What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
With the rapid development of electronic technology, the integration of circuit boards is getting higher and higher, and the number of layers of circuit boards is increasing. Press-fit and fix to ensure accurate alignment during riveting and pressing. The rivets used on PCB boards are basically brass rivets. When riveting and pressing multi-layer PCB boards, metal chips are prone to appear, inner layer short circuits or foreign objects between layers, and because of the brass rivets With higher hardness and larger wall thickness, the riveted area of the PCB is thicker than the non-riveted area, which is easy to cause damage to the middle steel plate of the auxiliary tool. At the same time, the protruding rivets hinder the free expansion of the copper foil, which is easy to produce copper foil. wrinkling phenomenon. Now there are improved plastic rivets used to manufacture multi-layer PCB boards. The advantage is that no metal debris is generated, and at the same time, the tool steel plate is not damaged to the greatest extent. However, the existing plastic rivets are insufficient due to the inherent strength of plastics. When the PCB board is riveted and pressed, it is easy to deform, and the positioning is inaccurate, resulting in dislocation between layers, resulting in poor improvement of the product defect rate.
As we all know, whether it is the necessities in people's life or the equipment in industrial production, there will be a structure of screws and screw holes on it. This kind of structure that can simply fix some components together has been widely used in various fields. For the installation and removal of screws, people invented manual screwdrivers, and then to electric screwdrivers and so on. For manual screwdrivers, the operator needs to manually install or remove the screws. When encountering small screws, it can still handle it. When encountering large screws, due to people's limited strength, they may not install the screws in place, so it was invented. Electric screw. When installing the screw, which is widely used in the market, the operator needs to hold the screw handle, fix the screw on the screw port, and then align the screw with the corresponding screw hole for screwing. The disadvantage of this kind of screw is that it is heavy in quality and laborious to operate, and secondly, the operator will be injured due to operating errors, and the consequences are extremely serious. In view of this deficiency, people fix the screws on a work frame, so that before installing the screws, the operator only needs to adjust the screws to the designated position, and then the screws can be installed, which is convenient and simple. However, there are still potential safety hazards. In the process of adjusting the screw, it is still possible that the power of the screw may be turned on by mistake due to operating errors, resulting in injury to the operator. In view of the above-mentioned defects, it is necessary to invent a screw installation method with an anti-missing function.
The core rivet is a new type of riveting fastener that is very convenient for riveting. It can show its unique advantages in a relatively small space or in an environment where there is no rivet gun or a rivet gun cannot be used. Two or more connected parts can be riveted successfully by hitting the mandrel on one side with a hammer or other utensils. Core rivets can be divided into oblate head core rivets and countersunk head core rivets according to the shape of the brim of the nail cap. According to different material combinations, they can be divided into all aluminum core rivets, aluminum steel core rivets, and all stainless steel core rivets. Rivets, steel rivets, aluminum stainless steel rivets, plastic rivets, etc. Core rivets do not have to be riveted with manual riveting guns or pneumatic riveting guns like blind rivets. They have better riveting and convenience, and can be widely used in the riveting of various connected parts.
The design of the existing shaft circlip is relatively simple, and the circlip is not fast enough to be fixed in the shaft groove. When the shaft circlip receives the repeated action of radial impact load, it is prone to loosening, which affects the use of the circlip.
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