PLA melting from heat sink all over the place  

RE: PLA melting from heat sink all over the place

Hi,

You are probably dealing with a bad assembly of the hotend, the nozzle must be tight against the heat break but leaving a gap between the nozzle and and the heat block as shown on this picture.

The heat break is the dark grey part.

The fist thing I would do would be do a cold pull. After this, heat the hotend until 290°C, wait 2 min to be sure that every part reach the temperature and tight the nozzle (not too much 3Nm, which is not very strong, 2 fingers on a wrench) and verify there is still a gap between the nozzle and the heat block. After let the thing cool down, load a filament and test again.

If there is no gap between the heat block and the nozzle you will have to disassemble the hot end and do a clean rebuild. The complete procedure is there. Remember to always tighten or loosen the nozzle at 290°C.

Good luck.

RE: PLA melting from heat sink all over the place

Some details: to tighten or loosen the nozzle you must hold the heat block with an adjustable wrench.

Here is a tutorial made by Prusa, you can forget the first step of the video "First loosen the heater block", in my opinion it may lead to problems, jump to "unscrew the nozzle".

RE: PLA melting from heat sink all over the place

You didn’t mention which way and which photos but I’m sure it’s either the wrong way, or it’s the right way but you did it wrong. As @loak showed, the nozzle got to be flush agains the heat break, with a gap between the nozzle and the heater block, not flush against the heater block, which is an all too common mistake. Follow @loak’s advice, and you’ll be fine,