Bypass cooling reduction on high pressure die cast machines

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.

1 . A system for casting parts, comprising:
 a die with cooling passages therein;   a cooling medium supplied to the cooling passages of the die;   a primary cooling loop including an automatically controllable valve through which the cooling medium passes;   a bypass cooling loop also including an automatically controllable valve through which the cooling medium passes;   wherein the controllable valves can be selectively changed between fully open and fully closed.   
     
     
         2 . The system of  claim 1 , wherein the cooling medium passing through the primary loop and the bypass loop originates from a common source. 
     
     
         3 . The system of  claim 1 , further comprising a PLC controller for controlling both automatically controlled valves. 
     
     
         4 . The system of  claim 3 , wherein the PLC controller for controlling the controlled valve on the primary loop closes the valve when there is an interruption in a production process of casting parts. 
     
     
         5 . The system of  claim 4 , wherein the PLC controller for controlling the controlled valve on the bypass loop closes the valve when there is an interruption in a production process of casting parts. 
     
     
         6 . The system of  claim 5 , wherein the PLC controller for controlling the controlled valve on the bypass loop reopens the valve after the production of at least two cast parts in a production process. 
     
     
         7 . The system of  claim 6 , wherein the PLC controller for controlling the controlled valve on the primary loop reopens the valve after the production of at least one additional part after the production of said at least two cast parts in a production process. 
     
     
         8 . The system of  claim 1 , wherein the bypass cooling loop also includes a flow restrictor. 
     
     
         9 . The system of  claim 1 , further comprising a heat exchanger system for recycling the cooling medium.