What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
A screw is a tool that uses the physical and mathematical principles of the circular rotation and friction of an object to fasten the mechanism of the object step by step. A drill-tail screw is a screw with a self-tapping drill head on the front end of the screw. The screw is a common invention in people's production and life for thousands of years. According to the application field, it is the first invention of mankind. Drilling screw is a new invention in recent years, also called self-drilling screw. A screw is a common term for fasteners, an everyday colloquial language.
The square nut is a fastener that needs to be used in the installation of the cable tray. In the prior art, the square nut 1 is pressed by the elastic force of the spring 2 below it and the opening of the C-shaped steel 3 (as shown in Figure 1, Figure 2), in the absence of external force, through the interaction of pressure and static friction, the C-shaped steel 3 will not move vertically or horizontally, which can facilitate engineering installation. The advantage of this installation method is that it can slide anywhere on the C-shaped steel 3, but the disadvantage is that it occupies the bottom space of the C-shaped steel 3, and the spring 2 will interfere with the installation hole of the square nut I, which affects the installation.
At present, with the development of the manufacturing industry, many parts with strange shapes are widely used in aviation, aerospace and other industrial fields, one of which is an L-shaped cylindrical pin. The upper end is provided with a 2.55×4.95 U-shaped boss. The parallelism error between the upper end face and the lower end face of the boss is required to be less than 0.01 mm. The L-shaped cylindrical pin requires high machining accuracy and is difficult to clamp on the machine tool. It is difficult to process. When the forming part is cut off, the cut surface, that is, the upper end surface of the boss, will leave a small column platform. When processing this end surface, in the prior art, a vise is generally used to process such an L-shaped cylindrical pin. Or copper sleeves are clamped, and then processed; however, due to the small size of the parts, the L-shaped cylindrical pin workpiece is difficult to clamp; due to the high precision required for each machined surface of the workpiece, when clamping with a vise , the clamping force of the vise is difficult to control, and it is easy to crush and scratch the surface of the workpiece; and when using a vise or a copper set clamp, only one workpiece can be clamped for each processing and production, and it is difficult to ensure the upper and lower planes of the parts after the clamping is completed. Parallelism machining error, resulting in low parts processing quality and low production efficiency.
The pressure riveting nut, also known as the self-tightening nut, is a kind of nut applied to thin plates or sheet metal parts. To facilitate the installation of other parts on the printed circuit board. The conventional process is to design prefabricated holes on the printed circuit board in advance, and squeeze the rivet nut into the board through pressure, so that the periphery of the hole is plastically deformed, so that the rivet nut is firmly fixed on the circuit board. In important positions, the use environment of pressure riveting nuts is relatively harsh. In display products, due to space constraints, pressure riveting screws are used a lot. The riveting quality of pressure riveting screws has a direct impact on the reliability of the system. The riveting process is correct. The key technology of using rivet nuts.
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