The Almost Working, DIY Underwater Scooter Pistol Thing

July 2, 2017 by Brian Benchoff 19 Comments

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

June 30, 2017 by Brian Benchoff 33 Comments

[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

June 30, 2017 by Lewin Day 14 Comments

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 ????[d] ???? for the tip]

The 3D Printer Packing Problem

June 28, 2017 by Brian Benchoff 20 Comments

Form Labs recently announced the launch of the Fuse 1, a desktop SLS printer that will print all your parts using nylon powder and a laser. This a fundamentally different method of 3D printing as compared to filament-based machines, and the best way to use a Fuse 1 is to fill the entire volume of the machine with 3D printed parts. [Michael Fogelman] decided to investigate the 3D packing problem, and managed to fill this printer with the maximum number of 3D printed tugboats. If you’re wondering, it’s 113, as compared with 82 tiny Benchies using naive bin packing.

The formal definition of this sort of problem is the bin packing problem, or simply calculating the maximum number of items can be packed into a finite volume. There is no general solution to this problem, and it’s probably impossible to create an algorithm that will solve this problem for any collection of 3D models. Nevertheless, it’s possible to create a solution that shows marked improvement over a naive solution.

[Michael]’s solution involves simulated annealing. This algorithm begins by randomly placing tugboats, then mutating the position or rotation of one of the boats for each iteration. The code is less than 1000 lines of Go and is available on GitHub if you already have an SLS printer at your disposal.

It should be noted this type of problem isn’t particularly new to the world of 3D printers. There have been a few tools to solve the bin-packing problem for filament-based printers, but the solutions to these problems are two-dimensional; since filling a bed is a problem that only uses the ‘shadow’ of the Z-axis of each part, it’s a slightly easier problem to solve.

Now that Form Labs’ Fuse 1 SLS printer has been announced, there is a new application for this type of problem in the space of 3D printers. It’s not a perfect solution — and it’s doubtful there will ever be a perfect solution — but if you’re looking for a way to fill the volume of your powder printer with parts, this is the best you’re going to do.

A Crash Course In Thingiverse Customizer

June 27, 2017 by Al Williams 19 Comments

OpenSCAD is a great way to create objects for 3D printing (or other purposes), especially if you are already used to programming. For things like front panels, it is great because you can easily make modifications and — if you wrote your code correctly–everything will just adjust itself to new positions.

However, what if you have a general-purpose piece of code, and you want people to have the ability to customize it? For example, consider this code:

$fn=100;
difference()
{
  cube([25,25,5]);
  translate([4,4,-1]) cylinder(h=7,r=2);
  translate([25-4,4,-1]) cylinder(h=7,r=2);
  translate([4,25-4,-1]) cylinder(h=7,r=2);
  translate([25-4,25-4,-1]) cylinder(h=7,r=2);
}

That creates the plate with four drill holes you see on the right.

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Another Helping Hands Build

June 25, 2017 by Al Williams 4 Comments

[Punamenon2] wanted a soldering station with integrated helping hands. He couldn’t find one, but he decided it would be a good 3D printed project. In all fairness, this is really 3D printing integrating several off-the-shelf components including a magnifier, a soldering iron holder, a soldering iron cleaner, a couple of “octopus” tripods, and some alligator clips. Total cost? Less than $30.

In addition to holding the Frankenstein monster together, the 3D printed structure also provides a storage tray with special sloped edges to make removing small screws easier.

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Animated Bathroom Sign

June 25, 2017 by Lewin Day 160 Comments

Once upon a time, pants were created. After a while, women were allowed to wear them too. This has made a lot of people happy and been widely regarded as a good thing. There is a problem, however – bathroom signage is largely predicated on the idea that there are two rigid genders which all humans must be sorted into, and they’re defined by whether you’re wearing pants or a dress. [Robb Godshaw], among others, disagrees with this, and set about building a gender fluid bathroom sign.

The project seeks to exploit the traditional symbols of “male” and “female” – the human figures wearing pants or a dress – by creating a sign that switches between the two every 15 seconds. This is likely to initially confuse – one might imagine the bathroom is actually changing its gender designation rapidly, forcing users to complete their business in an incredibly short timeframe. However, the message behind the project is to highlight the absurdity of defining gender by pants, colours, or indeed in a binary nature at all. [Robb] also helpfully points out that all humans have to pass waste, regardless of gender.

The sign is built with 3D-printed components, using a crank mechanism to actuate the moving parts. The mechanism is designed to give equal time to the pants and dress configurations. [Robb] shares the important details necessary to replicate the build, such as how to assemble the metal crank pin insert with a paperclip and a lighter. It’s particularly tidy the way the mechanism is integrated into the parts themselves. In true hacker style, the motor is a standard microwave oven turntable motor, which can be harvested easily from a junk appliance and can be plugged straight into mains power to operate, if you know what you’re doing. If you don’t, check out our primer on the topic.

Overall, the project is a great use of hacker techniques, like 3D printing and harvesting parts, to make a statement and start a conversation, while being fun, to boot. We’ve also seen some of [Robb]’s work before, like this giant hamster wheel for people. Video after the break.

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