Real-time feedback controlled conversion in vat photopolymerization of ceramics: A proof of principle

Hafkamp, Thomas; Baars, Gregor van; Jager, Bram de; Etman, Pascal

doi:10.1016/j.addma.2019.06.026

Cited by 14 publications

(7 citation statements)

References 31 publications

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“…Recoating blades provide solutions for specific resin types and viscosity ranges but typically remain limited in the use of a wide range of materials while also reducing the speed of the printing process. 347,348 Addressing the commonplace limitations of VP reactive formulations in a novel and innovative way will continue to drive the technology forward. Latex provides a novel approach to addressing these platform limitations, providing high molar mass materials at viscosities well below the upper limit accessible to VP (>10 Pa s).…”

Section: Additive Manufacturing Of Waterborne Latexes: a Platform For...mentioning

confidence: 99%

Polymer Colloids: Current Challenges, Emerging Applications, and New Developments

et al. 2023

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Polymer colloids are complex materials that have the potential to be used in a vast array of applications. One of the main reasons for their continued growth in commercial use is the water-based emulsion polymerization process through which they are generally synthesized. This technique is not only highly efficient from an industrial point of view but also extremely versatile and permits the large-scale production of colloidal particles with controllable properties. In this perspective, we seek to highlight the central challenges in the synthesis and use of polymer colloids, with respect to both existing and emerging applications. We first address the challenges in the current production and application of polymer colloids, with a particular focus on the transition toward sustainable feedstocks and reduced environmental impact in their primary commercial applications. Later, we highlight the features that allow novel polymer colloids to be designed and applied in emerging application areas. Finally, we present recent approaches that have used the unique colloidal nature in unconventional processing techniques.

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Section: Additive Manufacturing Of Waterborne Latexes: a Platform For...mentioning

confidence: 99%

Polymer Colloids: Current Challenges, Emerging Applications, and New Developments

et al. 2023

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“…To address these issues, both in-situ [26] tools for monitoring photopolymerization and effective models of the polymerized network formation in confined and complex architectures are needed. For instance, insitu and real-time inspection of photopolymerization is possible by measuring the intensity of the luminescence from embedded fluorescent monomers [22], by interferometric measurement of the thickness of the cured layer [27], by infrared spectroscopy [28], by using additional probe lasers [29],…”

Section: Introductionmentioning

confidence: 99%

Impact of size effects on photopolymerization and its optical monitoring in-situ

Camposeo

Arkadii

Romano

et al. 2022

Additive Manufacturing

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“…There are some examples of efficient integrations of feedback control loops in the irradiation system in SL equipment (Hafkamp et al , 2019; Hafkamp, 2020; Classens et al , 2021). However, the need for high accuracy and resolution of the sensing techniques for the on-the-fly measuring of the liquid surface topography introduce principal difficulties for the realization of real-time feedback control in the resin deposition process.…”

Section: Introductionmentioning

confidence: 99%

“…The mechanical properties of the final product in SL mainly depend on the quality of the solidification process on the intra- and inter-layer scales. Poor quality of the liquid deposited polymer (too thick or too thin resin layer, non-uniform surface topography) can be partially compensated by introduction of the control system to the irradiation step (Hafkamp et al , 2019). However, improvement of the recoating step itself will significantly simplify the subsequent compensatory actions of the ultraviolet curing process.…”

Section: Introductionmentioning

confidence: 99%

Feedforward control to suppress the leading edge bulge in photopolymerization-based additive manufacturing

Kozhevnikov

Kunnen

Baars

et al. 2022

RPJ

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Purpose This study aims to examine the feasibility of feedforward actuation of the recoater blade position to alleviate the resin surface non-uniformity while moving over deep-to-shallow transitions of submerged (already cured) geometric features. Design/methodology/approach A two-dimensional computational fluid dynamics (CFD) model has been used to determine optimized blade actuation protocols to minimize the resin surface non-uniformity. An experimental setup has been designed to validate the feasibility of the proposed protocol in practice. Findings A developed protocol for the blade height actuation is applied to a rectangular stair-like configuration of the underlying part geometry. The evaluation of the actuation protocol revealed the importance of two physical length scales, the capillary length and the size of the flow recirculation cell below in the liquid resin layer below the blade. They determine, together with the length scales defining the topography (horizontal extent and depth), the optimal blade trajectory. This protocol has also shown its efficiency for application to more complicated shapes (and, potentially, for any arbitrary geometry). Practical implications This study shows that incorporation of a feedforward control scheme in the recoating system might significantly reduce (by up to 80%) the surface unevenness. Moreover, this improvement of performances does not require major modifications of the existing architecture. Originality/value The results presented in this work demonstrate the benefits of the integration of the feedforward control to minimize the leading edge bulges over underlying part geometries in stereolithography.

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Real-time feedback controlled conversion in vat photopolymerization of ceramics: A proof of principle

Cited by 14 publications

References 31 publications

Polymer Colloids: Current Challenges, Emerging Applications, and New Developments

Polymer Colloids: Current Challenges, Emerging Applications, and New Developments

Impact of size effects on photopolymerization and its optical monitoring in-situ

Feedforward control to suppress the leading edge bulge in photopolymerization-based additive manufacturing

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