Mixing Colors On The Reprap

3d printing has come huge strides in ability to construct detailed objects. Unfortunately, color is still a considerable limitation. Here, some people at the Reprap blog are having fun coming up with an extruder head that actually mixes two colors as it deposits them. Don’t confuse this with the dual head that Makerbot is touting that allows you to switch colors on the fly, this is a single head that actually has a cavity where the material is melted, then stirred to create a combination of the two. It is an interesting method of overcoming a limited supply of colors.

Having this extra stirring chamber means that there would be a small amount of material wasted any time that you wanted to make a change to the color, as it would have to be purged. There are some interesting thoughts in their comments on how to use this extra material most efficiently.

3d Printing Saves The Day For Time-lapse Photography

Several of us here at Hackaday have discussed how much we’d like to have some tools, like a 3d printer, but just can’t justify the cost. What would we make? Why do we really need one? Why don’t we just bother [Brian Benchoff] who already has one to make us parts instead. That’s usually how the conversation goes.

[Alexander Weber] gave us another little reason to drop in our “list of reasons we need a 3d printer” list with this little hack. He wanted to play with CHDK but found the camera’s battery unable to stay alive for longer than 2 hours. There is a commercially available adapter to allow you to plug into the wall, but the cost was outrageous. At least it is outrageous to someone who already owns a 3d printer. We just need a few hundred more dollars worth of reasons to justify that sweet 3d printer we’ve been pining over.

[via Adafruit]

Hackday Links: March 16, 2012

Shamrock hat

[Josh] whipped up a shamrock themed hat by adding an outline of green LEDs to this bowler. Just remember, don’t drink and solder. Happy St. Patrick’s Day everyone!

Battery-powered Xmas lights can be more useful

[Karl] took a string of mostly useless battery-powered Christmas lights and found a good use for them. He replaced the stock board with a boost convert and uses the two AA batteries as a 5V power supply when mains power isn’t handy.

3D printed appliance repair

The broken plastic piece seen here keeps a dishwasher closed while running. The part couldn’t be sourced by a repairman but the best solution turned out to be printing a perfect replacement part.

Generating labels for resistor storage

[Darrell] picked up a surplus test-tube rack to use as resistor storage. It’s a great system, but his Ruby script that uses LaTeX to generate color-coded labels is a really nice touch as well.

DeLorean quadcopter build log

No, it’s not a dupe. [Alp_X] found the link to a build log for the DeLorean quadcopter that headlined our last Links post. It’s in Russian but the machine translation should help a bit.

Nanoscale 3D Printing

This 3D-printed model of the Tower Bridge is only 200 micrometers long. To put that into perspective, the distance between the towers is the width of a human hair. This model is the product of research at the additive manufacturing department of the Vienna University of Technology

The models were fabricated much like normal stereolithography – a laser shines onto a vat of light-sensitive resin. The resin hardens when exposed to light, and the model is built up layer by layer. These nanoscale models were made using a process called “two-photon lithography,” something we’re not going to pretend we understand completely but here’s a nice paper that provides a good overview. Needless to say, the precision these prints exhibit are nearly ludicrous. The researchers claim a precision of ±1µm, a respectable amount of precision for very high-tech machining applications.

The researches posted a video of the fabrication of a nanoscale F1 race car filmed in real-time. Check that out after the break.

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3D Printing From An Android Device

[skullkey] over at the House4Hack hackerspace in Pretoria, South Africa wanted a way to get kids excited about technology and desktop fabrication labs. Wanting to give kids a visceral feel for the march of technology, he created Makerdroid, an android app that allows for the creation 3D objects on an Android tablet and preparing them to be printed on a Reprap or Makerbot.

What’s really interesting about this build is not only the fact that [skullkey] and his lovely beta testers are generating .STL files on an Android device, the object files are also being converted to GCode on the Android, without the need for a conventional computer. Makerdroid uses the very popular Skeinforge to generate the instructions for the printer (although a lot of people are switching over to Slic3r).

Makerdroid doesn’t need a PC to print objects out on a 3D printer, but we think the process of shuffling GCode files from a tablet to the printer with an SD card is a little archaic. It might be possible to print directly from an Android tablet over Bluetooth with the Android Bluetooth Reprap app that is currently in development. Still, we love the idea of printing objects we just created on a touch screen, as shown in the Makerdroid demo video after the break.

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New Extruder 3D Prints Tasty Treats Using Chocolate

If you’ve never felt at home with a piping bag in your hands this chocolate extruder will come to your rescue. It can replace the plastic extruder head on your 3D printer (RepRap, Makerbot, most 3-axis CNC machines, etc.), letting you turn your digital creations into decadent reality.

The head uses a progressive cavity pump to feed the chocolate from a reservoir through the printing nozzle. It’s important to keep the chocolate warm or it will set up so when [Tomi Salo] designed the print head he included a heat shroud through which warm air can be circulated. He uses a shoe dryer to source the hot hair which is patched into the heat shroud with a length of tubing.

This extruder can be 3D printed but be careful what material you use. [Tomi] mentions that PLA is ‘sort of food-safe’ but ABS is not. We wonder if the design could be altered for milling out of aluminum or stainless? At any rate, if you’re going to give it a try you might find [Tomi’s] advice on working with chocolate useful.

[via @clothbot]

Multicolor RepRap Prints The Really, Really Hard Way

[Adrian Bowyer] just posted his progress with multicolored printing to the RepRap blog.

The new developments are a continuation of [Adrian]’s experiments with a mixer extruder that squirts four different colored filaments out of the same nozzle. [Myles Corbett] took this idea and ran with it producing the two-color print seen above. To squirt two different colored filaments out of the nozzle, [Myles] used two Bowden extruders mounted near the apex of the RepRap with tubes leading to the nozzle. Right now, the color of a print is controlled by loosening the grip screws of the extruder, but there are plans for moving that task over to electronic control of the extruders.

While it may be only black and white now, it’ll be a very interesting development once five extruders are loaded up with cyan, magenta, yellow, black, and white filament. Yes, it is now theoretically possible to print full-color 3D objects on a RepRap. While we’re not looking forward towards having to upgrade our one-motor extruder to a four- or five-motor model, the possibilities for desktop fabrication are becoming amazing.