Feasibility study of adhesively bonded drills with a small diameter for cutting of CFRP

Abstract

Adhesively bonded cutting tools possess many advantages over classic (insert) tools due to different manufacturing processes: With reduced manufacturing temperatures, the damage to the cutting edge decreases, and the damping effects of the adhesive enhance the tool’s life. In contrast to standard joining technologies like soldering, adhesive bonding enables the joining of various cutting materials and tool base bodies, like ceramic and steel. Furthermore, the usage of expensive, abrasive-resisted cutting materials, like carbide, has to be reduced in future because of the classification of the components (cobalt, wolfram carbide) as a critical resource. Therefore, this article conducts a feasibility study of adhesively bonded drills with a ceramic tip for cutting carbon-fiber-reinforced plastics. The main contents are investigations of different surface preparation methods (laser surface texturing and SACO-blasting), examining four different adhesives for cutting tool usage, and manufacturing and validating prototype drills for cutting operations. The experimental results show a high scattering of the toughness of the joints between 2.8 MPa and 27.8 MPa, depending on the combination of surface preparation and adhesives. Also, the choice of adhesive influences the performance of the manufactured drills. The maximum number of drilled holes scatters between 15 and 67 holes before breakage. A linear relation within the analysis of axial forces and factors of the covered area is observed. For further studies, the surface preparation needs to be improved, the glass transition temperature must be maximized, and the drill geometry must be optimized. Furthermore, a cooling concept for the cutting tools needs to be investigated.