HE280 Heating Stability Problem

[PMcG]

Hello everyone,

I have a problem with temperature stability when printing with the HE280 head on a modified Rostock Max v2 (upgraded with a new power supply). The print head heats up fine. Initially runs but at some time (could be 15 min or hours after) the temperature drops and throws a "DEF" error. I've done the PID autocalibration that gives results that undershoot the temperature. I hand calibrated the PID to get it to print.

What items should I check for on the head and the Rambo board?

Thanks in advance for any suggestions.

Paul

[geneb]

I would check to make sure that all your connections are solid - the connector on the HE280 can partially unseat sometimes.

g.

[PMcG]

I do have a clip on the whip connection, however, the clip does not feel like it would hold the connector tight. I will look into a better way.

Thanks,
Paul

[PMcG]

Zipped and tied the connector down so it could not move. Still, the problem persists. The print is fine initially then the temperature goes down slowly. I'm printing ABS at 240C and the temp drops down to 228C, sits there until it drops lower, and throws a DEF error.

The light for the heater on the RAMBO board is on continuously and the voltage on the extruder0 heat0 is steady at 12v+. It feels like there isn't enough wattage to heat.

What resistance should the thermistor be reading?

Base on P=V^2 / R = (12V)^2 / R=40W
the thermistor should be 3.6_ohms

The reading I'm getting is 5.4_ohms

Is this reasonable?

Paul

[geneb]

The thermistor value will change with heat. Are you referring to the heating cartridge? It may need to be replaced, but I'd reach out to support first.

g.

[PMcG]

Your right. The thermistor did change with the heat of my hand. I meant the heating cartridge.

I did reach out to support and they mention to take the voltage under full load at the rambo board. I did this and the voltage was at 12v+ with the bed heating the fan on 100% and the extruder heating up to 230C.

They also asked that I do a PID on the extruder (HE280(A)) M303 P0 S280 X0. This didn't work as the extruder(B) plateaued at 224C. Tried at a lower temperature and the same results occurred. The curve was smooth without jagged peaks of a poor connection.

I then changed to another HE280 (aka B) and with the PID set to 255,0,0 did the M303 P0 S280 X0 test again. This worked PID of 7.5341, 1.9651, 7.2215. The extruder (B) heated up quickly. Now trying a print with this HE280 (B).

Paul

[geneb]

if the hot end couldn't hit 280, you probably need to replace the heater cartridge.

g.