An improved VAT photopolymerization cure model demonstrates photobleaching effects

Mohammad Mahdi Emami, David W. Rosen

Research output: Contribution to conferencePaper

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 languageEnglish
Pages1940-1952
Number of pages13
Publication statusPublished - 15 Aug 2020
Event29th Annual International Solid Freeform Fabrication Symposium - An Additive Manufacturing Conference, SFF 2018 - Austin, USA United States
Duration: 13 Aug 201815 Aug 2018

Conference

Conference29th Annual International Solid Freeform Fabrication Symposium - An Additive Manufacturing Conference, SFF 2018
CountryUSA United States
CityAustin
Period13/08/1815/08/18

Keywords

  • Grayscale Stereolithography
  • Photobleaching
  • Photopolymerization
  • Volumetric Intensity

ASJC Scopus subject areas

  • Surfaces, Coatings and Films
  • Surfaces and Interfaces

Cite this

Emami, M. M., & Rosen, D. W. (2020). An improved VAT photopolymerization cure model demonstrates photobleaching effects. 1940-1952. Paper presented at 29th Annual International Solid Freeform Fabrication Symposium - An Additive Manufacturing Conference, SFF 2018, Austin, USA United States.