| Electronics > Beginners |
| 3D Printer Fire protection |
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| bd139:
That's "interesting". I suppose that's probably supplied off a resistor from the 24V supply then. |
| Monkeh:
--- Quote from: paulca on September 30, 2019, 02:21:17 pm ---Glue stick - I found Prit Stick did NOT work. It hardens into a solid with the heat and is an absoltely nightmare to remove, not alchohol soluable either. Blue painter tape (the printer came with yellow stuff which does work) Hairspray - makes the surface nice and tacky but can make a mess with overspray (at least it's alcohol soluable) --- End quote --- Glue stick is water soluble.. It's PVA. --- Quote ---Apparently people swear by PEI sheets but they are expensive. £10 for a 300x300 sheet. --- End quote --- How is that expensive? If you don't damage it it'll outlast most of the printer. --- Quote from: paulca on September 30, 2019, 03:31:15 pm ---On the topic of dodgy electronics, I discovered if I move the extruder head across the arm while the printer is powered off that the power generated from the stepper motor powers the display back light. :-DD --- End quote --- --- Quote from: bd139 on September 30, 2019, 03:51:31 pm ---That's "interesting". I suppose that's probably supplied off a resistor from the 24V supply then. --- End quote --- The LCD backlight is fed from the 5V rail. The protection diodes in the stepper drivers will feed the 24V rail if you move the steppers unpowered, which will feed the 5V reg and off we go. |
| janoc:
--- Quote from: paulca on September 30, 2019, 03:31:15 pm ---On the topic of dodgy electronics, I discovered if I move the extruder head across the arm while the printer is powered off that the power generated from the stepper motor powers the display back light. :-DD --- End quote --- Don't do that - you can blow your stepper drivers. If you need to move the extruder or the axes manually, do it slowly to limit the issue (or unplug the motor, if it is accessible). |
| dnwheeler:
Working on medical devices for a living has taught me that most consumer products (especially cheap ones from China) don't have even the simplest forms of fault detection systems. The 3D printer firmware should be designed to notice that the temperature isn't rising when the heater is on, and shut down the system. They should also be detect an open or short in the thermistor circuit. |
| bd139:
That's what the thermal runaway protection does. It notices that the control loop isn't functioning and shuts the thing down. To be honest it's no more dangerous than a Weller TCP with a stuck thermostat. Been there! :-DD |
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