Extruder doesn't keep temp after hitting target

Hi everyone

i'm having a weird problem in my reprap prusa mendel, for some reason, when it hits the temp target of the extruder, it doesn't maintain it and goes down till i hit "set" in pronterface.

i used slic3r to generate the gcode from the STL, and there i set 280 degrees for the first and the rest of the layers, then loaded in pronterface, and i enabled debugging, and only saw this 2 commands at the beginning:

N2 M104 S280 *77

N5 M109 S280 *77

i have Sprinter as firmware and using ramps 1.4 and arduino mega.

Any hints of what could be the problem or where i should look at? i'm completely clueless

thanks in advance !

What filament are you using that takes 280 degrees? Also in Marlin I think that the max temp for the extruder is set to 275degrees. Remember these are celsius and a lot hotter than you think. ABS runs at 220C and PLA at 195C.

Hi,

yes, you were right, there was a limit in the firmware, i could raise it in the end.

i'm having big troubles with with this filament, is labeled a PLA but at 195 doesn't go through the extruder and i need to raise at least to 220. and at 220 i have 0 adherence (i already tested with several heatbed config, from 60 to 120). i need to put it to 250/260 so it doesn't clog, even at pretty slow speeds (5mm/s).

i will keep trying later, or try to get another filament from another provider to compare it and try to figure it out what's going on.

Regards.

Your tip might be clogged. Find a welding tip cleaner. The smallest wire will run through a .4 nozzle, and the second wire will run through a .5 nozzle.

You might also be trying to run at too high of a speed.

If you are getting no adherence, your tip might be too far from the bed. Recheck your Z hight calibration. A lot of people like to use a piece of paper to set their hight, I like to use a .002 inch feeler guage to set my bed. Also set it at temps for both the bed and extruder.