Copying High Security Keys With OpenSCAD And Light

September 24, 2019 by Tom Nardi 24 Comments

The ability to duplicate keys with a 3D printer is certainly nothing new, but so far we’ve only seen the technique used against relatively low hanging fruit. It’s one thing to print a key that will open a $15 Kwikset deadbolt from the hardware store or a TSA-approved “lock” that’s little more than a toy, but a high-security key is another story. The geometry of these keys is far more complex, making them too challenging to duplicate on a consumer-level printer. Or at least, you’d think so.

Inspired by previous printed keys, [Tiernan] wanted to see if the techniques could be refined for use against high security Abloy Protec locks, which are noted for their resistance to traditional physical attacks such as picking. The resulting STLs are, unsurprisingly, beyond the capabilities of your average desktop FDM printer. But with a sub-$300 USD Anycubic Photon DLP printer, it’s now possible to circumvent these highly regarded locks non-destructively.

Of course, these keys are far too intricate to duplicate from a single picture, so you’ll need to have the physical key in hand and decode it manually. [Tiernan] wisely leaves that step of the process out, so anyone looking to use this project will need to have a good working knowledge of the Abloy Protec system. Hopefully this keeps bad actors from doing anything too nefarious with this research.

Once you have the decoded values for the key you want to duplicate, you just need to provide them to the OpenSCAD library [Tiernan] has developed and print the resulting STL on your sufficiently high-resolution printer. Generally speaking, the parts produced by resin-based printing have a high tensile strength but are very brittle, so perhaps not the kind of thing you want to stick in your expensive Abloy lock. That said, there are some “Tough Resin” formulations available now which produce parts that are at least as strong as those made with thermoplastics. So while the printed keys might not be strong enough for daily use, they’ll certainly work in a pinch.

3D Printing At The Speed Of Light

January 14, 2019 by Will Sweatman 35 Comments

3D printers now come in all shapes and sizes, and use a range of technologies to take a raw material and turn it into a solid object. We’re most familiar with Additive Manufacturing – where the object is created layer by layer. This approach is quite useful, but has a down side of being time consuming. Two professors at the University of Michigan have figured out a way to speed this process up, big time.

They start off with a VAT additive printing approach. These work by using an ultraviolet laser to harden or cure specific areas in a vat of resin, layer by layer, until the object is complete. The resin is then drained revealing your 3D printed object. Traditionally, VAT printing has been limited to small objects because the resin needs to have a relatively low viscosity.

The clever professors at U-M were able to get around this problem by adding a second laser that keeps the resin in a liquid state. By combining a curing laser with an ‘uncuring’ laser, they’re able to use resins that are more viscous, allowing them to print more durable parts. And do so about 100 times faster than traditional printers!

Thanks to [Baldpower] for the tip!

Cortex 2 Is One Serious 3D Printed Experimental Rocket

December 25, 2018 by Donald Papp 9 Comments

Rocketry is wild, and [Foaly] is sharing build and design details of the Cortex 2 mini rocket which is entirely 3D printed. Don’t let that fool you into thinking it is in any way a gimmick; the Cortex 2 is a serious piece of engineering with some fascinating development.

Cortex 1 was launched as part of C’Space, an event allowing students to launch experimental rockets. Stuffed with sensors and entirely 3D printed, Cortex 1 flew well, but the parachute failed to deploy mainly due to an imperfectly bonded assembly. The hatch was recovered, but the rocket was lost. Lessons were learned, and Cortex 2 was drafted up before the end of the event.

Some of the changes included tweaking the shape and reducing weight, and the refinements also led to reducing the number of fins from four to three. The fins for Cortex 2 are also reinforced with carbon fiber inserts and are bolted on to the main body.

Here’s an interesting details: apparently keeping the original fins would result in a rocket that was “overstable”. We didn’t really realize that was a thing. The results of overstabilizing are similar to a PID loop where gain is too high, and overcorrection results in oscillations instead of a nice stable trajectory.

Cortex 2 uses a different rocket motor from its predecessor, which led to another interesting design issue. The new motor is similar to hobby solid rocket motors where a small explosive charge at the top of the motor blows some time after the fuel is gone. This charge is meant to eject a parachute, but the Cortex 2 is not designed to use this method, and so the gasses must be vented. [Foaly] was understandably not enthusiastic about venting hot gasses through the mostly-PLA rocket body. Instead, a cylindrical cartridge was designed that both encases the motor and redirects any gasses from the explosive charge out the rear of the rocket. That cartridge was SLA printed out of what looks to us like Formlabs’ High Tempurature Resin.

Finally, to address the reasons Cortex 1 crashed, the hatch and parachute were redesigned for better reliability. A servo takes care of activating the system, and a couple of reverse-polarity magnets assist in ensuring the hatch blows clear. There’s even a small servo that takes care of retracting the launch guide.

The rocket is only half built so far, but looks absolutely fantastic and we can’t wait to see more. It’s clear [Foaly] has a lot of experience and knowledge. After all, [Foaly] did convert a Makerbot printer into a CNC circuitboard engraver.