Top-down Draken

nicolasnicolas Member, Backers
Hello,
i have been struggling these days with sticky problems on a new vat, and found this guy in France who make is own top-down printer

So i can see that the Draken would quite easily adapt itself to be transformed in a top-down 3Dprinter, withe the following things to do:
Move the projector upward and rotate it 180 degrees with it support (and some adaptation)
move the screw downward
suppress the plate arm
make a new printing plate arm and printing plate (with perforations)
suppress the VAT

i have been testing my B9 yellow resin mixed with salt water and my resin stays upward (which can be useful not to pour 1 liter resins in the printing compartment).

I suppose i miss some trouble so ask for your help if someone as made any test and has any exprerience with this kind of prints.

thanks.



Comments

  • Joseph_OsbornJoseph_Osborn Member, Backers
    Honestly, I think the Draken case is totally unsuited for conversion to top-down. The components (z axis, shutter, controller) could be used for top-down printing if you put them into a new framework.

    To address your sticking problems with the new vat: some of the newer vats need a longer base time to make sure the print sticks to the build plate. If that is the problem, try increasing your base time to 20-30 seconds. Also, use some sandpaper to roughen the build plate's surface. The Draken is extremely reliable, and there should be no reason why you can't have success with it.
  • nicolasnicolas Member, Backers
    I would like to agree with you.
    i have already rough sanded my base plate and have 30s for the base time.
    On one print, 1 ring came on two prints.
    Seconde and same prints, none with exactly the same set up.

    i would like to discover what i am doing wrong.
  • rkundlarkundla Member, Moderator, Backers, Ultimate Backer
    @nicolas please remind us which resin you are using. Also, what slot position do you have your projector mounted?

    There are two different failures. One is that it never adheres to the build plate from the start, and the second is that it fails part way through the print.

    There are a couple of things I have seen that impact the ability to print:

    1. Resin chemistry changes after too much use or sitting in the open

    This is when the chemical balance of the resin changes too much and it takes more exposure to cure or it has been contaminated and won't cure properly at all. The only thing you can do is dispose of the used resin and refill with fresh. Do not put old resin back in with the new resin. Also if you are not going to print for more than day, put the old resin in a storage bottle (I use those brown glass bottles).

    2. Dirty build plate or FEP film

    Fouling of the plate surface or film surface can interfere with the curing of the resin and the bond to the plate. I like to clean both the plate and the film with a small amount of isopropyl alcohol and a paper towel (plate) or a lint-free camera wipe aka "Pec-Pad" (film). Allow to dry and then buff with the same material dry to ensure no residue.

    3. Damage to FEP film

    Damage to the FEP will interfere with the build, from minor cosmetic issues to loss of adhesion. Avoid using metal tools to remove cured resin from the film and plastic tools must be used with care. If you ever have cured resin on the film that you cannot pluck off with your fingers, you are better off using the build plate and full frame exposure from the projector to remove it. Ask me if you have questions on this.

    4. Uneven plate/film surface

    If your build plate does not sit flush against the film, you might have problems curing due to the difference in thickness. Note that not all resins may have this problem depending on their chemistry and their cure layer thickness. I always check for flatness of the plate using a metal straightedge and if there are curves, I will use emery paper on a flat surface like a concrete floor and slowly grind down the build plate until it is as close to perfectly flat as possible.

    Hope that helps give you some pointers. I think a good cleaning is what you might need to get back on track with your Draken.
    Ron
  • nicolasnicolas Member, Backers
    Ok thanks, i am printing with a brand new vat now (the other one had not even a month).
    i will change the resin to test if it can be that.

    thanks
  • nicolasnicolas Member, Backers
    @rkundla thanks i had no idea the resin could be the problem.

    i made a print that failed but was much much better than before. Maybe because this VAT is brand new i need to use it a little but before my prints succed ?
    The fail is that the print starts good, then fail and finish good, so i have the base and top of my rings that are well printed but the medium part with big defects.

    i use B9 resin and my projector is in slot 3.
  • rkundlarkundla Member, Moderator, Backers, Ultimate Backer
    @nicolas take some pictures and if you want, post them to a new thread in the support section. 

    I need visuals to help me diagnose your problem. :-D
    Ron
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