Industrial assembly of parts with dimensional variations. Case study: Assembling vehicle headlamps

Presently, it is quite common, because of their benefits, to find plastic parts as the main elements of diverse commercial products. However, plastic components also present some drawbacks, such as their typical dimensional variations (especially in parts with complex geometry or with considerable size), making difficult, or even impossible, the correct assembly of the parts. 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 analyzed 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. The final goal of this work was to obtain a robust industrial prototype for vehicle headlamp assembly that could solve the high dimensional variations of the main plastic parts. To demonstrate the performance of the proposed solution, a wide set of experimental test was carried out 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, achieves a final product with minimum dimensional errors and offers an example of a solution to the problem of the assembly of pieces with dimensional errors.

► A new methodology of dynamic assembly, that requires an adaptive positioning of the parts that are to be assembled, is proposed.
► This work presents a successful example of an industrial prototype where different technologies were analyzed and tested.
► A robust industrial prototype for vehicle headlamp assembly has been built using this methodology.
► This prototype achieves a final product with minimum dimensional errors and offers an example of a solution to the problem of the assembly of pieces with dimensional errors.