The first type: non-removable anti-loosening
This is an anti-loosening method that changes the detachable threaded connection into a non-detachable threaded connection by means of welding, bonding or punching riveting. It is a very reliable traditional anti-loosening method. The disadvantage is that threaded fasteners cannot be reused. And the operation is troublesome. It is often used in some important occasions that require anti-loosening and high reliability without disassembly.
The second type: anti-loosening of mechanical fasteners
Use mechanical fasteners to fix and pin the threaded part and the connected part or between the threaded part and the threaded part to prevent loosening. The advantage of this method is that the anti-loosening reliability generally depends on the static strength or fatigue strength of the mechanical fastener (or the fastener itself, such as a slotted nut). Its disadvantage is that it increases the weight of the fastening connection, is troublesome to manufacture and install, and cannot be installed by motor, so the cost is relatively high. Due to its high reliability of anti-loosening, it is still widely used in some important parts of mechanical products and aerospace products.
The third type: anti-loosening with increased friction
The purpose of anti-loosening is achieved by increasing the friction force between the threads or the bolt (screw) head and the end surface of the nut, or increasing the friction force of both at the same time. This anti-loosening method is less reliable than the first and second methods, but its great advantage is that it is not limited by the use of space, can be repeatedly assembled and disassembled many times, and can be assembled dynamically. Some fasteners (such as nylon lock nuts and metal lock nuts) have reached a very high level of anti-loosening reliability. Therefore, this method of anti-loosening is widely used in the machinery manufacturing sector and the aerospace field.
