Data for: RF Losses in Selective Laser Melted GRCop-84 Copper Waveguide for an Additively Manufactured Lower Hybrid Current Drive Launcher

RF Losses in Selective Laser Melted GRCop-84 Copper Waveguide for an Additively Manufactured Lower Hybrid Current Drive Launcher

Recent advances in selective laser melting (SLM) 3D printing technology allow additive manufacture of lower hybrid current drive (LHCD) RF launchers from a new material, Glenn Research Copper 84 (GRCop-84), a Cr2Nb (8 at. % Cr, 4 at. % Nb) precipitation hardened alloy, in configurations unachievable with conventional machining. Rough surfaces in additively manufactured components are a limiting factor that increases RF losses. Surface roughness was found to be the dominant loss mechanism in SLM printed waveguide components. Wet blasting removes adhered powder grains from SLM printed GRCop-84 while vibratory mass finishing smooth’s and flattens waveguide surfaces. Mechanical polishing produced surfaces with low RF loss, however a further mass finishing step is recommended for the interiors of waveguides where polishing is not possible. Power loss in the upcoming LHCD launcher system for DIII-D is used to predict driven current in the plasma.

在选择性激光熔化（SLM）3D打印技术领域的最新进展，使得由新型材料——格伦研究铜84（GRCop-84），一种含有8原子百分比铬和4原子百分比钽的Cr2Nb（8 at. % Cr, 4 at. % Nb）时效硬化合金——制造的附加式激光熔化（LHCD）射频发射器得以实现，其构型为传统机械加工所无法达成。附加式制造组件的粗糙表面成为限制因素，增加了射频损耗。研究发现，表面粗糙度是SLM打印波导组件中主要的损耗机制。湿式喷砂可去除SLM打印的GRCop-84上附着的粉末颗粒，而振动质量抛光则使波导表面光滑并平整化。机械抛光产生了低射频损耗的表面，然而，对于无法进行抛光的波导内部，建议采用进一步的质量抛光步骤。DIII-D未来LHCD发射器系统的功率损耗被用于预测等离子体中的驱动电流。