Do you know how the hardness of mesh sanding discs is defined? Is it the same as the hardness of abrasive grains? Today, Xinhongrui will take you to analyze the hardness of the mesh sanding discs and several principles that should be considered when choosing the hardness of the grinding wheel.
Mesh sanding discs, also known as bonded abrasive, is a bonded abrasive with a certain strength that consolidates ordinary abrasives into a certain shape (mostly round, with a through hole in the center) by a bond. It is generally composed of abrasives, binders and pores. These three parts are often called the three elements of bonded abrasives.
1. The hardness of the mesh sanding discs refer to the bonding ability of the bonding agent to the abrasive. The hardness of the grinding wheel is determined by the bonding strength of the bond, not by the hardness of the abrasive. Under the same conditions and a certain external force, if the abrasive grains are easy to fall off from the grinding wheel, the hardness of the grinding wheel is relatively low (or called soft); otherwise, the hardness of the grinding wheel is relatively high (or called hard).
2. After the abrasive grains on the mesh sanding discs are passivated, the grinding force acting on the abrasive grains will increase, thereby prompting the abrasive grains on the surface of the grinding wheel to fall off automatically, and the sharp cutting edge of the new abrasive grains on the inner layer will be put into cutting, and the grinding wheel will recover the original cutting performance. This ability of the grinding wheel is called “self-sharpening”.
3. Whether the hardness of the mesh sanding discs are reasonable or not has a great influence on the quality and productivity of the grinding process. In general, the harder the part material, the softer the wheel should be. This is because the parts have high hardness and the abrasive grains wear quickly. Choosing a softer grinding wheel is conducive to the “self-sharpening” of the blunt grinding wheel. However, if the hardness is selected too low, the grinding wheel will wear out quickly, and it will be difficult to ensure the correct sand profile. If the hardness of the grinding wheel is too high, it will be difficult to realize the self-sharpening of the grinding wheel. Not only the productivity is low, but also the surface of the parts is prone to high-temperature burns.
4. In mechanical processing, the hardness range of the commonly used grinding wheel is generally H-N (soft 2-medium 2).
How to choose the hardness of mesh sanding discs depends on the workpiece to be ground, the surface quality requirements of the workpiece, and the grinding efficiency. When selecting a grinding wheel, attention should be paid to proper hardness. If the grinding wheel is too hard, the blunt abrasive grains will not fall off in time, thus generating a lot of grinding heat and causing burns to the workpiece. If it is too soft, the abrasive grains will fall off too quickly and cannot fully exert its cutting effect.
“Grinding wheel hardness” is the degree of difficulty that the abrasive grains fall off from the surface of the grinding wheel under the action of grinding force. It is two different concepts from the hardness of abrasive grains.
The following principles can be considered when choosing the hardness of mesh sanding discs:
- Workpiece hardness: The harder the workpiece material, the softer the hardness of the mesh sanding discs, the softer the workpiece, the harder the grinding wheel.
- Processing contact surface: When the contact surface between the grinding wheel and the workpiece is large, a soft grinding wheel should be used to make the abrasive particles fall off faster to avoid burns on the surface of the workpiece.
- Fine grinding and form grinding: during fine grinding and form grinding, a harder grinding wheel should be selected to ensure the necessary shape accuracy of the grinding wheel.
- The particle size of the grinding wheel: the larger the particle size of the grinding wheel, the lower its hardness, so as to avoid the surface structure of the grinding wheel being blocked by grinding debris.
- The workpiece material. When grinding soft and tough non-ferrous metals, or grinding materials with poor thermal conductivity, choose softer grinding wheels.
- For materials that are particularly difficult to grind, use superhard grinding wheels. This type of grinding wheel is selected because the grinding capacity coefficient of this type of mesh sanding discs are higher than that of ordinary grinding wheels, and it is less prone to wear, and the grinding wheel can cut and grind the workpiece with the minimum pressure.
I hope that you will pay more attention when choosing the hardness of mesh sanding discs, and choose suitable abrasives. Under the premise of ensuring the smoothness of the workpiece surface, try to use a thicker and harder grinding wheel, which can improve the grinding efficiency of the grinding wheel.
Zhuhai Xinhongrui Abrasives is a professional 3m trizact sanding discs manufacturer. The company’s production and processing efficiency and ability are strong, and there are many varieties of inventory, which can guarantee the quality and quantity of fast delivery. We purchase raw materials in large quantities from 3m company to meet customers’ customized size requirements. Each of our production machines has a dedicated person in charge and requires regular maintenance. Ensure that everything goes smoothly during the production process and improve efficiency. If you are interested in cooperation, please feel free to contact us, you are welcome to visit our factory.
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