Close
Login to Your Account
Results 1 to 9 of 9
  1. #1
    Join Date
    Dec 2013
    Location
    Posts
    16
    Downloads
    0
    Uploads
    0

    Tilt mechanism for my DLP printer

    Sure, I'll be the first to post here.

    One thing I found necessary when building a DLP 3d printer or any other resin based printer that prints from the bottom up is that you need a tilting build tray. When I first built the printer, I hadn't made the tilting mechanism yet. I found that it printed ok but there was still a lot of vacuum force to overcome as the part separated from the vat bottom when repositioning the z axis. The tilting makes a big difference and makes the part release smoother so less tug on the part which could lead to warping. I made a fairly simple solution using a stepper and a couple 3d printed levers. See the videos below of it in action.


    Last edited by watsonstudios; 12-20-2013 at 11:34 PM.

  2. #2
    Join Date
    Dec 2013
    Location
    Posts
    16
    Downloads
    0
    Uploads
    0
    Here is another video if it while printing.

    Last edited by watsonstudios; 12-20-2013 at 11:35 PM.

  3. #3
    Join Date
    Dec 2013
    Location
    Posts
    116
    Downloads
    0
    Uploads
    0
    That is a great solution. Curious, have you seen anyone else using the tilting technique out there?

  4. #4
    Join Date
    Dec 2013
    Location
    Posts
    16
    Downloads
    0
    Uploads
    0
    Oh yes. It is pretty much standard in the commercial machines like Envisiontec. A lot of others making DIY DLP printers are either using tilt or a sliding motion (B9 printer). Some have even combined tilt and sliding but it's not necessary. If a tilt is good enough for a $40,000 machine then it's good enough for mine.

    Here's an Envisiontec printer in action.


  5. #5
    Join Date
    Jan 2014
    Location
    NJ
    Posts
    133
    Downloads
    0
    Uploads
    0
    I did a bit of reading on DLP printing (which is new to me) and I guess I'm still befuddled.

    Where is the vacuum force coming from?
    Is it between the print-head and the non-solidified resin or between the solidified resin and the base of the tray for part removal?

    Somewhat related - why does the print-head actually penetrate the resin? Wouldn't that shorten the life significantly?

    Para

  6. #6
    Join Date
    Dec 2013
    Location
    Posts
    16
    Downloads
    0
    Uploads
    0
    The vacuum force is between the newly solidified resin and the base of the vat because once the resin is solidified, there is no physical gap between the 2 smooth surfaces. Since the resin does not chemically adhere to the PDMS at the base of the vat, vacuum force is the only thing to overcome. The build plate (print head) has to penetrate the resin because the point at which the resin is cured happens at the bottom of the resin, where it contacts the bottom of the vat.

    Submerging the build plate into the resin doesn't have any ill effects on the resin or build plate. Depending on how much resin is in the vat, the plate is only submerged for a short time before the part gets tall enough to where the plate isn't going into the resin any longer.

  7. #7
    Join Date
    Jan 2014
    Location
    NJ
    Posts
    133
    Downloads
    0
    Uploads
    0
    I think I am even more confused now than I was before.

    The vat is full of resin.
    The build plate enters the vat and cures a specific point.
    Don't you want that point to stay still until the part is complete? I feel obtuse, but wouldn't the vacuum holds the cured component in place until the entire project is done?
    I know from what you've shown that the tilt needs to happen regularly, but I'm not sure why

    The build plate contacts the resin at the bottom, cures it, and moves to the next space in the project until the entire first layer is done, then moves in the Z axis and does the same for layer two through layer n.
    But, once it is above the resin, how does the build plate get additional material to cure to add layers the part?

  8. #8
    Join Date
    Jan 2014
    Location
    Louisville, Kentucky
    Posts
    6
    Downloads
    0
    Uploads
    0
    Paragon, I think you misunderstood the process. The vat has a clear bottom and an image is projected up into the resin. Where the light hits, the resin solidifies. The build plate doesn't do any printing. The first exposed layer sticks to the build plate. It is used to lift the exposed layer off the bottom and leave a small gap of liquid resin between the already solid layer and the bottom of the vat. As more layers are exposed, the plate and the printed object are lifted up out of the resin.

    The vacuum force is the suction when the build plate or any large cross section of a slice is lifted off the bottom of the vat. Think of it as trying to separate 2 flat surfaces underwater. If you pull them straight apart it takes a significant amount of effort. The water (or resin) has to flow into the gap. If you pull one side away (tilt) it is much easier.

    I hope this helps.

  9. #9
    Join Date
    Jan 2014
    Location
    NJ
    Posts
    133
    Downloads
    0
    Uploads
    0
    Oh yea, that completely explains everything I was missing!

    So without the tilt the motor for the build plate must work significantly harder to remove the built material, shortening lifespan and potentially adding waste due to the vacuum breaking the part you're trying to make.

    I was trying to make this like a extrusion based process except in a vat. Wasn't working

    Thanks for the clarification!


Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •