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Roughness reduction and functional coating deposition on additive manufactured substrates with ultrasonic spraycoating. Prof. dr. ir. Wim Deferme. IMO - IMOMEC. IMO. IMOMEC. The Organic Electronics Value-Chain. Valorization : Innovative clean-tech region Science parks
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Roughness reduction and functional coating deposition on additive manufactured substrates with ultrasonic spraycoating Prof. dr. ir. Wim Deferme
IMO - IMOMEC IMO IMOMEC
The Organic Electronics Value-Chain • Valorization: • Innovativeclean-techregion • Scienceparks • Tech.Transfer Office
Functional Materials Engineering Group Printing of functional inks and coatings Developing ink testing systems Activities FME Developing devices with printing techniques Testing of commercial inks or inks from industrial partners
Motivation • Roughness • Porosity (absorption of the ink)
Outline • Additive manufacturing – the problem • Ultrasonic spraycoating – the solution • PVDF + aceton + silica nanoparticles – the coating formulation: • Roughness reduction • Superhydrophobicity • Adhesion • What if … roughness is your wish? • Conclusion
Problem Statement • Additive Manufacturing: • Low volumes, no serial production • Long production times • Manual post-processing • Complex structures are difficult to post-process Therefore: time-to-market and client-specific products and/or serial production are not competitive with standard production techniques Stereolithography (SLA) Fused Deposition Modeling (FDM) Selective Laser Sintering (SLS)
Subtractive [1] Problem Statement – Zoom in on post-processing • Blasting • Sanding • Vapor smoothing • High surface roughness after AM (between 10 and 30um) • Post-treatment needed: • Beadblasting • Sandblasting Pressurizedatomisation Ultrasonicatomisation [1] Materialise, “3D Printing Service,” Materialise. [Online]. [2] W. Fielding, “Texturing prospective with ultrasonically coated balloon catheters,” Sonotek.[3] Sonotek, “Nanotechnology Coatings Deposited Using Ultrasonic Spray,” Sonotek.
Solution: Ultrasonic Spray Coating WorkingPrinciple Sprayhead ‘Impact Edge’ ‘Vortex’ N2carrier gas Input: PMMA-aceton solution Figure 11: Types of sprayhead [4] Drop Generation f = 120 kHz 20 kHz PLA Substrate 40 kHz Drop Diameter ±20μm Figure 12: drop generationprocess [4] [4] Sonotek, “Ultrasonic Atomization Technology,” Sonotek. [Online]. [5] H. Yi, J. Huang, X. Gu, and Z. Ni, “Study on ultrasonic spray technology for the coating of vascular stent” [6] “Ultrasonic Spray Systems - Spray Shaping Technology.” [Online]. f = 120 kHz Figure 10: Influencefrequency[6]
Substrates • PA-12 (nylon) from Selective Laser Sintering
Coating formulation 1) Polyvinylideenfluoride (PVDF) 2) Aceton 3) Silica nanoparticles Toachieve: Roughnessreduction + functionality (superhydrophobicity – easy to clean) • Pa < 2 µm • WCA > 150°
Spraycoating parameters • Ink (wt%) and # layers: Amount of deposited material • Volume flow + Nozzle Speed: V% ink/Area/time • Hotplate temperature and Spraying height:Drytime
Roughness reduction – first results 10,4 µm 6,9 µm 4,4 µm
Addition of nanoparticles Influence on roughness of fraction nanoparticles 4,2 wt% PVDF and 0,8 wt% silica nanoparticles 3,9 µm 3,4 µm 2,5 µm 2,4µm 1,8 µm Industrial standard
Superhydrophobicity Influence on contact angle of fraction of nanoparticles 3,5wt% PVDF and 1,5wt% silica nanoparticles
Adhesion – the reason for ULTRASONIC spraycoating Ultrasonic Pneumatisch
What if … roughness is your wish … … but coating is needed ??? ‘Impact Edge’‘Vortex’
Case 1: Coating of non-flat surfaces – PVDF Patent: partially coated plunger: DE 10 2016 123 302 A1 2018.06.07
Case 2: Conformal coating on three-dimensional substrates Van den Ham, Ultrasonic Spray Deposition of Metal Oxide Films on High Aspect Ratio Microstructures for Three-Dimensional All-Solid-State Li-ion Batteries, ACS Energy Lett., 2016, 1 (6), pp 1184–1188
Conclusion Roughness reduction: Pa < 2µm Superhydrophobicity: WCA > 150°