Why my HotEnd Temperatur never reaches its set point

Hello, guys! Here is my problem..
Why my HotEnd Temperature never reaches its set point when printing?
I set it at 230°C, but it only runs at 220°C for so long and never pass 230°C. When I set it lower than 230°C, the temperature then goes lower and lower again. What's wrong with it?

I did auto-tunne for the HotEnd and it done well although there's so many overshoot. But after that, the temperature still never reaches the set point.
And when I try to send M303 E-1 C8 S60 for Heated Bed tunning, it goes to tune the HotEnd! What wrong with my GCode?



Thank you

I use Sprinter firmware, Pronterface and slic3r for the software

Hi,
I am also facing same issue..

Experts, please comment.

I am using Geetech all metal hotend with fan.

Marlin firmware for PLA 230 deg C.

airflow on your heater block can be a cause

Does your PSU do the job right?

I have run into this issue before. There can be a few causes all of which can be fixed. So you are getting close to the set temperature so nothing appears to be really bad. This is good. The cause is without a doubt that, your hot end is outputting more energy to the surroundings than the input energy once you get to 220C. To fix this you need to do one or both of the following:
1) Decrease the amount of energy dissipating from the hot end.

This could mean insulating some of the metal surrounding the hot end with a high temp fabric. Or moving the fan to make sure it is not dissipating heat from the hot end directly.

There are 3 methods for heat transfer. 1) conductive 2) convective 3) radiative. Doing as I mentioned before will reduce the convective heat transfer to the surroundings and should be enough to get the results you want.

2) Increase the input energy. I have found that not all heater resistors are the same. They all have different energy outputs. look for a heater resistor with a HIGHER WATTage.

You can attempt to try one of these suggestions at a time and see what reults you get. If you shut off the cooling fans and you see it go up to 250C that is a good indication that the issue is with the convective heat loss and you should look into making sure that fan doesn't blow on your hot end directly. If you still don't reach temp with the fan off.... Then get a higher watt heater resistor