Selecting the right grinding wheel is crucial in ensuring the quality of circular saw blades. Diamond grinding wheels are graded based on several performance factors such as abrasive particle size, binder type, grinding wheel hardness, grinding wheel structure, grinding wheel shape, grinding wheel size, diamond concentration, diamond material layer thickness and material layer width. These factors all play a role in determining the effectiveness of the grinding process. Therefore, careful consideration and selection of each of these factors are necessary to optimize the performance of diamond grinding wheels.
The synthetic abrasive used in a diamond grinding wheel is created by subjecting graphite to high pressure and high temperature alongside a catalyst. It takes the form of artificial diamonds that are mainly composed of carbon, exhibiting colorless transparent, light yellow, yellowish green, and black variations. In terms of hardness, the artificial diamond abrasive surpasses that of silicon carbide, resulting in a grinding productivity that is five times greater. Additionally, it yields a surface roughness that is one to three grades higher and possesses a tool durability that is one to three times longer.
Despite its advantages, the diamond grinding wheel does come with certain limitations. Firstly, it is quite expensive compared to other options. Furthermore, it lacks toughness and has a particular affinity for iron elements, making it unsuitable for grinding steel tools. Moreover, its thermal stability is not ideal as it tends to graphitize when exposed to temperatures ranging from 700 to 800℃ in an air medium. Hence, caution must be exercised while using the diamond grinding wheel to ensure its efficacy and longevity.
The grinding wheel composed of diamond and binder in its working part is known for its high price. Typically, the abrasive layer of this wheel is thin, measuring around 1.5mm, 2mm, 3mm, or 5mm in thickness. Just like ordinary grinding wheels, diamond grinding wheels come in various grain sizes ranging from 80# to 700#. The hardness of these wheels is considered to be intermediate. Concentration, on the other hand, refers to the amount of diamond present per unit volume in the material layer, with the standard concentration being 0.879g (4.39 carat) /cm3. When it comes to saw blade tip grinding, the recommended concentration falls between 70% and 100%. In summary, diamond grinding wheels offer exceptional performance despite their high cost due to their unique composition and carefully chosen specifications.
Diamond grinding wheels require bonding agents to hold the abrasive material in place during operation. There are four types of bonding agents commonly used: bronze, resin, ceramic, and electroplating. Of these, resin cement is often the preferred choice due to its effectiveness and durability.
Due to the extremely hard nature of cemented carbide, grinding it necessitates the application of substantial grinding pressure. However, due to its low heat conductivity, excessive generation of heat during the grinding process must be avoided. To ensure optimal cooling and heat dissipation conditions, it is often necessary to employ a coolant in order to mitigate the risk of grinding cracks.
In order to achieve high-quality saw blade grinding, it is important to divide the process into two stages: rough grinding and fine grinding. The diamond wheel used for rough grinding typically has a grain size of about 80#. On the other hand, fine grinding requires a diamond wheel with a smaller grain size ranging from 400# to 700#. It's worth noting that as the particle size decreases, the cost of the grinding wheel and the grinding process generally increases.