What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Since the sub-industrial revolution, electricity has been widely used in people's lives. The application and development of electric power liberates the social productive forces and improves the social production efficiency. It is indispensable to the progress of the society. As a necessary constituent element of electric equipment, screws play an important role in the field of electric equipment. Existing screws are composed of screw heads and studs, which require specific tools to be tightened. However, during the maintenance of electrical equipment, some high-altitude workers need to carry extra screws in order to tighten the screws. the tightening tool, the staff caused great inconvenience.
(1) Galvanized (blue-white, multicolored, black) 1. Pretreatment: thermal degreasing tank (5 tanks) - electrolytic degreasing tank (3 tanks) - rust removal tank (4 tanks) 2. Electroplating: electroplating tank (20 tank) (ammonium chloride, zinc oxide, gloss, softener solution). 3. Post-treatment: Melting tank (1 tank) - Green medicine tank (1 tank) - (blue-white/multicolored/black) (2), blackening: 1. Pre-treatment: thermal degreasing tank (4 tanks) - rust removal Tank (4 tanks) 2. Blackening: blackening (5 tanks) (flake alkali, sodium nitrite solution) 3. Post-treatment: anti-rust oil (1 tank) (3), phosphating: 1. Pre-treatment: heat Degreasing tank (1 tank) - Derusting tank (1 tank) - Electrolytic degreasing tank (1 tank), - Surface treatment (1 tank) 2. Phosphating: Phosphating (forming a film) 3. Post-treatment: dipping in anti-rust oil (2 tanks) (4) Hot dip galvanizing: 1. Pretreatment: degreasing tank (1 tank) - rust removal tank (1 tank) - FLUX tank (1 tank) - drying 2. Hot dip galvanizing: hot Zinc immersion tank 3. Post-processing: centrifugal treatment - ammonia chloride cooling - water cooling
1. The expansion phenomenon of the spring washer is generally not the problem of the spring washer itself. 2. The spring washer with the expansion ring must be subjected to a radial external tension. The external tension is derived from the tightening axial force generated by the tightening torque. The chamfer creates a radial component of the axial clamping force, which expands the opening of the spring washer. The smaller the chamfer diameter, the greater the possibility of ring expansion. 4. Adding a flat washer between the nut and the spring washer helps to slow down or prevent the expansion of the ring, but the flat washer is too thin or too soft. Prevent ring expansion 5. The reason for the hydrogen embrittlement fracture of spring washers is generally due to unreasonable heat treatment process and the failure of hydrogen removal treatment after electro-galvanizing. A large number of tests and long-term practical experience have confirmed the above analysis.
The contact surface between the existing chassis and the main board is generally not a horizontal plane due to processing reasons, especially the main board is prone to warping deformation. It will increase, resulting in deformation of the motherboard and poor memory contact, affecting normal use.
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