There are mainly the following points :
1. the casting ring roasting is not transparent, resulting in casting ring temperature is too low, metal melting into the casting ring circulation is not smooth. When casting cobalt-chromium alloy, the casting ring is roasted, it slowly heats up before 300℃, stays for 30min at 300℃ and 600℃ respectively, and then retains heat for more than 30min when the roasting reaches the highest temperature. (Please refer to the manufacturer's instructions for the highest temperature.)
2. the alloy melting gold is not complete, will cause the metal flow is not smooth, casting channel blockage. Treatment method: When dental hard cobalt chromium alloy is heated and melted, an obvious oxide film is formed on the metal surface, and when the oxide film breaks to form a mirror, it is the best casting time.
3. Improper casting path design and placement: such as the formation of an acute Angle between the casting path and the casting, so that the alloy flow is not smooth, and the casting path design is too much. (Adjustments should be made according to the actual situation.)