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Re: LCD Based Printer; Photopolymer Samples

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  • phife54@ymail.com
    Hi Ali, Im in Kelowna, BC. The printer is still in its early prototype stage, but it is working. Still much work to do to get it out as a DIY kit. As for
    Message 1 of 45 , Feb 24, 2013
      Hi Ali,

      Im in Kelowna, BC.

      The printer is still in its early prototype stage, but it is working. Still much work to do to get it out as a DIY kit.

      As for answers,

      The color LCD's color filters loose to much light and the red and green block all light leaving holes in the print.

      Im using a glass vat, you cannot use the LCD as a vat bottom because any pressure disturbs the liquid crystal. Light does diffuse, but I have it down to a resonable level using optics and having the light collimated. Cure times are around 8-10seconds, but hope to be less with Fernandos new resins.

      Bulb was only $45, its double ended and a 400w MH, you can use ones for Coral reefs in the 10000k+ range.

      Greyscale LCD's I get from a chinese supplier, they are pricey, $800/LCD with controller. Used ones can be found for $100-200 on ebay, but there is no telling if it will work or not. Most medical LCD require a special video card.

      Once I get some time i'll write up all my finding and help others build and perfect the LCD 3d Printer, It does have some great promise!

      --- In diy_3d_printing_and_fabrication@yahoogroups.com, Ali Punjani <ali.punjani.groups@...> wrote:
      > Hi Nick!
      > Thanks for replying to my post, I was hoping you might.
      > It's great to hear from a fellow Canadian! I'm in Toronto (East), how about
      > you?
      > I think it's awesome that you're planning to release a DIY kit for this
      > sort of project. Also self replication is a good idea. If you're working on
      > software, does that mean the mechanical/optical/chemical parts of the
      > printer are working well now?
      > If you have a minute, I have a few questions for you:
      > What exactly was wrong with a color LCD, were the blue color filters and
      > red/green pixels just blocking too much of the useful light?
      > How did you manage to solve the issue of diffusion of light leaving the LCD
      > Panel? Was it enough to simply use the LCD panel itself as the vat bottom?
      > Does the light from the MH lamp need to be collimated?
      > What kinds of cure times do you get?
      > I read a lot about metal-halide and mercury vapour bulbs over the last few
      > days, and I had looked into some MH lamps made for aquariums - They seem to
      > have the types of spectral output you mentioned. A custom lamp must have
      > been pretty expensive! Similarly with the Monochrome LCD panels - the only
      > place I can find them is on eBay, and they are very expensive - $700 to
      > $1000. I was hoping to get going with a plain color LCD which can be gutted
      > from a photoframe for ~$50. I assume you've found a way to get monochrome
      > LCDs for cheap, if you plan a DIY kit?
      > I'm certainly looking forward to when you have a chance to write about
      > everything you've learned through the testing process. I think I'll start
      > experimenting too, I just finished building a CNC router and I'm looking
      > for a new project to use it for :p
      > Ali
      > On Thu, Feb 21, 2013 at 10:53 PM, phife54@... <phife54@...>wrote:
      > > **
      > >
      > >
      > > Hi Ali,
      > >
      > > A fellow Canadian, where abouts are you?
      > >
      > > I have been developing an LCD based 3d printer for the last 6 months,
      > > While my thread has been quiet for some time, rest assured ive been
      > > plugging away at it.. Its not been a simple matter. Ive done a lot of
      > > testing with different resins, LCD's, Light sources, Lenses, and
      > > Electronics.
      > >
      > > I am hoping to release a DIY kit for others to build their own LCD 3D
      > > printer. Im working with Chris Marion and we are developing a great
      > > machine, I will be using a custom version of Chris's software.
      > >
      > > Dont waste your time with color LCD, you will need a monochrome LCD no
      > > matter what.
      > >
      > > My current setup is using a custom 400w MH bulb on a digital ballast, this
      > > bulb has a small arc and a very high output in the 390-420nm range and has
      > > a large spike at 450nm and not much of the spectrum after that, its a very
      > > nice purple/blue color. Optics are very important, and dealing with the
      > > heat of the 400w MH bulb must also be address.
      > >
      > > I havent had much success with any other bulbs, I was testing with a 150w
      > > MH and a regular 400w MH but they didnt work out.
      > >
      > > The nice thing about the LCD printer is the large build area, I hope to be
      > > able to print the entire structure of the printer with the prototype in a
      > > reprap style. Print panels, add hardware and electronics and you got a
      > > printer. Ive been designing printable panels but there is much to deal with
      > > before I even begin printing other machines.
      > >
      > > You will have to deal with all the issues youve listed and more, and its a
      > > big task. I encourage you to experiment and try. To start off save you
      > > money and dont bother with color LCD's get a monochrome or greyscale LCD
      > > used for medical purposes, x-ray imaging.
      > >
      > > If you wait a couple more months I hope to have a working printer and I
      > > can spend some time getting a DIY kit out there and write up all that ive
      > > learned from my testing ao rhat others can make their own.
      > >
      > > I wish you luck!
      > >
      > > Nick
      > >
      > >
    • chenw1115@yahoo.cn
      holle,do your lcd printer work now?
      Message 45 of 45 , Apr 23, 2014
        holle,do  your lcd printer work  now?
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