E3D hotend can't reach 210C with fan on
December 24, 2016 03:37PM
I upgraded my MakerFarm Prusa i3 to an E3D hotend a few months ago. It was printing fine for a while.
Recently, my daughter had an "argument" with the printer, tripped on a wire and sent the printer to the ground.
I lost the LCD display and had to replace the heated bed glass. Other than that, everything seemed fine.

When I reconnected everything, I noticed the fan on the E3D hotend was blowing air in the opposite direction.
I turned the fan around (with the sticker towards the hotend). Now, the hotend can't reach 210C. It hovers around 205C.

I don't know if it's the fan, or the fact that the printer fell.

Any suggestion on how to check this?

Note: If I stick my finger and stop the small hotend fan, the temperature gets above 210, but that's not sustainable ;-)

Re: E3D hotend can't reach 210C with fan on
December 25, 2016 12:47AM
Is the thermistor still secured properly? Otherwise it could be under-reading.

What is the resistance of the heater cartridge? You could be using a 24V cartridge with a 12V supply.

Are you sure you don't have a heater PWM limit set in the firmware?

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: E3D hotend can't reach 210C with fan on
December 26, 2016 01:56AM
you need to run a PID autotune for your extruder and check the thermistor and heater being secure but running autotune will optimize the heating had to do it on mine after cleaning my extruder fan the procedure is a little different for marlin from repetier
Re: E3D hotend can't reach 210C with fan on
December 26, 2016 03:23AM
What the others said above, plus...

Check the temperature of the heater block with a thermometer or whatever. The outside should be close to the temperature indicated. If the actual temperature is higher, check that the thermistor is in place correctly. Also check the wires to the thermistor and heater cartirdge; in particular, if the heater wires are *nearly* broken, that point may become hot (hot enough to glow even), and the energy not go into the heater.

Is the fan correctly aligned with the bottom of the heatsink? You don't want cold air blowing onto the heater block or nozzle.

Incidentally, I believe that the normal radial fans work at least as well sucking air through the heat sink as blowing it.
Re: E3D hotend can't reach 210C with fan on
December 29, 2016 02:35PM
I was wondering if possibly the fan was re-wired backwards after the accident, hence the reversed speed. Maybe try it the other way?

Perhaps the fan shroud was cracked, allowing air to blow on the thermistor?
Re: E3D hotend can't reach 210C with fan on
December 31, 2016 01:06AM
try it with the fan blowing out what extruder is it and next question is there a parts cooling fan as well and is it off make sure it is off for at least first layer print and you should be able to reduce its speed ? firmware marlin repetier or other and what control board
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