Method for producing a multi-layer blank with a through-hole

A method for forming a multi-layer blank of a ceramic material comprising the steps of:

• providing a mold that includes at least one side wall surrounding a lower press plunger to form a cavity therebetween, wherein the lower press plunger has a movable pin;
• extending the movable pin from an upper surface of the lower press plunger and into the cavity;
• filling into the mold a first ceramic material, wherein the first ceramic material is filled in a pourable condition into the mold and around the movable pin to form a first layer with a through-hole;
• pressing a first upper press plunger against the first layer so that a first open cavity is formed while at least a portion of the first upper press plunger is in contact with the movable pin to maintain the through-hole in the first layer;
• extending the movable pin into the first open cavity;
• filling into the mold a second ceramic material of different composition, wherein the second ceramic material is filled in a pourable condition into the first open cavity and around the movable pin to form a second layer while maintaining the through-hole in both the first and second layers;
• and
• pressing a second upper press plunger against the second layer so that a second open cavity is formed in communication with the through-hole that extends through the first and second layers, wherein the second open cavity and the through-hole define a screw-hole of the blank, the screw-hole having a generally cylindrical lower portion and an upper portion having a screw seat with an anti-rotation feature.

A method for forming a multi-layer blank of a ceramic material comprising the steps of:

• providing a mold that includes at least one side wall surrounding a lower press plunger to form a cavity therebetween, wherein the lower press plunger has a movable pin;
• extending the movable pin from an upper surface of the lower press plunger and into the cavity;
• filling into the mold a first ceramic material, wherein the first ceramic material is filled in a pourable condition into the mold and around the movable pin to form a first layer with a through-hole;
• pressing a first upper press plunger against the first layer and an upper portion of the movable pin so that a first open cavity is formed while at least a portion of the first upper press plunger is in contact with the upper portion of the movable pin to maintain the through-hole in the first layer;
• wherein while the first ceramic material of the first layer is being compacted by the first upper press plunger, the movable pin is partially retracted into the lower press plunger by the pressing movement of the first upper press plunger;
• removing the first upper press plunger to expose at least a portion of the formed first open cavity;
• extending the movable pin into the first open cavity;
• filling into the mold a second ceramic material of different composition than the first ceramic material, wherein the second ceramic material is filled in a pourable condition into the first open cavity and around the movable pin to form a second layer while maintaining the through-hole in both the first and second layers;
• and
• pressing a second upper press plunger against the second layer and the upper portion of the movable pin so that a second open cavity is formed in communication with the through-hole that extends through the first and second layers to form the blank:
• wherein as the second upper press plunger presses against the second layer and the upper portion of the movable pin, the first and second ceramic materials are compressed while at least a portion of the movable pin is retracted into the lower press plunger by the pressing movement of the second upper press plunger.