(Interferometric) Cure Monitoring As A Useful Tool In The Evaluation Of Resins For Stereolithography

1. Introduction
The development of resins for Stereolithography (SL)
needs its own formulation strategy, although some of the
components may be identical to those in resists or
coatings. In addition to the requirements arising from an
intended application of the SL part, the process of 3
dimensional laserpolymerization itself imposes stringent
requirements such as penetration depth of the
laser light, an appropriate fast rate of polymerization,
and sufficient stability of the partially cured part
(green strength), etc.

A thorough understanding of the laser cure process
in a layered structure together with computer modelling
of the local. (laser spot) process might be a toll to
design and evaluate a resin from basic physical
properties. Shrinkage, thermal effects, buildup of
mechanical strength have a strong influence on the
performance of.a material in the build process.

The formulater is thus faced with a considerable
number of parameters which he would like to quantify
directly on experimental formulations rather than model
systems.The test should be easy to do, efficient, and
should require only a mihimal thount of material'. Due to
the typically small light penetration depth of
Stereolithography resins (0.13 - 0.18 mm) quantitative
measurements on partially, but homogeneously cured
samples, be it the extent of cure, shrinkage, kinetics or
mechanical properties, are best done on thin layers