The 3D printers that I used

I am very fortunate that I used many of the 3D printers due to my work. Lets just talk about reasonable one. And forget about those that cannot make it.

Felix - The program, print is very good at the price of the printer. But I find that it does not stick to surface of the heated bed well. often need to add additional perimeters to stablelize it. Sometimes, half way through, the object just lift up and drop ...dead...  Other than that it is fine, especially when I print honey comb structure.


Next , I used Uprint. This is a more professional machine than the conventional Reprap family. It used propietry filament and support material. They sell in a carton of 7 sets. Costing about USD 1 K per box. The filament is ABS. The support material is soluble in acid. Print out is very hard, professional. But cost wise, it is higher.  The support material is actually not so hard to take out,  even if you are using simple tools like penknife and screw driver. Unless REPRAP machine, the support material is the same and hence hard to take out. Even if u can, it take a long time to clean up.

 

Also with this machine, I can tilt or adjust my printing to suit the force exerted on the layers. As we know, one of the weakness of  3D printing is due to the layers. If you exert a force parallel the layers, it might give way. So for Uprint, we can tilt the angles of the print  out till the forces are  not parallel to layering. Of course at the expense of the support material.

 

Next, we have OBjet.  

 OBjet is very expensive.The material is also very expensive. I would have though that this machine can print out molding quality. But I discover I was wrong. Conventional 3D printer including Uprint uses material that is quite brittle and not soft like injection molded  plastic. So under pressure, the printout might crack or give up. With OBjet, I thought it will be much better. Later I realised that  this is not the case. It still crack. Although the material is better the PLA or  ABS.

The printout is super smooth. It actually flatten every layers and make a smooth surface.

Another problem with OBjet is, you need to go through washing to clean the parts, as the parts is still wet after printing. Cleaning  will take a you while to do it. You can see it is very well protected, the material could be a bit toxic. The material is VERY expensive.

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.