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For industrial applications, additive manufacturing becomes more and more important due to its unrivaled design and materials freedom. In this light, additively manufactured polymer-polymer sliding combinations gain increasing interest for manifold tribological applications. This potential can be fully exploited, e.g., by using tribologically tailored compounds. For additive manufacturing not only the sliding combinations but also the understanding of the influence of printing parameters are important. Thus, this work is a first investigation of commercially available tribological compounds regarding their wear behavior by means of the ball-prism wear test. On that basis, influences of printing orientation and material combination on the wear behavior are investigated. In addition, interactions of these parameters will be discussed. Finally, the challenges of test specimen production as well as wear measurements are considered.

No abstract

Accurate assessment of the tribological system’s wear behavior is crucial for optimization. Common tribological test stands rely on a single measurement information—usually the indentation depth of the complete tribological system. If both counterparts experience wear—like polymer–polymer combinations—a subsequent assessment of the tested specimens is needed to estimate the contributions of each partner for determining the wear volume, and thus the wear rate. In this work, we propose a novel approach how an in-situ wear measurement of both simultaneously wearing counterparts can be implemented and generally demonstrate the feasibility on a ball-on-prism tribometer. This is achieved by measuring the system’s indentation depth while simultaneously scanning the ball’s surface with a laser profile scanner, providing information for calculation of the ball’s wear volume. While offering new possibilities for wear evaluation, challenges remain including radial runout of the measured specimen, testing in media and accumulation of large amounts of debris. Overall, this work presents an advancement in the evaluation of wear behavior, enabling better optimization of tribological systems with simultaneous wear. Refinements and adaptations to different setups can further enhance its utility.

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.