Heatbed can't keep up with extruder fan [thermal runaway] January 27, 2017 06:51AM |
Registered: 7 years ago Posts: 19 |
#define TEMP_BED_RESIDENCY_TIME 10 #define TEMP_BED_HYSTERESIS 4 #define TEMP_BED_WINDOW 1
Re: Heatbed can't keep up with extruder fan [thermal runaway] January 27, 2017 08:28AM |
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Re: Heatbed can't keep up with extruder fan [thermal runaway] January 27, 2017 09:12AM |
Registered: 7 years ago Posts: 19 |
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the_digital_dentist
Post a picture of the machine.
A 40mm square fan can't possibly move enough air to cool the bed by much. Maybe noise from the fan wires is coupling into the thermistor wires and causing problems for the control code. Don't share wires withe the thermistor, and keep the fan wires away from the thermistor wires. It is best to twist the fan wires and twist the thermistor wires (separately, no together!).
Re: Heatbed can't keep up with extruder fan [thermal runaway] January 27, 2017 09:26AM |
Registered: 11 years ago Posts: 5,780 |
Re: Heatbed can't keep up with extruder fan [thermal runaway] January 27, 2017 10:14AM |
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Re: Heatbed can't keep up with extruder fan [thermal runaway] January 27, 2017 10:23AM |
Registered: 7 years ago Posts: 19 |
Quote
the_digital_dentist
The bed should not vary by 1C. Turn on PID control or rerun the PID autotuning. You shouldn't see more than 0.2C or so variation in bed temperature unless the heater is underpowered and you're operating at its limit, in which case you should get a higher powered bed heater (and then a bigger power supply, and new controller that can handle the increased current, etc.- there's a reason that printer was cheap...).
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the_digital_dentist
How much power is the bed heater capable of delivering? How big is the bed? No matter how large it is, it certainly has a relatively large thermal mass and temperature changes at the bed should take a while - a few seconds at the very least. If the bed temperature reading drops as soon as the tiny fan turns on, there's a problem with the wiring.
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(5)With 15V on the 12V terminals will maintain approx. 115 degree Celsius without regulation.
Quote
the_digital_dentist
pictures of everything....
Re: Heatbed can't keep up with extruder fan [thermal runaway] January 27, 2017 11:27AM |
Registered: 11 years ago Posts: 5,780 |
Re: Heatbed can't keep up with extruder fan [thermal runaway] January 27, 2017 12:20PM |
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Re: Heatbed can't keep up with extruder fan [thermal runaway] January 27, 2017 01:58PM |
Registered: 7 years ago Posts: 19 |
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JamesK
If it's a pcb bed heater, it's normal to have problems holding 110C+ when using part cooling fans, but not being able to hold 60C suggests the heater isn't working properly. If it's a dual 12/24V bed, make sure it's correctly wired for 12V, two of the pads have to be shorted together. If it's correctly wired, measure the bed resistance to check it's in the normal range of about 1 to 1.5 Ohms.
Quote
the_digital_dentist
PCB heaters are universally awful, but that isn't the problem here. 60C should be well within its capability. Something else is wrong. A 40mm fan, even directed at the bed plate, can't move enough air to change the bed temperature by any amount that the controller and heater can't handle.
The problem started when you added the extruder fan (print cooling fan? or extruder cooling fan?). Check the wiring. An extruder cooling fan should be wired directly to the power supply. A print cooling fan should be wired to a MOSFET on the controller board.
Re: Heatbed can't keep up with extruder fan [thermal runaway] January 27, 2017 01:58PM |
Registered: 7 years ago Posts: 19 |
Re: Heatbed can't keep up with extruder fan [thermal runaway] January 27, 2017 02:18PM |
Registered: 7 years ago Posts: 19 |
Re: Heatbed can't keep up with extruder fan [thermal runaway] January 27, 2017 02:31PM |
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Re: Heatbed can't keep up with extruder fan [thermal runaway] January 28, 2017 05:47AM |
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Re: Heatbed can't keep up with extruder fan [thermal runaway] January 29, 2017 11:49AM |
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Re: Heatbed can't keep up with extruder fan [thermal runaway] January 31, 2017 11:05AM |
Registered: 7 years ago Posts: 19 |
Quote
Origamib
Check out the thermistor wiring like the Dentist said. Interference may be telling the thermistor it is colder than it actually is. Perhaps invest in an infra red thermometer to see what happens to the bed when the fan comes on. Is it actually losing temperature??
Re: Heatbed can't keep up with extruder fan [thermal runaway] January 31, 2017 11:10AM |
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Re: Heatbed can't keep up with extruder fan [thermal runaway] August 29, 2017 06:43PM |
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Re: Heatbed can't keep up with extruder fan [thermal runaway] August 31, 2017 03:09AM |
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Re: Heatbed can't keep up with extruder fan [thermal runaway] September 07, 2017 11:47AM |
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Re: Heatbed can't keep up with extruder fan [thermal runaway] August 14, 2019 01:21PM |
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Re: Heatbed can't keep up with extruder fan [thermal runaway] August 14, 2019 04:47PM |
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