Machine Metal With Electricity: An EDM Attachment For 3D Printers

June 24, 2015 by Adam Fabio 54 Comments

[SuperUnknown] has revealed a secret project he’s been working on. He’s cooked up an EDM attachment for 3D printers, or any CNC machine for that matter. Electrical Discharge Machining (EDM) is a method of using sparks to machine metal. EDM isn’t a new technology, in fact commercial machines have been around since the 1960’s. If you’ve ever had an arc scar up your multimeter probes, you’ve unwittingly done a bit of EDM.

The theory behind EDM is simple: High voltage between the tool and workpiece causes sparks to jump between them. Each spark erodes the workpiece (and the tool). Big EDM machines perform their magic in a liquid which acts as both a dielectric and a flushing medium. This liquid can be anything from deionzed tap water to specially formulated oil. [SuperUnknown] is using good old-fashioned tap water.

As you can imagine, a single spark won’t erode much metal. EDM machines fire tens of thousands of times per second. The exact frequencies, voltages, and currents are secrets the machine manufacturers keep close to their chests. [SuperUnknown] is zeroing in on 65 volts at 2 amps, running at 35 kHz. He’s made some great progress, gouging into hardened files, removing broken taps from brass, and even eroding the impression of a coin in steel.

While we’d love to say this is a free open source project, [superUnknown] needs to pay the bills. He’s going with crowdsourced funding. No, not another Kickstarter. This project is taking a different route. The videos of the machine will be uploaded to YouTube and visible to [superUnknown’s] Patreon supporters. They will also be available for rent using YouTube’s new rental system. [SuperUnknown] has pledged to figure out a way to make the content available for starving college students and others with limited incomes.

Based upon his previous adventures with lil’ screwy, his homemade 100 ton press, and various other projects on the Arduino verses Evil YouTube channel, we think [superUnkown] has a pretty good chance of making home EDM work. Click past the break to see two videos of the 3D printer EDM toolhead in action. We should mention that [SuperUnknown] is rather colorful with his dialogue, so make sure you’re using headphones if you’re at work.

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Crawlspace Warehouse Includes Midget Forklift

June 24, 2015 by James Hobson 32 Comments

Meet [Cliff Stoll], producer and entrepreneur-extraordinaire of the ACME Klein Bottles. Years back he helped a friend program a glass oven to get the right temperature profiles for glass blowing. When asked how he wanted to get paid for his help, he asked if they could blow a Klein bottle — and so they did.

Excited at the prospect of his creation, he showed it around to some friends, and was surprised to find out that people wanted to buy it! The one he created took 3 days of sweat and tears to build, so he wasn’t about to start manufacturing them himself. Instead, he decided to call around to some glass manufacturers and see how much he could get Klein bottles made for… That’s when he discovered the power of buying in large quantities.

So what do you do with over 1000 Klein bottles? You build a mini-warehouse in your crawlspace — that’s what.

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Down-Draft Table Keeps The Shop Dust Free

June 23, 2015 by Rich Bremer 17 Comments

Wood working is great but it can certainly get the shop dusty. [BigD] is a wood worker and needed a way to keep his shop from getting super dusty while sanding or routing. He ended up making a pretty slick dual-use downdraft table with a hidden filtration system.

The table’s frame is made from standard 2-by dimensional lumber you’d likely see most shop tables made from. It was built so that the top of the table would be flush with the table of the table saw. This allows the down-draft table to also act as an out feed support for the table saw, making it easier to cut longer pieces of wood.

To allow airflow to pull any generated dust down, a plethora of holes were drilled in the table top. Down below are a couple sealed chambers, one for the incoming dust and one for the air blower that creates the down-draft air flow. The two chambers are separated by a pair of filters which keep the dust from being blown back into the shop. A little door on the side of the table allows access to clean out the accumulated dust and debris. Now [BigD] can sand up a storm on his down-draft table without breathing in a sapling worth of dust.

DIY Rotary Tool

June 21, 2015 by Rich Bremer 17 Comments

[Shashank] has a modest tool collection but is missing a rotary tool. He needed one for a project he was working on but didn’t think that it would get much use after the current project was completed. So instead of buying a rotary tool, he decided to make one to get the job done.

The project started out with a 40mm PVC pipe that would serve a the main body of the tool. Two MDF disks were cut to fit inside the pipe. One was used for mounting an RC vehicle brushless motor and the other was bored out to accept a pair of bearings. The bearings supported a modified pin vise that acts as the chuck for securing rotary tool bits. A 20-amp ESC and a servo tester control the motor’s speed and can get the motor up to 18,000 rpm.

Although this worked for a while, [Shashank] admits it did fall apart after about 20 hours of use. The MDF bearing mounts crumbled, thought to be a result of vibration due to mis-assignment between the motor and pin vise. He suggests using aluminum for the bearing mounts and a flexible coupling to connect the motor to the pin vise. If you’re interested in making your own rotary tool but don’t have any spare motors kicking around, this 3D printed vacuum-powered rotary tool may be for you.

Hand Drill To Band Saw Conversion

June 21, 2015 by Rich Bremer 23 Comments

Need a band saw but only have a drill kicking around? That may not be a common problem but if you ever run into it, [Izzy] has got you covered. He’s on a mission to make a drill-powered workshop and in his YouTube video, he shows a small bench top band saw he made that is powered by a corded hand drill.

The main frame is made from doubled up 3/4″ plywood. The saw blade is strung between two wooden wheels. Those wheels have tape applied to their outer diameter to create a crowned roller. That crown keeps the saw blade tracking in the middle of the wheel. The bottom wheel is mounted to an axle that is supported by bearings in the main frame. That axle pokes out the back and is connected to the drill. The top wheel has integrated bearings and ride on a stud mounted to the frame. The blade seems to be pretty tight although there is no noticeable tensioning system.

The video shows that this DIY band saw can cut through 1.5 inch wood fairly easily. Even so, there are clearly some needed features, like guide bearings for the blade and an overall cover to prevent accidental lacerations. But we suppose, even professional saws can be dangerous if not treated with respect.

Altium Gives Away The Farm With New Circuit Maker Software

June 20, 2015 by George Graves 150 Comments

Things are about to get interesting in the world of PCB design software for the open source hardware community. This week, Altium launched the open public beta for its new Circuit Maker software, and it’s a major change from what we looked at previously. Everything is free.

You heard that right, free. Unlimited board size, and unlimited layers – all free. And this isn’t some stripped-down, bare-bones software here. They’ve thrown in almost everything under the sun; a 3D viewer, team project collaboration, EagleCAD and DFX import, integrated Octopart supplier and pricing information, no commercial usage limits, and project sharing. And if that isn’t enough, the “engine” seems to be the exact same back-end that is used in the full $10,000 Altium Designer as well(with a bit easier to use user interface on top). This is a major departure from the pre-beta we covered back in September. Altium was going have board size and layer limits, with the ability to “upgrade” at a cost. So by now you’re thinking to yourself “OK, what’s the catch?” Well there are a few gotchas – but only a few.

The software uses cloud based storage for your project files, and is community based. It won’t work without an Internet connection, there is no local storage, and it forces you to share your projects with the world. You do get two “Sandbox” designs that you can hide from the world before you generate your gerber files, but after that, your project is online for the whole world to see. Will that be a deal killer for the OSHW community? We’ll find out soon enough.

One thing is for sure, anyone with a doggy Internet connection is not going to enjoy using Circuit Maker (we’re hoping they remove that limitation in the final product). And as with any cloud based service, we wonder how many people will be willing to trust their designs to a free service that could be turned off on a whim? Or will the unlimited board size and layers, combined with Altium’s name and robust software win people over in the end?

If you want to see in-depth review of Circuit Maker, we highly recommend you watch the video after the break. [Dave Jones] of the eevblog, gives you a full rundown on the beta version. Dave’s in a unique place to review this software, not only has he been using Altium since the mid-80’s as a professional engineer, he’s also a former Altium employee.

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Mini Arc Furnace Melts Its Way Into Our Hearts

June 16, 2015 by Theodora Fabio 44 Comments

[Grant Thompson], aka “The King of Random,” threw caution to the wind when it came to his latest awesome project – a mini electric arc furnace (EAF) (YouTube link). [Grant] uses a refractory brick as a furnace and crucible for the molten metal. He wears eye protection and a respiratory mask as he cuts up the brick – a good idea, since you don’t want to inhale any of that dust. The electrode grips are made with things you can find at a hardware store, including copper wire and coupling, and 2 pairs of vice-grip style pliers. The copper wire is stripped and attached to the metal handle of the pliers using hose clamps. The pliers are now functional electrode grips- just put a carbon rod in each grip and hold them close to each other…but not without protection! [Grant] harvested the carbon rods from the cells of 6V lantern batteries – dead batteries work just as well for this. It’s also a better bet to do this outdoors with decent ventilation and away from anything flammable. [Grant] realized that the rods from the batteries have a wax-like coating on them that takes about 30 seconds to burn off in spectacular flames the first time they make electrical contact. However, you can purchase carbon rods by themselves if you want to avoid ripping open batteries and possibly setting yourself on fire. The mini EAF runs on a welding power supply [Grant] made from microwave oven transformers (YouTube link).

When it’s time to melt some metal, the scrap metal is placed into a bowl drilled into the brick. Using the electrode grips, the carbon rods are placed into the brick’s pre-drilled holes. It only takes ten seconds to melt pure zinc – do NOT do this with galvanized steel or brass castings, as zinc oxide is very hazardous to your health.

In the videos featured below, [Grant] shows a variety of metals are no match for his mini EAF. He even manages to melt rocks from his backyard! It goes without saying that an EAF (video link) can be very dangerous. When you’re dealing with high voltage, plasma, white-hot molten metal, and toxic fumes, you better know what you’re doing (or have a great life insurance policy). [Grant] has a penchant for showcasing projects that can make an OSHA inspector cringe, but you have to admire his gumption!

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