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Application of hybrid laser powder bed fusion additive manufacturing to microwave radio frequency quarter wave cavity resonators


In this paper, we present the first known experimental results in using hybrid additive-subtractive laser powder bed fusion (h-LPBF) to make a type of passive radio frequency component called a quarter wave resonator (QWR). The h-LPBF process uses in-situ, interlayer vertical milling to machine certain inaccessible, critical internal features of the QWR device during printing. Using h-LPBF, the as-built surface roughness of functionally important features improved to Ra ~ 2 µm compared to Ra ~ 8 to 20 µm for conventional (additive only) LPBF-processed QWRs. Additionally, the dimensions of certain critical features were closer to their intended design. These metrological improvements resulting from h-LPBF reduced RF losses by a factor of almost 2. Consequently, the RF performance (Q-factor) of h-LPBF-processed QWR components were 1.5 to 2 times superior compared to their conventional LPBF counterparts, and the performance advantage was sustained on stress relief and chemical etching. These results were verified with theoretical electromagnetic simulations.

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  1. Sames WJ, List FA, Pannala S, Dehoff RR, Babu SS (2016) The metallurgy and processing science of metal additive manufacturing. Int Mater Rev 61:315–360.

    Article  Google Scholar 

  2. Clymer DR, Cagan J, Beuth J (2017) Power–velocity process design charts for powder bed additive manufacturing. J Mech Des 139.

  3. Snyder JC, Thole KA (2020) Understanding laser powder bed fusion surface roughness. J Manuf Sci Eng 142.

  4. DebRoy T, Wei HL, Zuback JS, Mukherjee T, Elmer JW, Milewski JO, Beese AM, Wilson-Heid A, De A, Zhang W (2018) Additive manufacturing of metallic components – process, structure and properties. Prog Mater Sci 92:112–224.

    Article  Google Scholar 

  5. Gradl PR, Tinker DC, Ivester J, Skinner SW, Teasley T, Bili JL (2021) Geometric feature reproducibility for laser powder bed fusion (L-PBF) additive manufacturing with Inconel 718. Addit Manuf 47:102305.

  6. Kumbhar NN, Mulay AV (2018) Post processing methods used to improve surface finish of products which are manufactured by additive manufacturing technologies: a review. J Inst Eng (India) Ser C 99:481–487.

    Article  Google Scholar 

  7. Peng X, Kong L, Fuh JYH, Wang H (2021) A review of post-processing technologies in additive manufacturing. J Manuf Mater Proc 5.

  8. Benedict GF (1987) Nontraditional manufacturing processes. CRC Press.

  9. Jain VK (2008) Advanced (non-traditional) machining processes - machining: fundamentals and recent advances. In: Davim JP (ed). Springer London, London, pp 299–327.

  10. Sealy MP, Madireddy G, Williams RE, Rao P, Toursangsaraki M (2018) Hybrid processes in additive manufacturing. J Manuf Sci Eng 140.

  11. Sefene EM, Hailu YM, Tsegaw AA (2022) Metal hybrid additive manufacturing: state-of-the-art. Progr Addit Manuf.

  12. Eisenbarth D, Breuch M, Soffel F, Wegener K (2019) Challenges of combining direct metal deposition with milling for the fabrication of a rocket nozzle. In: Proceedings of the Special Interest Group Meeting on Advancing Precision in Additive Manufacturing, pp 83–86

  13. Du W, Bai Q, Zhang B (2018) Machining characteristics of 18Ni-300 steel in additive/subtractive hybrid manufacturing. Int J Adv Manuf Technol 95:2509–2519.

    Article  Google Scholar 

  14. Wüst P, Edelmann A, Hellmann R (2020) Areal surface roughness optimization of maraging steel parts produced by hybrid additive manufacturing. Materials 13.

  15. Sarafan S, Wanjara P, Gholipour J, Bernier F, Osman M, Sikan F, Molavi-Zarandi M, Soost J, Brochu M (2021) Evaluation of maraging steel produced using hybrid additive/subtractive manufacturing. J Manuf Mater Process 5.

  16. Torims T, Pikurs G, Gruber S, Vretenar M, Ratkus A, Vedani M, López E, Brückner F (2021) First proof-of-concept prototype of an additive manufactured radio frequency quadrupole. Instruments 5.

  17. Hähnel H, Ratzinger U (2022) First 3D printed IH-type linac structure—proof-of-concept for additive manufacturing of linac RF cavities. Instruments 6.

  18. Carriere P, Kutsaev S, Ronald A, Pedro CANF, Horn T, Kelly M, Smirnov A (2021) Fabrication approaches to 3d superconducting qubit resonators with a high Q-factor. In: Bulletin of the American Physical Society, p 66.

  19. Ives L, Bui T, Marsden D, Collins G, Horn T, Ledford C, Neilson J (2020). Additive manufacture of RF loads for ITER.

  20. Seltzman AH, Wukitch SJ (2020) Surface roughness and finishing techniques in selective laser melted GRCop-84 copper for an additive manufactured lower hybrid current drive launcher. Fusion Eng Des 160:111801.

  21. Sirci S, Menargues E, Billod M (2021) Space-qualified additive manufacturing and its application to active antenna harmonic filters, in. IEEE MTT-S International Microwave Filter Workshop (IMFW) 2021:239–242.

    Article  Google Scholar 

  22. Gill SS, Arora H, Jidesh, Sheth V (2017) On the development of antenna feed array for space applications by additive manufacturing technique. Addit Manuf 17:39–46.

    Article  Google Scholar 

  23. Mansour RR (2009) High-Q tunable dielectric resonator filters. IEEE Microwave Mag 10:84–98.

    Article  Google Scholar 

  24. Fox JC, Moylan SP, Lane BM (2016) Effect of process parameters on the surface roughness of overhanging structures in laser powder bed fusion additive manufacturing. Procedia CIRP 45:131–134.

    Article  Google Scholar 

  25. Kutsaev SV, Taletski K, Agustsson R, Carriere P, Cleland AN, Conway ZA, Dumur É, Moro A, Smirnov AY (2020) Niobium quarter-wave resonator with the optimized shape for quantum information systems. EPJ Quantum Technol 7:7.

    Article  Google Scholar 

  26. Aboulkhair NT, Simonelli M, Parry L, Ashcroft I, Tuck C, Hague R (2019) 3D printing of aluminium alloys: additive manufacturing of aluminium alloys using selective laser melting. Prog Mater Sci 106:100578.

  27. Tang M (2017) Inclusions, porosity, and fatigue of AlSi10Mg parts produced by selective laser melting, Ph.D presentation, Carnegie Mellon University

  28. Clark N, Hefford S, Porch A (2017) Effect of build orientation and surface finish on surface resistance in microwave components produced by selective laser melting. In: 2017 47th European Microwave Conference (EuMC), pp 508–511.

  29. Gumbleton R, Nai K, Hefford S, Porch A (2019) Effects of post-processing treatments on the microwave performance of additively manufactured samples. In: 2019 13th European Conference on Antennas and Propagation (EuCAP), pp. 1–4

  30. Curran B, Ndip I, Guttowski S, Reichl H (2009) On the quantification and improvement of the models for surface roughness. In: 2009 IEEE Workshop on Signal Propagation on Interconnects, pp 1–4.

  31. Hammerstad E, Jensen O (1980) Accurate models for microstrip computer-aided design. In: 1980 IEEE MTT-S International Microwave Symposium Digest, pp 407–409.

  32. Townsend A, Senin N, Blunt L, Leach RK, Taylor JS (2016) Surface texture metrology for metal additive manufacturing: a review. Precis Eng 46:34–47.

    Article  Google Scholar 

  33. Ramo S, Whinnery JR, Van Duzer T (1994) Fields and waves in communication electronics, 3rd edn. Wiley

    Google Scholar 

  34. Lumex Avance Hybrid Metal 3D Printer (n.d.). Accessed February 2, 2022

  35. Silbernagel C, Ashcroft I, Dickens P, Galea M (2018) Electrical resistivity of additively manufactured AlSi10Mg for use in electric motors. Addit Manuf 21:395–403.

    Article  Google Scholar 

  36. Smoqi Z, Gaikwad A, Bevans B, Kobir MH, Craig J, Abul-Haj A, Peralta A, Rao P (2022) Monitoring and prediction of porosity in laser powder bed fusion using physics-informed meltpool signatures and machine learning. J Mater Process Technol 304:117550.

    Article  Google Scholar 

  37. Kajfez D (1994) Linear fractional curve fitting for measurement of high Q factors. IEEE Trans Microw Theory Tech 42:1149–1153.

    Article  Google Scholar 

  38. Subramanian R, Rule D, Nazik O (2021) Dependence of LPBF surface roughness on laser incidence angle and component build orientation. .

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The authors would like to thank Alexander Smirnov for assistance with the RF measurements as well as Pedro Frigola for overseeing the overall project scope. This work was supported by the US Department of Energy, Office of High Energy Physics, under SBIR grant DE-SC0019973. Prahalada Rao thanks the National Science Foundation (NSF) and Department of Energy (DoE) for funding his work under awards OIA-1929172, CMMI-1920245, CMMI-1739696, ECCS-2020246, PFI-TT 2044710, CMMI-1752069, CMMI-1719388, and DE-SC0021136. Using the hybrid-LPBF process as a means to improve part quality was the major aspect of CMMI-1752069 (program officer: Kevin Chou). Supplemental funding for CMMI-1752069 was obtained through the NSF INTERN program (program officer: Prakash Balan) and CMMI Data Science Activities (program officer: Martha Dodson), which is greatly appreciated. The latter supplement funded Ziyad Smoqi’s research. The X-ray CT analysis was conducted on the instrument, partially funded through the Major Research Instrumentation grant (CMMI-1920245, program officer: Wendy C. Crone). Alex Riensche’s work was funded partially through the DoE grants DE-SC0021136 and OIA-1929172.

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All authors contributed to the study’s conception and design. Material preparation, data collection, and analysis were performed by Alex Riensche, Paul Carriere, and Prahalada Rao. Manufacturing of the part was carried out by Alex Riensche and Andrew Menendez. Technical guidance for experiments was provided by Paul Carriere and Prahalada Rao. Measurements were carried out by Alex Riensche, Ziyad Smoqi, Paul Carriere, and Nanda Gopal Matavalam. Analysis and characterization were carried out by Aurora Araujo. Supervision was provided by Prahalada Rao, Pedro Frigola and Sergey Kutsaev. The first draft of the manuscript was written by Alex Riensche, and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. The authors acknowledge the following students from the Spring 2021 ME 472/872 Additive Manufacturing class at University of Nebraska-Lincoln taught by Prahalada Rao for their kind assistance with experiments and X-ray CT measurements: Messrs. Jack Keating, Jack Dier, and Justin McEnroe.  

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Correspondence to Prahalada Rao.

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Riensche, A., Carriere, P., Smoqi, Z. et al. Application of hybrid laser powder bed fusion additive manufacturing to microwave radio frequency quarter wave cavity resonators. Int J Adv Manuf Technol 124, 619–632 (2023).

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