Design Strategy for Non-Contact Supports in Ti-6Al-4V Metal Additive Manufacturing

초록

In metal additive manufacturing, supports are crucial for producing parts with significant overhangs or potential deformations. However, traditional supports often degrade surface quality during post-processing, making them less suitable for high-precision applications. Recent studies have proposed non-contact supports as a promising alternative, demonstrating that maintaining a gap larger than the melt pool depth can yield optimal supports with satisfactory surface roughness. This study aims to improve the economic feasibility of non-contact supports by reducing their volume and addressing the heat accumulation issues associated with bulky designs. We focus on Ti-6Al-4V, a titanium alloy known for its excellent mechanical properties and widespread use in aerospace and biomedical industries. Despite these advantages, Ti-6Al-4V's low thermal conductivity leads to significant thermal gradients and resultant deformations during the additive manufacturing process. Previous research has often used bulky non-contact supports or combined blade-shaped upper sections with conventional lower supports, which failed to efficiently mitigate thermal gradients. To address these challenges, our novel approach involves designing the upper section of the non-contact support to resemble a blade, minimizing contact with the part, while the lower section undergoes topology optimization to reduce overall support volume and minimize deformation caused by the bulky design. We conducted extensive simulations using ANSYS Additive software, varying the support volume from 60% to 15% in 5% increments, with 100% as a comparison model, and measured the resulting deformation. Results indicate that while deformation increases slightly as support volume decreases, the deformation-to-volume ratio remains practical. Supports with reduced volume still provide adequate structural integrity, allowing for significant reductions in material usage and overall cost. Our analysis revealed that optimized non-contact supports can significantly reduce powder consumption, a major cost factor in metal additive manufacturing, and effectively address deformation issues. The blade-shaped upper section ensures minimal surface damage during post-processing, improving the overall surface finish of the manufactured parts. This dual approach, combining a blade-shaped upper section with a topology-optimized lower section, enhances the practicality and economic feasibility of non-contact supports. Our findings suggest that this approach enhances cost-effectiveness and efficiency in manufacturing, particularly in precision-focused industries. It also supports sustainable practices through reduced material usage. The proposed design maintains mechanical properties while advancing support structures in metal additive manufacturing. Future work will refine designs and validate them in real-world conditions to broaden their industrial applicability. © 2024 15th Asia-Pacific International Symposium on Aerospace Technology, APISAT 2024. All rights reserved.