Trying to figure out fan control

I want to get fan control figured out for two reasons. First the fan for the heat sink on the hot end almost never runs, only the odd random time. Second my printer can't bridge worth a damn (using ABS) and I hear having a fan cooling the filament during bridging really helps. I'm using repetier host and an azteeg X1 with marlin FW. The fan is plugged into the fan header on the azteeg. I only see one spot to plug a fan in on this board though I do see some extra spots labeled EXP1 and EXP2. I assume this means expansion, but I'm wondering if they can somehow be used for a fan?

Any help or guidance would be appreciated,
Ryan

I would wire the heat sink fan permanently to the power supply input. If it's an all metal hot-end, you cannot afford to have it switching intermittently. I am not familiar with Azteeg, maybe someone else is?

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Waitaki 3D Printer

I agree with Waitaki, just hotwire your fans. I use an all metal hot end with a fan cooling just the fins, not the heater block. Always cool down completely (<30C) with the fan on.

I'll look into that, though I'd like to have it automated somehow. I'm thinking a time delayed relay (or well a solid state version with a 555 and a FET) so it turns on when the heater starts up for the hot end and continues to run for something like 5 minutes after there is no power to the hot end. I still need to get fan control working for bridging though. I only have one fan on my X carriage right now pointed at the fins on the hot end. Last night I tried telling slic3r to have the fan running all the time but the fan never turned on during the print so I'm not sure why or when slic3r makes the decision to run the fan.

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Ryan_M
I'll look into that, though I'd like to have it automated somehow. I'm thinking a time delayed relay (or well a solid state version with a 555 and a FET) so it turns on when the heater starts up for the hot end and continues to run for something like 5 minutes after there is no power to the hot end. I still need to get fan control working for bridging though. I only have one fan on my X carriage right now pointed at the fins on the hot end. Last night I tried telling slic3r to have the fan running all the time but the fan never turned on during the print so I'm not sure why or when slic3r makes the decision to run the fan.

I made a board for the Ormerod that combines thermostatic fan control, infrared Z probe, and bed illumination. See [miscsolutions.wordpress.com].

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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].