Hot Plate Stirrer Dissolves Support Material In 3D Printed Objects

May 3, 2013 by Mike Szczys 13 Comments

Hot_plate_stirrer

When you want to print a 3D object you run into problems if there is a part that has nothing below it. The hot, soft filament coming out of the extruder will droop with gravity if not given something to rest on while it hardens. The solution is to use a second material as a support. But then you’ve got to find a way to remove the support structure when the printing is done. That’s where this beauty comes in. It’s a heated stir plate for dissolving PLA.

The PLA is printed using a second extruder head. Once the part is cooled [Petrus] puts it into a heated bath of sodium hydroxide (lye). The solvent will remove the PLA but not harm the ABS. Speaking of ABS, [Petrus] also mentions that this can double as a temperature controlled hot plate for polishing ABS prints using acetone vapor.

There’s all kinds of good stuff inside of this beast so do check out the full plans to learn more. Our favorite part is the stir bar which is a piece of threaded rod and a couple of nuts. To make it safe to submerge in the chemicals he 3D printed a pill-shaped enclosure for it.

[Thanks Matt]

Foot-powered Lathe Is A Tour De Force Of Joinery Techniques

April 26, 2013 by Mike Szczys 48 Comments

foot-powered-lathe

Meet [Quetico Chris]. He’s a master woodworker who likes to find his own alternatives to using power tools. Most recently, he was inspired by a fly-wheel from an old factory. He used it to build this foot powered wood lathe.

It works something like a foot powered sewing machine. There’s a lever for your foot which converts the downward force from your foot into a rotating force which drives the work piece. The mechanics of the lathe are pretty common, but we think the build techniques he uses are anything but. The video after the break shows each step [Chris] went through when crafting the human-power tool. His approach was to use wood as often as possible which includes foregoing modern fasteners for older joinery. He uses mortise and tenon, wood pinning, doweling, and a lot of puzzle-like tricks to get the job done.

We lack the skill and tools to replicate this kind of craftsmanship. We’re going to stick to letting a laser cutter form our wood connections.

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Semi-automatic Pick And Place Machine

April 18, 2013 by Mike Szczys 26 Comments

semi-automatic-pick-and-place

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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Stapler Hack Fastens Infinitely Large Sheets Of Paper

April 5, 2013 by Mike Szczys 78 Comments

infinity-stapler

It’s not called the infinity stapler, but we think it should be. This magnetic hack allows you to use a plain old stapler to fasten very large pieces of paper.

The limiting factor has always been the distance between the stapler’s hinge and where the staples come out. To get around this, the crimped connections between the base and the dispenser were drilled out. Larger holes were then drilled in both the top and bottom halves to accept a set of magnets. These were held in place temporarily with some tape while the super glue had time to set up.

The result is two halves which are placed on either side of the over sized paper. The magnets are responsible for aligning the staples with the die which bends them to their final shape. The whole process is shown in the video clip after the break.

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Melting Metal With A DIY Foundry Furnace

April 4, 2013 by Eric Evenchick 33 Comments

If you want to do casting at home, you’ll need a way to melt metal. [Jake]’s DIY foundry furnace gets hot enough to melt aluminium, and is built out a mix of scrap parts.

The chamber of the furnace is built out of a water heater tank which has been lined with a special cement that refracts heat. The furnace is heated by a Babington burner. This type of burner works by atomizing the fuel and injecting it into the furnace. They are good for burning waste oil to achieve high heats.

A scrap Volkswagen oil pump and a cordless drill are used to feed oil into the burner. Once it’s fired up, the furnace takes about 10 minutes to melt the 11 pounds of metal that it can hold. [Jake] melted about 40 pounds of aluminium alloy from scrap alloy wheels in 2 hours, which should be more than enough for a home casting project.

After the break, check out the overview of the device and a demo of melting aluminium.

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Microscope Ring Light With A Number Of Different Features

April 3, 2013 by Mike Szczys 41 Comments

microscope-ring-light

Microscopes magnify light. It makes sense that having more light reflecting off of the subject will result in a better magnified image. And so we come to Aziz! Light! It’s [Steve’s] LED light ring for a stereo microscope. It’s also a shout out to one of our favorite Sci-Fi movies.

He’s not messing around with this microscope. We’ve already seen his custom stand and camera add-on. This is no exception. The device uses a fab-house PCB which he designed. It boasts a dual-ring of white LEDs. But the controls don’t simply stop with on and off. He’s included two rotary encoders, three momentary push switches, and three LEDs as a user interface. This is all shown off in his demo video after the break.

An ATtiny1634 is responsible for controlling the device. When turned on it gently ramps the light up to medium brightness. This can be adjusted with one of the rotary encoders. If there are shadows or other issues one of the push buttons can be used to change the mode, allowing a rotary encoder to select different lighting patterns to remedy the situation. There are even different setting for driving the inner and outer rings of LEDs.

We haven’t worked with any high-end optical microscopy. Are these features something that is available on commercial hardware, or is [Steve] forging new ground here?

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Cooling A Photomultiplier Tube

April 2, 2013 by Mike Szczys 25 Comments

photomultiplier-tube-cooling-rig

A photomultiplier tube is a device used to measure very low levels of light. It’s a common tool of particle physics when trying to detect just a few photons. It turns out that running a tube at room temperature will not provide the best results. To improve the accuracy and sensitivity of his equipment [David Prutchi] built this thermoelectric photomultiplier tube cooling rig.

You can’t actually see the tube in this image but it looks similar to a vacuum tube or Nixie tube. The difference being that the components inside the glass dome make up the detector instead of an amplifier or filament display. To make a physical interface with the glass [David] wrapped it in magnetic shielding and finished with a layer of aluminum foil tape. This cylinder was then snugly fit inside of an aluminum heat sync. two Peltier coolers were attached to the outside of the heat sync, using Arctic Silver thermal compound to help transmit heat. A thermocouple was also added to monitor the temperature of this first stage of cooling. All of this fits into an aluminum enclosure which was filled with expanding spray foam before having a trio of fan-cooled heat syncs attached to it.