Classification of grinding wheels
The grinding wheel can be divided into ordinary abrasive (corundum and silicon carbide, etc.) grinding wheel and natural abrasive superhard abrasive and (diamond and cubic grinding wheel boron nitride, etc.) grinding wheel according to the abrasive used;
The diamond abrasive is used as the raw material, and metal powder, resin powder, ceramics and electroplated metal are used as binders. The circular fixed abrasive with a through hole in the center is called a diamond grinding wheel (alloy grinding wheel). The structure of diamond wheel is generally composed of three parts: working layer, substrate and transition layer. The working layer, also known as the diamond layer, is composed of abrasive, bond and filler, and is the working part of the grinding wheel. The transition layer, also called non-diamond layer, is composed of binder, metal powder and filler, and is the part that firmly connects the diamond layer to the substrate.
Stainless steel wheel
Stainless steel grinding wheel is a professional cutting stainless steel grinding wheel. Everyone knows that stainless steel is a hard material. If you want to cut it, the thick grinding wheel is very difficult. The characteristic parameters of the grinding wheel mainly include abrasive, viscosity, hardness, bonding agent, shape, size and so on.
Grinding wheel model
The specifications are written on the grinding wheel, and the words such as A30Q4BF can be seen on the printing. This shows a lot of things. First, A represents abrasive brown corundum, and there are other WA white corundum BA black corundum and so on. The 30 behind A represents the particle size. The finer particle size is smoother, the surface roughness is lower, but the grinding speed is slow; the coarse particle size surface is rougher, but the grinding speed is faster. Q stands for hardness. 4 represents the organization number. The thickest BF stands for resin binder
Grinding wheel specifications
Grinding wheels have different shapes and sizes, suitable for different grinding processes. The grinding wheel is subjected to a large centrifugal force when it rotates. If there is not enough strength, the grinding wheel will burst and cause a serious accident. The size of the centrifugal force is proportional to the square of the peripheral speed of the grinding wheel, so when the peripheral speed of the grinding wheel increases to a certain value, the centrifugal force will exceed the allowable range of the strength of the grinding wheel, causing the grinding wheel to burst, so all kinds of grinding wheels The safe working speed is specified. The speed is much lower than the speed at which the grinding wheel bursts. The safe working speed of the grinding wheel is marked on the grinding wheel with the highest working speed, and its safety factor is 1.5
1. Abrasives and selection principles
The abrasive is the basic material of the grinding wheel, and it mainly plays the role of cutting when grinding. Abrasive hardness refers to the hardness of abrasive material itself. Abrasives are divided into two categories: natural abrasives and artificial abrasives.
Natural abrasives include: quartz, garnet, natural corundum and natural diamond.
Man-made abrasives include: Baidu corundum-based and carbide-based ordinary abrasives; artificial diamond, cubic boron carbide and other super-hard abrasives; and lower hardness abrasives chromium oxide, iron oxide, glass powder, etc.
Abrasive tools refer to grinding wheels, oil stones, sandpaper, abrasive belts, etc., which are bonded with abrasives or binders according to certain requirements, and abrasive pastes prepared with oils and water agents for grinding. tool. The modern abrasive manufacturing industry mainly selects artificial abrasives to manufacture abrasives.
Ordinary abrasive consolidated abrasives (the grinding wheels described in this book) are composed of abrasive particles, bonding agent and voids. The abrasive grains use the edges and corners exposed on the surface as cutting edges; the bonding agent binds the abrasive grains together, and has a certain shape and strength after being pressed and sintered; the gaps are used to accommodate chips and grinding during grinding The effect of cutting fluid and dissipating grinding heat. Abrasives, binders and voids constitute the three elements of the wheel structure.