How to check and repair polyurethane seals with excellent properties?

Polyurethane seals are made from rubber with the following excellent properties:

Polyurethane seals have excellent elasticity, wear resistance, oil resistance, cold resistance and high tensile strength, but water resistance, especially alkali resistance, is poor. They are available in heated vulcanised, room temperature vulcanised and hot melt types. The room temperature vulcanisation type is divided into one-component and two-component. They are widely used for sealing materials in buildings and for sealing in car manufacturing.

Detection and maintenance of polyurethane O-rings (seals): check that the hydraulic control components are fault-free, and the maintenance work enters a blind spot for a while. Disassemble and check the longitudinal cylinder of the tool holder, found that the piston oil seal “O” seal outer circle has been ground flat, at the same time found that the piston outer circle size does not meet the requirements (machine tool manufacturing reasons), the diameter direction is less than the standard size 0.8MM, the piston and cylinder body clearance is very large, resulting in the longitudinal cylinder two cavity interchangeable oil. Maintenance when the replacement of qualified piston and “O-type” seals after the machine tool punching troubleshooting. Analysis of the cause is in the knife frame down the knife in place at the moment, the knife frame as a whole by an impulse, can be broken down into its pressure condition, speed control valve oil return condition, the impact of the force area.