What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The existing spring pads are generally composed of longitudinal support springs, transverse connection springs, support springs, frames and frame clips. (Commonly known as string spring) is a slender and constant warp spring, used to connect the longitudinal support spring. The support spring is located at the edge of the spring pad to increase the shear resistance of the spring pad and the support strength of the frame. The surrounding frame connects the spring to the spring. up, fixed. The existing treatment method is to first heat-process the longitudinal support spring and the support spring made of 70# steel wire through the winding spring in a chemical solution, arrange them, and fix and connect them with a string spring, a frame and a clamping piece. Because the string spring and the frame have not been chemically heat treated, there is a large internal stress. Therefore, this treatment method has two disadvantages. One is that the processing efficiency of the heat treatment support spring is low. Larger, the spring is easily deformed and the service life is affected. In addition, the chemical solution after heat treatment is easy to cause environmental pollution
At present, the electrical control boxes of the market regulators all include a box body with built-in circuit board components and a box cover that is fastened together with it. The box cover is mostly fastened on the box body by self-supplied screws. The following problems are: First, there are many electric control lines on the circuit board in the box. When installing the self-supplied screws, the electric control lines may be damaged, which may easily cause a short circuit of the electric control, which is a potential safety hazard; Electric batch and other tools are inconvenient to install and disassemble, and the production cost is high.
The global economy continues to slump and overseas export trade is sluggish. Many fastener companies at home and abroad are facing severe tests. Accelerating economic transformation and structural upgrading is imminent, and developing overseas markets is undoubtedly an important way out for the development of the current fastener industry. From the fourth quarter of 2011 to the first half of 2012, affected by the objective environment, the development speed of the fastener industry may slow down, but from the third quarter of 2012, with the policy in place, the convening of the 18th National Congress of The upcoming series of development policies, etc., can promote the further development of the industry. And we must insist on innovation and adjustment and transformation, we must continue to rely closely on key industries such as automobiles, new energy, aerospace, shipbuilding, urban transportation, IT, electronic appliances, construction, etc., accelerate the optimization and upgrading of fastener products, and promote fasteners. The whole industry develops healthily and steadily. The global fastener market size exceeds 50 billion US dollars, and China's total fastener production in 2012 is also expected to reach about 6.8 million tons. However, compared with the manufacturing powerhouses such as the United States and Japan, there is still a big gap in my country's fastener industry.
The post-treatment of nickel-phosphorus plating includes two main processes of driving hydrogen and polishing. ①Hydrogen drive; according to the relevant standards, the hydrogen drive temperature after plating is 200±10℃, and the treatment time is 2h. 200 ℃ is beneficial to eliminate hydrogen embrittlement, relax internal stress, improve the bonding force between the coating and the substrate, and improve the corrosion resistance of the coating. ②Polishing; the polished bolt has a bright appearance, but in order to better improve the quality of the coating, smooth the tiny traces, and obtain a bright mirror-like surface, the coating needs to be polished with a polishing machine.
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