US Patent 7651657 Manufacturing of controlled porosity metallic tools

A process for making a metal tool having controlled porosity is disclosed. The process includes the step of preparing metal powder by gas atomization. The metal powder is filled into a metal container. The powder-filled container is placed in a metal vessel and surrounded with glass frit. The metal vessel is then heated to a temperature sufficient to melt the glass frit. The metal vessel is then compacted under sufficient pressure to partially consolidate the metal powder so as to retain porosity therein in an amount sufficient to permit air to vent through the metal tool.