Re-imagining The Crossed Gantry 3D Printer

August 19, 2020 by 36 Comments

Simply having a few go-to 3D printer motion system designs is no reason to stop exploring them, as even small iterations on an existing architecture can yield some tremendous improvements. In the last few months, both [Annex_Engineering] and [wesc23] have been piloting a rail-derived crossed gantry architecture, a “CroXY” as it’s come to be known. Borrowing concepts from Ultimaker’s crossed gantry using rods, the Hypercube Overkill project, and perhaps even each other, the results are two compact machine frames capable of beautiful prints at extremely high speeds–upwards of 400 mm/sec in [Annex_Engineering’s] case!

Both gantry designs take a rotated MGN12 rail (a la the Railcore) and cross two of them, mounting the carriage at the intersection point much like an Ultimaker. Each crossed rail controls a degree of freedom with vanilla Cartesian kinematics, but each degree of freedom also has a redundant motor for added torque. Like the CoreXY design, this setup is tailored for clean prints at high speeds since the motion-related motors have been removed from the moving mass. However the overall belt length has been reduced tremendously, resulting in a much stiffer setup.

But the innovation doesn’t stop there. Both gantries also feature a unique take on a removable Z probe. When the machine needs to level the bed, it travels to a corner to “quickdraw” a magnetically attached limit switch from a holster. Once mounted, this probe becomes the lowest point on the carriage, allowing the carriage to travel around the bed probing points. When finished, the probe simply slots back into its holster, and the print can begin.

Both [wesc23’s] CroXY and a variant of [Annex_Engineering’s] K2 are up on Github complete with bills of materials if you’re curious to poke into the finer details. With commercial 3D printer manufacturers spending the last few years in a race to the bottom, it’s exciting to still see new design pattern contributions that push for quality and performance. For more design patterns contributions, have a look at [Mark Rehorst’s] Kinematically coupled bed design.

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Mercurial Light Box Has A Secret Switch

August 17, 2020 by 14 Comments

Hit up the lighting aisle of any big box hardware store these days and you’ll probably find a variety of Edison bulbs — modern bulbs meant to evoke the bare, complicated tungsten filament bulbs from the early days of electric candlelight. Edison bulbs use filament LEDs, which resemble skinny candles with wicks at both ends and give off a nice light, especially when diffused by acrylic.

This simple light box uses two filament LEDs that float inside on an internal circuit sculpture. [lonesoulsurfer] likes to use old cell phone batteries and USB charging boards in his builds, and that’s exactly what’s inside this box.

Our favorite part of the build elevates this simple light box into a curiosity for those not in the know. It’s controlled with a mercury tilt switch, so all you’d have to do in a power outage is locate the box and turn it upside down, provided it has a charge.

We love elemental switch design around here, like this light box that switches on with salt water.

Modular Vibrating ‘Bots Made From PCBs

August 10, 2020 by 2 Comments

Printed circuit boards, they’re a medium designed primarily to mount electrical components with the wires themselves places as copper traces on the boards. To accommodate wide range of needs that have arisen over decades, board houses have evolved all manner of advanced techniques in routing and plating. To our benefit, this also makes it possible to leverage PCBs in an entirely artistic way, taking advantage of the highly-optimized manufacturing process. [GeeekClub] did just that, creating awesome vibrating robots out of custom-made PCBs.

The ‘bots come as a single PCB, with the parts snapped out akin to removing parts from sprues in a plastic model kit. They can then be assembled, with a pair of pager vibration motors installed to provide motive power. But really it’s the aesthetic of the boards and not the functionality that make these so incredible.

The design nestles a coin cell in the base of each bot, providing power and using the weight to help keep them upright. There’s a smattering of LEDs on board, and the art style of the ‘bots draws from Hopi Indian, Asian, and South American influences.

Cyphercon 2017 featured these exciting cubic badges, created from PCBs and soldered by hand.
This Star Trek inspired piece shows just how far you can go with the right color soldermask and some creativity.

This “flat-pack” style of PCB design that comes to life with creative use of angles and layers is becoming its own sub-genre of the art. The Star Trek Enterprise inspired build in another great example. We’ve also seen a growing trend of using the PCB as enclosures, take the Cyphercon badge and Queercon badge projects from 2017 as examples. Get yourself up to speed on design techniques for using FR4 as an enclosure from [Voja Antonic’s] in-depth guide.

Perfect Your Beer Pong Game With The PongMate CyberCannon Mark III

August 5, 2020 by 3 Comments

[Grant] was inspired to help his party guests improve their beer pong game. What he created is a fairly impressive contraption, sure to make him unstoppable in his next bout.

The device uses a gyroscope and a time-of-flight sensor to calculate the optimum trajectory for the ping pong ball. The user is guided to the correct launching position using two bubble levels and a series of indicator LEDs that turn green when the optimal position is reached.

The launching mechanism uses a servo motor to push the ball into the circular wheel machine which then propels the ping pong ball to its target. The circular wheel machine is powered by two DC motors whose speeds are determined by the distance from the target. [Grant] calibrated the DC motor speed to the distance from the target and found a pretty reproducible relationship favoring a cube root function. You can see his calibration data on his Instructable page as well as a cool demo video showing how the device automatically adjusts motor speed to distance from the target.

We should combine the PongMate with the Auto-Bartender we wrote about a few weeks ago. What are your favorite beverage hacks? Please share in the comments below.

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3D Printing Latex Is Now Possible

July 27, 2020 by 14 Comments

For those getting started with 3D printers, thermoplastics such as ABS and PLA are the norm. For those looking to produce parts with some give, materials like Ninjaflex are most commonly chosen, using thermoplastic polyeurethane. Until recently, it hasn’t been possible to 3D print latex rubber. However, a team at Virginia Tech have managed the feat through the combination of advanced printer hardware and some serious chemistry.

Sample cubes printed with the new process. Note the clarity of the sample at the top right.

The work was primarily a collaboration between [Phil Scott] and [Viswanath Meenakshisundaram]. After initial experiments to formulate a custom liquid latex failed, [Scott] looked to modify a commercially available product to suit the project. Liquid latexes are difficult to work with, with even slight alterations to the formula leading the solution to become unstable. Through the use of a molecular scaffold, it became possible to modify the liquid latex to become photocurable, and thus 3D printable using UV exposure techniques.

The printer side of things took plenty of work, too. After creating a high-resolution UV printer, [Meenakshisundaram] had to contend with the liquid latex resin scattering light, causing parts to be misshapen. To solve this, a camera was added to the system, which visualises the exposure process and self-corrects the exposure patterns to account for the scattering.

It’s an incredibly advanced project that has produced latex rubber parts with advanced geometries and impressive mechanical properties. We suspect this technology could be developed quickly in the coming years to produce custom rubber parts with significant strength. In the meantime, replicating flexible parts is still possible with available filaments on the market.

[via phys.org]

Tiny Circuit Sculpture Keeps The Night Watch

July 27, 2020 by 8 Comments

If you’re planning to get into circuit sculpture one of these days, it would probably be best to start with something small and simple, instead of trying to make a crazy light-up spaceship or something with a lot of curves on the first go. A small form factor doesn’t necessarily mean it can’t also be useful. Why not start by making a small automatic night light?

The circuit itself is quite simple, especially because it uses an Arduino. You could accomplish the same thing with a 555, but that’s going to complicate the circuit sculpture part of things a bit. As long as the ambient light level coming in from the light-dependent resistor is low enough, then the two LEDs will be lit.

We love the frosted acrylic panels that [akshar1101] connected together with what looks like right angle header pins. If you wanted to expose the electronics, localize the light diffusion with a little acrylic cover that slips over the LEDs. Check it out in the demo after the break.

There’s more than one way to build a glowing cuboid night light. The Rubik’s way, for instance.

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There’s An Engineer In Germany I’d Like A Word With; Tale Of A Crumbling Volkswagen Lock

July 20, 2020 by 149 Comments

In common with quite a few in the hardware hacking community, I have a fondness for older vehicles. My “modern” ride is an older vehicle by today’s standards, a Volkswagen Polo 6N made in the late 1990s. It’s by my estimation a Good Car, having transported me reliably back and forth across the UK and Europe for several years.

Last week though, it let me down. Outside the church in a neighbouring village the driver’s door lock failed, leaving me with my igniton key stuck in the door, and a mildly embarrassing phone call to my dad to bring the Torx driver required to remove the assembly and release it. I am evidently not 1337 enough, I don’t carry a full set of Torx bits with me everywhere I go. The passenger side lock has never worked properly while I’ve had the car, and this is evidently my cue to sort it all out.

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