LCD Based 3D Printer - Introduction

[abdrumm]

I've built a couple dlp based printers, but am intrigued by the lcd approach. I would love to help research and design an lcd printer. Anyone want to collaborate? I have a budget for r&d so could help by providing equipment to further the cause.

So where do I start? What lcd is the best starting point? Are there links to appropriate LEDs? Instructions for preparing the screen?

I can talk to madesolid guys for custom resin if needed.

Thoughts?
Brook

[Phife]

Like I said before, Ive been reseaching and designing LCD printers for the past 2 years. Not really all that much left to research or design, I do need some help/collaborators but Im looking for people in Western Canada.

As for the answers to your questions, you will find a lot of that info reading this thread and my other one. But there is still some things to be figured out. I wont be releasing this info until I have it all solved and can prove a working system.

If you want to start on your own LCD project I suggest you get reading and be prepared to fork over a lot of money to get LED arrays made and buy LCD panels for testing.

[hp_]

abdrumm,

I'm also very interested in starting this investigation towards lcd resin printers.
first thing is first. pcb design with uv less the will function as backplate light for the lcd screen. main challenge here i think that you don't want the leds light interfear with each other..


phife looking forward to your info. but until then i guess we have to start doing our own development i guess..
phife.. this came up after googling http://physics.stackexchange.com/questi ... d-by-a-led

hp

[CidVilas]

@all: This post is originally an introduction post not meant as a development discussion. Has a development thread been started for the rest of us to discuss LCD Resin printers?

I'm just getting started in this development. I'm not looking for large scale printers. Ill be focusing on small but high resolution printers. Preferably around smart phone sized LCD screens. Keys items that need to be determined are:
- Best suited LCDs which block as much UV as possible in black space, and allow maximum UV to pass through in white space
- A thread should be started simply focused on LCDs people have used and tested so effort isn't wasted by everyone trying the same LCD
- As everyone is aware resolution is king, otherwise why bother. Pixel density needs to be high
- Ways to create UV source, whether led or lamp. Options on diffusing light to create uniform exposure

Etc...i'm new so hope i'm not stepping on toes posting this. I've already began testing parts for my printer. Hope others are also experimenting and look forward to a final product!

PS: I've backed this printer: https://www.kickstarter.com/projects/82 ... e-3d-print
Exactly what is being done here, and i'm sure that the LCD could be expanded easily enough.

[Phife]

Just to give you guys some direction to head in..

-LCD's
There are tons of them out there, most wont work. Obviously you want high resolution so your looking at least at a 2048x1536 resolution or higher. Problem is, these panels require special controller boards. You cant just take an LCD from a cell phone or tablet and make it work, the control boards are not available. So far the IPAD3 Lcd is the easiest to implement. Monochrome medical LCD's work great.

-LED's
Tightly packed high watt LED's (3w mostly) with optics are needed with color LCD's. Monochrome LCDs allow a lot more light through so you can get away with less LED's. You will need somewhere around 1-1.5w/sq" for Color LCD's as long as you are using Optics, double or more if you are not. Finding cheap LED's is easy, finding matching optics for a decent price is much harder. Also, the arrays must be heatsinked and current controlled.

-UV Light
Everyone seems stuck on trying to get UV light though an LCD, it aint gonna happen. Forget about trying to use UV with LCD's, stick with 405nm LED's. Also, No LCD will block all the light when its black, with the brightness of the LED arrays you will always have light bleeding through. You need to turn the LED array on and off with each layer.


The reason I am not releasing all my info now is because even after two years of research and a ton of money dumped into this project I dont have a working printer. If it was easy everyone would be doing it.

The main technical aspect you guys need to figure out is,

-LED Array, 405nm LEDS and Custom PCB. Collimating Optics. Custom Power supply and Current Regulation.
-LCD Panel w/ Controller Board.
-Part Release Mechanism

Ive got the first point down, I have a custom PCB and LED array made up, I have a supplier in China making them for me. The LCD, I am using a Monochrome LCD Panel similar to the IDTech ITQX21H. You will need to make a custom controller board for this panel. I am currently testing the Ipad3 LCD, It should work, but needs displayport on the PC, not a common port.

Part release is the real issue, Large LCD's and large parts = large sticking forces. I am trying a new type of vat in the next couple weeks that should allow bottom up and easy part release. Otherwise I am redesigning the whole machine and going top down with resin floating.

Thats all I would like to share for now. I promise that in the new year I will have a working printer and release all of the info to you guys.

[Glacian22]

I've also been working on this problem for a while (a little over a year), with lots of trial and error. If I ever get everything working, I'd also be happy to share my design

[oliveenchine]

here's a photo of the ipad 3 lcd and control board , my LED board isn't finished yet, only about 32 running ( 1/3rd ) .
- LEDs are 405-407nm 3W , with PC lens about 20˚ angle.
- mounted on a 200x180x50 aluminium radiator
- control board is from abusemark.

My actual problem is the resin, I got only sone transparent UV adhesive , normally designed to work with UV ( 365-385nm). I could get some positive results but with a really long exposure (about 3-4 minutes) , I waiting to receive some SubG+ to conduct more tests .

The LCD need a really good cooling or it will get black (and probably damaged) , got a 120mm fan 140CFM running on the side cooling both LED radiator and LCD panel.

[dpizzle]

I'm surprised you are getting an even cure with your leds spaced so far apart. My original array was set up like yours with 15 degree lenses which would cure in between the spaces but would take a lot longer because of it. My second attempt has the leds stacked on top of each other, but that means I can't use off the shelf metal core pcb's, and that present so many other issues to deal with... Anyways, curious what your cure times will be when you get your resin with your current set up, I might be doing something wrong. Please let us know if you could.

[Phife]

Yeah youre going to run into issues if you dont have very uniform even lighting. But good progress!! I tried over a dozen lens types and angles to find the right ones.

[hp_]

hi oliveenchin,

Really Nice!!, thank you for sharing

it looks like Kast are using 96 LEDS
if you look at this video https://www.youtube.com/watch?v=ZzTUqrLZIkQ
and stop at time slot : 0:31

cheers,
hp