Analysis of UV Curing Strategy on Reaction Heat Control and Part Accuracy for Additive Manufacturing.

Fengze Jiang,Dietmar Drummer

doi:10.3390/polym14040759

Abstract

In this research, the relationship between the curing strategies and geometrical accuracy of parts under UV light was investigated. An IR camera was utilized to monitor the process using different combinations of photosensitive resin and curing strategies. The influences of curing strategies on different material compositions were studied with single-factor analysis. With the different exposure frequencies of the UV light, the peak temperature was adjusted to avoid overheating. The three-dimensional geometry of casting tensile bars was measured to investigate the shrinkage and warpage during the curing process. Different material compositions were also selected to study the effects of the maximum temperature on the shrinkage of the parts. The findings of this work show that, with the same amount of energy input, a more fragmented exposure allows for a more controllable max temperature, while one-time exposure leads to a high temperature during the process. With the decrease of the released heat from the reaction, the shrinkage of the casting part has a slightly increasing tendency. Moreover, the warpage of the parts decreased drastically with the decrease of temperature. The addition of fillers enhances the control over temperature and increases the geometrical accuracy.

Highlights

UV curing additive manufacturing is one of the most important branches of the additive manufacturing system
The peak temperature reveals a minute difference, the increase of temperature was significantly altered in the presence of the fumed silica, which indicates that the nanoscale silica particles may reflect the UV light to the surroundings, enhancing the curing
The differences in curing strategies with identical total exposure times were evaluated to understand the effects on temperature control

Summary

Introduction

UV curing additive manufacturing is one of the most important branches of the additive manufacturing system. Researchers have tried different methods to solve this issue: the classic path is lifting the printing platform to let parts cool in the air and using a stirring bar to remix the resin tank to help heat distribution; the surface exposure method using micro shaking of the platform through a vacuum effect promotes the resin heat exchange between the printing area and non-printing area; and, from the chemical side, using a thinner layer or smaller exposure area to limit the heat release in the unit time can partially solve the problem Most of these solutions result in a lower printing efficiency. With different fillers inside, will affect the absorption and reflection of the UV light; the majority of the research focuses more on the final part properties and the double bond conversion rate [14,15]

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Conclusion