An improved VAT photopolymerization cure model demonstrates photobleaching effects

Mohammad Mahdi Emami; David W. Rosen

An improved VAT photopolymerization cure model demonstrates photobleaching effects

Mohammad Mahdi Emami, David W. Rosen

Department of Mechanical Engineering

Research output: Contribution to conference › Paper › peer-review

6 Citations (SciVal)

Abstract

An improved high-fidelity simulation model for a grayscale projection micro-stereolithography process has been developed. The modeling purpose is to accurately predict cured part shapes and dimensions, given a radiation intensity distribution. The model employs COMSOL to solve a series of chemical reaction differential equations that model the evolution of chemical species (photoinitiator, monomer, and polymer) concentrations. Additionally, the model incorporates the effects of oxygen inhibition and species diffusion. This research offers two primary contributions to the cure model: the consideration of volumetric intensity to model variations in photoinitiator absorbance as a function of depth into the resin and a change to the rate model for photoinitiator to free radical conversion. The effects of these changes demonstrate observed photobleaching effects. Simulated cured part profiles are compared to experiments and demonstrate good agreement. Additionally, initial results are presented on the usage of the simulation model in a new process planning method.

Original language	English
Pages	1940-1952
Number of pages	13
Publication status	Published - 15 Aug 2020
Event	29th Annual International Solid Freeform Fabrication Symposium - An Additive Manufacturing Conference, SFF 2018 - Austin, USA United States Duration: 13 Aug 2018 → 15 Aug 2018

Conference

Conference	29th Annual International Solid Freeform Fabrication Symposium - An Additive Manufacturing Conference, SFF 2018
Country/Territory	USA United States
City	Austin
Period	13/08/18 → 15/08/18

Funding

This research was supported by the Singapore National Research Foundation through the NAMIC program under fund no. 2016215. Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of the NAMIC.

Keywords

Grayscale Stereolithography
Photobleaching
Photopolymerization
Volumetric Intensity

ASJC Scopus subject areas

Surfaces, Coatings and Films
Surfaces and Interfaces

Cite this

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AB - An improved high-fidelity simulation model for a grayscale projection micro-stereolithography process has been developed. The modeling purpose is to accurately predict cured part shapes and dimensions, given a radiation intensity distribution. The model employs COMSOL to solve a series of chemical reaction differential equations that model the evolution of chemical species (photoinitiator, monomer, and polymer) concentrations. Additionally, the model incorporates the effects of oxygen inhibition and species diffusion. This research offers two primary contributions to the cure model: the consideration of volumetric intensity to model variations in photoinitiator absorbance as a function of depth into the resin and a change to the rate model for photoinitiator to free radical conversion. The effects of these changes demonstrate observed photobleaching effects. Simulated cured part profiles are compared to experiments and demonstrate good agreement. Additionally, initial results are presented on the usage of the simulation model in a new process planning method.

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KW - Photobleaching

KW - Photopolymerization

KW - Volumetric Intensity

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An improved VAT photopolymerization cure model demonstrates photobleaching effects

Abstract

Conference

Funding

Keywords

ASJC Scopus subject areas

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