In the present study, a fully controlled experimental protocol is used to investigate the difference in milling Invar and HexTool® for composites curing tools. The main difference is the use of the different strategies: conventional milling is better than climb milling, high feed/low speed better than low feed/high speed, high depth of cut better than low depth of cut, air coolant better than water coolant, diamond coating better than solid carbide, sand finishing better than chip removal, torus tools better than ball nose tools. Therefore, using metal machining strategy on composite curing tools leads to cracking and delaminations in the composite surface which causes the resin flow to infiltrate these cracks during the molding process. Consequently, parts demolding will destroy the surface of the curing tool and make it unusable without repair. The new technology approach will lead to a higher integrity of the composite surface and enhance the life cycle of the curing tool.