What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
screw is a common threaded connection part, which is mainly used to fix a part on the connection body. When it is necessary to connect, use the screw to pass through the hole on the connected parts, and screw the external thread on the screw into the connecting body to tighten it; The coupling part is separated from the coupling body. Existing common tools for screw disassembly and assembly are generally adjustable wrenches, open-end wrenches, Torx wrenches, socket wrenches, Allen wrenches, flat-blade screwdrivers, cross-shaped screwdrivers, etc., and a screw can only be disassembled with one or one type of tool. Assembly work; when the types of tools are not complete, the screw disassembly and assembly work is difficult to complete, and the screw disassembly and assembly work is greatly limited by the tools.
If the above-mentioned nuts and screws are used as a kind of fasteners that can prevent others from being disassembled, such as when installing iron doors-steel windows, people usually tighten the nuts first, and then use a welding machine to weld the nuts and screws. To prevent the nut from loosening, it may be necessary to use a tool to mill the threads on the screw. It can be seen that this approach is very inconvenient.
The circuit board is often the circuit board that plays a major role in electrical equipment, and the main electrical components of the circuit are often integrated on the motherboard. For single-layer circuit motherboards, rivets are used on the circuit motherboard in order to make the components more firmly fixed on the pcb board. In the prior art, the rivets are all set on the circuit board by an automatic riveting machine, which is controlled by an internal program to automatically complete the rivet-setting operation. This internal program is pre-set. If you need to rivet different motherboards, you must change the internal program. If you need to temporarily rivet a circuit board, it will be cumbersome to change the program again. Moreover, this kind of automation equipment is produced on a large scale and is not suitable for temporary operations.
The main operation method of the embedded knurled copper nut of the lock nut is injection molding. After heating, it is embedded into the plastic part or directly injection molded. If injection molding is used, the melting point of P/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 hardens. 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.
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