Optimization design of an articulated arm for laser beam delivery

Abstract

The design of an articulated beam delivery arm, having 6 rotational axes, is discussed in this paper. The device has been conceived for laser surface processing applications (e.g. cleaning, hardening, coating, etc), conducting a maximum 6 mm beam diameter of up to 150 W. To establish the geometrical attributes (i.e. shape, mass and size) of its components, a three-fold design process was followed, namely: attributes definition, preliminary design and optimization. For the operator to perceive a sensation of lightness when holding the focusing head and hence achieve smooth displacements, the total moment of inertia must be minimized subjected to an allowable off-axis beam deflection at the focusing lens. The device must also develop the accelerations required by the aforementioned laser processes under an estimated load limit exerted by the operator’s hand. Discrimination variables, defined from practical considerations (e.g. working zone height), were introduced to isolate the optimal design solution from the set of uniform solutions obtained. Thus, allowing the selection of optimal design parameters from a practical point of view.The design of an articulated beam delivery arm, having 6 rotational axes, is discussed in this paper. The device has been conceived for laser surface processing applications (e.g. cleaning, hardening, coating, etc), conducting a maximum 6 mm beam diameter of up to 150 W. To establish the geometrical attributes (i.e. shape, mass and size) of its components, a three-fold design process was followed, namely: attributes definition, preliminary design and optimization. For the operator to perceive a sensation of lightness when holding the focusing head and hence achieve smooth displacements, the total moment of inertia must be minimized subjected to an allowable off-axis beam deflection at the focusing lens. The device must also develop the accelerations required by the aforementioned laser processes under an estimated load limit exerted by the operator’s hand. Discrimination variables, defined from practical considerations (e.g. working zone height), were introduced to isolate the optimal design solution from...