In-process assembly of micro metal inserts in a polymer matrix

New functionalities and smaller dimensions of micro products can be achieved by means of a higher degree of integration of both materials and components. Smart micro assembly techniques (such as on-the-machine assembly) together with hybrid structures (as metal inserts in polymer matrix) are suitable solutions to manufacture new micro products with several integrated functionalities, reduced number of components and assembly phases, as well as the possibility to be replicated in a high number of specimens. Innovative manufacturing systems, as well as new design rules and testing methodologies, have to be established in order to be able to develop new and more integrated micro products. In this paper a method for testing the bonding between micro thickened metal inserts and the polymer matrix they are moulded in is presented. A specific demonstrator has been manufactured by means of a hot embossing-like process which allows fast developing time and the possibility of batch process. Different levels of surface roughness and metal insert thickness were applied in a systematic design of experiments. The results show a strong influence of surface texture on bonding strength. The testing procedure assists the designer in giving data to be used when dimensioning micro products involving integrated metal parts in a polymer product.