International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The paper presents an innovative method for joining Al alloy sheets and polymer fibre-reinforced composites by thermal drilling. A proposal for modifying the joint geometry by reverse drilling with a larger diameter tool is presented. The proposed modification demonstrated a statistically significant increase in the failure energy of the resulting joints.

This paper deals with the change of joint geometry of non-ferrous metal sheets and composite plates reinforced with bi-directional glass and carbon fiber by thermal drilling due to the effect of different drilling strategy. Joints formed by direct and sequential drilling were tested. Sequential drilling represents a convenient way to minimize delamination of layered composites during joining.

This paper presents the results of scanning fiber continuity in the joints of thin sheets made of aluminum and magnesium alloys with bi-directionally glass and carbon fiber-reinforced composites formed by thermal drilling technology using computed tomography. The scans show the progression of the bushing forming and the closure of the fibres in the hem joint. Little delamination, but no fiber fracture are visible in metal-composite joints.

The paper discusses the possibilities of joining thin-walled metals and composites reinforced with bidirectional carbon/glass fibres. The experimental part of the paper contains metallographic sections and results of load-bearing capacity testing of pilot metalcomposite joints with thermoplastic matrix and glass and carbon fiber reinforcement, formed by thermal drilling technology. As a result, a sequential joining method is proposed which can achieve the optimum joint geometry with a hem to keep the joint from opening under tensile stress.

The article deals with determinatin the optimum parameters for thermal drilling of selected Al, Mg and steel alloys to be subsequently used for joining with thermoplastic matrix composites reinforced with bidirectional continuous fibers. The optimum thermal drilling parameters will be considered to be those which produce a bushing of sufficient length and thickness to penetrate the composite material to a thickness of 1.5 mm.

The paper focuses on the evaluation of the quality of joints of thin-walled dissimilar overlapped materials, formed by thermal drilling without a screw. The shaped interference fit joint is formed by simultaneously forming both overlapped materials, preheated by the friction of a flowdrill tool, and forming a pair of embedded concentric bushings. The joints were made on a CNC milling centre, at constant speed, with tool feed being the only variable. Three tool movement strategies – three movement schemes – were tested. By evaluating the quality of the joints using metallographic sections, the optimum tool movement strategy was selected.