Temperature on hotend to low

Controllers Smoothie
1

Hi,

I have been haven som troubles extruding PLA with temperature set to 190 degrees, so I have mounted a thermocouple type K on the outside of the hotend, just next to the EPCOS100K.

The 2 sensors seems to read very different temperatures. It seems like the EPCOS100K is reading to low temperature since I can extrude PLA with temperature set to 212 which then gives me approximatly 190 degrees on the external thermocouple.

To me it seems like this issue has nothing to do with the PID settings since the temperature is really stable, it is just to low.

What could cause this?

Imported from wikidot

2

This simply isn’t a reliable measurement method, I wouldn’t expect it to give reliable results. The thermistor is *inside* the heater block, the thermocouple outside …

If you have trouble extruding, maybe just increase temperature somewhat ?

3

So you would expect a temperature difference of allmost 25 degrees?
Even when the thermocouple has such small Mass? I mean, it is only 2 small wires.

Is 215 a “normal” temperature for PLA? It sounds like that 190 would be a pretty standard value for extruding PLA when reading forums.

4

190 is the temperature for *very good quality* PLA. A lot of chinese/lower quality PLA requires temperatures up to 220.