Papers by Keyword: Self-Sharpening

Abstract: According to the standard process, normal electrocorundum is heat treated at 700°C in a rotating drum followed by air cooling. Such heat treatment increases the strength characteristics of abrasive grain. When abrasive paper made from grains with reduced brittleness is working, the effect of reducing the cutting ability due to damage and failure of the cutting surfaces is observed. An increase in the performance characteristics of the abrasive paper was studied by improving the self-sharpening of the grain. Improvement of this performance is achieved by thermochemical treatment in a regulated gas atmosphere and cooling according to a special schedule. Normal electrocorundum during heat treatment in an oxidizing atmosphere changes the structural characteristics due to the decomposition of a solid solution of Ti₂O₃ in α-Al₂O₃ by oxidation to TiO₂. The formation of a block grain structure with microcracks increases the probability of chipping during the grinding tool operation and the appearance of new cutting surfaces.

Abstract: A Si₃N₄ ceramic tool material with high mechanical properties was fabricated by hot-pressing sintering process. The high speed machining of Inconel 718 tests were carried out with round ceramic inserts. The failure surface and microstructure were analyzed by scanning electron microscopy (SEM) to reveal the ceramic tool failure mechanisms. The results showed that the main failure mechanisms of the Si₃N₄ ceramic tool were flaking, micro-chipping, abrasive wear and adhesive wear in the turning process. On the other hand, chipping, flaking and adhesive wear were the main failure reasons in the milling process. Meanwhile, some small flaking along the cutting edge and step-shaped flaking on the rake face closed to the cutting edge were found on the failure surfaces, which was a typical self-sharpening failure characteristic of the ceramic tool in the high-speed cutting process. This tool failure evolution characteristic of the ceramic tool can be attributed to its higher flexural strength and fracture toughness, which was beneficial to improve the tool life and was constrained by cutting conditions.

Abstract: To achieve the components of the highest quality in terms of shape, dimension, surface integrity and high efficiency in the course of processing difficult-to-cut material, the concept of self-sharpening fine super-hard abrasive tool as machining tool is put forward, this method not only improves the dressing performance of the abrasive tool, but also ensures the accuracy and durability of the abrasive tool, self-sharpening fine super-hard abrasive tool lapping technology is developed by using Zn as abrasive fillers and using FeCl₃ solution as lapping liquid, the wear form of the self-sharpening fine super-hard abrasive tool and the influence of abrasive wear on the material removal form is studied, research shows that the wear of the self-sharpening fine super-hard abrasive tool is mainly in breakage wear, which has a good self-sharpening performance, and the material removal form is mainly in two-body material removal mode., which means this method has good holding force of abrasives.

Abstract: The water soluble grinding fluids (coolants) with 3M^TM Trizact^TM Diamond Tile（TDT）used in thinning process of the flat glass contains lubricants, extreme pressure antiwear agents, surfactants and anti-rust additives, which are expected to provide the functions of lubricating, cooling, cleaning, anti-rust. The results showed that the water soluble grinding fluids can improve the processing performance of 3M TDT effectively, keep excellent self-sharpening, increase processing efficiency, extend the service life of the abrasive pads and reduce surface roughness of the glass .

Abstract: In order to improve the efficiency of ultra-precision processing, the self-sharpening fine super-hard abrasive tool is presented to reduce or eliminate the surface and subsurface defects and improve the process efficiency. In the study of efficient experimental research of self-sharpening fine super-hard abrasive tool, base on single factor experiments such as additives composition, grinding speed, grinding pressure and processing liquid. The results showed that the wear rate of the self-sharpening fine super-hard abrasive tool can reach appropriate rate when the additive concentration 30wt%, grinding pressure 45N, grinding speed 60rpm and processing liquid 1wt%.

Abstract: The dressing principle of a newly developed metal bonded superabrasive tool named porous self-generation superabrasive tool (PSST) is introduced. It is found that the ‘soluble’ filler added in the bond material can be dissolved by certain solution, and porous structure can be formed on the highly compacted surface layer of the metal-bonded superabrasive tool. The dressing process of PSST are investigated by a series of lapping experiments. Surface topography of PSST during lapping process is observed. It is found that the porous structure can be maintained on the PSST surface layer during the lapping process. There is little jam happened on the PSST surface. The generated porous binder on PSST surface layer is more susceptible to bond fracture, which is benefit to the self-sharpening of the metal bonded superabrasive tool.

Abstract: This paper presents a fractal analysis of the self-sharpening phenomenon of the grain cutting edges in cBN grinding. To clarify the self-sharpening mechanism due to the micro fracture of the cutting edges, the changes in three-dimensional profile of the cutting edges in the grinding process have been measured using a scanning electron microscope with four electron probes and evaluated on the basis of the fractal analysis. The fractal dimension for surface profile of the cutting edge formed by the micro fracture is higher than that of the cutting edge formed by the ductile attritious wear. Therefore, the complicated changes in shape of the cutting edge due to the self-sharpening can be evaluated quantitatively using the fractal dimension.

Abstract: Magnetic Abrasive Finishing (MAF) is relatively a new finishing technique that employs the magnetic force for finishing. In the paper, finishing mechanism of MAF is studied and four self-sharpening modes of abrasive particles are put forward. With the cylindrical magnetic abrasive apparatus designed and made by the author, a series of experiments on finishing the cylindrical surfaces of nonferromagnetic materials and ferromagnetic materials are carried out. The influence of technical parameters (finishing speed, feed speed, finishing time and so on) on finishing performance is analyzed. Choosing the optimized technical parameters, , the surface roughness of ferromagnetic materials changes from Ra 0.825µm to Ra 0.045µm after the 12-minute finishing experiment; the surface roughness of nonferromagnetic materials changes from Ra 0.434µm to Ra 0.096µm after the 20-minute finishing experiment.