Today we continue to discuss how deep the screw industry is and what are the various processing techniques for screws. The first one is the well-known grinding process, which means that after the screw blank is quenched and tempered to achieve considerable hardness and toughness, it is ground using a grinder. Grinding threads involves the grinding wheel grinding the material, with the grinding wheel moving along the lead of the screw to finally form the thread. The advantage is that the ground products have very high precision, can process materials with hardness up to HRC60 and above, can process longer screws, and can maintain relatively high precision. The disadvantage is low efficiency, and this efficiency is relative to other processes I will discuss next. Some people might argue that their grinding efficiency is very high, and they can finish one in a few minutes. But can you compare that to rolling? They can do one in 2 seconds.
Advantages and Disadvantages of Ground Screws
If the grinding speed is very fast, the grinding wheel will deform, that is, it will wear, and cannot reach its original shape and precision. In addition, particularly fast grinding speeds can cause burns on the product surface. Surface burns bring disaster by annealing the material. We mentioned earlier that grinding can process materials with HRC60 hardness, but if the grinding speed is too fast, you will ruin it. The speed we're talking about here is relative to the speed you should have. Some can be mitigated by using high-pressure oil pumps for cooling, but it cannot violate mechanical principles. One process cannot process particularly slender products because there is a certain clamping force when the product is held between two centers. Coupled with the radial cutting force from the grinding wheel, regardless of how much force it is, the combination will cause the material to deform. Furthermore, when processing shorter workpieces, we must add process handles at both ends to avoid the grinding wheel hitting them, so subsequent processing also takes time and wastes materials. Therefore, grinding efficiency is one of the lower processing solutions.
Equipment Cost
The second disadvantage is that the cost of grinding is very high. Take our country as an example, a good thread grinder is similar to buying a car with options. The system you choose determines the spindle you use, the bed you use, and also determines the stability of your equipment. The beds are made of cast iron, artificial marble, or natural marble, and there are differences between them.
Whether you choose high-precision screws, hydrostatic guides, or linear motors, each has its own differences. Good configurations lead to high prices. Good thread grinders in our country cost over a million yuan, and good foreign thread grinders cost over ten million yuan. One internal grinder plus one external grinder basically costs over ten million yuan. In the next issue, I will share other processing techniques with you. Welcome to like and follow.
