Comparing J-head hotends

I had bought quite a few hotends. I bought
1) J-head , Aluminium nozzle , Plastic body
2) J-head with aluminium heat sink and brass nozzle.
3) Mk7Direct extruder
4) E3D Hotends.

Also , I had many sizes of nozzles. 0.2 to 0.5  And in the end, I prefer to use 0.4.

Let's talk about this type of J head hot end. Plastic high temperature body and aluminium nozzle. The nozzle is relatively expensive to replace. I use it when I first started my Prusa I3. What happen is even with this body, YOU NEED A COOLING FAN. If not, your PLA might melt and solidify in it.

 

This nozzle clot easily. residue stick to Aluminium and hence you will find that the flow gets smaller and smaller. Then after I cleared it, one might accidentally enlarge it. Because Aluminium is soft. How I clear the choke. Basically I heat it using bare flame of my cooking hob. Then I have to get a stiff wire or the right size drill bit to clear it. After clearing afew times, I got fedup with it. I changed to brass nozzle.  And stop using J head. Now I have 2 sets of J head with 3 nozzles.

 

Next I bought a all metal J-head. I bought it cheap. probably less than  5 USD. I bought the heat sink , stem and nozzle separately. It works very well. Only thing is , YOU MUST HAVE A COOLING FAN. If you do not put a fan, the PLA filament will melt in the heat sink portion and solidify. then it will be hard to extrude.  I machined My own heater block. Just for fun. Now I am still using this extruder/ hotend.  The Brass nozzle is very important . It just don't choke. Ever since using this, I had never need to resort to barbeque my nozzle. I used a  0.4 mm nozzle.

 

 

 

 

 

 

 

 

 

 

 

 

Also I tried using direct extruder. Mk7 direct extruder with non contact heat sink but  with fan.

This is a very simple but good extruder. Once I realised that  maybe I do not need geared extruder, I put this into use. with indirect heat sink and fan. It works quite well but I still prefer the all metal j-head. I do get jam once in a while. But I think probably I did not set it well. I think this is simple and good. and importantly, nozzle must be brass.

 

lastly, I bought a E3D hotend. this is just a smaller version of all metal J-Head. so the result is comparable,  but the size is smaller.

 

Additional cooling fan for the printed parts. I had a chance to use Felix 3D printer. I am very impressed by the printout. It is so simply built and printout is so good. I realised from Felix that you need another cooling fan for the printout. This is to make sure that the previous layer harden and make the structure more rigid. especially at slope. previous layer need to solidify or else some times, you see a big lump on the curve or slope at the side of it.