STEREOLITHOGRAPHY CURE PROCESS MODELING
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INTRODUCTION
In this chapter, the stereolithography (SL) technology is introduced, the objective of
this work is addressed, and the strategy to achieve the goal is demonstrated.

Introduction to Stereolithography
Stereolithography is currently the most widely used process in the rapid prototyping
and manufacturing (RP&M) field. “It translates computer aided designs (CAD) into solid
objects through a combination of laser, photochemistry and software technologies”1.


Project Strategy
In this work, a complex SL cure process model is established that captures effects that
are ignored in the exposure threshold model. It incorporates laser exposure,
photoinitiation, polymer chain propagation and termination, species diffusion in the
curing polymer network, and heat transfer via conduction in the exposed region and its
vicinity. This model investigates during the part building process the spatial and temporal
distributions of temperature, rate of polymerization, and degree of cure (DOC), which are
necessary to characterize the cured part.



MATERIAL CHARACTERIZATION
As listed in Table 1, some process and material parameters need to be determined in
order to simulate the SL cure process. The process and laser parameters (such as laser
scanning speed Vs, bath temperature Tb, laser power PL, and laser beam radius wo) are
obtained from the actual part building process in SLA-250/50 (3D systems, laser
wavelength λ = 325nm5). h = 4.18 W/m2-K is taken as the value of heat convection
coefficient at the interface of the natural air flow and the resin (Pananakis & Watts,
2000). i
φ = 0.6 is taken as the quantum efficiency of initiation for DMPA (Goodner et
al., 2002).