What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Length conversion The length of the American screw must be converted to be the metric mm size. Conversion formula: (Length Code / 32) x 25.40 = metric length mm B-3,B-4,B-5 : The marking method is the same as the metric system.
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 technical process of nickel-phosphorus plating for high-strength bolts consists of three parts: The first part is the pre-treatment process, including the precision and appearance inspection of high-strength bolts before plating, manual degreasing, immersion degreasing, pickling, electro-activation and flash nickel plating and other processes; the second part is the electroless nickel plating treatment process; the third part is the post-treatment process, including the processes of hydrogen-displacing heat treatment, polishing and finished product inspection. As follows: Bolt chemical composition inspection → bolt pre-plating accuracy, visual inspection → manual degreasing → visual inspection → immersion degreasing → hot water washing → cold water washing → pickling → cold water washing → electric activation → cold water washing → flash nickel plating → cold water washing → Deionized water washing → Electroless nickel plating → Deionized water washing → Cold water washing → Hydrogen removal → Polishing → Finished product inspection.
In another embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the discharge port of the vibrating plate 2 is matched with the screw receiving hole 35, and the screws can enter the screw receiving hole 35 through the discharge port after sorting and sorting in the vibrating plate 2. . Preferably, a guide rail 6 is provided between the discharge port of the vibrating plate 2 and the screw accommodating hole 35 , and the screws enter the screw accommodating hole 41 from the discharge port through the guide rail 6 . The slotting is carried out, which improves the efficiency and saves the labor cost.
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