What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The machinery industry is one of the main users of fasteners. Due to China's late understanding of the important position of mechanical basic parts in the machinery industry and a long-term lack of investment, the entire industry has a poor foundation, weak foundation and weak strength. Especially with the improvement of the level of the main engine in China, the bottleneck phenomenon that the mechanical basic parts lag behind the main engine has become increasingly apparent. Today, although the state has given certain support in technology introduction, technological transformation, scientific research and development, etc., there is still a big gap compared with the current market demand and foreign levels. Unstable quality, high early failure rate and poor reliability. Fasteners are the main basic products in the machinery industry, and the development of the machinery industry also puts forward higher requirements for fastener products. Domestic ordinary standard fasteners have always been in oversupply, while high-end fasteners (high temperature, special-shaped, titanium-plastic composite, special performance and other fasteners) are in short supply, and they also rely on imports. The State Machinery Bureau lists ordinary standard fasteners as restricted development products, and high-strength special-shaped fasteners as currently encouraged development products. With the improvement of the country's industrialization level and technological progress, the use of high-strength fasteners has gradually increased.
Process equipment for aircraft production (hereinafter referred to as tooling) is directly used for part forming and component assembly. In order to satisfy the loading and unloading of aircraft parts and components during the use of the tooling, the tooling generally adopts a structural form that is easy to disassemble as a whole. In the field of aircraft process equipment manufacturing, positioning pins are usually used to connect and position the detachable parts of the tooling. At present, this kind of locating pin is divided into two types: direct pull-out locating pin and tie-suspended locating pin.
Guangdong Yueluo Hardware Industry Co., Ltd. provides a kind of rivet, parts and parts are riveted by the rivet, the part has a fixed plate and a fixed plate, and the part is located between the fixed plate and the fixed plate, The rivet includes a nail head, a nail post and a nail post which are connected in sequence, the diameter of the nail post is larger than the diameter of the nail post, the nail head is matched with the outer end surface of the fixing plate, and the length of the nail post is It is greater than the sum of the riveting length of the fixing plate and the riveting length of the part. The rivet can control the distance between the parts, so that the relative rotation of the two parts is more smooth and easy to operate.
Screws are a common fastener widely used in machinery, electrical appliances and buildings. The general material is metal or plastic, it is cylindrical, and the grooves engraved on the surface are called threads. Due to the different units of measurement, the representation methods of various threads are also different. For example, M16-2X60 represents a metric thread. His specific meaning is that the nominal diameter of the screw is 16MM, the pitch is 2MM, and the length is 60MM. Another example: 1/4—20X3/4 means the inch thread, what he specifically means is the nominal diameter of the screw It is 1/4 inch (one inch = 25.4MM), there are 20 teeth on one inch, and the length is 3/4 inch. In addition, if you want to express American screws, UNC and UNF are usually added to the back of the British screws to distinguish between American coarse teeth or American fine teeth.
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