What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Standards are norms, and each country and sector has its own standards. The most commonly used standards in our daily business are as follows: GB—China National Standard (National Standard) ANSI—American National Standard (American Standard) DIN—German National Standard (German Standard) ASME—American Society of Mechanical Engineers Standard JIS - Japanese National Standard (Japanese Standard) BSW - British National Standard GB - National Standard is one of many standards in my country, as well as industry standards, professional standards and department standards. National standards are divided into: GB (mandatory standards) and GB/T (recommended standards) and GBn (national internal standards) and so on. We usually see GB30, GB5783, etc. are mandatory standards. In addition to some basic dimensions such as head-to-side, head thickness, etc., the above standards are mainly different in the threaded part. The threads of GB, DIN, JIS, etc. are all in MM (millimeters), which are collectively referred to as metric threads. Another thread like ANSI, ASME, etc. is called American standard thread in inches. In addition to metric threads and American threads, there is also a BSW-imperial standard, whose threads are also in inches, commonly known as Wyeth threads.
In the design of electrical products, in order to avoid the problem of electromagnetic radiation interference, it is necessary to isolate the conduction between metal parts (parts). Especially when the metal parts are locked by metal screws, the conduction between the locked pair of metal parts (parts) is often caused, so it is necessary to try to isolate them. For example, when screws are used to lock the structure iron of the liquid crystal display screen and the iron structure of the foot base, the electromagnetic waves generated by the liquid crystal display screen are easily radiated from the foot base, causing electromagnetic radiation interference.
self-locking screw comprises a screw main body, a metal screw head is arranged on the upper part of the screw main body, a thread is arranged in the middle part of the screw main body, an interference groove is arranged on both sides of the upper part of the screw main body, and the line of the interference groove is arranged. The included angle is 280-356° with the horizontal line. The bottom of the screw body is provided with an elastic chuck, and the elastic chuck includes an optical axis and a conical head. Guangdong Yueluo Hardware Industry Co., Ltd. Guangdong Yueluo Hardware Industry Co., Ltd. adopts the design of elastic collet, and the screw is provided with threaded segments and interference grooves, so that during the screwing process, the interference groove of the optical axis between the two threaded segments is formed along the screw. The axial elastic force achieves the effect of reliable self-locking, which is easy to use and has high tuning efficiency.
Bolt material: 18Cr2Ni4W, 25Cr2MoV steel; bolt specification: M27～M48. Because this kind of steel is easy to form a passivation film on the surface, and this passivation film will make the bolt unable to obtain a good adhesion chemical nickel phosphorus layer, so special pretreatment measures must be taken to remove the film first, and measures should be taken To prevent its regeneration, it is possible to ensure a good bonding force between the plated coating and the substrate. At the same time, due to the large geometric size of the bolt, it increases the difficulty of nickel-phosphorus plating treatment and quality inspection of the process.
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