CTC thermocouple

I wanted to print with the bed heater off but I can't find a setting in makerbot program to turn it off during print.
I just set it to 30deg. then noticed, when the print wouldn't start, that the display was showing 40deg when the printer was cold.
So I see when I first turn on the machine and check the temps monitor the two extruders are at 29deg. and the bed is 40deg. Since it's 29deg here today then two of them are correct.

Does anyone know how to calibrate the bed thermocouple on a CTC 3D printer ?

Quote:

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Originally Posted by Kokobi

I wanted to print with the bed heater off but I can't find a setting in makerbot program to turn it off during print.
I just set it to 30deg. then noticed, when the print wouldn't start, that the display was showing 40deg when the printer was cold.
So I see when I first turn on the machine and check the temps monitor the two extruders are at 29deg. and the bed is 40deg. Since it's 29deg here today then two of them are correct.

Does anyone know how to calibrate the bed thermocouple on a CTC 3D printer ?

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You will need another accurate digital thermometer with thermocouple-probe
to get an accurate temp of bed.
The bed-temp circuit on Mobo will not read accurately below about 50C

Using digital-meter, I found that temp on top of glass-plate is about 12.C lower than at the metal-plate below it, also.
So if using a glass-plate on bed, like you should, then adjust temp up to compensate for that difference.
I found that setting of 85.C, for bed, is good for PLA filament,
which is about 73.C on top of glass.
(center of bed gets a little hotter than outer edges)

Quote:

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Originally Posted by Kokobi

I wanted to print with the bed heater off but I can't find a setting in makerbot program to turn it off during print.
I just set it to 30deg. then noticed, when the print wouldn't start, that the display was showing 40deg when the printer was cold.
So I see when I first turn on the machine and check the temps monitor the two extruders are at 29deg. and the bed is 40deg. Since it's 29deg here today then two of them are correct.

Does anyone know how to calibrate the bed thermocouple on a CTC 3D printer ?

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If you have the bed at the bottom of the machine when you preheat, the residual heat from the motherboard will rise naturally and heat the bed by 1 or 2 degrees, and if left long enough even more. My ambient temperature in the room is 26c and the bed reads 40c..

As Eagle said, the thermo couple not very accurate under about 50c, this goes for the Flashforges too, same thing. For me, off is off.. I just have to deal with whatever the temp is in the room, but I never need a cold bed... or never have in all the time ive been printing.

Quote:

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Originally Posted by Geoff

If you have the bed at the bottom of the machine when you preheat, the residual heat from the motherboard will rise naturally and heat the bed by 1 or 2 degrees, and if left long enough even more. My ambient temperature in the room is 26c and the bed reads 40c..

As Eagle said, the thermo couple not very accurate under about 50c, this goes for the Flashforges too, same thing. For me, off is off.. I just have to deal with whatever the temp is in the room, but I never need a cold bed... or never have in all the time ive been printing.

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Ah but does that mean the temp is accurate over 50 ? ... I guess I'll have to get my IR thermometer out and see.

As far as I know it isn't even a thermocouple, it's a thermistor or a diode, can't remember which.