Abstract: Within an improved method of maintaining a die during interruptions in production and of subsequently returning the die to an optimal operating temperature, instead of having a manual control valve in the bypass loop of cooling medium, a PLC controlled valve is provided which can automatically allow or stop the flowrate through the bypass loop. Instead of circulating cooling medium through the die continuously, and at a reduced rate, during the interruption, the cooling medium is not circulated at all initially during the interruption. When the restart of production is desired, the first two preheat shots produced are made without the circulation of any cooling medium through the die. The valve within the bypass loop is then opened to let some cooling medium circulate through the die, however the circulation rate is less than the rate associated with normal production. The bypass loop is then left open while the valve in the primary loop is reopened.

Abstract: Within an improved method of maintaining a die during interruptions in production and of subsequently returning the die to an optimal operating temperature, instead of having a manual control valve in the bypass loop of cooling medium, a PLC controlled valve is provided which can automatically allow or stop the flowrate through the bypass loop. Instead of circulating cooling medium through the die continuously, and at a reduced rate, during the interruption, the cooling medium is not circulated at all initially during the interruption. When the restart of production is desired, the first two preheat shots produced are made without the circulation of any cooling medium through the die. The valve within the bypass loop is then opened to let some cooling medium circulate through the die, however the circulation rate is less than the rate associated with normal production. The bypass loop is then left open while the valve in the primary loop is reopened.