Ask Hackaday: Open Fire Suppression And Safety Standards

April 12, 2016 by Gerrit Coetzee 74 Comments

We posted about a 3D printer fire a while back. An attendee of the Midwest RepRap Fest had left his printer alone only to find its immolated remains on his return. In the spirit of open source, naturally, he shared his experience with the rest of us. It occurred to me that hackers are never powerless and there are active things to be done and avenues to explore.

An animation of a commercial fires suppression system, fire trace's, operation. http://www.firetrace.com/fire-suppression-systems/direct-release-systems/ — An animation of a commercial fires suppression system, fire trace’s, operation. Firetrace‘s website has more.

There are really fantastic commercial fire extinguishing systems out there. One implementation, which is commonly deployed in cabinets and machining centers, is a plastic tube pressurized with an extinguishing agent by a connected tank. When a fire breaks out the tube melts at the hottest locations, automatically spraying the area with a suppressant. Variations of this involve a metal nozzle filled with a wax or plastic blended to melt at a certain temperature, much like the overhead fire sprinklers.

This system is also used inside engine compartments with success. For example, this item on amazon, is nothing but a pressurized plastic tube with a gauge on one end. Since the inside of an engine compartment can be treated as an enclosed space, very little fire suppressant is needed to extinguish an unexpected flame. It is important to note that this system works in a high temperature environment like an engine compartment, which bodes well for enclosed build envelopes on 3D printers.

BlazeCut Automatic Fire Suppression System 6' TV200FA, Automotive Extinguisher — BlazeCut Automatic Fire Suppression System 6′ TV200FA, Automotive Extinguisher Installed under Car Hood.

Another option is to construct a suppressant mine. A Japanese and a Thai company have both come out with a throwable fire extinguisher. In the Japanese device, the outside of the extinguisher is a breakable glass vial which shatters upon impact; releasing the agent. The Thai device looks like a volley ball, and releases the agent upon the application of heat. This device seems like a better candidate for 3D printing or home projects. Imagine a small rectangular pack with adhesive on one side that sits near the possible fire points of the printer, such as under the bed or above the nozzle. In the event of a fire, the casing will melt and the system will automatically deploy a spray of extinguishing agent.

Most of the chemicals used in these constructions are benign and readily available. High pressure tubing and waxes can all be purchased and the desired melt points can be aligned with their datasheets by need. Plastic sheets are not hard to procure. These offer a nice solution due to their entirely passive nature. They don’t need power to operate and rely entirely on the properties of the materials they are constructed out of.

There are other options in active systems. Hackaday readers suggested things such as flame sensors for adding automatic cut-offs in case of a fire. Thermal fuses can also be considered in some cases. There are other tricks too, which are less kosher but will work nonetheless. For example, placing a critical wire, fuse, or component in the likely path of a fire so that it is destroyed first, stopping the operation of the device quickly. These avenues should be explored. At minimum there should be at least one project that uses a Raspberry Pi and an Arduino to tweet that fire suppression failed and the house is on fire.

fire-extinguishing-balls — The Thai invention is a volleyball that melts upon contact with flame and releases a pressurized extinguishing agent.

Some of the big questions to ask are on the legal and ethical side. If someone started selling kits for a DIY fire suppression system and a fire ends up destroying someone’s property despite the device, who is responsible? Is it even safe to post instructions? What if a kit prematurely sets off and injures someone. I imagine a big part of the cost of these professional systems is some sort of liability insurance and certification. Still, putting a six hundred dollar fire suppression system on a six hundred dollar printer seems silly, and something is better than nothing.

Lastly, the comments directed a ton of flak towards the certification systems. There should be no reason that open source projects can’t produce their own specification for safety. An open source specification without an agency naturally couldn’t provide a legal defense against property damage, but a thought-out test program would provide piece of mind. For example, in the case of 3D printers, one could have a set of basic fail-safe tests. One example would be bringing the printer up to temperature and rapidly disconnecting the thermistor, does the printer erupt into fire? No? Good, it meets the spec. I wouldn’t mind knowing that the latest version of Marlin was tested on the popular boards and still met the community specification for fire safety.

As far as I can tell, there’s been very little work in open sourcing safety systems or in providing a testing framework for ensuring open hardware meets basic safety conditions. Many of you have experience with these systems. Some of you have gone through the entirely un-enjoyable process of getting a UL certification. What does Hackaday think?

Error Correction Of 3D Printers

April 7, 2016 by Brian Benchoff 42 Comments

From the very first RepRaps to the newest and latest printers off the Makerbot assembly line, nearly every consumer 3D printer has one significant shortcoming: it cannot recover from missed steps, slipped belts, or overheating stepper drivers. Although these are fairly rare problems, it does happen and is purely a product of the ~~closed~~ open-loop control system used in 3D printer firmware.

[Chris Barr] has come up with a rather clever solution to this problem. He’s designed a system that will detect and correct problems with the mechanics of 3D printers. It’s technically not a closed-loop control system, but it does allow him to get the absolute position of a nozzle on the build plate, detects error states, and can automatically calculate the number of motor steps per millimeter. It’s also much simpler than other closed loop control systems we’ve seen in the past, requiring only a few bits and bobs attached to the axes and to the printer controller board.

[Chris]’ system uses a magnetic encoding strip, a single chip, and a little bit of support circuitry. It’s actually not that much different from the moving axis on a desktop inkjet printer. It’s not closed loop, though; the firmware hack is only a ‘basic error correction’ that moves the nozzle back to where it should be. Although this is somewhat of a kludge, it is much simpler than refactoring the entire printer firmware.

In the video below, [Chris] demonstrates his solution for error correcting the printer by jerking his axis around during a print. The nozzle miraculously returns to where it should be, producing a usable part.

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Machines That Build Other Machines

April 6, 2016 by Brian Benchoff 18 Comments

When the RepRap project was founded in 2005, it promised something spectacular: a machine that could build copies of itself. RepRaps were supposed to be somewhere between a grey goo and a device that could lift billions of people out of poverty by giving them self-sufficiency and the tools to make their lives better.

While the RepRap project was hugely successful in creating an open source ecosystem around 3D printers, a decade of development hasn’t produced a machine that can truly build itself. Either way, it’s usually easier and cheaper to buy a 3D printer than to build your own.

[castvee8]’s entry into the 2016 Hackaday Prize does just what the RepRap project promised ten years ago. It’s all about building machines with the ability to reproduce, creating an ecosystem of machines to build household goods. The best part? You can 3D print most of the machines. It’s the RepRap project, but for mills, lathes, microscopes, and routers. It’s an entire shop produced entirely in a 3D printer.

The idea of creating a machine shop from the most basic building materials has been around for a while. At the turn of the last century, concrete lathes and mills bootstrapped industrial economies. Decades later, [David J. Gingery] created a series of books on building a machine shop starting with a charcoal foundry. The idea of building a shop using scrap and the most minimal tools is very old, but this idea hasn’t been updated to the era where anyone can buy a 3D printer for a few hundred dollars.

So far, [castvee8] has a few homemade machine tools on the workbench, including a lathe, a tiny mill easily capable of fabricating a few circuit boards, and a little drill press. They’re all machines that can be used to make other useful items, and all allow anyone to create the devices they need.

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The State Of 3D Printing At MRRF

April 5, 2016 by Brian Benchoff 17 Comments

Only a few days ago, a significant proportion of the Hackaday crew was leaving Goshen, Indiana after the fourth annual Midwest RepRap Festival. We go to a lot of events every year, and even when you include DEF CON, security conferences, ham swap meets, and Maker Faires, MRRF is still one of the best. The event itself is an odd mix of people rallying under a banner of open source hardware and dorks dorking around with 3D printer. It’s very casual, but you’re guaranteed to learn something from the hundreds of attendees.

Hundreds of people made the trek out to Goshen this year, and a lot of them brought a 3D printer. Most of these printers aren’t the kind you can buy at a Home Depot or from Amazon. These are customized machines that push the envelope of what consumer 3D printing technology. If you want to know what 3D printing will be like in two or three years, you only need to come to MRRF. It’s an incubator of great ideas, and a peek at what the future of 3D printing holds.

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Ethernet Controller Discovered In The ESP8266

April 1, 2016 by cnlohr 54 Comments

The venerable ESP8266 has rocked the Internet of Things world. Originally little more than a curious $3 WiFi-to-serial bridge, bit by bit, the true power of the ESP has become known, fully programmable, with a treasure trove of peripherals it seemed that the list of things the ESP couldn’t do was short. On that list, at least until today was Ethernet.

No, despite the misleading title, the ESP does not have a MAC and/or PHY, but what it does have is an incredible 80 MHz DMA-able shift register which can be used to communicate 10BASE-T Ethernet using a new project, espthernet. Join me after the break for video proof, and a deep dive into how this is possible.

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MRRF: Launching An Adorable Printer For Fun

March 31, 2016 by Gerrit Coetzee 12 Comments

Patrick and Matt hold a running Kitten Printer. The frame is stiff enough that the printer can be held or turned upside down and it can keep printing. — Patrick and Matt hold a running Kitten Printer. The frame is stiff enough that the printer can be held or turned upside down and it can keep printing without visible defects in the print.

[Patrick] and [Matt] have been coming to the Midwest RepRap Festival from Minneapolis for the past few years and bringing their trusty Tantillus printers with them. However, sometime between this year and the last [Patrick] decided that it would be really fun to make his own 3D printer, and liking the size and accuracy of the Tantillus, started there.

The adorably sized printer is adorably named too: Kitten 3D printer. The printer is certainly an enthusiast’s choice. It’s expensive at 1200 and small, but very well made. Its one big advantage? It prints really accurate parts.

The Tantillus also printed well, but the extruder left a lot to be desired, and the low stretch fishing line movement was very difficult to get tensioned just right. The secret behind the Tantillus and Kitten’s great print quality, aside from good design, is the small xy movement and low weight of the extruder set-ups. By having a movement over a very small range, cumulative errors in construction never get to add up. Also vibrations are less likely to show and smaller moments on the joints mean less flex at the extremes of the movements.

Really stunning print quality almost entirely free of ringing and z-wobble. 100mm x 100mm tray. These are very small parts.

[Patrick] is a mechanical engineer for his day job, and since this was a just for fun printer, he cut no corners. The frame is made with Misumi extrusions and linear movements. The build plate sits on a machined aluminum plate. It’s not flexing or going anywhere.

Part of what really stood out to me about the printer are a lot of neat little features which show careful thought. For example, the extruder movement sits neatly under one of the motors. All the parts except for one can be printed inside its build envelope without support. It uses around 200g of plastic. Every axis is constrained just enough, rather than the common tendency to over constrain that plagues 3D printer design. The spec sheet reads like my printer part wishlist: Bondtech extruder, Rambo board, E3d nozzle, heated bed, flat borosilicate build plate, name brand linear movements, and a well designed Z.

cleverdetails — The entire extruder assembly tucks under one of the XY motors at the corner of its movement. Compare its size to the size of a NEMA14 stepper motor.

Another interesting aspect of the design is the extremely light extruder assembly. The lighter an extruder can get, the less ringing will show in your parts at speed. This is one of the most compact designs I’ve witnessed. It consists of two fans, an E3d v6 lite nozzle, and two small linear bearings. The cold end is handled by a bowden set-up and a Bondtech extruder at the back of the printer. The only way to get it lighter would be a different nozzle, such as the upcoming insanely light 13g Pico from B3 unveiled at the festival. I was also interested to see that the bearings on the supporting rails were printed bushings to keep the weight even lower. [nop head] has tested these extensively, they should be fine as long as the rods have a good finish.

I’ve mentioned the size before, but it’s hard to grasp just how adorable this printer is without seeing it. The build envelope is 100mm x 100mm x 100mm, the printer itself is 200mm x 200mm x 240mm. That’s only 50mm wider than the build footprint. It’s a really fun design just to look at and see how they fit it all in there. There are lots of neat little tricks with belt routing and part design to get it all right.

For the enthusiast this would make a good small parts printer and travel printer. However, for me, it was neat to see people still setting out to try designing their own printer. In some ways the 3d printer movement has become crowded with Chinese knock-offs, and I was excited to see something new at the festival. It wasn’t the only new printer design there, but it stood out to me the most. I like the uncompromising nature of it, many people try to design for the lowest BOM and not the nicer print. There are still lots of low-hanging fruit in the 3d printer world and many of them are just getting the mechanics right.

PLA Bushing

Seriously serious Z.

[Patrick] and [Matt] came to the festival with their printer to see if people would like it. They didn’t have grand dreams of selling tons of printers and making millions. They were quite aware that their price point and the small size made it not for everyone. However, their table always had a small crowd. They just really like 3D printers, and that honesty resonated. They didn’t even have a website up at the start of the convention, but by the end they had gotten so many requests they had to oblige. They expect to have 3 kit options available by the end of April. If you’re interested there’s a mailing list sign up on their website. Let’s hope we see them at MRRF again next year with another cool design to look over.

MRRF: Innovating Extruders And Dissolvable Filament

March 30, 2016 by Brian Benchoff 6 Comments

Think laying down molten plastic on a 3D printer is as easy as squeezing plastic filament out of a hot tube? It’s not, and anyone who had a 3D printer in 2009 would tell you as such. There were hobbed bolts that stripped the plastic into a gooey paste, extremely large x carriages that made everything wobbly, and nothing worked as well as it does today.

Technology marches on, and this year’s Midwest RepRap Festival had people showing off the latest advances in pushing plastic, and something that hasn’t seen much use yet – dissolvable filament.

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