Jump to content
Ultimaker Community of 3D Printing Experts

Blobs/Zits on Walls with Octoprint

Recommended Posts

Posted (edited) · Blobs/Zits on Walls with Octoprint

Hi All, I've got a UM2+ running TinkerFW 19.03 connected to Octoprint 1.5.3. It's loaded onto an older Raspberry Pi 2. I've been using it for awhile without any issues. But lately I've noticed that printing from Octoprint will cause blobs/zits to appear on outer walls. I've watched it happen, the printhead will pause momentarily, depositing a small amount of material. Same g-code printed from the SD does not cause this issue. Sliced with Cura 4.2. 


An initial search shows that this is due to a buffer issue, that Cura creates a lot of small move commands which basically overwhelms the Octoprint server feeding  the UM2+. 


It's not a power issue since I'm powering the RPi with an iPad charger (12W). 


Only thing I can think is that the RPi2 is too slow for newer versions of Octoprint? I had been using it for some time without any issues so it's odd that it recently started. 



Edited by dfrez
  • Link to post
    Share on other sites
    • dfrez changed the title to Blobs/Zits on Walls with Octoprint
    Posted (edited) · Blobs/Zits on Walls with Octoprint
    4 hours ago, Cuq said:

    When I saw that thread title before making this post, I (stupidly) assumed it was actually for an arc welder 🤦‍♂️... looking closer, I think this is solving my exact problem! 


    The buffer underrun that is caused by too many g-code commands, do you think that would be mitigated by a newer Raspberry Pi? I figured my 2 is a bit long in the tooth anyway.


    or is it more of a bottleneck caused by the USB protocol itself?  

    Edited by dfrez
  • Link to post
    Share on other sites
    Posted (edited) · Blobs/Zits on Walls with Octoprint

    Since I wanted to be able to access both of my UM2's through Octoprint, I ended up getting a Raspberry Pi 4 (didn't want to mess with trying to run two instances on the same Pi). I printed the same exact models that caused blobs on the RPi2 and they came out flawless with the RPi4. So FWIW, it does seem that part of the issue can be caused by an older Pi. No post processing with the Arc Welder plugin on either set. 


    RPi2 on the left and RPi4 on the right.


    Edited by dfrez
    • Like 1
    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
    • Our picks

      • Startups, apply for the Forward AM Innovation Award!
        Are you a startup using 3D printing? Perhaps you should continue reading... 
        Together with BASF we are launching the Forward AM Innovation Award - the very first global contest for startups developing new applications with 3D printing!
        Why apply?
        The winning startup will receive €100,000 in goods and services*, along with coaching and marketing exposure from top-notch leaders in the industry.

        Who can apply?
        Your startup creates products using Additive Manufacturing, is less than 5 years old, and has less than 50 employees. We are looking for 3D printing applications with a strong focus on innovation, sustainability and scalability.
        Dental aligners, shoes, tools, automotive parts, music instruments, industrial tooling and molding, medical implants, sports equipment, toys, architecture, fashion, construction... all are welcome to join!
        Do you have an innovative, sustainable and scalable idea that leverages the unique possibilities of 3D printing? Then it is time to apply!
        More information can be found here.
        Applications close on March 28th, 2021
        * What does "in goods and services" mean?
        The winner will be able to pick any item from the overall product and service portfolio of the sponsors, e.g. printers, materials, consulting, software... Choose whatever you need to accelerate your startup.
          • Like
        • 0 replies
      • New here? Register your Ultimaker for free 3D printer onboarding course
        Often getting started is the most difficult part of any process. A good start sets you up for success and saves you time and energy that could be spent elsewhere. That is why we have a onboarding course ready for
        Ultimaker S5 Pro Bundle, Ultimaker S5, Ultimaker S3 Ultimaker 2+ Connect.   
        They're ready for you on the Ultimaker Academy platform. All you need to do to gain access is to register your product to gain free access. 
        Ready? Register your product here in just 60 seconds.
          • Like
        • 0 replies
    • Create New...