Design for additive manufacturing of a nonassembly robotic mechanism

Abstract

The growing potential of additive manufacturing technologies is currently being boosted by their introduction in directly manufacturing of ready-to-use products or components, regardless of their shape complexity. Taking advantage from this capability, a full set of new solutions to be explored is related to the possibility to directly manufacture joints or mechanisms as a unibody structure. In this paper, the preliminary design of a robotic mechanism is presented. The component is designed in order to be manufactured as a unibody structure by means of an Additive Manufacturing technology. Fused Deposition Modelling technique is used to print the mechanic arm as a single component, composed by different functional parts already assembled in the CAD model. Soluble support material is commonly used to support undercuts: in this case it is also deposited in the space between two adjacent parts of the same component, in order to allow the relative motion and the kinematic connection between them. The design process considers component optimization in relation to both the specific manufacturing technique and both the interaction between the different parts of the same component, in order to guarantee the proper relative motions. The conceived mechanism consists in a robotic structure in which the mechanical arm is bounded to a base and connected to a plier on the opposite side. The effect of clearance between all the kinematic parts is evaluated in order to assess mechanism degree of mobility in relation to the manufacturing process and components tolerances and geometry.