CNC Machine Design – Pin Connection

The pin is mainly used to fix the relative position between parts, which is called positioning pin, it is an important auxiliary part in combination processing and assembly. It can also be used for connections, called connecting pin, which can transmit small loads. Also it can be used as a safety device in the overload shear element, known as the safety pin.

Classification

– Cylindrical pin. By interference fit fixed in the pin hole, after multiple assembly and disassembly will reduce its positioning accuracy and reliability.

– Taper pin. It has a taper of 1:50 and can self-lock when subjected to transverse forces. It is easy to install, high positioning accuracy, can be assembled and disassembled for many times without affecting the positioning accuracy. Tapered pins with threaded ends may be used for blind holes or in positions where disassembly is difficult. Taper pin with open tail is suitable for positions with impact and vibration.

– Groove pin. There are three longitudinal forged grooves on the groove pin. After the groove pin is driven into the pin hole, the pin is squeezed in the pin hole due to the elasticity of the material, which is not easy to be loosened, so it can bear vibration and variable load. The hole of installation groove pin does not need to be reamed, easy to process, can be assembled and disassembled for many times.

– Shaft pin. The hinge joint is formed by the hinge position of the two parts. Pin shaft commonly used split pin for locking, reliable work, easy to disassemble.

– Split pin. Separate the ends during assembly to prevent them from coming out. Cotter pins are also commonly used in threaded connections for anti-loose devices.

– Positioning pins, usually subject to no load or only a small load, may be of structurally determined diameter and generally using not less than two. The length of the pin into each connected piece is about 1-2 times of the diameter of the pin.

– Safety pin. It will cut when the machine is overloaded, so the diameter of the pin can be determined according to the conditions of being cut when the machine is overloaded.

Pins are standard parts, usually made from Q235, 35 and 45 steel. Also it can be customized by CNC machining, as per the actual use of the location processing.