Injection molding of ceramic cores

Claim 1

A PROCESS FOR MAS PRODUCING CERAMIC CORES IN A CLOSED METAL MOLD COMPRISING PREPARING A CERAMIC SLURRY COMPRISING A MAJOR PROPORTION BY WEIGHT OF REFRACTORY PARTICLES AND A MINOR PROPORTION OF A BINDER FOR SAID REFRACTORY PARTICLES, COOLING THE SLURRY TO A TEMPERATURE BETWEEN -75*C. AND 0*C., FEEDING THE RFRIGERATED SLURRY THROUGH A METAL SUPPLY TUBE INTO THE MOLD CAVITY BY APPLYING A PRESSURE TO THE SLURRY SUFFICIENT TO FORCE ALL OF THE RESIDUAL GAS OUT OF THE MOLD CAVITY AND TO FILL THE CAVITY COMPLETELY IN NO MORE THAN ABOUT 3 SECONDS, HEATING THE MOLD CAVITY TO CAUSE THE SLURRY TO HARDEN RAPIDLY WHILE SIMULTANEOUSLY MAINTAINING THE TEMPERATURE OF THE SUPPLY TUBE AT ABOUT -20* TO -75*C. TO PREVENT HARDENING OF THE SLURRY AT THE ENTRANCE TO THE MOLD AND IN SAID SUPPLY PASSAGE, HOLDING SAID SUPPLY TUBE OUT OF CONTACT WITH THE METAL OF SAID MOLD TO MINIMIZE HEAT TRANSFER FROM SAID MOLD TO SAID SUPPLY TUBE, REDUCING THE PRESSURE ON SAID SLURRY TO PERMIT OPENING OF THE MOLD AFTER THE PATTERN IN THE MOLD CAVITY HAS BECOM RIGID,OPENING THE MOLD,REMOVING THE PATTERN FROM THE MOLD CAVITY TO COMPLETE A FIRST MOLDING CYCLE, CLOSING THE MOLD, AND REPEATING THE CYCLE BY AGAIN FEEDING THE REFRIGERATED CERAMIC SLURRY THROUGH SAID SUPPLY TUBE INTO SAID MOLD CAVITY.