Reduction of acquisition time through optimal component presentation at an assembly workstation

Abstract: "An effective presentation of components at the workstation can have a significant impact in reducing assembly time. Our goal is to develop optimal presentation plans based on design for assembly theory. The assembly factors recognized as relevant to both parts acquisition and assembly workstation layout are recognition, orientation, weight, and handling distance. This study considers a single manual operator at an assembly station, with the components in rectangular bins of differing sizes and aspect ratios. Ninety degree rotations of the bins are allowed for minimizing potential handling distance. The assembly task is modeled with multiple assembly points representing the final location of the components. Components may or may not be preoriented in the bins, with preorientation removing the recognition and orientation time penalties. The problem formulation employs Mixed Integer Non-Linear Programming (MINLP), and numerical evidence suggests an NP-hard problem. Heuristic methods reduce computational effort to practical levels for realistic assembly tasks. Our results show that numerical optimization of assembly workstation layout can reduce the expected level of difficulty over random or manual workstation design methods."