I’ve been wondering about this for awhile. Anyone leave their printers running while they’re away from home for large prints? Parts of the printers get hot so I’ve never done it personally.
Hmm, look into smoke signal for 3D printers, did a Kickstarter, it’s a relay that shuts off the printer power when it senses smoke. You could probably rig this into a suppression system
I have left mine running, but I have cameras on it as well as a smoke detector directly on top of it that shuts off power connected to it (from a kickstarter project) and a filament monitor that pauses the print if it looses filament feed.
@Jesse_Laird did an awesome board for the printrbord and pi that allows for remote shutoff… He has an eye on safety features like this
Brook
Ive seen too many fires (usually start at the bed connector) to do that. I sit and watch mine.
I didn’t know there were so many safety options. I let mine run in the basement while I’m home and I’ll go and check on it every hour or so, but longer prints kind of waste a day for anything else I’d like to do at this point for me.
sit and watch the printer? I can’t imagine a bigger waste of time. Maybe the DMV… It was fascinating to watch it do the first few prints, but once its calibrated, I set it and forget it. Its a robot. Robots exist to save time. If i’m babysitting a robot, it isn’t saving time, its costing time Defeats the purpose. Might as well be machining parts by hand.
Ive got a pc with a 40 inch monitor, a 55 inch tv , an xbox one , racing chair and wheel, full theater setup and my printer in one room, Im not trying to mass produce a million widgets , and i dont believe i am going to ‘save time’ with a 3d printer. If that was my goal id pay someone else to print it . Just because something doesn’t suit you doesnt mean its wrong 
To each his own. We leave multiple printers running overnight, but that’s me. I want to build on Jesse’s work and sell an ultra-safe add-on with redundant safety features to help the safety conscious effort!
Some peoples houses have caught on fire due to 3d printers. Thats why I advocate for having a smoke detector nearby, and a fire extinguisher. I also advocate for 24v power supplies, much less chance of things catching on fire.
Though I developed the Pi interface board and included in an external power cutoff for safety circuits and additional fuse protection, I still do not (and cannot) advocate leaving printers unattended.
It really comes down to your own risk assessment and imagination for what can happen to these printers.
Think about what you’re doing to control risk, and why. No one “safety” system can manage all the risks.
We’ve stopped running “lights out” on the farm. There have been two close calls, no flames but significan smoldering even with safety measures that kill the power. Prior to that we ran almost 24/7 for a year and a half. We’d put 8-1- hour plates on the machine and let it rip.
Just because there is a shutoff mechanism that won’t stop something that is about to combust or has already combusted. We don’t sit and watch them but someone is around when they are running. We’ve got smoke detectors and fire extinguishers and that will give enough warning if something happens.
When you really dig into things like safety code, heater control, watchdog timers, circuit failure modes, etc… the average consumer/hobbyist 3d printer is vastly more likely to burn your house down than any other “appliance” type machine you might have in your home. The quality of safety engineering is BAD, full stop. At best, a few safety features are added at the last minute, without any real consideration of architecture-level design-for-safety.
For example, the universal use of low-side switching for high current loads is an egregious design error in a machine without ground fault detection, or safety ground chassis wiring, or (in many cases) adequate fusing. The heater is always energized: the control board only switches the ground path. That’s bad.
Marlin’s combined use of software PWM for heater control with lack of watchdog support is another particularly bad decision.
Many boards have bootloaders which don’t assert heaters low on start-up, meaning the heaters can stick on during programming or in a start-up crash/reset loop.
I could go on. It’s really surprising to me that we haven’t seen even more houses burn down than we have. There are just insane numbers of “near misses” where people walk in on their hot end melting or pull the plug when smoldering starts. Sooner or later, someone is going to die because an overnight print catches on fire. It’s really only a matter of time.
If you use a 3d printer with any less attention than you treat an oven with food in it, you’re relying on luck.
I leave mine on 24\7 on a power backup. ( backup is vital for long prints ). My longest print was 64 hours. Normally the motors would shut down from heat buildup, even they they’re idle, as long as they’re engaged (ringing), they will heat up. I printed fan brackets for X Y and Z, they all have their own fans. That’s how I keep it on that long, they’re cool to the touch. Make sure your power supply can handle more fans, if not, try using the computer tower’s Molex for the time being. (4 pin power cables)
You need the battery backup and regulator. That way power loss doesn’t fail a print, and turning an oven, blow dryer or AC on,it won’t fail your PID system or trigger a heater fault. Turn the stove on with it plugged into the raw outlet, watch the extruder temp fluxuate. That’s what the backup stops. Sometimes they’ll swing widly out of control. Mine melted out a PEEK insulator and the extruder fell right off. Since I got the backup, no problems. I got it for free too from Battery Backup Power. If you show them your printer and give some good words on their posts about how you would love to get one for your printer, they may send a basic unit out. I don’t know the policy on it, I co-own TechNation.IT so that may have had something to do with it, but see what they say.
They don’t need constant attention either, mine prints without me being there. I can even view and control it remotely from my cell. You need to understand the engineering and thermodynamic properties, as well as material dynamics and force equations before you can get it to print without supervision. I spent 10 years across 4 degrees and 2 campuses (Rasmussen and AI) on a cross study that allowed me to drop right into this field, but a normal person isn’t gonna be able to do that until they study and understand. Each new filament gets burn tests, glass transition temps with a laser thermomiter, tests for CuMm\Min max. Check water content and store or dry accordingly, they get break tests, sheer tests, etc, etc… Using calipers and digital force guages. Then you have to know trigonometry and algebra to plug them in properly (this stops having to waste a roll learning it) and you’ll need geometry and CAD skills to make things on your own. The media said it was mainstream, but that’s just to get you to watch. Buy one without the education and intellectual background, you’re gonna have a bad time, and spend a lot of time just tuning for filaments and still getting failed prints. You also need to be able to look at it and see where problems started, what problems happened because of the previous issue, what caused it to begin with, and how to fix it. 9 out of 10 people can’t do that. We don’t even consider hiring unless you meet those credentials.
@Dev_Wolf you missed the biggest issue that many people have stated in this thread. It’s nothing to do with reliability of the print and materials. Its safety. There is a lack of safety devices on these machines. It’s not if, it’s WHEN your house burns down because a connector failed, a mosfet failed, a thermistor failed. We’re pushing 20amps or more on a hobbiest machine that runs for hours at a time. This is just a hazard waiting to happen. @Ryan_Carlyle nailed it. (unfortunately low side fets are easy and cheap, high side fets are expensive and requires a driver).
there is a reason we can build them for 200-400$ but they are NOT industrial machines you should be trusting with life or property. Keeping a healthy skepticism of the machine , and not growing complacent is the best mitigation imho. I try to stay in the room and do other stuff. Smoke detector, fire extinguisher . When my number comes up, and im sure it will, I hope only to lose a ramps board at most.
Depends on what kind of insurance you have and if you can afford to burn your house down. Do you leave your house when your cooking with your oven? I print my parts in pieces and just pause it when I’m away.
My experience from a few years ago: http://www.printrbottalk.com/forum/viewtopic.php?f=6&t=524
Remember you likely have acetone soaked rags and lots of little squiggly pieces of plastic laying around. Doesn’t take much of a spark in the wrong place…