Dual-Wielding Robot Carves 3D Shapes From Foam With Warped Wire

June 3, 2020 by Dan Maloney 28 Comments

“Every block of expanded polystyrene foam has a statue inside it and it is the task of the dual-arm hot wire-wielding robot to discover it.” — [Michelangelo], probably.

Be prepared to have your mind blown by this dual-wielding hot-wire 3D foam cutter (PDF). We’ve all seen simple hot-wire cutters before, whether they be manual-feed cutters or CNC-controlled like a 3D-printer. The idea is to pass current through a wire to heat it up just enough to melt a path as it’s guided through a block of polystyrene foam. Compared to cutting with a knife or a saw, hot-wire cuts are smooth as silk and produces mercifully little of that styrofoam detritus that gets all over your workspace.

But hot-wire cutters can’t do much other than to make straight cuts, since the wire must be kept taut. “RoboCut”, though, as [Simon Duenser] and his colleagues at ETH Zurich call their creation, suffers from no such limitations. Using an ABB YuMi, a dual-arm collaborative robot, they devised a method of making controlled curved cuts through foam by using a 1-mm thick deformable rod rather than a limp and floppy wire for the cutting tool. The robot has seven degrees of freedom on each arm, and there’s only so much the rod can deform before being permanently damaged, so the kinematics involved are far from trivial. Each pass through the foam is calculated to remove as much material as possible, and multiple passes are needed to creep up on the final design.

The video below shows the mesmerizing sweeps needed to release the Stanford bunny trapped within the foam, as well as other common 3D test models. We’re not sure it’s something easily recreated by the home-gamer, but it sure is fun to watch.

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Build A Tiny Hot Wire Foam Cutter

February 8, 2018 by Kristina Panos 34 Comments

Let’s face it: cutting foam with a knife, even a serrated plastic knife meant for the job, is a messy pain in the ass. This is as true for insulation board as it is for the ubiquitous expanded polystyrene kind of foam used for everything from coffee cups to packaging material.

Those stick-type hot wire cutters from the craft store that plug into the wall aren’t much better than a knife. The actual cleaving of foam is easier, but dragging a long, hot flexible wand through rigid foam just right, without making burn marks, is pretty frustrating. It’s not like you can hold the other end to keep it steady. A foam cutter built like a coping saw but held parallel to the wire would offer much better control.

[Techgenie]’s handheld hot wire foam cutter is a simple build based on a single 18650 and a piece of nichrome wire. While this is probably not the most Earth-shattering hack you’ll see today, it’s a useful tool that can be made in minutes with items on hand. Laptop chargers are full of 18650s, and nichrome wire can be sourced from old toasters, hair dryers, or space heaters.

You shouldn’t use just any old wire for this, though, or the battery will get hot and potentially explode. Nichrome wire has a high resistance, and that’s exactly what you want in a tool that essentially shorts a battery to make heat. [Techgenie] used a momentary button instead of a switch, which is a good way to stay safe while using it. It wouldn’t hurt to add some protection circuitry and take the battery out when you’re done. Burn past the break to watch him build it and cut a few tight turns with ease.

If you have bigger, more complicated foam-cutting jobs in mind, why not build a CNC version out of e-waste?

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Simple Headphone Bracket Shows Off Carbon Fiber Basics

February 12, 2016 by Dan Maloney 12 Comments

The carbon fiber look is a pretty hot design element for things these days. Even things that have no need for the strength and flexibility of carbon fiber, from phone cases to motorcycle fenders, are sporting that beautiful glossy black texture. Some of it only looks like the real stuff, though, so it’s refreshing to see actual carbon fiber used in a project, like this custom headphone rack.

True, this is one of those uses of carbon fiber that doesn’t really need it – it just looks cool. But more importantly, [quada03]’s build log takes us through the whole process, from design to mold construction to laying up the fiber mats and finishing, and shows us how specialized equipment is not needed to achieve a great result. A homemade CNC router carves the two-piece mold out of Styrofoam, which is then glued up and smoothed over with automotive body filler. The epoxy-soaked carbon fiber mats are layered into the mold with careful attention paid to the orientation of the fibers, and the mold goes into one of those clothes-packing vacuum bags for 24 hours of curing. A little trimming and sanding later and the finished bracket looks pretty snazzy.

We’ve discussed the basics of carbon fiber fabrication before, but what we like about [quada03]’s build is that it shows how approachable carbon fiber builds can be. Once you hone your skills, maybe you’ll be ready to tackle a carbon fiber violin.

[via r/DIY]

Super Slick, Super Portable Styrofoam Slicer

January 28, 2016 by Dan Maloney 12 Comments

[The King of Random] always seems to have something fun going on in his shop, and his builds tend to be impressively complete. No exception to that rule is his recent hot-wire foam cutter that looks like a ton of fun both to build and to use.

Starting with a simple PVC tubing frame to form the bow of the cutter, the rig ends up looking a little like a scroll saw when [Random] is done with it. A generous work surface sits atop a wood frame, which houses the electrics. A light dimmer and step-down transformer control the cutting wire’s temperature, and the bow even pivots to allow the wire to make miter cuts. A nice final touch is that the frame holding the bow detaches from and store inside the base, making the whole thing portable. It even runs off solar or batteries if you need to work off-grid, which might be handy for quick repairs on the R/C flight line.

Speaking of R/C, check out these hot-wire cut foam airplane wings. And the completeness of this build gets us thinking about the potential for CNC foam cutters.

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A Remote Control, Swing Wing F-14

November 2, 2014 by Brian Benchoff 19 Comments

Anyone can build a remote control airplane with a sheet of foam, some glue, and a handful of servos. Building an F-14, complete with the swing wing mechanism? [Thomas] found built one that’ll take you right into the danger zone.

This was [Thomas]’ first go at scratch building a RC airplane, and wanted a lot of electronics inside. His choice of airframe was the venerable F-14 Tomcat, complete with wings that swing out for landing and swing in for high-speed flight. This isn’t just taking off-the-shelf receivers and putting them in a fancy airframe, either: [Thomas\ is reading the PWM signals from the receiver with a small electronics board, mixing the elevons with his own code, and implementing an auto stabilization system with an accelerometer.

Most of the work on the airframe was done by [Maybz] over on the RCGroups forums. That’s an impressive thread spanning seven years of posts. [Thomas] doesn’t see his F-14 as an end goal, though: he’s using this as a stepping stone to learn about building unstable planes for a more complex UAV.

Videos below, with a warning to headphone users.

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Minicut2d And Omniwheel Robot

October 1, 2014 by Adam Fabio 13 Comments

You’d think we would be done with the World Maker Faire posts by now, but no! We keep looking at our memory cards and finding more awesome projects to write about.

[Renaud Iltis] flew over from France to show off MiniCut2D, his CNC hot wire foam cutter. MiniCut2D uses X and Y~~, and Z~~ stepper motors much like a 3D printer. Rather than print though, it pulls a heated nichrome wire through styrofoam. Foam cutting is great for crafts, but it really takes off when used for R/C aircraft. [Renaud] was cutting some models out of Depron foam in his booth. [Renaud] has set up FrenchFoam.com as a central location for users to upload and share designs in DXF format.

One of the neater features of MiniCut2D is that it can be loaded with a stack of foam boards to make several cuts at once. Not only is this a time saver when cutting repeating designs like wing ribs, but it also ensures the cut pieces are identical. Hey, even CNCs make mistakes once in a while.

Omniwheel Robot

In the MakerShed booth, we found [Victor Aprea] showing off Wicked Device’s new product, the Omniwheel Robot. Omniwheel utilizes a holonomic drive with omnidirectional wheels. The kit comes with a Nanode Zero, Wicked Devices’ own Arduino Uno clone, a motor control board, 3 motors, 3 omnidirectional wheels, and a whole list of hardware. The only thing needed to complete the kit is a radio control unit and receiver. Omniwheel may be simple, but we found driving it around to be mesmerizing – and a bit challenging. It’s a good thing [Victor] brought that plexiglass cover, as we bumped it a few times.

We’d love to see one of these little bots with a couple of sensors and autonomous control. If you build one, make sure to post it to Hackaday.io!

Cutting Styrofoam With A CNC Machine And Turning It Into Aluminum

November 20, 2012 by Brian Benchoff 17 Comments

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.

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