Fabrication of precise non‐assembly mechanisms by multi‐material fused layer modeling and subsequent heat treatment

Abstract

Additive manufacturing techniques offer several potentials for future design and production. One of these potentials is non‐assembly mechanisms, movable mechanisms which need no assembly after production. Especially non‐assembly mechanisms consisting of kinematic pairs face major tolerance issues. This work advances into the new field of non‐assembly mechanisms consisting of kinematic pairs from multi‐materials. The research described in this article shows how tolerance issues can be overcome by the deliberate use of intrinsic and printing‐induced shrinkage processes. Therefore, non‐assembly mechanisms produced by multi‐material printing using fused layer modeling (FLM) are heat‐treated after the printing process to reduce and adjust the joint clearance. It was found that PLA was a suitable material for this process due to its relaxation and recrystallisation behavior during heat treatment. The printing techniques and relevant shrinkage mechanisms were analyzed and explained. Furthermore, it was found that relaxation of orientations and recrystallization could be separated in two different heat treatment steps creating a possibility for “induced self‐healing.” In addition, tribological aspects of such mechanisms will be discussed.