The role of ordinary abrasives in the manufacture of superhard material grinding wheels

The role of ordinary abrasives in the manufacture of superhard material grinding wheels

 

Superhard grinding wheels (such as diamond grinding wheels and CBN grinding wheels) are extremely hard and durable, and are good at grinding hard things. But sometimes they are not enough, and some ordinary abrasives need to be added as "helpers" to make the grinding wheel perform better, grind faster, and produce higher quality work.

1. Two types of superhard grinding wheels, each with its own strengths

Diamond grinding wheel:

• It uses diamond particles, which are top hardness, particularly wear-resistant, and have fast heat dissipation.
• It is mainly used to grind non-metallic hard materials such as cemented carbide and ceramics, or work that requires ultra-high precision and smooth surfaces.

 

CBN grinding wheel:

•  It uses cubic boron nitride (CBN) particles, which are second only to diamond in hardness, have good heat resistance, and are very stable when grinding ferrous metals such as steel. Specially used to deal with difficult metal materials such as hardened steel and cast iron.

 

2. Basic principles for choosing a "helper"

When choosing ordinary abrasives as helpers for super-hard grinding wheels, you need to consider several points:

1. Hardness should match: The helper should not be too soft (easy to wear out), nor too much harder than the super-hard abrasive (may steal the work), and should be well matched.
2. Heat resistance: The temperature during grinding is very high, and the helper must be able to withstand high temperatures and cannot become ineffective when heated.
3. The temper should be suitable (chemically stable): Do not react chemically with the material being ground and damage the workpiece.
4. Calculate the cost (economic efficiency): Choose the one with the highest cost-effectiveness while ensuring good usability.

 

3. The best "helper" for diamond grinding wheels

First choice: Silicon carbide (SiC)

• Why? Because it is very similar to diamond: very hard, very wear-resistant, and good at heat dissipation. Adding it can enhance the overall hardness and wear resistance of the grinding wheel, grind faster, and help dissipate heat to prevent the workpiece from being "burned".

 

Alternative: Corundum (Al₂O₃)

• Corundum is a bit harder than diamond, but it is also useful in some special cases. For example, if you want to adjust the "grinding character" of the grinding wheel (make it easier to expose new edges for self-renewal), or if you want to save some costs. Corundum itself is also relatively wear-resistant and relatively affordable. However, in most cases, silicon carbide is more "compatible" with diamond.

 

4. The best "helper" for CBN grinding wheels

First choice: Corundum (Al₂O₃)

• Corundum and CBN work well together in terms of hardness and heat resistance. Moreover, corundum is very "calm" (chemically inert) to ferrous metals such as steel and will not react randomly. Adding it can enhance the hardness and wear resistance of the grinding wheel, and the grinding efficiency and processing quality will naturally increase.

 

Careful selection: Silicon carbide (SiC)

• Although silicon carbide is also very hard, it is relatively brittle and has poor toughness. When added to the CBN grinding wheel, it is easy to break into small particles during grinding, which may make the grinding process unstable and the processed surface rough. Therefore, it is usually not a good choice for CBN grinding wheels. Unless there are some special requirements or special considerations about cost, it is necessary to evaluate whether it can be used separately.

 

• To summarize:

Choosing ordinary abrasives as helpers for super-hard grinding wheels needs to be selected according to different usage scenarios. In general, you can refer to the following:

• Diamond grinding wheel: The best helper is silicon carbide (SiC).
• CBN grinding wheel: The most suitable helper is corundum (Al₂O₃).

 

This combination can make the grinding wheel perform at its best and grind faster and better. Of course, in actual production, it is necessary to fine-tune the type of helper, particle size and amount of addition according to the specific grinding task, what to grind, and how high the precision required, so as to achieve the best grinding effect.