What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The screw is usually installed in the threaded hole of the part, and its main function is to fix the relative position between the two parts. It is widely used in various industries. A traditional screw generally includes a screw rod and a head located at one end of the screw rod. During installation, the screw rod is connected with a threaded hole, and the head is located outside the screw hole and abuts on the edge of the screw hole.
The research on rivet nuts started in the 1970s in my country and is still in the design and development stage. In the mid-1980s, equipment for the production of blind rivets was introduced from abroad, but no rivet nut has been produced so far. After the inventor's search, no low-carbon steel rivet nut was found to be publicly used.
Sometimes, the iron screws are often seen broken, and sometimes, the stainless steel screws are also seen broken. But generally speaking, stainless steel screws rarely break. Because the stainless steel screw wire itself is relatively hard. But under certain circumstances, stainless steel screws can still break. So what are the main reasons for stainless steel screws to break? The reasons for the fracture of stainless steel screws are as follows: 1. The quality of raw materials used for stainless steel screws is poor, and the quality of stainless steel screws is not good. There are many impurities, impure, resulting in insufficient hardness of stainless steel screws. 2. The production process of stainless steel screws. For example, stainless steel screws with eccentric head and eccentricity, and the Q value is too deep and the R position design is too small during the down punching operation during production. 3. The customer uses too much force when using stainless steel screws. Generally, you do a torque test to see how much the minimum breaking force is, and then adjust the torque. Of course, stainless steel screws must be broken for more than three reasons. But the above three reasons are the main reasons for the fracture of stainless steel screws. When the stainless steel screw is found to be broken, it can be checked step by step. Find out what's causing it.
The embedded nut is made of copper nuts made of various embossed wires (usually lead brass, such as H59, 3604, 3602). The embedded knurled copper nuts that we come into contact with on a daily basis are processed by precision automatic lathes. The reference standard for embedded knurled copper nuts comes from the national standard GB/T809. The main operation method of the anti-loose nut is to inject the embedded knurled copper nut. After heating, it is embedded into the plastic part or directly injected into the mold. If the mold is injection-molded, the melting point of PA/NYLOY/PET is above 200°C , After the embedded nut is hot melted into the plastic part, the temperature rises rapidly. After injection molding, the plastic body rapidly cools and crystallizes and becomes hard. If the embedded nut temperature is still at a high temperature, it may fall to the place where the copper nut contacts the plastic part. Start to loosen or crack. Therefore, copper nuts are used instead of carbon steel nuts in the injection molding of embedded nuts. There are two ways to form the external knurling of the embedded copper nut. One is to use copper raw material to draw the knurl and then to produce it on the upper equipment. Generally, the pattern of this method is straight, and the other is to use The round copper material is directly embossed while tapping during the production process. This processing method can produce some non-standard size knurled copper nuts. The embossed shape of the embedded copper nut can be selected by the user, such as mesh, Character embossing, herringbone embossing and other knurling patterns.
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