundamental experimental results are introduced, and the truing performance is discussed. Research results show that the proposed new method is effective for truing metal bonded diamond grinding wheels.

An Investigation of Grinding and Wheel Loading Using Acoustic Emission

1984 ◽  
Vol 106 (1) ◽  
pp. 28-33 ◽  
Author(s):  
D. Dornfeld ◽  
He Gao Cai
Keyword(s):  
Acoustic Emission ◽  
Chip Thickness ◽  
Process Efficiency ◽  
Grinding Wheel ◽  
Force Measurements ◽  
Wheel Wear ◽  
Emission Signal ◽  
Wheel Loading ◽  
Loss Of Contact ◽  
Higher Sensitivity

This paper investigates the potential for using acoustic emission signal analysis for a monitoring technique for process automation as well as a sensitive tool for investigation of grinding fundamentals. The acoustic emission generated during the grinding process is analyzed to determine its sensitivity to process efficiency and the condition of the grinding wheel. Acoustic emission from surface grinding is used to measure wear-related loading of the grinding wheel and sparkout (or loss of contact) between the wheel and the work surface. A discussion of energy dissipation in grinding and the generation of acoustic emission is included. This investigation showed that the acoustic emission energy, (RMS)2, increases with the combined effects of wheel wear and loading, the signal energy, (RMS)2, is a function of the undeformed chip thickness and that the signal accurately detects work-wheel contact and sparkout with a higher sensitivity than force measurements.

Ultra-High Speed Grinding Using a CBN Wheel for a Mirror-Like Surface Finish

2005 ◽  
Vol 291-292 ◽  
pp. 67-72 ◽  
Author(s):  
M. Ota ◽  
T. Nakayama ◽  
K. Takashima ◽  
H. Watanabe
Keyword(s):  
Surface Finish ◽  
High Speed ◽  
High Efficiency ◽  
Ground Surface ◽  
Machining Process ◽  
Grinding Wheel ◽  
Cbn Wheel ◽  
Ultra High Speed ◽  
High Speed Grinding ◽  
Grinding Conditions

There are strong demands for a machining process capable of reducing the surface roughness of sliding parts, such as auto parts and other components, with high efficiency. In this work, we attempted to grind hardened steel to a mirror-like surface finish with high efficiency using an ultra-high speed grinding process. In the present study, we examined the effects of the work speed and the grinding wheel grain size in an effort to optimize the grinding conditions for accomplishing mirror-like surface grinding with high efficiency. The results showed that increasing the work speed, while keeping grinding efficiency constant, was effective in reducing the work affected layer and that the grinding force of a #200 CBN wheel was lower than that of a #80 CBN wheel. Based on these results, a high-efficiency grinding step with optimized grinding conditions was selected that achieved excellent ground surface quality with a mirror-like finish.

Wear Monitoring on Microcrystalline Aluminum Oxide Grinding Wheels on Profile Grinding with the Aid of Acoustic Emission

2014 ◽  
Vol 894 ◽  
pp. 95-103 ◽  
Author(s):  
Lucas Benini ◽  
Walter Lindolfo Weingaertner ◽  
Lucas da Silva Maciel
Keyword(s):  
Acoustic Emission ◽  
Wear Behavior ◽  
Grinding Wheel ◽  
Wheel Wear ◽  
Profile Grinding ◽  
Grinding Wheel Wear ◽  
Abrasive Grains ◽  
Profile Deviation ◽  
Synthetic Materials ◽  
External Cylindrical Grinding

The localized wear on grinding wheel edges is a common phenomenon on profile grinding since the abrasive grains are less attached to the bond. The grinding wheel wear depends heavily on the process parameters, workpiece and wheel composition, causing changes on the process and profile deviation behaviors. In order to cope with these uncertainties, many natural and synthetic materials have been used in different grinding processes. However, the influence of mixed compositions of different types of abrasive grains on external cylindrical grinding is not well known. In order to assess this relation, a methodology procedure was developed providing an overview of the cinematic edges behavior on a progressive wheel wear. The methodology procedure is based on the acoustic emission technology, using a transducer with a 50 μm radius diamond tip. The tip, when in contact with a rotating grinding wheel, enables the evaluation of the cinematic cutting edges. The abrasive grain density was evaluated for different grinding wheel compositions and specific wear removal values. Furthermore, these results were compared to the profile deviation observed on the same tool, allowing the assessment of the influence of different microcrystalline corundum grains on the overall grinding wheel wear behavior.

Wear of Diamond Grinding Wheel during Low Speed Dressing by Alumina

2015 ◽  
Vol 658 ◽  
pp. 120-124
Author(s):  
Tachai Luangvaranunt ◽  
Natthawat Tangkaratanakul ◽  
Patchanok Sakultantimetha
Keyword(s):  
High Hardness ◽  
Large Mass ◽  
Diamond Wheel ◽  
Grinding Wheel ◽  
Work Piece ◽  
Wheel Wear ◽  
Diamond Grinding Wheel ◽  
Diamond Grinding ◽  
Dressing Tool ◽  
Pin On Disk

Diamond grinding wheel is used in high precision grinding process, when work piece has a very high hardness. For a specific grinding interval, the wheel must be properly dressed, in order to remove swarf, sharpen the worn diamond grits, open up new diamond protrusions, and recondition the bond material. Dressing of diamond grinding wheel by alumina dressing tool has been simulated in a pin-on-disk machine in the research. Sharpening of the wheel is indicated by the increase of its roughness value, and surface microstructure with protruding sharp diamond grits. It was found that increasing of sliding distant from 100 to 500 m will increase the roughness of the wheel. The increase of contact load from 10 to 20 N will also increase roughness of the wheel, and the severity of wheel wear, indicated by high values of friction coefficient. A proper dressing of this nickel bonded SD1200 diamond wheel is by sliding against alumina dressing tool for at least 300 m under 10 N load. Sliding velocity has minimal effect to the results. A too large sliding distant and load will cause severe damage to wheel surface, and severe wheel wear, indicated by its large mass loss.

Experiment Study on ELID Grinding of TN85 Cermets

2011 ◽  
Vol 175 ◽  
pp. 131-135
Author(s):  
Fu Qiang Tong ◽  
Fei Hu Zhang ◽  
Dian Rong Luan
Keyword(s):  
Metal Matrix ◽  
High Hardness ◽  
Diamond Powder ◽  
Diamond Wheel ◽  
Precision Machining ◽  
Grinding Wheel ◽  
Powder Particle Size ◽  
Matrix Composites ◽  
Elid Grinding ◽  
Ultra Precision

TN85 cermets is one kind of particle reinforced metal matrix composites, which is high hardness, good wear resistance, and bring great difficulties in processing, so it is necessary to study the processing performance. During the test on ELID grinding TN85 cermets, it is found that plastic removal is the main ways during grinding TN85 cermets materials. The powder particle size of W2.5 diamond wheel is successfully used in full removal of TN85 cermets plastic, the surface roughness value of rms: 16.81nm and Ra: 12.52nm. The results showed that: ELID grinding wheel with diamond powder technology can be used in ultra-precision machining TN85 cermets.

Effects of Impregnation of Grinding Wheel on Grinding Hardened Tool Steel

1985 ◽  
Vol 9 (1) ◽  
pp. 39-44 ◽  
Author(s):  
M.A. Younis ◽  
H. Alawi
Keyword(s):  
Structural Changes ◽  
Metal Removal ◽  
Removal Rate ◽  
Ground Surface ◽  
High Hardness ◽  
Grinding Wheel ◽  
Tool Steels ◽  
Wheel Wear ◽  
Beneficial Effects ◽  
Hardened Tool Steel

The high hardness and chemical effects of tool steels M2 and T15 cause a rapid grinding wheel wear and micro structural changes in the ground surface. The performance of sulphur-, wax-, and varnish-impregnated grinding wheels in grinding hardened tool steels M2 and T15 is investigated and compared with the performance of conventional alumina wheels. Impregnation with sulphur had in all cases beneficial effects by decreasing the grinding forces, increasing the maximum metal removal rate, improving surface integrity, and increasing considerably the grinding ratio. It also gave cost saving compared to the plain grinding wheel. The improvement was a result of the sulphur being more efficiently supplied into the chip formation process as compared to using grinding coolant only.

Study on Acoustic Emission in the Grinding Process Automation

1999 ◽  
Author(s):  
Ming Chen ◽  
Bing-Yuan Xue
Keyword(s):  
Acoustic Emission ◽  
High Efficiency ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Process Automation ◽  
Grinding Burn ◽  
Sensing System ◽  
Monitoring Technique ◽  
Ae Signal ◽  
Process Prediction

Abstract Comprehensive experiments have been conducted to investigate the monitoring technique for grinding process automation with acoustic emission (AE) signal. The AE signal generated during the grinding process is analyzed to determine its sensitivity to process. The detection of contact between the grinding wheel and workpiece and in-process prediction of grinding burn have been discussed in sequence. The results have been obtained as follows: (1) AE contact detector can save the non-machine time remarkably, thus high efficiency is available. (2) An effective intelligent sensing system has been developed and grinding burn can predicted. As mentioned above, AE technique has found wide applications in the grinding process automation.

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