Jump to content
UltiMaker Community of 3D Printing Experts

Flow rate compensation factor. What is it?


d-lee

Recommended Posts

Posted · Flow rate compensation factor. What is it?

There is a couple of settings in the Experimental section in Cura 3.6.0. "Flow rate compensation factor" & "Flow rate compensation max extrusion offset". What do these two things affect? 

 

I couldn't find any documentation or explanation for these two settings. The tooltips in Cura for these two are a bit cryptic. 

  • Link to post
    Share on other sites

    Posted · Flow rate compensation factor. What is it?

    Some materials are a bit strange when you extrude them. If you ask for 100 (whatever the unit is, doesn't matter), some materials only extrude 96 (or something like that).

    This is mostly an issue for machines that have flow measurement (Such as the S5). There are basicly 2 things that you can do to fix this. If you don't have a flow sensor, you "simply" pre compensate for this factor. So instead of asking for a 100 if you want 100, you ask for 105 in order to get a 100. The problem with that is that if you have a flow sensor, it will give a warning (Because you asked for 105 and got 100, which should be seen as underextrusion).


    Those two settings are meant to be used to solve this problem.

  • Link to post
    Share on other sites

    • 1 month later...
    Posted (edited) · Flow rate compensation factor. What is it?

    so these settings doesn't have effect on "flow rate" at all, these are indications for the flow sensor to compensate, how to interpret what actually happens? Because it's set to 90% by default and I really like to have control over settings, but here, I'm puzzled. Your description is good, but "you "simply" pre compensate for this factor" is not clear.

    Edited by stema84
    • Like 1
    Link to post
    Share on other sites

    • 3 years later...
    Posted (edited) · Flow rate compensation factor. What is it?

    Cura slicer explanation of settings "Experimental" --> "Flow Rate Compensation Factor" vs "Material" --> "Flow":

     

    Quote

    so these settings doesn't have effect on "flow rate" at all, these are indications for the flow sensor to compensate, how to interpret what actually happens?

     

    The following is according to my understanding.

     

    No, I believe this "Flow rate compensation factor" does have an affect on flow rate, it just does it withOUT further triggering flow rate sensor errors. 

     

    Let's walk through an example:

     

    Imagine your "Flow" setting under the "Material" settings section is set to 100% and your "Flow Rate Compensation Factor" under the "Experimental" settings is also set to 100%. BOTH control the actual flow rate by changing the commanded flow rate to the extruder, but the "Flow" setting also sets the "expected" flow rate used by the flow rate sensor, while the "Flow Rate Compensation Factor" does *not* also set the "expected" flow rate used by the flow rate sensor

     

    Imagine you have a flow rate sensor on your printer and it keeps throwing warnings that your actual flow rate is 95% when the commanded flow rate is 100%. To compensate, you need to increase your flow rate by a factor of 100%/95% = 1.053. So, multiple that by your current commanded rate of 100% and you get 1.053 x 100% = 105.3%. Now, if you increase your commanded flow rate to your extruder from 100% to 105.3% you'll end up with an actual extrusion rate of 105.3%*95%/100% = 100%. It is reduced by the 95%/100% = 0.95 factor as a result of the material's resistance to extrusion. Each material you use can have a different resistance-to-extrusion constant, which is an indicator of the material's slipperiness, excessive thickness, excessive thinness, or viscosity/higher melting temp.

     

    For materials with a higher resistance-to-extrusion constant, for which you must compensate, there are 2 ways to increase the commanded flow rate to 105.3% so that you end up with an actual flow rate of 100%. One of these options to increase the actual flow rate will continue throwing the under-extrusion warning, and one will not:

     

    1. Option 1: Change the "Flow" setting under the "Material" section from 100% to 105.3%. Now, your actual flow rate will become 105.3%*95%/100% = 100%. BUT, changing this setting also sets your flow sensor's expected flow rate to 105.3%. Since you are getting only 100% instead of the commanded 105.3%, the flow rate sensor continues to throw under-extrusion warnings even though the extrusion is now exactly perfect!
    2. Option 2: Change the "Flow Rate Compensation Factor" under the "Experimental" section from 100% to 105.3%. Now, your actual flow rate will become 105.3%*95%/100% = 100%. AND, changing this setting does NOT also set your flow sensor's expected flow rate. Rather, the "Flow" setting under the "Material" section does! Since it is still set to 100%, and you are now getting an actual 100% instead of 95%, the flow rate sensor shows your extrusion is now perfect!

    If you don't have a flow rate sensor, it doesn't matter which setting you adjust above. You can adjust actual flow rate using the "Flow" setting OR the "Flow Rate Compensation Factor" setting. If you DO have a flow rate sensor, however, you need to set the "Flow Rate Compensation Factor" under the "Experimental" section to both adjust actual flow rate AND to stop the flow rate sensor error at once.

     

    Make sense?

     

    Can an Ultimaker employee/Cura software developer confirm the above?

    Edited by GabrielStaples
  • 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

      • UltiMaker Cura 5.3 stable released
        In this stable release, Cura 5.3 achieves yet another huge leap forward in 3D printing thanks to material interlocking! As well as introducing an expanded recommended print settings menu and lots of print quality improvements. Not to mention, a whole bunch of new printer profiles for non-UltiMaker printers!
          • Thanks
          • Like
        • 24 replies
      • Here it is. The new UltiMaker S7
        The UltiMaker S7 is built on the success of the UltiMaker S5 and its design decisions were heavily based on feedback from customers.
         
         
        So what’s new?
        The obvious change is the S7’s height. It now includes an integrated Air Manager. This filters the exhaust air of every print and also improves build temperature stability. To further enclose the build chamber the S7 only has one magnetically latched door.
         
        The build stack has also been completely redesigned. A PEI-coated flexible steel build plate makes a big difference to productivity. Not only do you not need tools to pop a printed part off. But we also don’t recommend using or adhesion structures for UltiMaker materials (except PC, because...it’s PC). Along with that, 4 pins and 25 magnets make it easy to replace the flex plate perfectly – even with one hand.
         
        The re-engineered print head has an inductive sensor which reduces noise when probing the build plate. This effectively makes it much harder to not achieve a perfect first layer, improving overall print success. We also reversed the front fan direction (fewer plastic hairs, less maintenance), made the print core door magnets stronger, and add a sensor that helps avoid flooding.
         

         
        The UltiMaker S7 also includes quality of life improvements:
        Reliable bed tilt compensation (no more thumbscrews) 2.4 and 5 GHz Wi-Fi A 1080p camera (mounted higher for a better view) Compatibility with 280+ Marketplace materials Compatibility with S5 project files (no reslicing needed) And a whole lot more  
        Curious to see the S7 in action?
        We’re hosting a free tech demo on February 7.
        It will be live and you can ask any questions to our CTO, Miguel Calvo.
        Register here for the Webinar
          • Like
        • 18 replies
      • UltiMaker Cura Alpha 🎄 Tree Support Spotlight 🎄
        Are you a fan of tree support, but dislike the removal process and the amount of filament it uses? Then we would like to invite you to try this special release of UltiMaker Cura. Brought to you by our special community contributor @thomasrahm
         
        We generated a special version of Cura 5.2 called 5.3.0 Alpha + Xmas. The only changes we introduced compared to UltiMaker Cura 5.2.1 are those which are needed for the new supports. So keep in mind, this is not a sneak peek for Cura 5.3 (there are some really cool new features coming up) but a spotlight release highlighting this new version of tree supports.  
          • Like
        • 22 replies
    ×
    ×
    • Create New...