CASTING METHOD FOR MATRIX DRILL BITS AND REAMERS

摘要

An apparatus and method for manufacturing a down hole tool that reduces manufacturing costs and enhances the tool's performance. A belted mold assembly includes a casting assembly, a belt assembly, and a mid-belt. The belted mold assembly is used to fabricate a casting that allows for a larger diameter blank to be used which displaces the more expensive casting material and for using a smaller outer diameter thin-walled mold. The casting assembly is disposed within the belt assembly and the mid-belt is loaded in the volume created between the casting assembly's outer surface and the belt assembly's inner surface. The mid-belt provides a bracing for the casting assembly during the casting process. Optionally, a cap can be disposed on top of the blank for preventing metallurgical bonds from forming between the binder material and the upper portion of the blank. This allows for the excess binder material to remain high in purity so that it can be reprocessed. The cap can be used with the belted mold assembly or with a casting assembly known in the prior art.