Method of forming a thermally stable diamond cutting element

In one aspect, a vacuum-sealed can is used during the bonding process to improve the properties of an infiltrated TSP cutting element. In one embodiment, ultra hard diamond crystals and a catalyst material are sintered to form a polycrystalline diamond material (PCD). This PCD material is leached to remove the catalyst, forming a thermally stable product (TSP). The TSP material and a substrate are placed into an enclosure such as a can assembly, heated, and subjected to a vacuum in order to remove gas, moisture and other residuals that can inhibit infiltration of the infiltrant into the TSP layer. The can assembly is then subjected to high temperature, high pressure bonding to bond the TSP material to the substrate. During bonding, material from the substrate infiltrates the TSP layer.