Ensamblaje automático de piezas con desviaciones dimensionales

The automatic assembly of parts can create some problems because of the dimensional variations of the elements to be assembled (mainly because of mechanical inconsistencies). A representative example of this kind of assembly problem can be found in the production of vehicle headlamps, where one of the main stages is the assembly of the cover lens, which is made of polycarbonate, over a black housing made of polypropylene. This process is currently done statically and does not consider possible size variations of the plastic parts, thus resulting in headlamps with dimensional errors. This paper introduces a new methodology of dynamic assembly for an industrial application that requires an adaptive positioning of the parts that are to be assembled. In addition, this work presents a successful example of an industrial prototype where different technologies, which aim to solve different problems, have to be analysed and tested. In particular, different approaches were studied: surface measurement sensors for transparent and deformable objects, actuation systems that could modify the assembly position of the parts, and control algorithms that could carry out this adaptive assembly automatically. A robust industrial prototype for vehicle headlamp assembly has been designed and built. It has been validated in both a research lab and in the assembly line of a vehicle headlamp factory. The new prototype solves the problem of assembling vehicle headlamps, achieving a final product with minimum dimensional errors and offering an example of a solution to the problem of the assembly of pieces with dimensional errors.