FAQ's

General discussion of topics that don't seem to fit anywhere else.
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PacManFan
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FAQ's

Postby PacManFan » Mon Dec 09, 2013 3:58 pm

Creation Workshop and this forum/ site are a collaborative project. By posting here, you're actively contributing to the community. Please help other users when possible, and contribute to documenting and expanding upon the SLA process. Be sure to post pictures of your machines and prints!


Good information on mask projection stereolithography:
http://utwired.engr.utexas.edu/lff/symposium/proceedingsArchive/pubs/Manuscripts/2011/2011-21-Pan.pdf

Hardware and Firmware setup supported by Creation Workshop.
http://www.buildyourownsla.com/forum/viewtopic.php?f=6&t=102

Various Resins and suppliers:
http://www.buildyourownsla.com/forum/viewtopic.php?f=13&t=68

List of DLP projectors and mods:
http://www.buildyourownsla.com/forum/viewtopic.php?f=6&t=156

I'm going to start to answer some of your questions below:

- 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 DLP projectors. The mod there is swapping out the usual RGB LEDs with UV LEDs.

- 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).


Fell free to contribute to this thread, and I'll incorporate as much info into this post as possible.

fleming
Posts: 22
Joined: Sun Dec 01, 2013 3:41 pm

Re: FAQ's

Postby fleming » Mon Dec 09, 2013 5:18 pm

Why not start with the Vat design and ???? (=fixture/surface where the first layers of resin gets photo-polymerized to be lifted by Z-Axis)
Materials (different designations between different regions), types of cristals, sources to be buy, construction techniques, etc...
Tristan and Youtube explain quite well the Sylgard 184... but, what are your experiences??

johnrpm
Posts: 128
Joined: Sun Dec 01, 2013 5:25 pm
Location: UK

Re: FAQ's

Postby johnrpm » Tue Dec 10, 2013 2:14 pm

What is the meaning of life the universe and everything....43..

just joking.

What causes the part to stick to the vat bottom, is it chemical bonding or vacuum adhesion.
Is the origonal bulb in the projector the best for the job.
Is sylgard the only option, and must it be used.
what projectors are best for modification, and which to avoid.
is top down or bottom up the best.
how do I build a time machine... joking again

a few that spring to mind.
Random Precision

AndersonTa
Posts: 189
Joined: Mon Dec 09, 2013 4:28 pm
Location: Houston, TX
Contact:

Re: FAQ's

Postby AndersonTa » Thu Dec 12, 2013 4:57 pm

I'm going to start to answer some of your questions below:

- 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!
@AndersonHTa

johnrpm
Posts: 128
Joined: Sun Dec 01, 2013 5:25 pm
Location: UK

Re: FAQ's

Postby johnrpm » Thu Dec 12, 2013 5:21 pm

AndersonTa,
Thanks for the reply,
have you tried the alternative films, I really would like some alternatives.

If it is mainly vacuum effect, then this could be broken with ultrasonic vibration perhaps.

since you swap out all the LEDs for UV ones, you will always be emitting UV even on a blank screen.
Not sure about pico projectors, but on the ones I have, the light engine has a diecast cover,
the top has fins for cooling, I assumed the light park position for the dlp was this area, where the light goes during blanking, but this is only my assumption.

What about the time machine????.
Random Precision

karthik
Posts: 4
Joined: Wed Aug 10, 2016 11:40 am

Re: FAQ's

Postby karthik » Sat Feb 25, 2017 2:27 am

hi

Iam converted my printer bottom up to top down,
I wish to connect the viper.
how the viper mechanism works and where to connect in Ramps?
codes for CW ?

i need yours help to fix