Improving the service life and grinding efficiency of grinding wheel is the key problem in manufacturing research of the metal bond mesh diamond
. This paper reviews the progress of metal bond on diamond abrasive grinding and grinding wheel dressing and sharpening. The application of high temperature brazing technology and the research results of grinding wheel topography optimization are also introduced in the article. Based on the analysis of existing technical defects, it comes up with the ideas and concepts of innovated ly manufacturing method of metal bond superhard abrasive wheel replacement, which takes high temperature brazing technology as the core combining with the grinding wheel design.
Tool life and processing efficiency are the main performance indexes of metal bond mesh diamond grinding wheel. As far as the influencing factors are concerned, the ability of metal bond to hold diamond abrasives is the key factor affecting tool life. The difficulty of dressing and sharpening metal bond mesh diamond grinding wheel is an important obstacle to improve processing efficiency.
1. Increased abrasive holding capacity of binder
In the traditional manufacture of metal bond mesh diamond grinding wheel, two kinds of technological measures are mainly adopted to enhance the grinding ability. One is to directly add active Ti(TiH2), Cr, rare earth elements to sintering raw materials, the other is to deposit active metals such as Ti and Cr or their alloy coatings on the surface of abrasives by metallization of diamond surface. Through their reaction and diffusion with diamond abrasives and metal binders during high temperature sintering, chemical metallurgical bonding can be formed between abrasives and metal binders to improve abrasive holding capacity of high metal binder.
2. Improvement of dressing and sharpening ability of grinding wheel
The metal bond mesh diamond
grinding wheels are all compact. In order to achieve high grinding power during the process, the density of metal bond mesh diamond grinding wheels is generally regarded as an important index to measure the manufacturing quality of grinding wheels. Due to the high densification of metal bonded mesh diamond grinding wheel, it is difficult to shape and sharpen it at the beginning of its use and after wear.
3. Application of High Temperature Brazing Technology
High temperature brazed diamond single-layer grinding wheel fundamentally improves the bonding strength between abrasive and bond, and is generally considered as a replacement product of single-layer electroplated diamond grinding wheel. In the mid and late period of 1990s, we took the lead in conducting extensive research on this technology in China. The main process used was adding Cr powder to active Ni-Cr or Ag-Cu alloys and manufacturing single-layer brazed diamond abrasive grinding wheel by high temperature brazing process. The research shows that the interface bonding strength provided by high temperature brazing is so high that only the bonding layer thickness is maintained at a low level of 20%-30% of the abrasive height, which is enough to hold the abrasive firmly in high speed and high efficiency grinding of the heavy load.