Motor only moves in one direction

Comments

• frans87

  January 2015 edited January 2015

  UPDATE :
  
  I can move the extruder motor just fine in both directions with the LCD command , even when extruder is cold !
  In repetier host the same problem persists, so might be a problem between UI settings and FW ?
  
  I tried to post configuration.h but it is to long for the forum...
  
  
  Cheers,
  
  Frans
  
• frans87

  January 2015

  Excuse me for the multiple posts, i've discovered something new :
  
  In repetier host, the "bad" direction = retraction, is much faster than the extrusion speed. I can retract if i lower the feedrate setting to about 35, It doesn't work with the default feedrate of 100. When i move the motor from  the LCD both retraction and extrusion speeds are the same and all is fluent.
  
  Thanks for your interest,
  Frans
  
  
  
• Repetier

  January 2015

  Ok, so it is only your max feedrate that is too high in firmware. Host has speeds stored in printer settings for fast and slow.

  The ui in firmware uses other speeds. So reduce your extruders max feedrate to something retract can handle and adopt host settings to it.
• frans87

  January 2015

  OK, thanks for your answer.
  
  So just to see if i understand well :
  
  My settings in FW are :
  
  Feedrate : 50
  Start feedrate : 20
  Accelleration : 5000
  
  Nozzle : E3D-V6 0.4mm
  ABS 3mm
  
  Those were the default settings in the FW wich i didn't touch.
  
  Now, if every thing's fine in manual control at 35 % feedrate, should i set Max Feedrate to 17.5 in FW ? isn't that very low ?
  The difference between extusion and retraction seems very big, is this a fixed ratio ? 
  If my extruder doesn't work with the default values, could that mean that there's to much friction in the extruder ?
  What are normal values for my extruder ?
  
  Thanks again,
  
  Frans
  
  
• Repetier

  January 2015

  Remember your true speeds are in eeprom, not exactly the one in configuration.h.

  
  

  It takes force and time to melt filament so extrusion is slow. Retraction should be fast and there is much less force required (if the end is molten so you can pull back at all).

  
  

  I would change speeds in host and see what works and what not. Then you know the maximum speed.

  
  

  Speed depends on feeder and steps per mm and motor force you have. There are feeder that can do 100mm/s retraction and others have problems with 10mm/s. Most feeder should be able to handle 50mm/s. There is no fixed ratio. Most extruders can melt around 12mm^3 which then gives the limit, retraction has no such restriction.
• frans87

  January 2015

  Thanks for your help, i'm printing right now !
  I realised my extruder was not performing well. I made an other hobbed bolt my self and it extrudes well now.
  
  I bought a kit, and i must say, i had to change a lot of things to make it a working machine.
  
  The hobbed bolt i got with the kit, was made of theaded rod and i think the teeth were to coarse and sharp and because of the tread, not nicely centered.  When the idler was adjusted too loose it scraped the filament and the tooth filed up with plastic, when tighted, it damaged the filament so it had to much friction in the extruder.
  
  The hobbed bolt i made, has the the hobbed part in a plain shaft, has a finer thead, and is not as coarse, but it's a very hard bolt (from a volkswagen timing belt idler). It works very well now. I used this method :
  
  Thanks for your help !
  
  Frans