Scratch-Built CO2 Laser Tube Kicks Off A Laser Cutter Build

When we see a CO2 laser cutter build around these parts, chances are pretty good that the focus will be on the mechatronics end, and that the actual laser will be purchased. So when we see a laser cutter project that starts with scratch-building the laser tube, we take notice.

[Cranktown City]’s build style is refreshingly informal, but there’s a lot going on with this build that’s worth looking at — although it’s perhaps best to ignore the sourcing of glass tubing by cutting the ends off of an old fluorescent tube; there’s no mention of what became of the mercury vapor or liquid therein, but we’ll just assume it was disposed of safely. We’ll further assume that stealing nitrogen for the lasing gas mix from car tires was just prank, but we did like the rough-and-ready volumetric method for estimating the gas mix.

The video below shows the whole process of building and testing the tube. Initial tests were disappointing, but with a lot of tweaking and the addition of a much bigger neon sign transformer to power the tube, the familiar bluish-purple plasma made an appearance. Further fiddling with the mirrors revealed the least little bit of laser output — nowhere near enough to start cutting, but certainly on the path to the ultimate goal of building a laser cutter.

We appreciate [Cranktown City]’s unique approach to his builds; you may recall his abuse-powered drill bit index that we recently covered. We’re interested to see where this laser build goes, and we’ll be sure to keep you posted.

Continue reading “Scratch-Built CO2 Laser Tube Kicks Off A Laser Cutter Build”

How Much Is Too Much?

I definitely tend towards minimalism in my personal projects. That often translates into getting stuff done with the smallest number of parts, or the cheapest parts, or the lowest tech. Oddly enough that doesn’t extend to getting the project done in the minimum amount of time, which is a resource no less valuable than money or silicon. The overkill road is often the smoothest road, but I’ll make the case for taking the rocky, muddy path. (At least sometimes.)

There are a bunch of great designs for CNC hot-wire foam cutters out there, and they range from the hacky to the ridiculously over-engineered, with probably most of them falling into the latter pile. Many of the machines you’ll see borrow heavily from their nearest cousins, the CNC mill or the 3D printer, and sport hardened steel rails or ballscrews and are constructed out of thick MDF or even aluminum plates.

All a CNC foam cutter needs to do is hold a little bit of tension on a wire that gets hot, and pass it slowly and accurately through a block of foam, which obligingly melts out of the way. The wire moves slowly, so the frame doesn’t need to handle the acceleration of a 3D printer head, and it faces almost no load so it doesn’t need any of the beefy drives and ways of the CNC mill. But the mechanics of the mill and printer are so well worked out that most makers don’t feel the need to minimize, simply build what they already know, and thereby save time. They build a machine strong enough to carry a small child instead of a 60 cm length of 0.4 mm wire that weighs less than a bird’s feather.

I took the opposite approach, building as light and as minimal as possible from the ground up. (Which is why my machine still isn’t finished yet!) By building too little, too wobbly, or simply too janky, I’ve gotten to see what the advantages of the more robust designs are. Had I started out with an infinite supply of v-slot rail and ballscrews, I wouldn’t have found out that they’re overkill, but if I had started out with a frame that resisted pulling inwards a little bit more, I would be done by now.

Overbuilding is expedient, but it’s also a one-way street. Once you have the gilded version of the machine up and running, there’s little incentive to reduce the cost or complexity of the thing; it’s working and the money is already spent. But when your machine doesn’t quite work well enough yet, it’s easy enough to tell what needs improving, as well as what doesn’t. Overkill is the path of getting it done fast, while iterated failure and improvement is the path of learning along the way. And when it’s done, I’ll have a good story to tell. Or at least that’s what I’m saying to myself as I wait for my third rail-holder block to finish printing.

Arduino Takes Control Of Dead Business Card Cutter

It’s a common enough situation, that when an older piece of equipment dies, and nobody wants to spend the money to repair it. Why fix the old one, when the newer version with all the latest bells and whistles isn’t much more expensive? We all understand the decision from a business standpoint, but as hackers, it always feels a bit wrong.

Which is exactly why [tommycoolman] decided to rebuild the office’s recently deceased Duplo CC-330 heavy duty business card cutter. It sounds like nobody really knows what happened to the machine in the first place, but since the majority of the internals were cooked, some kind of power surge seems likely. Whatever the reason, almost none of the original electronics were reused. From the buttons on the front panel to the motor drivers, everything has been implemented from scratch.

An Arduino Mega 2560 clone is used to control four TB6600 stepper motor drivers, with a common OLED display module installed where the original display went. The keypad next to the screen has been replaced with 10 arcade-style buttons soldered to a scrap of perfboard, though in the end [tommycoolman] covers them with a very professional looking printed vinyl sheet. There’s also a 24 V power supply onboard, with the expected assortment of step up and step down converters necessary to feed the various electronics their intended voltages.

In the end, [tommycoolman] estimates it took about $200 and 30 hours of work to get the card cutter up and running again. The argument could be made that the value of his time needs to be factored into the repair bill as well, but even still, it sounds like a bargain to us; these machines have a four-figure price tag on them when new.

Stories like this one are important reminders of the all wondrous things you can find hiding in the trash. Any time a machine like this can be rescued from the junkyard, it’s an accomplishment worthy of praise in our book.

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

“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.

Continue reading “Dual-Wielding Robot Carves 3D Shapes From Foam With Warped Wire”

On-Demand Manufacturing Hack Chat

Join us on Wednesday, March 4 at noon Pacific for the On-Demand Manufacturing Hack Chat with Dan Emery!

The classical recipe for starting a manufacturing enterprise is pretty straightforward: get an idea, attract investors, hire works, buy machines, put it all in a factory, and profit. Things have been this way since the earliest days of the Industrial Revolution, and it’s a recipe that has largely given us the world we have today, for better and for worse.

One of the downsides of this model is the need for initial capital to buy the machines and build the factory. Not every idea will attract the kind of money needed to get off the ground, which means that a lot of good ideas never see the light of day. Luckily, though, we live in an age where manufacturing is no longer a monolithic process. You can literally design a product and have it tested, manufactured, and sold without ever taking one shipment of raw materials or buying a single machine other than the computer that makes this magic possible.

As co-founder of Ponoko, Dan Emery is in the thick of this manufacturing revolution. His company capitalizes on the need for laser cutting, whether it be for parts used in rapid prototyping or complete production runs of cut and engraved pieces. Their service is part of a wider ecosystem that covers almost every additive and subtractive manufacturing process, including 3D-printing, CNC machining, PCB manufacturing, and even final assembly and testing, providing new entrepreneur access to tools and processes that would have once required buckets of cash to acquire and put under one roof.

Join us as we sit down with Derek and discuss the current state of on-demand manufacturing and what the future holds for it. We’ll talk about Ponoko’s specific place in this ecosystem, and what role outsourced laser cutting could play in getting your widget to market. We’ll also take a look at how Ponoko got started and how it got where it is today, as well as anything else that comes up.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, March 4 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

Restoring A Rusty Rebar Cutter

We’ve all probably come across hunks of junk that used to be tools, long-neglected and chemically welded into a useless mass of solid rust. Such items are available for a pittance at the local flea market, or more likely found in an old barn or rotting on a junk pile. They appear to be far beyond salvage, but with the proper application of elbow grease and penetrating lubricants, even a nasty old seized-up rebar cutter can live again.

We honestly almost passed up on the video below when it came across our feed. After all, a rebar cutter is a dead-simple device, and half the fun of restoration videos like those made by [my mechanics] is seeing all the parts removed, restored, and replaced. But it ended up being far more interesting than we expected, and far more challenging too.

The cutter was missing its original handle and looked for all the world like it had been cast from a solid piece of iron oxide. [my mechanics] was able to get the main pivot bolts free with a combination of leverage, liberal application of penetrating oil, drilling, and the gentle persuasion of a hydraulic press.

These efforts proved destructive to both bolts, so new ones were made on the lathe, as were a number of other parts beyond saving. New cutters were fabricated from tool steel and a new handle was built; before anyone comments on anyone’s welding skills, please read [Jenny]’s recent article on the subject.

The finished product is strikingly dissimilar to the starting lump of oxidized junk, so there’s going to to be some debate in calling this a “restoration” in the classical sense. The end result of a [my mechanics] video is invariably a tool or piece of gear that looks far better than it did the day it was made, and any one of them would get a place of honor on our shelf. That said, he’d probably be swiftly shown the door if he worked at the Smithsonian.

Whatever you want to call these sort of videos, there are tons of them out there. We’ve featured a few examples of the genre, from the loving rehabilitation of classic Matchbox cars to rebuilding an antique saw set. They’re enough to make us start trolling garage sales. Or scrap yards.

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Making An Ultrasonic Cutter For Post-processing Tiny 3D Prints

An ultrasonic knife is a blade that vibrates a tiny amount at a high frequency, giving the knife edge minor superpowers. It gets used much like any other blade, but it becomes far easier to cut through troublesome materials like rubber or hard plastics. I was always curious about them, and recently made my own by modifying another tool. It turns out that an ultrasonic scaling tool intended for dental use can fairly easily be turned into a nimble little ultrasonic cutter for fine detail work.

Cheap ultrasonic scaler. The blue disk is for adjusting power. Foot switch not shown.

I originally started thinking about an ultrasonic knife to make removing supports from SLA 3D prints easier. SLA resin prints are made from a smooth, hard plastic and can sometimes require a veritable forest of supports. These supports are normally removed with flush cutters, or torn off if one doesn’t care about appearances, but sometimes the density of supports makes this process awkward, especially on small objects.

I imagined that an ultrasonic blade would make short work of these pesky supports, and for the most part, I was right! It won’t effortlessly cut through a forest of support bases like a hot knife through butter, but it certainly makes it easier to remove tricky supports from the model itself. Specifically, it excels at slicing through fine areas while preserving delicate features. Continue reading “Making An Ultrasonic Cutter For Post-processing Tiny 3D Prints”