Update: Lost PLA Metal Casting — The Movie

May 10, 2013 by Mike Szczys 29 Comments

lost-pla-metal-casting-movie

Turning 3D printed plastic parts into metal objects is not a new concept. But we don’t see a lot of it and enjoyed watching the documentary version of [3DTOPO’s] lost PLA metal casting process so much we figured you’d want to see it too.

The thirty-five minute video walks through every part of the process which we originally learned about in September of last year. The process was developed as a way to fabricate parts that will be used in high-stress applications. For instance, the part seen above is a mounting bracket for the ball screws that moves the Z axis on a huge CNC build he’s been working on. A plastic part will break under the strain so he needed to make it out of aluminum alloy.

To start, the piece is modeled and printed in plastic to check the fit. Once it’s just right he scales it to 103% and prints it again to account for the shrinking of the metal as it cools. The next step is pictured above, adding paths using rigid foam insulation that allow for the metal pour and for air to escape. This is packed into a plaster and sand mold which dries before being cooked in a furnace to vaporize the foam and PLA. This leaves a perfect mold for the metal pour.

After the break you can see a 5-minute overview version of the project.

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Voice Controlled Chess Robot

May 9, 2013 by Mike Szczys 11 Comments

voice-controlled-chess-robot

[Ben Yeh] wrote in to tell us about this voice-controlled chess robot he built along with three others as a final project for their Georgia Tech ECE 4180 Embedded Systems Design class.

To handle the speech recognition they grabbed an EasyVR board. This is a fine solution because it prevents the need for a computer to process voice commands (remember, it’s an embedded systems class). This concept breaks down when you find out that the desktop computer next to the robot is where the chess game is running. Perhaps that can be moved to a microcontroller by the next set of 4180 students.

The robot arm portion of the project is shown off well in the clip after the break. Normally we’d expect to see stepper motors driving the axes of a CNC machine but in this case they’re using servo motors with built-in encoders. The encoders are i2c devices which feed info back to the main controller. There was a parts ordering snafu and the z axis motor doesn’t have an encoder. No problem, they just added a distance sensor and a reflector to measure the up and down movement of the claw.

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Semi-automatic Pick And Place Machine

April 18, 2013 by Mike Szczys 26 Comments

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This is a fascinating take on building your own pick and place machine. It does an amazing job of automating the hardest parts of hand assembly, while relying on human dexterity to achieve the hardest parts of automation. It’s a semiautomatic pick and place machine driven by an Arduino and controlled by an Android tablet.

The machine is built in two parts. The portion in the upper left feeds components from reels and is fully automated. The portion on the lower right consists of a padded arm-rest which slides smoothly along two axes. A mechanical arm with multiple articulations is attached to the end, culminating in a tip connector for some vacuum tweezers. Right handers are the only ones who will find this convenient, but oh well. The clip after the break shows it in action. The assembly technician first selects the component from an icon on the Android tablet. The reel machine then dispenses that part, which is picked up by the vacuum tweezers using the left hand to switch the vacuum on and off again. If the part orientation needs to be rotated it can done using the jog wheel on the Android app. It smooth, quick, and best of all, clever!

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CNC Tic Tac Toe

April 2, 2013 by Mike Szczys 5 Comments

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This computer controlled physical Tic Tac Toe game is built from parts scavenged from common consumer goods. Specifically, the sled is made up of a combination of printer and DVD drive parts.

The build is delightful, and you can’t move on to the next feature until you watch it play a game in the clip after the break. The game board can move along two axes. It’s obvious from the image above that the printer ink cartridge sled has been reused to let the board move left and right. But the DVD lens sled hidden under the board lets it move forward and back. The piece of protoboard seen on the left is an IR reflectance scanner. The board moves systematically under this sensor. Whenever a black square (placed by the human player) is in play it prevents the IR beam from reflecting back. What you can’t see in this image is the yellow disc dispenser which is just out of the frame. It uses the DVD disc tray motor to place the computer’s pieces. We think this build is just begging to be turned into a Turing Machine demonstration.

If you liked this one we’re sure you’ll also appreciate CNC chess.

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Wooden Teeth For Your USB Keyboard

March 29, 2013 by Mike Szczys 15 Comments

wooden-keyboard

We just got an ergonomic keyboard for the first time and absolutely love it. But the look of this keyboard hack has us second guessing ourselves. [Will Pretend] pulled off an absolutely stunning wooden retrofit for his USB keyboard. Be warned, his project log includes 175 photos, and most of them have captions.

He started off by taking apart the original USB keyboard to see what he was working with. Before digging in to the valuable wood stock he cut test pieces using some thin MDF. But once he had a clear plan to get to the end of the project it was full stem ahead.

The keys are not simple Chicklet style overlays, they have depth like you would expect to find on low-grade plastic peripherals. This was accomplished by milling each key, then sending them through the laser cutter to each the letter on top.

Take some time to make your way through the entire project (here’s a thumbnail layout if you get frustrated). Unfortunately [Will] says he doesn’t actually use the keyboard because of grains catching and the keys move around a bit too much. But it does work.

Oil Feed Retrofit For A CNC Mill Starting To Come Together

March 29, 2013 by Mike Szczys 8 Comments

Here is the first real fruit of [Joel’s] labor on his oiling system for a CNC mill. Regular readers will remember hearing about his quest to go from a manual mill to a CNC version. As part of the overhaul he decided to add a system that can dispense oil to the different wear parts on the machine. We first looked in on the project when he showed off the pipe bender he built for the task. Now that he has that at his disposal he was able to route tubing to many of the parts.

The system starts with a central brass manifold which is pictured in the foreground. Each pipe was bent and cut to reach its destination with a minimum of wasted space. After a test fit showed good results he brazed the pieces together using silver solder. Each of the ball nuts have been drilled out so that oil will be injected onto the threads of the ball rod. Three input ports on the manifold will eventually let [Joel] connect the oil injection system via flexible tubing.

Handwriting Robot Arm Is A Little Stiff-wristed

March 27, 2013 by Mike Szczys 13 Comments

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Check out this robot arm capable of handwriting which is orders of magnitude clearer than our own. It was built by [Patrick Barnes] as contract work for a campaign to raise funding for research into Duchenne Muscular Dystrophy.

Don’t miss the video after the break which starts off with the satisfying whine of some serious stepper motors. Judging scale from this image is a bit tough, but [Patrick] tells us that the entire assembly stands almost fourteen inches tall and the arm has a reach of around twenty inches. The demonstration shows off it’s abilities by drawing a Hilbert Curve. From watching the action you’ll realize that, though this arm and hand look fantastic, this is really a SCARA plotter. The wrist and fingers are for looks only, providing a place where the felt-tipped pen can be mounted (held flush to the paper with a rubber band). Whether that’s a disappointment or not, the precision and look of the machine bring it very high marks. It could take a bit of a lesson in penmanship from another we’ve seen though.

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