Root cause: 1. Insufficient cooling
Solution: Increase inlet water flow for calibrating sleeve, or prolong the distance between bush and calibrating sleeve.
Root cause: 2. Sealing ring size is inappropriate, and forms vibration.
Solution: Confirm the size of sealing ring the vacuum tank. If small, replace it. Otherwise, slightly reduce the vacuum degree of the first section in the vacuum chamber, then increase the vacuum degree of the second section in th vacuum chamber.