Resinoid Bonded Diamond Wheel Research Articles

Influence of Combination of Grains and Bonds on Grinding Performance of Matrix Type Diamond Wheels.

This paper reports a study on the grinding performance of various wheels with different types of bond materials and diamond grains. Both moderate and aggressive grinding conditions are adopted in this study. Under the moderate grinding condition, grain rotation motion is observed in resinoid-bonded diamond wheels during the grinding process. This motion contributes to a reduction in the grinding force. Based on this finding, grain rotation motion is introduced as a new self-sharpening mechanism of resinoid-bonded diamond wheels. Also, attritious wear is found to dominate the wear process of all kinds of diamond wheels. Under the aggressive grinding condition, four typical wear types are found, with each corresponding to a specific combination of bond materials and diamond grains. It appears that the tearing off or macro-cracking of grains dominates the wheel wear process when the wheel grades are low ; but micro-chipping or attritious wear plays a decisive role when the wheel grades are high.

レジンボンド極微粒ダイヤモンドホイールによる円筒鏡面研削技術の研究

The goal of this paper is a mirror grinding of ceramic cylinder with an extremely fine grit diamond wheel. An ultra precision cylindrical grinding machine and a truing and dressing device for it are designed and built. For a mirror grinding, a very fine infeed motion and a low vibration are needed to avoid sinking diamond grits into a bond material with an unexpectedly large force on individual grits. Therefore, the grinding machine has a hydrostatic wheel spindle and a hybrid infeed mechanism. The latter one consists of a ball screw and a DC servomotor for a rough feed, and four piezoelectric actuators for a fine feed. The piezoelectric actuators are mounted in the ball screw nut. Vibration amplitude of the wheel head was less than 0.1 μm and the minimum depth of cut was 0.01 μm/step. After truing and balancing a resinoidbonded diamond wheel (SD5000B) on the machine precisely, a mirror grinding of a partially stabilized zirconia cylinder was carried out. A peak-to-valley height of the ground surface was 53 nm and a maximum chipping length on the edge was 0.5 μm or below.

High-Efficiency Grinding of Cermet.

TiC-TiN-cermet cutting tools are coming into wide use today in metalworking industries because of their excellent properties. Particularly, improved toughness of cermet with increasing content of nitrogen makes applications for milling or drilling cutters possible. However, it is quite difficult to grind cermet with high efficiency because of its high degree of hardness and toughness. This results in the rapid wear of the diamond grains, and the need for frequent dressing of the grinding wheel surface. In this study, three different kinds of cermet are ground with a surface grinding machine using a resinoid bonded diamond wheel. The measurements of grinding force, surface roughness and grinding ratio are carried out to obtain a guide for high-efficiency grinding of cermet. To achieve the stable cermet grinding, it is important to take full advantage of the self-sharpening phenomenon of the grinding wheel. With respect to the grinding wheel, the friable grinding wheel will be suitable to attain the stable grinding processes. However, the surface roughness obtained is large and, therefore, finish grinding with a finer grinding wheel should be carried out to meet the demand for the cutting inserts.

Ultraprecision Grinding of Optical Glasses to Produce Super-Smooth Surfaces

Summary The typical 11 kinds of optical glasses have been ground by the ultra-precision surface grinder having a glass-ceramic spindle of extremely-low thermal expansion with various cup-typed resinoid-bonded diamond wheels of #200-#3000 in grain size. All kinds of glasses can be ground in the ductile mode and the surface does not contain a micro-crack under the surface. The surface roughness is related with grain size, feed per wheel revolution and glass material, not with depth of cut. Super-smooth surfaces less than 0.2nm rms. 2nm Rmax have been obtained by the ultra-precision grinding.

Surface Structure of Mn-Zn Ferrite Single Crystals Ground by an Ultraprecision Surface Grinder with Various Diamond Wheels

Manganese-zinc ferrite single crystals have been ground by the ultra-precision surface grinder having a glass-ceramic spindle of extremely-low thermal expansion with various resinoid-bonded diamond wheels of #200-#3000. The ground surface can be classified into three categories, that is. fracture mode, ductile mode and ductile & fracture mode grinding by observing the surface with a Nomarski interference microscope. There is no micro crack under the surface ground in the ductile mode. The relationship between the surface roughness and grinding conditions has been also clarified. The micro-surface structure has been also discussed with an STM and AFM measurement.

Dressing of Resinoid Bonded Diamond Grindling Wheels

The importance of improving the truing and dressing efficiency for the super-abrasive grinding wheel has been increased. In this study, a series of dressing and grinding tests were carried out to improve the dressing efficiency of a resinoid bonded diamond wheel. Through the experimental investigations, it is confirmed that monitoring the dressing force is useful in determining the amount of time needed in dressing. This is particularly important so that wasting of the dressing time, dresser and the diamond wheel is avoided. With respect to the dressing condition, it is concluded that the condition which gives a large grain load is preferable for obtaining a wheel topography that attains a higher material removal rate.

Creep-feed grinding of advanced ceramics.

Advanced ceramics have some excellent properties which are suitable for mechanical components. It is, however, quite difficult to grind ceramics with high efficiency because of their high strength, hardness and brittleness. Now, creep-feed grinding is well known as an effective technology to increase the productivity of form grinding. In this study, creep-feed grinding is carried out for representative advanced ceramics, such as Al2O3, Sic and Si3N4. The grinding force, surface roughness, chipping size and grinding ratio are experimentally investigated. In addition, some proposals are made to resolve adverse effects in creep-feed grinding. Experimental results show that a resinoid bonded diamond wheel with grooves on the grinding surface, which is proposed in this study, has an excellent performance. Furthermore, the influence of the grinding fluid on the creep-feed grinding is investigated.