Knitting Machine Rebuild Takes It To The Next Level

June 11, 2020 by Jenny List 6 Comments

Those of us who to textile work may own a sewing machine and even if we’re really into it and have the funds, an overlocker. But there’s another machine in that field that few of us will have, and that’s a knitting machine. These machines have a sliding carriage over a long array of needles, and even the cheaper ones are way more expensive than for example a pretty decent oscilloscope. [Irene Wolf] has a Passap E6000 computerised knitting machine that is by no means an inexpensive one, and she’s made significant improvement to it by giving it new brains, a new motor controller, and replacing the mechanical rear needle bed with a set of computerised ones from the front of another machine.

In her write-up she goes in depth into the arrangement of sensors and electromagnets that operate the machine. She started with a lot of inspiration from a project at Hackerspace Bamberg, but used all the available Passap sensors as inputs where they had used only one. She has two Arduino M0 boards handling the inputs and a Raspberry Pi with control and user interface, and has posted some videos of the system in action one of which we’ve placed below the break.

We probably wouldn’t have had the courage to fearlessly hack such a high-value machine, and we’re particularly impressed by the result. The write-up is particularly interesting not only for the work itself, but for the detailed insight it gives to the workings of these machines. The best news – she’s not finished and there will be more installments.

While you’re waiting for more, remember this is by no means the first hacked knitting machine we’ve brought you.

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Tiny Laser Cutter Puts Micro Steppers To Work

June 3, 2020 by Dan Maloney 33 Comments

The influx of cheap laser cutters from China has been a boon to the maker movement, if at the cost of a lot of tinkering to just get the thing to work. So some people just prefer to roll their own, figuring that starting from scratch means you get exactly what you want. And apparently what [Mike Rankin] wanted was a really, really small laser cutter.

The ESP32 Burninator, as [Mike] lovingly calls his creation, is small enough to be in danger of being misplaced accidentally. The stage relies on tiny stepper-actuated linear drives, available on the cheap from AliExpress. The entire mechanical structure is two PCBs — a vertical piece that holds the ESP32, an OLED display, the X-axis motor, and the driver for the laser, which comes from an old DVD burner; a smaller bottom board holds the Y-axis and the stage. “Stage” is actually a rather grand term for the postage-stamp-sized working area of this cutter, but the video below shows that it does indeed cut black paper.

The cuts are a bit wonky, but this is surely to be expected given the running gear, and we like it regardless. It sort of reminds us of that resin 3D-printer small enough to fit in a Christmas ornament that [Sean Hodgins] did a while back. We’d suggest not trying to hang this on a tree, though.

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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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Conduit, Birdhouse, And Skateboard Become Giant Pen Plotter

May 23, 2020 by Elliot Williams 3 Comments

If you think you need fancy parts to build a giant robot drawing machine, think again! [Cory Collins] shows you how he built his Big-Ass Wall Plotter v.2 out of stuff around the house or the hardware store, including electrical conduit, gang boxes, scrap wood, and skateboard bearings, alongside the necessary stepper motors, drivers, and timing belt. (You should consider having this trio of parts on hand as well, in our opinion.) With a span of 48″ (1.2 m) on a side, you probably don’t have paper that’s this big.

And while the construction is definitely rough-and-ready, there are a ton of details that turn this pile of parts into a beautifully working machine in short order. For instance, making the rails out of electrical conduit has a few advantages. Of course it’s cheap and strong, but the availability of off-the-shelf flanges makes assembly and disassembly easy. It also hangs neatly on the wall courtesy of some rubber cuphooks.

Note also the use of zip-tie belt tensioners: a simple and effective solution that we heartily endorse. [Corey] makes good use of custom 3D printed parts where they matter, like the compliant pen holder and linear mechanism for the z-axis, but most of the mechanical accuracy is courtesy of wooden shims and metal strapping.

[Corey] uses the machine to make patterns for his paper sculptures that are worth a look in their own right, and you can see the machine in action, sped up significantly, in the video below. This is the perfect project if you have a DIY eggbot that’s out of commission post-Easter: it reuses all the same parts, just on a vastly different scale. Heck, [Corey] even uses the same Inkscape Gcodetools extension as we did in that project. Now you know what we’re up to this weekend.

Can’t get enough pen plotters? Check out this one that lets you write whatever you want!

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Bricking Your 3D Printer, In A Good Way

May 20, 2020 by Dan Maloney 15 Comments

In our vernacular, bricking something is almost never good. It implies that something has gone very wrong indeed, and that your once-useful and likely expensive widget is now about as useful as a brick. Given their importance to civilization, that seems somewhat unfair to bricks, but it gets the point across.

It turns out, though, that bricks can play an important role in 3D-printing in terms of both noise control and print quality. As [Stefan] points out in the video below, living with a 3D printer whirring away on a long print can be disturbing, especially when the vibrations of the stepper motors are transmitted into and amplified by a solid surface, like a benchtop. He found that isolating the printer from the resonant surface was the key. While the stock felt pad feet on his Original Prusa i3 Mk 3S helped, the best results were achieved by building a platform of closed-cell packing foam and a concrete paver block. The combination of the springy foam and the dampening mass of the paver brought the sound level down almost 8 dBA.

[Stefan] also thoughtfully tested his setups on print quality. Machine tools generally perform better with more mass to damp unwanted vibration, so it stands to reason that perching a printer on top of a heavy concrete slab would improve performance. Even though the difference in quality wasn’t huge, it was noticeable, and coupled with the noise reduction, it makes the inclusion of a paver and some scraps of foam into your printing setup a no-brainer.

Not content to spend just a couple of bucks on a paver for vibration damping? Then cast a composite epoxy base for your machine — either with aluminum or with granite.

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CNC Plasma Cutter Filter Gets The Slag Out

May 16, 2020 by Dan Maloney 10 Comments

No matter what kind of tools and materials you use in your shop, chances are pretty good that some process is going to release something that you don’t want to breathe. Table saw? Better deal with that wood dust. 3D-printer? We’ve discussed fume control ad nauseam. Soldering? It’s best not to inhale those flux fumes. But perhaps nowhere is fume extraction more important than in the metal shop, where vaporized bits of metal can wreak respiratory havoc.

Reducing such risks was [Shane Wighton]’s rationale behind this no-clean plasma cutter filter. Rather than a water table to collect cutting dross, his CNC plasma cutter is fitted with a downdraft table to suck it away. The vivid display of sparks shooting out of the downdraft fans belied its ineffectiveness, though. [Shane]’s idea is based on the cyclonic principle common to woodshop dust collectors and stupidly expensive vacuum cleaners alike. Plastic pipe sections, split in half lengthwise and covered in aluminum tape to make them less likely to catch on fire from the hot sparks, are set vertically in the air path. The pipes are arranged in a series of nested “S” shapes, offering a tortuous path to the spark-laden air as it exits the downdraft.

The video below shows that most of the entrained solids slow down and drop to the bottom of the filter; some still pass through, but testing with adhesive sheets shows the metal particles in the exhaust are much reduced. We like the design, especially the fact that there’s nothing to clog or greatly restrict the airflow.

Looking for more on CNC plasma cutter builds? We’ve got you covered, from just the basics to next-level.

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Is It A Toy? A Prototype? It’s A Hack!

May 16, 2020 by Elliot Williams 2 Comments

Some of the coolest hacks do a lot with a little. I was just re-watching a video from [Homo Faciens], who after building a surprisingly capable CNC machine out of junk-bin parts and a ton of ingenuity, was accidentally challenged by Hackaday’s own [Dan Maloney] to take it a step further. [Dan] was only joking when he asked “Can anyone build a CNC machine out of cardboard and paperclips?”, but then [Homo Faciens] replied: cardboard and paperclip CNC plotter. Bam!

My favorite part of the cardboard project is not just the clever “encoder wheel” made of a bolt dipped in epoxy, with enough scraped off that it contacts a paperclip once per rotation. Nor was it the fairly sophisticated adjustable slides and ways that he built to mimic the functionality of the real deal. Nope.

My favorite part of this project is [Norbert] explaining that the machine has backlash here, and it’s got play there, due to frame flex. It is a positive feature of the machine. The same flaws that a full-metal machine would have are all present here, but due to the cheesy construction materials, you can see them with the naked eye instead of requiring a dial indicator. Because it wiggles visible tenths of an inch where a professional mill would wiggle invisible thousandths, that helps you build up intuition for the system.

This device isn’t a “prototype” because there’s no way [Norbert] intends it for serious use. But it surely isn’t just a “toy” either. “Instructional model” makes it sound like a teaching aid, created by a know-it-all master, intended to be consumed by students. If anything, there’s a real sense of exploration, improvisation, and straight-up hacking in this project. I’m sure [Norbert] learned as much from the challenge as we did from watching him tackle it. And it also captures the essence of hacking: doing something unexpected with tech.

Surprise us!