Fast and reliable quality inspection of micro parts

A continuous trend of function integration, miniaturization and densification opens new opportunities in industry and research. Tools, materials and technologies have to be scaled down from the macro to the micro range in order to manufacture micro products fast and reliable. Thereby, the downscaling leads to unexpected process behavior, so called size effects, which show higher variances due to a high number of influence factors [1]. In order to handle these issues a reliable quality inspection is needed. Besides appropriate metrology also exact part handling is required. For example the exact positioning of micro parts is required due to narrow field of view (FOV). Based on these findings we introduce a novel setup for achieving fast automated optical control of micro parts using a light field camera (LFC), for additional depth of field as well as depth information. We measured micro cups produced in a combined micro blanking and deep drawing process. Correct positioning of micro cups within the LFC’s FOV is ensured by placing it in sequence with an additional conventional camera. Incorrectly positioned cups can thus be regarded as defective or reintroduced into the setup. Information provided by the LFC is then used to automatically sort out fault cups using an algorithm based on support vector machines (SVM). The presented setup allows fast and completely automated 100% quality inspection of micro parts by use of different defect classes and inspection characteristics. [1] Vollertsen, Frank, et al. "Size effects in manufacturing of metallic components." CIRP Annals-Manufacturing Technology 58.2 (2009): 566-587.