Build Your Own SLA/SLS

I have been refreshing my vats sylgard 184 anti stick properties by putting my printers vat under pressure for a half an hour before using it for a print run. It seems to work. I'd like to hear any comments.

Here is the write up: http://projectsinterestsandetcetera.com ... -could-be/

Nice write up I will have to try that once I am up and running since I have both vac and pressure chambers.

Clinton

Hi HTL,

Thanks for sharing your thoughts & experiments about this subject.
I also read your yahoo post: .
This is also the reason, why I started a post for creating a list of vat-solutions, which might work, in the hope, some other solutions will popup.

Since I don't have either vacuum-unit or pressuriser-unit, it's very hard for me to repeat your tests.
I was thinking in the opposite direction. Since I didn't print for weeks (because of this issue), my Sylgard vat hasn’t seen air for weeks now. So I'll defiantly try to print with this oxygen-less vat and (hope to) damage it even further...
I also like to ask you, how necessary it will be, to pressurise the vat, or just 'vent' the vat in normal atmosphere. Is there a difference? Or how big is this difference in 'number of reusing' the vat again?


I was also discussing this topic with a friend, while we both counter the same issues. (In the end, we all do!)
The bottom-up process is very nice, but not robust at all...

So we also thought about some solutions (wiper), which could be helpful, for getting air in.
(Something like: every 10 exposures, wipe the floor & wait 10 seconds for getting air in.)

Does anyone know, if this oxygen-issue also counts for FEP/Teflon sheets??

Hi Edge,

chechout the solidator patent, it mentions this part a little..

hp

The non stick property of pdms, as it applies to 3d printing, is a surface effect caused by a thin layer of oxygen on the surface of the pdms that inhibits curing of the resin ensuring that a layer of liquid resin is between the build plate and the vat floor during layer exposures, sticking occurs when that layer of liquid resin is not maintained (the oxygen on the surface is depleted) and the resin solidifies on the surface of the pdms during exposures. It in fact does not take a lot of oxygen on the surface to cause this effect, if it did neither the B9 (expose the pdms to air for a couple of seconds every exposure cycle) or the solidator method (diffusing air through the release layer) would work. PDMS is an oxygen permiable material, I believe by pressurizing the pdms oxygen in the air is diffused into the pdms to a depth determined by the amount of pressure it is exposed to and the length of time, when the pressure is released the oxygen diffused into the surface of the pdms "sees" normal atmospheric pressure as a slight vacuum and begins to slowly diffuse back out thus refreshing the oxygen layer at the surface of the pdms until the pressure is equalized.

Occams razor.

I go with what works. The method I'm using is a variation on the b9 and solidator methods of refreshing the release layer which work via refresh of the pdms/fep surface oxygen layer. The method I'm using works for me. If you have the equipment I would be happy to know what results you have using variations of this method.

Having over 40 years of successfull hardware and software projects I no longer feel the need to be proven right or wrong as you seem to. The projects and methods I discuss here and on my website are what I do for fun. I will leave it to others to determin if the suggestions I make are useful to them.