What is the Screw Torque Standard?
1 Answers
Screw torque standards are as follows: 1. Class A: Fixing of iron screws and iron nuts, such as: assembly of various components of the box body. Fixing of grounding screws and nuts. PCB fixed to the box body. 2. Class B: Iron screws and copper nuts (screw holes and screw holes of aluminum alloy materials), such as: fixing of transistors or wire terminals to aluminum heat sinks. Aluminum heat sinks fixed to the PCB. Fixing screws for large capacitors or transistor terminals (TERMINAL). Fixing of RS-232 hexagonal copper pillars. 3. Class C: Iron screws (self-tapping) locked into plastic holes. Such as: plastic panel fixed to the box body. PCB fixed to the plastic panel. 4. Class D: Iron screws (self-tapping) locked into drawn holes with a plate thickness of 1.0. M3 drawn holes are ф2.8(+0, -0.05), and M4 drawn holes are ф3.65(+0.05, -0). 5. Class E: Iron screws (self-tapping) locked into drawn holes with a plate thickness of 1.2, with the same dimensions as Class D.