Hot forming die having a nickel oxide layer

Abstract

A hot forming die (10) has forming surfaces (16,18) and the forming surfaces have a nickel oxide layer (20). A stop off material coating (22) builds up on the nickel oxide layer (20) in operation. A method of cleaning the forming surfaces (16,18) of the hot forming die (10) includes washing the forming surfaces (16,18) of the hot forming die (10) in water to remove the stop off material (22) without removing the nickel oxide layer (20) from the forming surfaces (16,18). The forming surfaces (16,18) may be soaked in water (26) and/or a jet (30) of pressurized water may be directed onto the forming surfaces (16,18). The stop off material is quickly removed without damaging the forming surfaces (16,18). The retention of the nickel oxide layer (20) improves the quality of the hot-formed articles and the interval between cleaning of the hot forming die (10) is increased.

Dependencies are inferred from the claim text.