LEDs for the Cure

Worried as the LED backlight market approaches saturation? Consider this innovative new application area.

In the span of 12 minutes, Kickstarter's Titan 1 project by San Francisco's Kudo3D has broken through $100,000 in pledges, and, as this is written during the first day of its 30-day campaign, has blown past 400% of its campaign goal at $50,000. Crowdfunding trend-analytics site Kicktraq is forecasting the Titan 1's campaign to hit $3.5 million. At $2,000 apiece, that's 1,750 units. It seems very likely that they could hit a number like that.

At this point, you're scratching your head in trying to connect "$2,000 apiece" with the mission of the AllLEDlighting.com site. What LED luminaire is this, why the frenzy, and why are people paying so much for it? The thing is, it's not a solid-state lighting device at all, it's a 3D printer. Now you know why there aren't any spoiler images of the printer here.

Kudo3D Titan 1 curing box

To further agitate your scalp, this Stereo-Lithography Additive (SLA) printer doesn't even use LEDs, but, instead, uses a 3000-hr. UHP bulb housed in a garden-variety 1080p DLP projector (Kudo4D claims the projector is removable and can be dual-purposed as an actual digital projector for movie buffs) to image 1920 x 1080 pixels into the bottom of a translucent tub of 400nm-cured resin.

Semi-cured

A stepper-motor-based "build platform" carries a baseplate that moves upward, out of the tub of resin. The first layer is imaged/cured at the build plate, it moves up a programmable layer thickness, a new pixel matrix is imaged, and the process continues, generating a semi-cured 3D part at the rate of about 2 inches per hour.

Now, "semi-cured" means that an organized pile of mush has been created, which needs exposure to 400nm UV light to harden fully. The most popular UV-curing solution to date: Leave your 3D mush out in the sun. Kudo3D is stepping it up a notch by offering a UV curing box for an additional $349. Cure-iously, only a bit more than 10% of campaign supporters have opted for the UV cure unit in addition to their SLA printer.

Head unit of curing box

The unit itself appears to be made of an 80/20-style extruded aluminum framework, with flat wall panels. While it's not readily apparent, one can surmise that these walls are mirror finished on the inside.

The light source comprises a 4x5 array of 1W 390nm LEDs, each one lensed, with the wavelength being "close enough" to fully cure the "400nm" semi-cured resin model that came out of the printer. The LEDs are horizontally mounted on a natural convection heatsink, to which the LED driver box is attached. While this design appears simple, the thermal design appears to have lost the tug-of-war with the optical design, which sited the LED/heatsink assembly on a pyramid-shaped reflector/lid. As good an optical design could have placed the LEDs on a side panel for better thermal performance. Gravity paradigms are hard to break.

LED printhead

It is exciting to see myriad LED applications in emerging and exploding markets like general lighting, and, now, replacing the sun in 3D printer applications. While we in the All LED Lighting community tend to focus primarily on white light sources, and UV-curing LEDs are nothing new in fields like dentistry, the exploding 3D-printer market might represent another lucrative opportunity for LED technology as the backlight market approaches saturation.

So, who will be the first to produce a UV LED bar to replace that unwieldy DLP-based projector, where 1024 UV LEDs, a kilowatt of 'em, are used to image a full line of a build layer, much like an LED "laser" paper printer does? Who wants to step up to the bar and be innovative?