Monday, August 20, 2012

Print quality is actually exceeding my Sells Mendel at the moment

Its actually hard to tell here as this red transparent PLA I am using is impossible to photograph, It comes out looking like crap but I am really happy with the results I managed to get tonight.
After many many failures at trying to print Admiral Akbar on the rostock, I finally found the settings that worked best.
The first picture on the left shows the fine support structures that I was able to print even with a bowden extruder which amazed me. Even on my Mendel, some of these finer structures would not print or would collapse. The second picture shows the final model which looks so much better in real life than it does here. These models are a tranparent red plastic. They look really terrible here but the actual model look quite good.

Basically the mods I made to the extruder tonight really seem to have paid off.
* Replacing the standard hobbed bolt with a precision Arcol Hyena
* Mounting the Extruder in a bridge and shortening the PTFE tube
* Much tweaking and playing around with the settings in Slic3r (I think the most important changes in slicer were experementing with the retract settings and adding a 1mm lift.


  1. I have to reiterate how bad the transparent red photographs. The actual model looks much better in real life. There is still a way to go but I am pretty happy so far as long as I can get through the long print jobs without fails which was my goal for tonight

    1. Perhaps you could spraypaint it with some flat grey paint to eliminate the internal flash reflections.

  2. Would video help? How much height did your extruder positioning require you to give up?

    1. The way the rostock works when it homes the axis to the top, there is a V shaped inverted pyramid with the head suspended at the bottom. Mounting the Extruder in the gap above this did not result in any loss of print height. I currently have a print height of about 170mm but this is limited by the size of the belts I am using. I have left the excess rods sticking out the top, so by replacing the belts I can increase build height if I need to.

  3. Great Job! I'm still piecing my Rostook together. I'm using, as Johann has, the Airtripper Bowden but, I've selected a Steves Hot End. I'll be using cartridge heaters which are still coming and I need to make the base and tops.

    Compiling Marlin:
    I'm having trouble compiling the Marlin firmware. For some reason on my first couple of attempts the compiling does not recognize the #include location util/ so every call to the *.h files there give an error.

    Anyway - Congratulations! Very Satisfying!

    1. Hi Bas,
      I dont know if it has changed recently which is causing the issue but the files always have to be in a folder called Marlin. I dont know if that helps your problem.

      I am a bit grumpy with the rostock. Although I have managed to improve on the quality even more I am finding it highly unreliable in that all it needs is just one little drop of plastic to get in the way somewhere which can happen with the bowden and it skips a step somewhere and its all over. It Ruined another big print one hour in last night. I have no idea how to get over this issue. Its most annoying. The print quality was excellent, the object was looking great and then all of a sudden one axis missed a step somewhere and the head is crashing into the object. The only thing I can think of trying is getting smaller diameter pulleys to increase the torque or spring loading the base to let it possible absorb the shock of a hit. I am out of ideas at the moment.