Method and apparatus for cooling a glass pressing plunger

A method of differentially cooling a plunger for press forming glass articles in a cooperative forming mold, the plunger having a upper body portion requiring low heat removal rates and an integral lower nose portion requiring higher heat removal rates, each having a glass contacting surface, the method comprising:

• introducing a cooling fluid into an inlet cooling cavity located in the upper portion of the plunger and causing the cooling fluid to flow from the inlet cooling cavity into a cooling passage located along the periphery of the nose portion while maintaining a substantially uniform thermal profile on the glass contacting surfaces, and thereafter to flow into a outlet cooling cavity located in the upper portion of the plunger and thereafter exhausting the spent cooling fluid from the plunger.

A plunger for use in press-forming glass articles comprising an upper portion having a glass contacting surface and an inlet cooling cavity and an outlet cooling cavity, and a nose portion having a second glass contacting surface and a cooling passage, the cooling passage having an inlet and an outlet end connected to the inlet and outlet cooling cavities, respectively, the shape, location and size of the cooling cavities and the cooling passage are selected such that the glass contacting surfaces exhibit a substantially uniform thermal profile during molding.