Read it here:
Here’s a diagram from the article:
All of this is my interpretation of what’s happening, from both the article and experience, so take it all with a grain of salt…
The tldr;/2 is: Before a model is fully cured, i.e. just out of the printer, it’s in what’s called the ‘green state’. Each layer’s shared surface still contains unreacted monomers. These later intermingle and react together during post-cure to fully harden the model into a chemically bonded solid. This green state is something FL has dialed in, and it’s why there are color profiles in Preform. Each resin gets to green, and behaves at green uniquely.
The diagram shows sharp edged brick-like layers with defined green ‘mortar’ areas, but I suspect it’s the most brick-like immediately at the PDMS-interface, then softening as the laser energy is absorbed and scattered into the layer. This rate of softening, or more precisely, non-hardening is likely a function of resin type and colorant to name only two obvious considerations.
So the green level of any resin is just a point on a multi-line graph, and each point makes tradeoffs. Keep it really green as a print, and then nail it in a UV curing over, and you’ll have a very solid part as all of the layers are now chemically merged to a greater degree. However, it’s probably more likely to fail during print, especially where tensile loading is highest.
But if you can minimize the amount of green during printing, it might produce a less isotropic part, but you may be able to take advantage of superior stiffness and strength of the object and support structure overall during the print - possibly in varying degrees between them - to achieve a desired outcome. Intuitively, I believe this will allow thinner wall thicknesses and finer detail, albeit at the expense of isotropy. Sometimes isotropy is less important.
This is why we as makers need knobs and gauges and levers and modular plugins in Preform. We need to, well frankly, help design the machine we’re using. Makers are typically tool makers in some form as well. There are so many things all of us will learn if we all had more freedom to explore and tweak and share our findings. A failure can be way more educational than a one-click-and-it’s-done kind of thing. I’m certain the software would improve at a much more rapid pace if advanced users had access to a mode that allowed more settings changes.
OpenFL is a great thing, and it’s awesome you’re doing it. Please also build it all into the gui - I want to experiment, but I don’t have time to do OpenFL right now. I think many feel that way.
. Like “Hey, this setting produced very precise hole diameters for me in clear”, or “Don’t use this setting with Black, as it won’t stick to the platform, but for flexible it allows tiny support point sizes” - or whatever.