Tuesday, December 13, 2016

3D Printing 101 - Safety First

It's important to realize that 3D printers are machines, and like most machines there are risks associated with their use. Most of these risks are minimal and the number of incidents involving 3D printing are low, especially compared with the number of 3D printers in use. However, unless you're going to only use 3D printing services and let them handle the machines, it's still best to start any 3D Printing course with a discussion about the safety of 3D printing.

The purpose of this section isn't to scare you away from 3D printing. The purpose is to make you aware. We deal with potentially dangerous situations every day. Being aware of the dangers, how we are managing those risks, and how we aren't, are what makes us safer. No one is going to be perfectly safe in every situation, but those who are aware are better off.

There are many types of 3D printing and each has it's own associated risks to take into account. The most common type of 3D printing that you're likely to encounter is FFF. If the 3D printer you are going to use is a different type than this, like SLA or power based printers for example, then be sure to familiarize yourself with the safety procedures for using that type of 3D printing.

FFF 3D Printers

Good 'ol FFF
Most FFF 3D printers that are affordable to most users are not built with safety in mind. They consist of cheaper components and minimal safety features. They tend to be open with moving components and electronics exposed where an unaware person might interact with them. And there tends to be a number of chemicals commonly used with 3D printers that have dangers associated with them. 3D printers, by their nature, also tend to run without supervision, which is when bad things happen.

3D printers are electrical devices and electrical wiring, especially when built on the cheap, can spark. A spark can ignite anything flammable. To date there have been 3 incidents of a fire that involved a 3D printer. Two involved only the loss of property (and the printer) and one involved the loss of a life. In two of those cases it isn't exactly clear where the initial spark that started the fire came from. It might have not been the 3D printer, but it might have, there's no way to be sure at this point so it can't be ruled out.
One of the 3 fires involving a 3D printer
Many 3D Printers have a big power brick on them and for many 3D printers that brick is external. That power brick generates heat, and potentially, electrical sparks. If the wires leading to the power brick or to the printer get cut, pinched, or damaged, they could heat up, melt, and ignite something around them that could start a fire.

So far these warnings are true of any electrical devices, but 3D printing has is own unique dangers associated with it.

FFF or FDM 3D printing involves the laying down of layers of melted plastic on top of each other with a mechanical movement system. Plastics are polymers and when heated can generate a flammable gas that could be ignited by a spark. Usually 3D printers do not get to the sorts of temperatures required to turn a plastic into a gas, but a broken temperature sensor could cause a heater element to run away with it's heat. Some 3D printers have safeguards to prevent this, but not all do.

If these thermo-polymers plastics do get hot enough to melt and generate heat there is a risk that they will flow, meaning the danger isn't contained to the 3D printer or the area immediately around them. It will quickly spread as the melted plastics flow.

The end of the 3D printer where the material comes out, known as the "hot end", can be the point of contact for ignition if it comes in contact with some foreign material, not the plastic, but something else that burns or melts at a lower temperature than plastic. The hot end can also burn your skin and while hot ends are small and the burn will be minimal, it can still hurt a lot.

Finishing a 3D print often uses common chemicals that are known to be very flammable. Acetone can easily fill an area with flammable gas that is undetectable to the eyes, and since it's heavier than air, will linger far below the nose and may not be detected. Many first time 3D printer owners use hairspray to adhere prints to their build surface and hairspray uses a propane based propellant to expel itself from the can. It's important to remember that fire is never safe and should never be played with, no matter how cool it is to watch burn. Always be careful with these materials, and doubly so when around a 3D printer.

3D printers consist of moving parts. Gears, driving filament and belts, screw lead driving gantries. All of these points are potential pink points for curious fingers or clothes. While the motors that drive most 3D printers aren't strong enough to do any significant damage, and while it's much more likely that the printer will take the brunt of the encounter, there are other printers with stronger motors or points where the torque is more focused. Finger or loose clothes could get caught and pinched.

How to be safe

There are some simple, and some more involved things that anyone can do if they're concerned about safety.
Among the more involved solutions there are systems like "Smoke Signal" that attaches a sensor to a power relay that will immediately shut down power to your printer in case a potentially hazardous situation is detected. This is an okay solution provided it catches a problem before it becomes more life threatening. There are also companies like 3D Print Clean that will build an enclosure for your printer complete with air filtration and fire suppression system designed to deploy in case a fire is detected. These are extreme measures, but insure a great degree of security concerning your 3D printing.
While you are saving up for a system like that, however, consider these simple precautions to safeguarding yourself from the risks of 3D printing:

  • Keep the area around and near your 3D printer clear of flammable materials. This includes paper, rags, cloth, insulation, debris, and the chemicals commonly used for 3D printing. Keeping these things near your printer may be convenient, but it's safer to keep them further away.
  • Use your printer in a well ventilated area. This goes double for common finishing chemicals. Always be near a window or door that will open to the outside to clear any vapor or fumes that may be generated in the process of 3D printing.
  • Have a fire detection system and fire extinguisher near by
  • Use caution around your printer's moving parts. Keep dangling clothes and fingers, especially little fingers, away from the 3D printer while it's in motion. 
  • Do not run your 3D printer unattended. When a machine is left to run unattended, that's when bad things happen. If there's always someone near by then you can be sure any danger is minimized. Fires can be caught before they start, prints can be turned off before they dramatically fail, and even minor printing errors can be caught quickly.
Maybe at this point you're thinking, "There's no way I can do all these things all the time. The fact that 3D printers can be small, fit on a desk in a small office, and run without you standing over them is the best part about them! How can you expect anyone to never leave their printer unattended or do all these things?"

That's true. No one is perfectly safe in anything. But, again, this section isn't about making you scared or even worried, it's about making you aware. Knowing what you need to do to be safe, and what you are or are not doing, you'll adjust your behavior and be on the lookout for potential pitfalls. Maybe as a result of this you'll change something to be a little safer or you'll think twice about starting a big print before you leave on a long vacation.

For as many people as are running cheap, poorly built 3D printers, and as few incidents as there have been with them, home and prosumer FFF 3D printing has a pretty good track record. But you don't want to be the next statistic. 3D printing is fun and I encourage you to have fun with it. Just remember, safety first.

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.