New DLP build started! / Pico-projector part 3

I keep saying this, but it's been too long a time since I updated my project blog. It's not for the lack of progress mind you. Things have been very busy for me lately. I'm not sure if I mentioned it before, but I started a new forum dedicated to all things DLP/SLA www.buildyourownsla.com . I have to say, never expected the explosion of interest! It's only been up for less than 2 months, but there are hundreds of active users (and about 1000 spammers).

Creation Workshop http://www.envisionlabs.net/ continues to advance rapidly, largely due to the herculean efforts of the co-programmer Shai (Thanks man!) . I've had a lot of interest with DLP/SLA printer manufacturers wanting to distribute Creation Workshop along with their printers, and I've been signing them on rapidly. I've devised a plug-in system that allows me to create vendor plug-ins to completely customize the GUI and code for each machine. It also allows me to distribute custom machine and slicing profiles tailored to each machines unique capabilities.

I've been talking with a bunch of groups/ start-ups/ companies about their machines for months, and I'm in a pretty unique position to see exactly what's going to be coming out on the market this upcoming year. I'm under NDA with a few of them, so let's just say that 2014 will be the rise of the SLA machine in the 3d printing world.

That all being said, I've been giving some thought as to how to create the 'Best' machine possible. 'Best' is an arbitrarily chosen words really. 'Balanced' would be a better descriptor. As I noted elsewhere http://www.buildyourownsla.com/forum/viewtopic.php?f=17&t=149 , there will always be tradeoffs between build size, resolution, and print speed. I think I've come upon a good balance between the 3.

What I came up with is a pico-projector mounted on an x/y linear assembly. The projector can expose smaller image tiles on a much larger vat bottom. This allows the pico-projector to maintain a 25micron (or greater) x/y resolution. The vat can be arbitrarily large. This is a good trade-off between size and print speed.

I'm still in the early stages of the build, but it's all coming along nicely.

New parts for the build

Shown above are a few parts I'm using for the build. Here's an incomplete BOM of items so far:

• 12v 6A power supply
• 5x Nema 17 steppers (I'll probably use 4)
• 12x LMU88 linear bearings
• 6 meters of GTK belt and 4 pulleys
• 10W UV LED 405nm on an alum heatsink
• Modified AAXA P2JR DLP projector
• 3' of 1/8 hose for the resin pump
• 3 prong outlet
• Mains switch
• Printed 3 way corner brackets for the 80/20 construction
• 4 printed feet

A bunch of 350mm and 300mm 25mm 80/20 aluminum.

The constructed bottom portion of the machine. Measures 350x350mm.

I'm still waiting on a few more parts in mail:

• Arduino 2560 with RAMPs board
• 8mm hardened steel rails
• 8mm threaded rod
• UV transmissive plexiglass for the vat
• UV blocking plexiglass for the outer casing/window
• Other things I forgot

I'm probably going to do a bit more construction today. Look for the next part of this build soon.
-Steve

UV DLP Pico Projector Experiments Part 2

I know I left many of you hanging with my part 1 of the pico-projector experiments. To recap from part 1, I had successfully dis-assembled my pico-projector & examined the optic path, trying to determine how to insert a 10W UV LED into it all.

First, I'd like to offer a few words of caution. UV light can and will hurt your eyes. This is the exact reason why welders wear goggles. Sunburn on your eyes is no joke. I highly recommend wearing a good pair of sunglasses, or welding goggles if you have them.

Safety First...

 Last I posted, I was pointing out various bits of the optic path, and what they do. Shown below is a top-down view of the optic path of the axaa p2jr projector. http://www.aaxatech.com/products/p2jr_pico_projector.html

The L-Bracket with the LEDs has been removed.

 Initially, my efforts focused on attempting to collimate the light from a 10W LED into the existing port from one of the removed LEDs. The 10W UV LED I had purchased from Ebay had a 3x3 grid of individual LEDs. The actual emitter portion measured approximately 1cm across. I needed to channel this light somehow into an area approximately 4mm in diameter.

I tried several methods for building a suitable reflector/collimator, including dis-assembling and removing elements from various LED flashlights, and even building a simple light-pipe from acyclic rod.


In the end, I decided I was over-thinking it and decided to do something drastic.

Something drastic

I decided to remove almost the entire optic path. No mirrors, 1 lens. If you compare the above picture with the second picture I posted, you can see the portions of the optic path (and plastic)  that I removed. All that I left was a simple lens in front of the splitter/reflector portion of the DLP. Coincidentally, the lens in front was approximately 1cm across, which meant the LED was a good fit.

I taped over the lens while removing plastic

Most of the optic path removed.

 What I ended up doing was (temporarily) taping the 10W UV LED directly to the face of the lens prior to the DLP's splitter/reflector. This acted as a last-stage collimator to focus the LED's light onto the DLP chip and through the optics.

Projected onto a sheet of white paper.

A little light leakage around the edges can be fixed...

 Overall, I'm fairly happy with the way this turned out. The light emitted through the DLP was strong enough to cure resin (more timed tests are required) and it has even light across the image. The LED is was using was completely un-heatsinked, so it became very hot very quickly.

The next order of business is as follows:
1) Heatsink the LED (probably with a fan)
2) Build a mount for the DLP assembly / heatsinked LED

I'm currently designing a FDM 3d-printed 'carrier' right now.
Stay tuned for part 3, which will include some curing times and the initial design of a pico-SLA machine.
-Steve

Creation Workshop Version 13 - Last BETA release

This is probably the quickest turn-around I've had between releases. Version 13 doesn't have anything earth-shattering in it, but it does have the following:

• Fixed all reported issues in version 12
• Improved Camera Controls (Thanks Shai!)
• Huge reduction in memory usage
• Instant Slicing
• Volume & Cost Estimator
• Revised future-proof config files
• Additional support generation tools
• Fixed the intersection issues in support generation & object selection
• Simplified GUI (G-Code controls)
• New Plug-In System
• Other things I forgot...

Now that I look at the list, this release actually does have quite a bit to offer. You can download version Beta 13 from the usual spot here: https://github.com/Pacmanfan/UVDLPSlicerController/tree/master/UVDLP/Published