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Re: New LCD Based 3D Printer

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  • phife54@ymail.com
    Plain tap water, i ll see if I can get a good reading before and after tomorrow, I know last time I checked it was around 30,000lux before lenses and LCD and
    Message 1 of 90 , Oct 30, 2012
      Plain tap water, i'll see if I can get a good reading before and after tomorrow, I know last time I checked it was around 30,000lux before lenses and LCD and at the same distance as the vat test. But Im not 100% sure.

      --- In diy_3d_printing_and_fabrication@yahoogroups.com, Ben Mahony <ben.mahony@...> wrote:
      >
      > Soaked with water or a stronger solvent?
      > I have $50 Lux meter, I'll get a reading for you,I don't know how much I
      > would trust it though.
      > Also it is a bit meaning less as it is spread visible spectrum. Really
      > need to test at the specific wave length according to the resin you are
      > using.
      > Out of interest would be nice to know the reading before your LCD and after
      > to work out the transmissive ratio of the LCD, when displaying a full white
      > image.
      >
      > Benjamin Mahony
      > Tecevo
      > This email was sent from a phone.
      > On Oct 31, 2012 8:08 AM, "phife54@..." <phife54@...> wrote:
      >
      > > **
      > >
      > >
      > > It wasnt difficult to remove the antiglare layers from the LCD, just
      > > soaked them for about 3-4h with moist paper towel to soften up the adhesive
      > > and peeled right off without leaving residue.
      > >
      > > I did that on both sides and its much clearer image now. The LCD is not
      > > transparent when off, it is fairly good at blocking out the light when
      > > totally black but a bulb image is slightly visible through the LCD when
      > > black, I dont get a reading on my lux meter though, so 0 lux when black and
      > > around 4500 when clear (white image), this is a reading in the center of
      > > the LCD through the Glass vat and 2mm PDMS layer.
      > >
      > > Im wondering what readings others are getting on their DLP systems? Does
      > > anyone one have a lux meter they could check with? or is there someone who
      > > already has this info?
      > >
      > > Ive done some research into the Greyscale LCD and it seems to be pretty
      > > exclusive to Medical and Military uses, the most common 20" LCD Panel in
      > > greyscale seems to be the IDTech ITQX21G, I found it available from a
      > > Chinese supplier for $800/panel and $250 for the controller.
      > >
      > > Im having some issues with my fresnel, it was for my original 15" LCD but
      > > this new LCD is much larger, im waiting for a new fresnel to show up.
      > >
      > > I also need to build a new vat as the old one is also too small, I have to
      > > mount my linear slide and get software working too.
      > >
      > > I tried projecting some simple lines, 1px 2px and 4px wide, only the 4px
      > > wide pixel resulted in a line of hardened resin after 30sec exposure. Line
      > > was about 0.6x0.5mm and not straight, it had a bow in it.
      > >
      > > I will do more testing when I get my optics in.
      > >
      > > Nick
      > >
      > > --- In diy_3d_printing_and_fabrication@yahoogroups.com, Ben Mahony
      > > <ben.mahony@> wrote:
      > > >
      > > > The 'transparent' LCD I have here does not have any anti glare layers, as
      > > > it is meant to be transparent, so that would be good, Sadly as I wrote
      > > > before the colour filters is internal. I Don't think they make a
      > > grayscale
      > > > but I'll check.
      > > >
      > > > Benjamin Mahony
      > > > Tecevo
      > > > This email was sent from a phone.
      > > > On Oct 29, 2012 7:18 AM, "pzamov" <pzamov@> wrote:
      > > >
      > > > > **
      > > > >
      > > > >
      > > > > Ohh! Congrats! That should bring the price down quite a bit for the
      > > large
      > > > > formats!
      > > > >
      > > > > Peter
      > > > >
      > > > > --- In diy_3d_printing_and_fabrication@yahoogroups.com, "phife54@"
      > > > > <phife54@> wrote:
      > > > > >
      > > > > > Success!!
      > > > > >
      > > > > > Ive got my new monochrome LCD working with the new bulb. I did a
      > > quick
      > > > > test today,
      > > > > >
      > > > > > 4"x4" Area in the center of the LCD, with about 2mm of resin in
      > > there. I
      > > > > displayed a white screen and cured a 1mm thick slab of resin in 60
      > > seconds!
      > > > > That should be about 10-12 seconds per layer. (0.2mm Layers)
      > > > > >
      > > > > > I still need to tweak my lenses and remove the antiglare coating
      > > that is
      > > > > on both sides of the 20" monochrome LCD. That should help get even more
      > > > > light through.
      > > > > >
      > > > > > Im very please with my results..
      > > > > >
      > > > > > Ive even come up with another idea since I have such a large build
      > > area.
      > > > > I think it should be possible to make a vat with multiple separated
      > > build
      > > > > areas. Each area would have either a different color resin or a resin
      > > with
      > > > > different properties allowing for parts to be built with multiple
      > > colors or
      > > > > even different material properties! All that would be needed is an
      > > addition
      > > > > to the Z axis to allow a smaller build platform to move (X and Y) from
      > > > > section to section. Oh the possibilities!
      > > > > >
      > > > > > Im in desperate need of some software to run my machine, If anyone is
      > > > > willing to help me get something going I would greatly appreciate it. I
      > > > > have a RAMPS 1.4 board (Audrino)that's used for Reprap style 3D
      > > printers
      > > > > that I hope to be able to use as my control electronics.
      > > > > >
      > > > > > Please message me if you can help.
      > > > > >
      > > > > > Thanks!
      > > > > >
      > > > > > Nick
      > > > > >
      > > > > > --- In diy_3d_printing_and_fabrication@yahoogroups.com, "phife54@"
      > > > > <phife54@> wrote:
      > > > > > >
      > > > > > > Im using visible light resin from Spota, cures under violet/blue
      > > > > light, 400-450nm
      > > > > > >
      > > > > > > The lexan sheet im using as a heat/uv blocker blocks wavelengths
      > > below
      > > > > 380nm.
      > > > > > >
      > > > > > > Im trying to save the LCD from UV and heat damage to prolong its
      > > life.
      > > > > > >
      > > > > > > Ive found an interesting paper online from some guys back in 2008
      > > who
      > > > > were developing an LCD gated RP system.
      > > > >
      > > http://f1.grp.yahoofs.com/v1/8ImAUNywcOrLu0aY5yxQFxQB_vlEKmFE_jhfe8zj4_aeBA2nSMkq3ENKU9OwAXYn7NVWbVLCsblOItPzXT5-IhYGYMuVq0_aljz5YdH5bRs/LCD-Gated.pdf
      > > > > > >
      > > > > > > It looks like they were using a resin that cured under 680nm
      > > light, so
      > > > > red light.
      > > > > > >
      > > > > > > --- In diy_3d_printing_and_fabrication@yahoogroups.com, "pzamov"
      > > > > <pzamov@> wrote:
      > > > > > > >
      > > > > > > > Hi Phife54,
      > > > > > > >
      > > > > > > > >I have a Lexan sheet that I'm using as a UV and heat blocker to
      > > > > keep >the Fresnel and LCD safer...
      > > > > > > >
      > > > > > > > Isn't the point to get the UV to the resin? Or are you using a
      > > resin
      > > > > polymerized by another wavelength...? ( green/blue/red )
      > > > > > > >
      > > > > > > > Also the heat can be your friend...just look at changes in resin
      > > > > viscosity @22C and again @25C.
      > > > > > > >
      > > > > > > > Peter
      > > > > > > >
      > > > > > > >
      > > > > > > > --- In diy_3d_printing_and_fabrication@yahoogroups.com,
      > > "phife54@"
      > > > > <phife54@> wrote:
      > > > > > > > >
      > > > > > > > > im using a fresnel and glass condenser lens to collect and
      > > > > collimate my light. I have a Lexan sheet that im using as a UV and heat
      > > > > blocker to keep the fresnel and LCD safer, Also cooling is important
      > > as the
      > > > > 400w bulb puts out a lot of heat.
      > > > > > > > >
      > > > > > > > > --- In diy_3d_printing_and_fabrication@yahoogroups.com, John
      > > > > Harding <nonzerojohn@> wrote:
      > > > > > > > > >
      > > > > > > > > > It might be an idea to try a fresnel lense to even out light
      > > > > distribution
      > > > > > > > > > to the panel, most lcd's have these but for uv you might
      > > need a
      > > > > glass
      > > > > > > > > > fresnel to withstand prolonged exposure
      > > > > > > > > >
      > > > > > > > > > On Thursday, October 18, 2012, Graham Stabler wrote:
      > > > > > > > > >
      > > > > > > > > > > **
      > > > > > > > > > >
      > > > > > > > > > >
      > > > > > > > > > >
      > > > > > > > > > > On Thursday, October 18, 2012, lapozan78 wrote:
      > > > > > > > > > >
      > > > > > > > > > >> **
      > > > > > > > > > >> in theory the LCD is coupled with the bottom of the Vat,
      > > > > maybe the lcd
      > > > > > > > > > >> could be the bottom itself... so the image would be as
      > > sharp
      > > > > as possible,
      > > > > > > > > > >> the eveness of illumination could be solved with a
      > > diffuser
      > > > > may be, or by
      > > > > > > > > > >> adding lamps, regarding the speed of cure, i thought that
      > > the
      > > > > Stronger the
      > > > > > > > > > >> light the faster the cure, right? <
      > > > >
      > > http://groups.yahoo.com/;_ylc=X3oDMTJlbmFiOTJyBF9TAzk3MzU5NzE0BGdycElkAzIyNjE3ODUyBGdycHNwSWQDMTcwNTEzNzA3OARzZWMDZnRyBHNsawNnZnAEc3RpbWUDMTM1MDU3MjE5Mw--
      > > > > >
      > > > > > > > > > >>
      > > > > > > > > > >
      > > > > > > > > > > You need something on the vat base to prevent adhesion,
      > > > > preferably
      > > > > > > > > > > something like pdms, it might be thin but for large areas
      > > you
      > > > > are likely to
      > > > > > > > > > > require more thickness for some clever technique.
      > > > > > > > > > >
      > > > > > > > > > > Yes more light means faster cute but you don't want to be
      > > > > needing an array
      > > > > > > > > > > of arc lamps cooking the LCD just to get a decent cure
      > > time.
      > > > > And I know
      > > > > > > > > > > what someone will say "use an array of LEDs" but you need a
      > > > > pretty
      > > > > > > > > > > consistent preferably collimated light.
      > > > > > > > > > >
      > > > > > > > > > > Graham
      > > > > > > > > > >
      > > > > > > > > > >
      > > > > > > > > > >
      > > > > > > > > > >
      > > > > > > > > > >
      > > > > > > > > >
      > > > > > > > >
      > > > > > > >
      > > > > > >
      > > > > >
      > > > >
      > > > >
      > > > >
      > > >
      > >
      > >
      > >
      >
    • zhangqitao
      Yes, I recently also try, fep films failed, hope to the point, I like large print, SYLGARD184 not be long before the release effect on the poor,
      Message 90 of 90 , Jun 2, 2014
        Yes, I recently also try, fep films failed, hope to the point, I like large print, SYLGARD184 not be long before the release effect on the poor,
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