Clever Chemistry Leads to Much Faster 3D Printing

Resin printing, it can be messy but you get really great resolution thanks to the optical nature of curing the sticky goo with light from a projector. Soon it will have a few more notches in its belt to lord over its deposition cousins: speed and lack of layers. A breakthrough in resin printing makes it much faster than ever before and pretty much eliminates layering from the printed structure.

The concept uses an oxygen-permeable layer at the bottom of the resin pool. This inhibits curing, and apparently is the source of the breakthrough. The resin is cured right on the border of this layer and allows for what is described as a continuous growth process rather than a layer-based approach. One of the benefits described is no need for resin to flow in as the part is extracted but we’re skeptical on that claim (the resin still needs to flow from somewhere). Still, for us the need to work with resin which is expensive, possibly messy, and has an expiry (at least when compared to plastic filament) has kept deposition as a contender. The speed increase and claims of strength benefits over layer-based techniques just might be that killer feature.

The technology is coming from a company called Carbon3D. They are branding it CLIP, or Continuous Liquid Interface Production. After the break you can see a video illustration of the concept (which is a bit too simple for our tastes) as well as a TED talk which the company’s CEO, [Joseph Desimone] gave this month. Of course there is also the obligatory time-lapse print demo.

So what do you think: game changer or not, and why do you feel that way? Let us know in the comments.

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Optimized Molds With 3D Printing

[Florian] has a few arcade games and MAME machines, and recently he’s been trying to embed objects in those hard plastic spheres on the end of joysticks. A common suggestion is to 3D print some molds, but even though that’s a great idea in theory the reality is much different: you’re going to get layer lines on the casting, and a mirror finish is impossible.

No, a silicone mold is the way to do this, but here 3D printing can be used to create the mold for the silicone. Instead of a few pieces of hot glued cardboard or a styrofoam cup, [Florian] is 3D printing a a container to hold the liquid silicone around the master part.

After printing a two-piece part to hold both halves of a silicon mold, [Florian] put the master part in, filled it up with silicone, and took everything apart. There were minimal seam lines, but the end result looks great.

In addition to making a 3D printed mold container, [Florian] is also experimenting with putting 3D printed parts inside these joystick balls. The first experiment was a small 3D printed barrel emblazoned with the Donkey Kong logo. This turned out great, but there’s a fair bit of refraction that blows out all the proportions. Further experiments will include a Pac-Man, a skull, and a rose, to be completed whenever [Florian] gets a vacuum chamber.

A UV Lightbox For Curing Prints

With resin printers slowly making their way to hackerspaces and garages the world over, there is a growing need for a place to cure these UV resin prints. No, they don’t come out of the machine fully cured, they come out fully solid. And no, we’re not just leaving them in the sun, because that’s not how we do things around here.

[Christopher] whipped up a post-cure lightbox meant to sit underneath his Form 1 printer. It’s made of 1/2″ MDF, with adjustable feet (something the Form 1 lacks), a safety switch to keep the lights off when the door is open, and a motor to rotate the parts around the enclosure.

The light source for this lightbox is 10 meters of ultraviolet LED strips. The LEDs shine somewhere between 395-405nm, the same wavelength as the laser diode found in the Form 1 printer. Other than a bit of wiring for the LEDs, the only complicated part of the build was the motor; [Christopher] bought a 2rpm motor but was sent a 36rpm motor. The vendor was out of 2rpm motors, so a PWM controller was added.

It’s a beautiful build that shows off [Christopher]’s ability to work with MDF. It also looks great sitting underneath his printer, and all his parts are rock solid now.

The Hackaday Prize Semifinalist Update

There are only a few more days until The Hackaday Prize semifinalists need to get everything ready for the great culling of really awesome projects by our fabulous team of judges. Here are a few projects that were updated recently, but for all the updates you can check out all the entries hustling to get everything done in time.


Replacing really, really small parts

accThe NoteOn smartpen is a computer that fits inside a pen. Obviously, there are size limitations [Nick Ames] is dealing with, and when a component goes bad, that means board rework in some very cramped spaces. The latest problem was a defective accelerometer.

In a normal project, a little hot air and a pair of tweezers would be enough to remove the defective part and replace it. This is not the case with this smart pen. It’s a crowded layout, and 0402 resistors can easily disappear in a large solder glob.

[Nick] wrapped the closest parts to the defective accelerometer in Kapton tape. That seemed to be enough to shield it from his Aoyue 850 hot air gun. The new part was pre-tinned and placed back on the board with low air flow.

How to build a spectrometer

spec

The RamanPi Spectrometer is seeing a lot of development. The 3D printed optics mount (think about that for a second) took somewhere between 12 and 18 hours to print. Once that was done and the parts were cleaned up, the mirrors, diffraction grating, and linear CCD were mounted in the enclosure. Judging from the output of the linear CCD, [fl@C@] is getting some good data with just this simple setup.

Curing resin and building PCBs

uv[Mario], the guy behind OpenExposer, the combination SLA printer, PCB exposer, and laser harp is chugging right along. He finished his first test print with a tilted bed and he has a few ideas on how to expose PCBs on his machine.

You don’t need props to test a quadcopter

bladesGoliath, the gas-powered quadcopter, had a few problems earlier this month. During its first hover test a blade caught a belt and bad things happened. [Peter] is testing out a belt guard and tensioner only this time he’s using plywood cutouts instead of custom fiberglass blades. Those blades are a work of art all by themselves and take a long time to make; far too much effort went into them to break in a simple motor test.

Hackaday Links: July 6, 2014

hackaday-links-chain

Power for your breadboards. It’s a USB connector, a 3.3V voltage regulator, and a few pins that plug into the rails of a breadboard.

“Have you seen those ‘Portable battery chargers for smartphones?’ Well the idea of the device is based on it , but the difference here is the internet part.” That’s a direct quote from this Indiegogo campaign. It’s funny because I don’t remember losing my damn mind recently. Wait. It’s $200. Yep. Yep. Definitely lost my mind there.

Putting the Internet on a USB stick not weird enough? Hair Highways. Yep, human hair. It’s just embedding human hair into resin, cutting everything up into plates, and assembling these plates into decorative objects. As a structural material, it’s probably only as strong as the resin itself, but with enough hair set in layers perpendicular to each other, it would be the same idea as fiberglass. Only made out of hair.

Tesla is building a $30,000 car and Harley is building an electric motorcycle. The marketing line for the bike will probably be something like, “living life on your own terms, 50 miles at a time”.

PixelClock? It’s a 64×64 array of red LEDs built to be a clock, and low-resolution display. It looks blindingly bright in the video, something that’s hard to do with red LEDs.

Huge RGB Ring Light Clock

ring

After several months of work, [Greg] has completed one of the most polished LED clocks we’ve ever seen. It’s based on the WS2812 RGB LEDs, with an interesting PCB that allowed [Greg] to make a huge board without spending a lot of money.

The board is made of five interlocking segments, held together with the connections for power and data. Four of these boards contain only LEDs, but the fifth controller board is loaded up with an MSP430 microcontroller, a few capsense pads for a 1-D touch controller, and programming headers.

Finishing up the soldering, [Greg] had a beautiful LED ring light capable of being programmed as a clock, but no enclosure. A normal plastic case simply wouldn’t do, so [Greg] decided to try something he’d never done before: casting the PCB inside a block of resin.

A circular mold was made out of a piece of MDF and a router, and after some problems with clear resin that just wouldn’t cure, his ring light was embedded in a hard, transparent enclosure.  Conveniently stuck in the mold, of course. The MDF had absorbed a little bit of the resin, forcing [Greg] to mill the resin ring free from the wood, with a lot of finish sanding to make the clock pretty.

It’s a clock that demonstrates [Greg]’s copious manufacturing skills, and also his ability to troubleshoot the problems that arose. While he probably won’t be casting things inside an MDF mold anymore, with the right tools [Greg] could easily scale this up for some small-scale manufacturing.

 

MRRF: 3D Printed Resin Molds

 

Visiting the Midwest RepRap Festival, you will, of course, find a ton of 3D printed baubles and trinkets. A slightly more interesting find at this year’s MRRF was a lot of resin cast parts from [Mark VanDiepenbos]. He’s the guy behind the RotoMAAK, a spinny, ‘this was in the movie Contact‘-like device designed for spin casting with resins. At the festival, he’s showing off his latest project, 3D printed resin molds.

With the right mold, anyone with 2-part resins can replicate dozens of identical parts in an hour. The only problem is you need a mold to cast the parts. You could print a plastic part and make a silicone mold to cast your part. The much more clever solution would be to print the mold directly and fill it with resin.

[Mark] printed the two-part rabbit mold seen above out of ABS, filled it with urethane resin, and chucked it into his RotoMAAK spin casting machine. Six minutes later the part popped right out, and the mold was ready to make another rabbit.

Video below.

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