- What causes the part to stick to the vat bottom (in a bottom-up setup)?
You guessed right with vacuum force is the reason it sticks, more or less its the Van der Waals effect is what we are dealing with.
- Is the original build in the projector best?
Yeah, bulbs in general are expensive, you can go out and buy bulbs with more UV output but for the most part stock bulbs in DLPs output sufficient amounts. The one thing you should mod is the color wheel mechanism, so that you can allow more UV to come through. There is some concern on the UV damaging some of the components on the insides, but I don't have specifics.
- Is Sylgard 184 the only option for vat coatings?
No, you can get PTFE/ETFE film (adhesive or non-adhesive) as well. Sylgard is just what a lot of folks started to use.
- Which projectors are best to use?
What I've been told in my search is a DLP with at least 2500 lumens. Steve and others out there are starting to look into moving pico projectors. The mod there is swapping out the usual RGB LEDs with UV LEDs. Though that can also provide some issues, for instance since you swap out all the LEDs for UV ones, you will always be emitting UV even on a blank screen.
- Is top-down or bottom-up better?
It's debatable. Bottom-up's major benefit is the savings on materials. You only need a shallow pool of resin as opposed to an entire vat that has a constant fill. On the other hand, bottom-up will need a release mechanism to free the newly cured layers from the bottom of the vat, while top-down might just need a wiper to help distribute the resin on the surface (depends on the viscosity).
Please correct me if I'm wrong anywhere and elaborate where you see fit. We're all here to learn!Statistics: Posted by AndersonTa — Thu Dec 12, 2013 4:57 pm
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