STEP-NC Process Planning for Powder Bed Fusion Additive Manufacturing

Powder bed fusion (PBF) is an additive manufacturing (AM) technology that uses high-power beams to fuse powder material into layers of scanned patterns, thus producing parts with great geometric complexity. For PBF, the selection of appropriate process parameters, environmental control, and machine functions play critical roles in maintaining fabrication consistency and reducing potential part defects such as cracks and pores. However, poor data representations in the form of approximated geometry and incoherent process plans can negatively impact the relationship between the selected parameters. To address this issue, the Standard for the Exchange of Product model data Numerical Control (STEP-NC) recently added standardized data entities and attributes specifically for AM applications. Yet, the current STEP-NC data representations for AM do not have definitions for process parameters and scan strategies that are commonly used in PBF processes. Therefore, there is a need for defining data models that link process parameters with process control. 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 the technology and scan strategy controls, are defined. Simulation results demonstrate the feasibility of granular process planning control and the potential for producing high-quality parts that meet geometric requirements and tight tolerances. The contributions of this paper highlight the importance of information models in AM, promoting data representations as key enablers of the AM technology and supporting the neutrality and interoperability of data across AM systems.