MakerGear Forum

A customer reported their M2 caught on fire. I talked to him and we are waiting for the printer to be returned for analysis. Until we have the printer I can't provide accurate information. We will post updates here as we learn more.

The M2 has proven to be safe and reliable over the five years the M2 has been available. We will carefully investigate what happened and share our findings with the MakerGear community. I learned about this through an Amazon review and could barely breath after reading it.

Rick

Odd, if anybody could set an M2 on fire, you'd think it'd be me. It's right up my alley

I've had the intermittent thermistor failure before, ON AN E3Dv6, but it failed in such a way that the firmware saw the hotend at about 45C regardless of the actual temp. I caught it when there was grey smoke shooting out the top of the hotend like a little jet, and a water-thin liquid puddle of black (formerly blue) PLA. However, the V4 isn't immune to this kind of failure, and it's one of the more consistent tech support requests on the forum.

In my instance, I didn't have the thermal runaway protection enabled in the firmware, because I get annoyed when it triggers by the fan kicking on.

I checked Mouser for 9 seconds and didn't find any 400C-rated thermal cutoffs, so they must not exist anywhere, but that might be the end game if a firmware "fix" isn't found. Alternately, the thermistor might be replaced with a thermocouple -- they are significantly more robust, but have their own problems.


To anybody else reading here: this is a systemic concern with any FDM/FFF-style printer. It's an inherent risk that's by design of the technology. It is not, in any way, unique to MakerGear.

If I had a concern and I do not because my printing is done away from any combustibles I would wire in a Thermal fuse in series with the extruder heater. Non- resettable one time. Oops I see insta already suggested. It could be lower rated than the heater temp, just mounted close by and not on it. The highest temp I could find was 240 DegC
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insta wrote:didn't have the thermal runaway protection enabled in the firmware

You can tweak the temperature & time required before the firmware shuts everything down. I had that happen with the platform heater after the basement cooled down: when the platform fan kicked in, the platform would cool down enough to trigger the "thermistor failure" detector. Adding a few degrees and seconds solved the problem, before I stopped using the platform fan.

this is a systemic concern with any FDM/FFF-style printer

Indeed it is! However, a firmware crash can do it without a bad thermistor, as my Thing-O-Matic demonstrated:

http://softsolder.com/2011/06/07/thing- ... l-runaway/

The thermal lockout circuit for that plywood-and-acrylic hulk may be relevant:

https://softsolder.com/2011/03/02/cartr ... t-doodles/

The general idea is that you must not depend on firmware to save your bacon. My lockout design used separate thermal switches controlling a relay that drove the +Power On signal of an ATX supply, but you could substitute a stiff relay / DC SSR for the current from M2's brick:

https://softsolder.com/2011/03/14/thing ... t-circuit/

You could tap the supply upstream of the relay to power only the lockout circuit, because power bricks lack the small always-on +5 V output found in ATX supplies.

I haven't built one for the M2, because I never leave it operating unsupervised … just because I'm that type of guy.

i have always said that 3d printer of any make and model need a secondary, independent overtemp shutdown. i have looked for small thermal switches before but like insta, i have not been able to find any with a high enough temp. i am actually surprised you dont hear about more accidents like this happening in the 3d printing community. since its been available i have always printed all my filament drive parts with fire retardant plastic. usually epc. atleast if something does go wrong i have some type of chance. abs is just a fuel source.

First, we need to get the printer back and figure out what actually happened.

jimc wrote:i have always said that 3d printer of any make and model need a secondary, independent overtemp shutdown. i have looked for small thermal switches before but like insta, i have not been able to find any with a high enough temp. i am actually surprised you dont hear about more accidents like this happening in the 3d printing community. since its been available i have always printed all my filament drive parts with fire retardant plastic. usually epc. atleast if something does go wrong i have some type of chance. abs is just a fuel source.

Relying on an sort of electronics to shut the system down in case of a overheat danger is asking for problems. A mechanical overheat device of some sort, inexpensive and user replaceable would be the answer. It could be a on the market UL listed thermal fuse mounted away and above the actual print head where it would only be opening the power source on a overheat.
We have the same issues with laser machines, the heat and smoke generated during normal operation make it pretty much impossible to fire proof, so you stay by the machine or use a video camera to monitor.

Rick is correct Until he sees the machine its all speculation, it could also be user error or misspeak..

Are TPE/TPU materials flammable?

hybridprinter wrote:Are TPE/TPU materials flammable?

Everything is.

Polyurethanes are especially hilariously flammable. I had some cast polyurethane parts roughly the size of a VHS cassette, which burned with a 2 foot tall flame for 19 minutes.

Ninjaflex and Cheetah?