Beautiful DIY Spot Welder Reminds Us We Love 3D Printing

[Jim Conner]’s DIY tab spot welder is the sweetest spot welder we’ve ever seen. And we’re not ashamed to admit that we’ve said that before.

The essence of a spot welder is nothing more than a microwave oven transformer rewound to produce low voltage and high current instead of vice-versa. Some people control the pulse-length during the weld with nothing more than their bare hands, while others feel that it’s better implemented with a 555 timer circuit. [Jim]’s version uses a NodeMCU board, which is desperately overkill, but it was on his desk at the time. His comments in GitHub about coding in Lua are all too familiar — how do arrays work again?

Using the fancier microcontroller means that he can do fancy things, like double-pulse welding and so on. He’s not even touching the WiFi features, but whatever. The OLED and rotary encoder system are sweet, but the star of the show here is the 3D printed case, complete with soft parts where [Jim]’s hand rests when he’s using the welder. It looks like he could have bought this thing.
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3D printed Math Grenade

Calculator hacks are fun and educational and an awesome way to show-off how 1337 your skills are. [Marcus Wu] is a maker who likes 3D printing and his Jumbo Curta Mechanical Calculator is a project from a different era. For those who are unfamiliar with the Curta, it is a mechanical calculator that was the brainchild of Curt Herzstark of Austria from the 1930s. The most interesting things about the design were the compactness and the complexity which baffled its first owners.

The contraption has setting sliders for input digits on the side of the main cylindrical body. A crank at the top of the device allows for operations such as addition and subtraction with multiplication and division requiring a series of additional carriage shift operations. The result appears at the top of the device after each crank rotation that performs the desired mathematical operation. And though all this may seem cumbersome, the original device fit comfortably in one hand which consequently gave it the nick name ‘Math Grenade’.

[Marcus Wu] has shared all the 3D printable parts on Thingiverse for you to make your own and you should really take a look at the video below for a quick demo of the final device. There is also a detailed set of images (82 or so) here that present all the parts to be printed. This project will test your patience but the result is sure to impress your friends. For those looking to dip your toes in big printed machines, check out these Big Slew Bearings for some inspiration.

Using 3D Printing To Speed Up Conventional Manufacturing

3D printers, is there anything they can’t do? Of course, and to many across the world, they’re little more than glorified keychain factories. Despite this, there’s yet another great application for 3D printers – they can be used to add speed and flexibility to traditional manufacturing operations.

A key feature of many manufacturing processes is the use of fixtures and jigs to hold parts during machining and assembly operations. These must be developed before manufacturing begins and must be custom made to suit the given application. Many manufacturers outsource the development of such fixturing, even in large operations – even major automakers will often outsource development of fixtures and new process lines to outside firms. This can have major ramifications when changes need to be made, introducing costly delays. However, 3D printers can be used to rapidly iterate fixturing designs to suit new parts, greatly reducing development time. As stated in the article, Louis Vuitton uses this to great effect – the reduced time of development is incredibly useful when changing manufacturing lines every few months in the fashion industry.

Obviously there are limitations – in a factory producing large steel castings, it’s unlikely a FDM-printed fixture will be much use when it comes to the wear and tear of machining hundreds of castings a day. However, as a development tool, it can prove very useful. What’s more, jigs for light industrial work – think electronics assembly, woodworking glue-ups, or any form of delicate work by hand – need not be as robust. Lightweight, readily produced 3D printed parts may be just the ticket.

Another great benefit of 3D printing is its ability to be used for mockups. You may be designing a product that requires several aluminium parts to fit together, but alas – the parts won’t be ready for weeks. Rather than wait all that time, only to find out something doesn’t fit right, it may be advantageous to print out a plastic version of the parts. Being able to check geometry with actual parts is often very useful, and makes a great tool if you need to present your work to others. It’s much easier to communicate an idea to people if they can hold and touch what you’re talking about!

It’s something worth considering if you’re setting up any sort of small production line – perhaps you’re looking for a way to make populating a run of PCBs faster, or ease the assembly of a series of distributed sensor modules. These techniques may prove particularly useful if you consider yourself a scrappy hacker.

[Hat tip to George!]

Fidget Spinners Put The ‘S’ In STEAM Education

Centrifuges are vital to the study of medicine, chemistry, and biology. They’re vital tools to separate the wheat from the chaff figuratively, and DNA from saliva literally. Now, they’re fidget spinners. [Matlek] designed a fidget spinner that also functions as a simple lab centrifuge.

The centrifuge was designed in Fusion 360, and was apparently as easy as drawing a few circles and hitting copy and paste. Interestingly, this fidget spinner was designed to be completely 3D printable, including the bearings. The bearing is a standard 608 though, so if you want to get some real performance out of this centrispinner, off-the-shelf bearings are always an option. The design of this fidget spinner holds 2 mL and 1.5 mL vials, but if your lab has 500 μL tubes on hand, there are handy 3D printable adapters.

Still think using a toy to do Real Science™ is dumb? Contain your rage, because a few months ago a few folks at Stanford devised a way to build a centrifuge out of paper. This paperfuge can — at least theoretically — save lives where real commercial centrifuges or even electricity aren’t available. Fidget spinners save humanity once again.

The Almost Working, DIY Underwater Scooter Pistol Thing

A dive scooter, or a submersible ducted fan used by divers, is not a new invention. They’ve been around for years, used by everyone from the villain of the week on Miami Vice to professional divers. Now that high-capacity Lipos, 3D printers, and powerful brushless motors are cheap, it was only a matter of time before someone built a DIY dive scooter. [Peter Sripol] is the man, and he also built a dive scooter, underwater pistol thing.

[Peter]’s dive scooter is almost entirely 3D printed. That includes the ducted fans/thrusters. The electronics are what you would expect from a grab bag from Hobby King and include two 2530 sized 400Kv motors from Avroto. These are massive motors made for massive quadcopters but they do seem to work just as well pulling a human underwater.

While this dive scooter was a marginal success, there were a few problems [Peter] had to work through. These were the lowest pitch propellers [Peter] has ever printed. To be fair, most of the props [Peter] has printed were used in air, not a fluid that’s hundreds of times denser. The electronics held up very well, considering the bath in salt water.

You can check out [Peter]’s video build and demo below.

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Printrbot Teases Infinite Build Volume Printer

[Brook Drumm] of Printrbot is teasing a new 3D printer. This is no ordinary 3D printer; this is an infinite build volume 3D printer, the Next Big Thing™ in desktop fabrication.

The world was introduced to the infinite build volume 3D printer last March at the Midwest RepRap Festival with a built by [Bill Steele] from Polar 3D. The design of [Bill]’s printer began as simply a middle finger to MakerBot’s Automated Build Platform patent. This was patent engineering — [Bill] noticed the MakerBot patent didn’t cover build plates that weren’t offset to the plane of the print head, and it just so happened a printer with a tilted bed could also build infinitely long plastic parts.

While [Bill Steele]’s unnamed printer introduced the idea of an infinite build volume printer to the community, a few pieces of prior art popped up in the weeks and months after MRRF. Several years ago, [Andreas Bastian] developed the Lum Printer, an unbounded conveyor belt printer. A month after MRRF, Blackbelt 3D introduced their mega-scale tilted bed printer and later started a Kickstarter that has already reached $100,000 in pledges.

Right now, details are sparse on the Printrbelt, but there are a few educated guesses we can make. The belt of the Printrbelt appears to be Kapton film attached to some sort of substrate. The hotend and extruder are standard Printrbot accouterments, and the conveyor is powered by a geared stepper motor. All in all, pretty much what you would expect.

We do know that [Brook] and [Bill Steele] are working together on this printer, apparently with [Brook] in charge of the hardware and [Bill] taking either his slicing algorithm or firmware modifications (we’re not exactly sure where the ’tilt’ in the Gcode comes from) and getting this printer running.

While the Printrbelt isn’t ready for production quite yet, this is a fantastic advance in the state of consumer, desktop 3D printing. You can check out [Brook]’s teaser videos below.

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Using Nanotubes to Strengthen 3D Prints

3D printing has brought the production of plastic parts to the desktops and workshops of makers the world over, primarily through the use of FDM technology. The problem this method is that when squirting layers of hot plastic out to create a part, the subsequent vertical layers don’t adhere particularly well to each other, leading to poor strength and delamination problems. However, carbon nanotubes may hold some promise in solving this issue.

A useful property of carbon nanotubes is that they can be heated with microwave energy. Taking advantage of this, researchers coated PLA filament in a polymer film containing carbon nanotubes. As the layers of the print are laid down, the nanotubes are primarily located at the interface between the vertical layers. By using microwaves to heat the nanotubes, this allows the print to be locally heated at the interface between layers, essentially welding the layers together. As far as results are concerned, the team reports an impressive 275% improvement in fracture strength over traditionally printed parts.

The research paper is freely available, which we always like to see. There’s other methods to improve your print strength, too – you could always try annealing your printed parts.

[Thanks 𐂀[d] 𐂅 for the tip]