Method of Multiaxis Three-Dimensional Printing with Intralayer Height Variation for Stairstep Effect Compensation.

The recent developments in multiaxis three-dimensional (3D) printing have got a large potential for expanding the capability of material extrusion based methods. Especially curved and nonplanar methods can improve buildability, surface quality, and mechanical performance. However, the challenges that arise from using them complicate their deployment. In this article, we propose a hybrid planar method, based on varying the layer height and deposition speed in combination with tool reorientation, that allows us to get a lot of the same benefits that come from using nonplanar layers. The goal of the method is to keep the deposition constant regardless of the overhang angle. This is achieved by simultaneous control of layer height, deposition speed, and tool orientation. The method is the most beneficial for large-scale, single-wall 3D printing, such as clay, concrete, and other composites. The main restriction of the method depends on the minimum/maximum ratio between the nozzle diameter and layer height. A description of the method is provided, and sample objects are evaluated either as trajectories or as test prints. The claims are confirmed by microscopy measurement of the contact patch width. The method as presented allows printing of overhangs up to 82.34°, can be applied to complex geometry without difficulties, and further possibilities of limit expansion are discussed. The contact patch width decreases only by 20% at the 80° of overhang.