MakerGear Forum

Yeah they are polyurethanes. I think its less about the material you are printing since there is very little there. Its the abs plastic prinded parts on the printer used in the whole extruder.

Wouldn't the TPU filament catch fire in the hot end and travel upwards to the spool?

Only if you have your spool mounted above the printer. Big fuel source

Here is an updated on what we know:

Prior to the fire, the printer was shutting down with a temperature error - this means there was a problem in the temperature regulation system. The owner did not contact us for support but did order replacement parts (thermistor, cartridge heater and some other parts). While waiting on the replacement parts to arrive, the owner continued to use the printer and run it unattended.

We have analyzed the printer and attempted to reproduce the fire but have not been able to reproduce it. We do not know what happened. We have contracted a 3rd party specialist to help with the investigation.

We'll post updates as they are available.

Rick

What happens if you let a thermistor dangle outside of the hotend, and try and heat to 220C, on stock Rev. E firmware?

Could there be a feature (or accessory item), which monitors if filament is no longer extruding during an active print (i.e. filament is stuck in the hot end), which after XX amount of seconds it will power down the hot end and printer to prevent any possible issues.

Prior to the fire, the printer was shutting down with a temperature error - this means there was a problem in the temperature regulation system. The owner did not contact us for support but did order replacement parts (thermistor, cartridge heater and some other parts). While waiting on the replacement parts to arrive, the owner continued to use the printer and run it unattended.

Well that doesn't sound so smart..... bet that tidbit of info wasn't in his amazon review was it?

hybridprinter wrote:Could there be a feature (or accessory item), which monitors if filament is no longer extruding during an active print (i.e. filament is stuck in the hot end), which after XX amount of seconds it will power down the hot end and printer to prevent any possible issues.

There are devices on the market that do this already but a filament jam isnt going to turn into a fire. That is strictly in software, hardware failure and temp sensing circuit.

so what conditions could result in a fire?

jimc wrote:

hybridprinter wrote:Could there be a feature (or accessory item), which monitors if filament is no longer extruding during an active print (i.e. filament is stuck in the hot end), which after XX amount of seconds it will power down the hot end and printer to prevent any possible issues.

There are devices on the market that do this already but a filament jam isnt going to turn into a fire. That is strictly in software, hardware failure and temp sensing circuit.

Thermistor goes bad, hardware component on rambo board goes bad, glitch in the firmware. Any one of these items would have to fail in a way to keep power on constant to the heater cartridge. I have watched a forced failure video awhile ago. The cartridge will melt the aluminum heater block and catch the filament drive on fire and anything flammable around it