STEP-NC Compliant Data Representations for Powder Bed Fusion in Additive Manufacturing

Abstract

Powder bed fusion (PBF) is an additive manufacturing (AM) technology that uses powerful beams to fuse powder material into layers of scanned patterns, thus producing parts with great geometric complexity. For PBF, process parameters, environmental control, and machining functions play critical roles in maintaining fabrication consistency and reducing potential part defects such as pores and grain growth. However, a major contributor to such defects can be attributed to poor data representations in the form of tessellated geometry and incoherent process plans. To address this issue, the Standard for the Exchange of Product model data Numerical Control (STEP-NC) recently added standardized data elements, entities, and attributes specifically for AM applications. Yet, the current STEP-NC data representations for AM lack definitions of process parameters and scan strategies that are commonly used in PBF processes. Therefore, characterization of the relationship between joint features, especially for PBF in AM, is missing. To bridge this gap, in this paper, an amended STEP-NC compliant data representation for PBF in AM is proposed. Specifically, the characteristics of the interlayer relationships in PBF, along with beam technology and AM strategy controls, are defined. Simulation results demonstrate the feasibility of granular process planning control, and the potential for producing high-quality parts with exact geometry and tolerance.