What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
As shown in FIG. 1 and FIG. 2 , a rivet die in the prior art includes a set of top die 1 and cover die 2 arranged opposite to each other. The top die 1 is provided with a cavity 1 in the center that matches the shape of the rivet dome head 3-1. -1, the center of the cover mold 2 is provided with a mold cavity 2-1 that matches the shape of the rivet dome head 3-3.
The anti-theft screw of this structure has two disadvantages. One is that the polygonal block moves up and down in the polygonal hole, and the polygonal hole in the connecting piece and the polygonal hole on the threaded part have no limit structure. Because of the polygonal structure, the two If the polygonal holes of the parts cannot be aligned, dislocation occurs, and any edge may block the up and down movement of the polygonal block, which is very unsmooth during use. The second is that the shell of the lock cylinder and the hexagonal part are connected by pins, and the pins are exposed on the hexagonal parts, which are easily damaged and leave opportunities for theft; once the pin is pried off, the lock cylinder will be taken out, and the entire anti-theft screw will be lost. and the pin fixation is sometimes unstable, which is detrimental to theft.
hand screw is a screw with a plastic head, and the user fixes the hand screw by turning the plastic head by hand. At present, a hand-tight screw is disclosed in the market publication number CN202203253U, which includes a plastic head and a screw rod, the plastic head and the screw rod are connected together, and the height of the plastic head is higher than that of ordinary screws, and the height is 11 cm. The screw of the hand screw is fixed in the plastic head by glue. After a period of use, the aging of the glue leads to the loosening of the screw and the plastic head. When the plastic head is stressed, the screw rod comes out of the plastic head, which affects the normal use of the hand screw.
Surface treatment process of screws 1. Types of surface treatment: Surface treatment is the process of forming a covering layer on the surface of the workpiece by a certain method. The purpose is to give the surface of the product a beautiful and anti-corrosion effect. The following methods are as follows: 1. Electroplating: Immerse the part to be electroplated in an aqueous solution containing the metal compound to be deposited, and pass the current through the plating solution to precipitate and deposit the electroplated metal on the part. Generally, electroplating includes galvanized, copper, nickel, chromium, copper-nickel alloy, etc., and sometimes blackening (blue), phosphating, etc. are also included. 2. Hot-dip galvanizing: It is done by immersing the carbon steel parts in a zinc-melting bath with a temperature of about 510°C. The result is that the iron-zinc alloy on the surface of the steel gradually becomes passive zinc on the outer surface of the product. Hot dip aluminizing is a similar process. 3. Mechanical plating: The surface of the product is impacted by the particles of the plated metal, and the coating is cold welded to the surface of the product.
The above content is uploaded by Yueluo or the Internet. If there is any copyright issue, please contact [email protected].
