Jump to content
Ultimaker Community of 3D Printing Experts
Sign in to follow this  
stonemonkee

odd over extrusion??

Recommended Posts

Hi guys,

new to this forum and new to Cura.

previously been using Kisslicer but moved onto Cura as it seems well develped and supported.

Im currently trying to tweek my printer . its printing ok with some good retraction then all of a sudden it will over extrude on one layer (randomly) it does this on both the support and the body of the object being printed.

oddly it leaves a band on the object a layer thick, further inspection reveals it extends out of both the internal and external side of the print, when it does this my extruder makes a louder sound and then it will carry on prinitng nicely for a while anyway until the next random "fat layer" kicks in.

Any ideas whats causing this?

 

Share this post


Link to post
Share on other sites

Welcome, stonemonkee. What sort of printer are you using?

Does the problem always happen at the same point, if you print the same file over again? Or is it random each time you try the same gcode?

A possible cause is that your retractions are sometimes failing - perhaps because you have Cura set to retract too far/fast. If the extruder motor skips steps on the retraction, then when it tries to reverse the retraction, it will, instead just force a bunch of previously unretracted filament out of the nozzle. The skipped steps on the retraction would also account for the louder noise.

If you're printer isn't an Ultimaker, and especially if it isn't Bowden-fed, then you can probably get away with much shorter retraction amounts than the default 4.5mm in Cura. And depending on your set up, you might also want a slower speed.

 

Share this post


Link to post
Share on other sites

hi thanks for the warm welcome and prompt responses

I have read those links and thank you however.I have missed out some important info in my first post.

im using a rostock printer with bowden tube and an airtripper extruder , a 0.35 nozzle 1.75mm ABS.

the other thing is that the filament is not under extruding , quite the opposite and over extruding.

It is random , i can run the same print twice and it happens in different areas.

I have always used kisslicer but prefer Cura and would like to get it working correctly.

im retracting 4mm at 21mm/s any faster grinds my extruder and seems to have a negative effect.

oh by the way the problem is much more pronounced when using support.

I can print a vase with spiral flawlessly

 

Share this post


Link to post
Share on other sites

A possible cause is that your retractions are sometimes failing - perhaps because you have Cura set to retract too far/fast. If the extruder motor skips steps on the retraction, then when it tries to reverse the retraction, it will, instead just force a bunch of previously unretracted filament out of the nozzle. The skipped steps on the retraction would also account for the louder noise.

This has to be the reason..I think you hit the nail on the head.my 4mm retraction was set from my kisslicer settings.I have not tried a lower setting but have tried higher which resulted in the same banding but longer print times.I will try a shorter retract tomorrow

 

Share this post


Link to post
Share on other sites

A picture of your part would be nice. If it's a Z screw issue where the bed doesn't move as far as it is supposed to then you get over extrusion on a given layer and then it corrects on the next.

 

Share this post


Link to post
Share on other sites

Well thank you guys, the problem was with my retraction as Illuminarti said, seems the retraction was skipping and then extruding a retracted amount plus the backlog from the skipped layer.Printing sweet as a nut right now.

just printing a new fan head i designed at.24 layer height so we will see how it manages that, but I have printed a couple of test heads and hands and Im certainly getting the same quality Kisslicer was giving ...very happy :-P

BTW i was originally retracting 4mm at 21mm/s had to bring this down to 2mm at 16mm/s ...shocking

 

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

  • Our picks

    • Architect Design Contest | People
      The goal of this contest is to design a set of people figurines that could be used in such a project to make an area, office or mall seem populated. 
      Think of different types of people in different environments, like walking people, people standing still, working people, and both men and women.
       
      • 31 replies
    • Taking Advantage of DfAM
      This is a statement that’s often made about AM/3DP. I'll focus on the way DfAM can take advantage of some of the unique capabilities that AM and 3DP have to offer. I personally think that the use of AM/3DP for light-weighting is one of it’s most exciting possibilities and one that could play a key part in the sustainability of design and manufacturing in the future.
        • Like
      • 3 replies
×

Important Information

Welcome to the Ultimaker Community of 3D printing experts. Visit the following links to read more about our Terms of Use or our Privacy Policy. Thank you!