All metal hotend - plastic melting at the start of body

Hello guys,

I recently bought the all metal hot end, image attached.
I fixed it to my Greg's Wade cold end today and had a problem for which I need help. This is my first experience with all metal hot end, and previously I used a j-head,
the problem with j-head was, after a month or so of printing, now whatever I print (even at 200 degrees) the nozzle pops out of the PEEK body, I went upto 245 degrees
when this problem started. But before I have gone upto 248-250 and nothing happened. After that even at 200 degrees the nozzle gradually comes out under extruder
forces.

For the metal hot end, I think the problem is I am not using the fan, but how much is the temperature supposed to be of the metal body? I heated the extruder to 200 degrees
for PLA and while trying to extrude I realized the PLA was getting melted at the starting point of the hot end itself, that is, the temperature of the hot end body was enough to
melt it right there and without having it to reach the nozzle. I do use a small fan which is attached to the carriage, not the way the all metal hot ends come with.

Also I tried to heat to 230 degrees and my cold end started becoming soft and the position of the hot end shifted inside the cold end socket. So this is because the complete
temperature is getting passed on to the hot end body. Is this because I am not using the fan or there is a problem with the hot end I received?

Kindly help me with this.
Thank you for your time.

Regards.

Edited 1 time(s). Last edit at 06/29/2014 06:59AM by hamsn.

You definitely need a fan on the heatsink of the hot end what happened with to the original one they sent you try to use it

Did they use a small/thin stainless steel tube as a thermal break between the heater block and cooling fins? If not, that is the problem. Stainless conducts heat poorly, so it serves as a heat break between the block and fins.

My two cents is to look at the E3D web site for an exploded view and the fan shroud, and then buy a real E3D to solve all of your problems.....

you have the right thermistor setting in firmware,

It definitely needs a fan. The bottom fin of my E3D hotend remains cool to the touch in use.
An original E3D, as stated already, is advisable: [e3d-online.com]

Well, thanks for your replies everyone. I just figured out there was literally no gap between the heating block and the heat sink, they were directly in contact with each
other, thus all the heat was getting transmitted to it, causing even melting of my cold end groove. I have asked for a replacement.

Can anyone suggest me what to do with the j-head hotend? I cant even print PLA at 190-200 degrees, the nozzle just comes out of PEEK holder. This wasn't a problem
since the beginning, I did print about 2 kgs of material, it just started recently when I had a maxtemp error and the temperature of the nozzle never went beyond 248-250 degrees.

I don't think that you can fairly ask for a replacement if it was supplied as a kit but you haven't posted the supplier details so I can't really say.
As far as the j-head goes you could try wrapping ptfe tape around the top of the nozzle. If that doesn't work then give it a decent burial :-)