Lost PLA Casting With A Little Help From Your Microwave

August 20, 2014 by Adam Fabio 45 Comments

lost-pla

[Julia and Mason] have been perfecting their microwave-based lost PLA casting technique over at Hackaday.io. As the name implies, lost PLA is similar to lost wax casting techniques. We’ve covered lost PLA before, but it always involved forges. [Julia and Mason] have moved the entire process over to a pair of microwaves.

Building on the work of the FOSScar project, the pair needed a way to burn the PLA out of a mold with a microwave. The trick is to use a susceptor. Susceptors convert the microwave’s RF energy into thermal energy exactly where it is needed. If you’ve ever nuked a hot pocket, the crisping sleeve is lined with susceptor material. After trying several materials, [Julia and Mason] settled on a mixture of silicon carbide, sugar, water, and alcohol for their susceptor.

The actual technique is pretty simple. A part printed in PLA is coated with susceptor. The part is then placed in a mold made of plaster of paris and perlite. The entire mold is cooked in an unmodified household microwave to burn out the PLA.

A second microwave with a top emitter is used to melt down aluminum, which is then poured into the prepared mold. When the metal cools, the mold is broken away to reveal a part ready to be machined.

We think this is a heck of a lot of work for a single part. Sometimes you really need a metal piece, though. Until metal 3D printing becomes cheap enough for everyone to do at home, this will work pretty well.

Cutting Records Out Of CDs

August 12, 2014 by James Hobson 38 Comments

3D Printed Record Lathe

Lovers of records rejoice! Did you know you can cut your own vinyl using something called a record lathe? [Beau Walker] just put the finishing touches on his 3D printed record lathe, and the results speak for themselves!

A Recording Lathe was once used for cutting records, and previously, wax cylinders – if you want to get really old school. [Beau], being an analog lover, decided he had to try making his own. He designed the whole thing in FreeCAD and got 3D printing. A single stepper motor drives the lead screw which moves the writing head back and forth as the record spins in place. As to not waste materials, he’s reusing old CD’s for his newly created vinyls. Two 25W speakers cause vibrations in the needle to cut into the disc, via a clever little mechanism.

The system works pretty well, but he wants to replace the turntable with another stepper motor for finer control of the recording — sometimes the turntable slows down during recording under load which messes up the sound. There’s a video of it in action on his site that we can’t embed here, so you should definitely go check it out!

Of course you could skip the middleman and go straight to 3D printing your records…

LittleRP, The Latest Of The Resin Printers

August 11, 2014 by Brian Benchoff 26 Comments

LitleRP Over the last few years, a few resin / stereolithography printers have been made a few headlines due to print quality that cannot be matched by the usual RepRap style filament printers. These used to be extremely expensive machines, but lately there have been a few newcomers to the field. The latest is the LittleRP, an affordable DLP projector-based resin printer that can be put together for under a kilobuck.

Instead of proprietary resins, the LittleRP is designed to use as many different formulations of UV curing resin as possible, including those from MadeSolid and MakerJuice. These resins are cured with a DLP projector, providing a print area of 60x40x100mm with the recommended 1024×768 projector, or 72x40x100mm with the alternative 1080p projector.

This isn’t the only resin printer that’s come out recently; SeeMeCNC recently announced their cleverly named DropLit resin printer kit, going with the same ‘bring your own projector’ idea as the LittleRP. With the price of the printer, both of these kits should cost less than $1000 USD. With the price of UV resin dropping over the last few years, it might be just the time to get in the resin printer game.

George Crowdsourcington: A 3D Printed, Community Built Statue

August 7, 2014 by James Hobson 7 Comments

George Crowdsourcington and Distributed Ben Franklin

Macro 3D printing is some cool stuff — but it’s extremely time consuming and can be very expensive. Introducing We The Builders, a 3D printing crowd source site which creates large scale projects the whole country can enjoy.

Their first project was George Crowdsourcington — a 1:1 copy of the Baltimore George Washington statue made out of 110 individual pieces. They chopped the model up into 4″ cubes and created the website in order to organize and distribute the files. One of their sponsors, Tinkerine Studio, reimbursed the shipping costs for makers who helped print out parts! Since his creation, Crowdsourcington has traveled all over the country, making stops at 3D printing shows in New York, mini-Maker Faires, art galleries, science centers and more — he even did a short residency in the Adafruit office in Manhattan!

It was quite the success, so they’re starting a new statue called the Distributed Ben Franklin. This one has a whopping 198 pieces, and they hope to have it built in time for the Silver Spring and World Maker Faires.

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Restarting 3D Prints

August 2, 2014 by Eric Evenchick 18 Comments

If a 3D printer is interrupted during a print, it will usually result in a junk part. Resuming the print can be very difficult. A group of researchers at MIT have built an add-on for 3D printers that uses a laser scanner to evaluate the state of the print, and allows the printer to restart.

While this will allow you to salvage some partially competed prints, the interesting application is switching between materials. In the image above, the lower piece was printed in ABS. The print was interrupted to change materials, and the top cube was printed in PLA. This allows for prints to mix materials and colors.

The add-on was tested with the Solidoodle 3D printer, and can be built for about $60. It requires a laser mounted to the print head, and a low-cost webcam for performing the measurements. While the group will not be continuing work on this project, they plan to open source their work so others can continue where they’ve left off.

After the break, we have a video of the printer performing a scan and resuming a print.

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A 3D(ollar) Scanner

July 31, 2014 by Brian Benchoff 23 Comments

Once you have a 3D printer, making copies of objects like a futuristic Xerox machine is the name of the game. There are, of course, 3D scanners available for hundreds of dollars, but [Joshua] wanted something a bit cheaper. He built his own 3D scanner for exactly $2.73 in parts, salvaging the rest from the parts bin at his local hackerspace.

[Josh]’s scanner is pretty much just a lazy suzan (that’s where he spent the money), with a stepper motor drive. A beam of laser light shines on whatever object is placed on the lazy suzan, and a USB webcam feeds the data to a computer. The build is heavily influenced from this Instructables build, but [Josh] has a few tricks up his sleeve: this is the only laser/camera 3D scanner that can solve a point cloud with the camera in any vertical position. This potentially means algorithmic calibration, and having the copied and printed object come out the same size as the original. You can check out that code on the git.

Future improvements to [Josh]’s 3D scanner include the ability to output point clouds and STLs, meaning anyone can go straight from scanning an object to slicing it for a 3D printer. That’s a lot of interesting software features for something that was basically pulled out of the trash.

A 3D Printed Brushless Motor

July 30, 2014 by Brian Benchoff 35 Comments

brushless Building electronics with 3D printers is something we see hitting the tip line from time to time, but usually these are printed circuits, not electromechanical parts like motors, solenoids, and relays. [pitrack] thought he could do better than printing out a few blinking LED circuits and designed and built a brushless motor, the same kind you would find on electric model planes and quadcopters.

In every brushless DC motor, there are a few common parts: the rotor has a few powerful magnets embedded in it, a stators with coils of wire, and the an enclosure to keep everything together. [pitrack] printed all these parts off on his Makerbot, winding each of the three coils with about 400 turns of 26 AWG magnet wire. Also embedded in the stator are a trio of hall effect sensors to make the control via an Arduino and an L6234 motor driver easy.

For his next trick, [pitrack] is going to test the efficiency of the motor and attempt to optimize it. In the long term, it should be possible to parameterize the design of one of these printed motors, effectively allowing anyone to type in the torque and Kv rating of a desired motor, plug that into an equation, and have a motor design come out the other end.
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