Feature-based process parameter variation in continuous paths to improve dimensional accuracy in three-dimensional printing via material extrusion

Abstract

Dimensional accuracy in additive manufacturing and especially for parts produced via material extrusion has been actively investigated in an effort to proceed from a prototyping process to a mature technology capable of manufacturing functional parts. Typically, accuracy in material extrusion is not the same along the different printing directions or it may vary according to the geometric feature that is fabricated. Therefore, it is considered as a problem with multiple responses and is typically tackled with multiple-objective optimization strategies in order to achieve optimal parameter settings that simultaneously satisfy contradicting requirements. In this work, response surface methodology is applied on the part, in order to obtain feature-specific models that predict dimensional accuracy. According to the proposed methodology, dimensional accuracy on every included feature and along the different printing directions is separately optimized with enhanced flexibility regarding the derived optimal solution. Optimal settings are fed directly to the material extrusion system as modified machine instructions. Different parameter settings for different regions of the same layer, or even varying material extrusion rate and feed rate along continuous trajectory, are validated. A specific part is used for demonstration purposes. The efficiency of this novel approach is compared with multiple-objective optimization based on the desirability method. The results exhibit enhanced dimensional accuracy of the part when adaptive settings are adopted for every feature.