[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.
While most of the time the name of the game is to remove a lot of metal, etching is an entirely other process. If you just want to put a logo on a piece of steel, or etch some labels in a piece of aluminum, You need to think small. Mills and CNC routers will do, but they’re expensive and certainly not as easy to work with as a small, homebrew electrochemical etcher.
This etchinator is the brainchild of [Gelandangan], and gives the techniques of expensive commercial etchers to anyone who can put together a simple circuit. This etcher can etch with both AC and DC thanks to a H bridge circuit, and can be fabbed up by anyone who can make their own circuit board.
To actually etch a design in a piece of metal, simply place the piece on a metal plate, put the stencil down, and hold a felt-covered electrode moistened with electrolyte down over the stencil. Press a button, and in about 30 seconds, you have a wonderfully etched piece of metal.
[Gelandagan] has some templates that will allow you to make your own electro etcher, provided you can etch your own boards and can program the PIC16F1828 microcontroller. All this info is over on the Australian blade forum post he put up, along with a demo video below.
Continue reading “Electrochemical Etching With a Microcontroller”
This is a solder paste stencil machined from a beer can. [Simon Ludborzs] spent quite a bit of time dialing in his process to get to this point. Note the nice crisp edges of the openings. That’s a big change from his first attempt.
When looking for a way to make his own stencils he considered two options: plastic and aluminum. He produced both (more about the plastic stencil and his reflow process is discussed in this post). Plastic is a bit easier to work with since it lays flat. But it proves to be too thick. After applying paste with a squeegee there’s way too much solder on the pads. Aluminum beverage can walls are much thinner, depositing less paste.
We’ve seen soda cans used in the past, but they were produced through an etching process. [Simon] cut these holes using a CNC mill. This required a bit of futzing to figure out the right settings. For instance, he used Altium to produce CAM files from his circuit design. But the program is set up to mill the outside of traces, resulting in openings that are too large. He fixed this by setting the pasted expansion rule in the program to a negative value. The other advantage to using a mill is that he can cut precision tooling holes to ensure proper alignment. You can see them in the upper corners of this image.
From concept to completion this delta-style 3D printer (translated) is a sweet build. The quality of the work comes as no surprise. We’re familiar with [Arkadiusz Spiewak’s] craftsmanship from that H-bot type 3D printer we saw from him back in April.
Planning started off with a render of the design using Blender 3D. Not only did this give him a 3D model to use as his building reference, but the animation framework allowed him to test the kinematics of the design. After ordering an extruded rail system and assembling the frame he found the pillars had too much flex to them due to the rails used on the top and bottom. The fix was to mill a top and bottom plate to stiffen things up. After testing out the motors and the extruder head mount he made one final design change. He exported his Blender design as dxf files to cut and weld an aluminum replacement for the extruder mounting platform. As you can see in this video, the preliminary results are looking good!
Continue reading “Delta-type 3D printer built using extruded rails”
Apartment dwellers who are living the nomadic lifestyle take note. You don’t need to live your tinkering lifestyle out of a toolbox. Here is a great example of a respectable electronics bench which breaks down when it’s time to move (translated). We’re sure you already belong to your local hackerspace for the big projects, but this corner office will let you take some of your creations home for continued tweaking.
The bench uses slotted aluminum rails as the support structure. The slots accept small nuts, which have a spring-loaded ball bearing to keep them from sliding freely ([Nerick] mentions this is especially nice for working with the vertical runs). These fasteners ended up being the most costly component. The desktop itself is the largest solid piece. It was machined using a CNC mill (we already mentioned having a hackerspace membership) so that the mounting screws are countersunk to leave a perfectly flat surface. It’s clean, has a small footprint, and gives you a place to dump all of your gear. What else could you ask for?
One of the most popular ways of turning an object trapped inside the world of a computer into a real, metal object is the art of lost wax, or lost foam casting. In this process, a full-scale model of the object to be made in metal is crafted in either foam or wax, placed in a pile of sand, and burned away by molten metal.
[ptflea] over at the Bamberg, Germany hackerspace Backspace came up with a very clever build that automatically cuts foam into the desired shape, ready to be taken out to the backyard foundry. The build is based around an old flatbed scanner and a hot wire cutter. The old scanner conveniently had an equal number of steps per axis, so attaching an Adafruit motor shield and replacing the old control electronics was just an issue of finding the correct resistors.
Software control is provided by a Processing app [ptflea] whipped up and is able to carefully cut very delicate shapes that even the steadiest hand would have trouble with.
Making stuff out of styrofoam is cool and all, but the real goal for this project was setting things on fire and melting old heatsinks. The styrofoam molds were placed in a bucket full of sand, and the furnace – a few ytong bricks, a crucible, and a propane burner – started to melt some aluminum. The molten aluminum was poured onto the mold and after cooling, the makers of Backspace had a few very cool aluminum trinkets.
A nice build that is able to produce some very nice metal objects. We suspect, though, that a higher-density foam (something along the lines of blue or green insulation sheets, if they have those in Germany) could produce an even higher level of detail if you’d like to build your own.
Videos after the break.
Continue reading “Cutting styrofoam with a CNC machine and turning it into aluminum”
If you think this thing looks good you should see it move. [Martin Smith] hit a home run on the project, which was his Master’s Thesis. Fifteen servo motors provide a way for the bot to move around. Having been modeled after a small canine the gait is very realistic. The tail is even functional, acting as a counterweight when moving the legs.
The project was meticulously built in a 3D environment before undertaking any physical assembly. The mechanical parts are all either milled from aluminum or 3D printed. Two mBed boards mounted on its back allow it to interact with its environment. One of them handles image processing, the other drives the array of motors. And of course it doesn’t hurt that he built some Larson Scanners in as eyes.
Don’t miss the video after the break which shows off the entire project from planning to demonstration. We can’t help but be reminded of the rat-thing from Snow Crash.
Continue reading “Professional looking dog robot was actually [Martin’s] Master’s Thesis”