Papers by Keyword: Electro-Contact Discharge Dressing

Abstract: In cut-off grinding of natural stone the tool performance and stability mainly depends on the self-sharpening behaviour of the cutting segments. Therefore, it is essential to adjust the bonding composition and the process parameters according to the specific separation mechanisms of the work piece material. Different tool wear mechanisms resulting from the different natural stone categories currently avoid the continuous use of one bonding specification. To overcome this limitation an electro-contact discharge dressing (ECDD) process was implemented in the cut-off grinding process. In this way, the backspacing of the bonding can be controlled in-process. The research presented in this paper focuses on the introduction of this technology in the field of stone machining. The demands for applying ECDD in the environment of a stone saw as well as the main influences and interdependencies of ECDD onto the segment topography are discussed.

Abstract: Harder workpiece materials and increased efficiency requirements for grinding processes make the use of super abrasive grinding wheels indispensable. This paper presents newly developed processes for the dressing of super abrasive grinding wheels. The different bond systems of grinding wheels require distinct dressing process. In this paper, dressing processes for metal and vitrified bonded grinding wheels are investigated. It introduces the method of electro contact discharge dressing for the conditioning of metal-bonded, fine-grained multilayer grinding wheels. A description of the essential correlation between dressing parameters and the material removal rate of the bond material is presented. The considered parameters are the dressing voltage, the limitation of the dressing current and the feed as well as the infeed of the electrode. For the grinding of functional microgroove structures, multiroof profiles with microscopic tip geometries are dressed onto the grinding wheel. For this, a profile roller in combination with a special shifting strategy is applied on finegrained vitrified bonded grinding wheels.

Abstract: This paper conducted Electro-Contact Discharge (ECD) dressing experiment for #600 diamond grinding wheel to understand how fine diamond grits protrude from metal-bonded wheel surface. The SEM observation, EDS analysis, image processing and 3D grit modeling on wheel surface were carried out to investigate grit protrusion characteristics. Then ECD dressing and mechanical dressing experiments were carried out to identify the effect of grit protrusion feature on grinding performance. It is confirmed that the dressed wheel surface topography is sensitive to open circuit voltage Ei, discharge polarity and electrode composition. Meanwhile, ECD dressing with Ei=15V and straight polarity can produce superior protrusion topography without the damage of diamond crystal faces and the bond tail behind protrusive grit. It can obtain better ground surface of hard-brittle material than mechanical dressing with the bond tail.