Jump to content
Ultimaker Community of 3D Printing Experts

Estimated Time Algorithm


joshuaSmith2021
 Share

Recommended Posts

Posted · Estimated Time Algorithm

I have noticed that print times are often way off of actual print times. I use ~v3.0.0 with a Printrbot Simple Pro w/heated bed, if it matters. Almost all of my prints take about 30-40% longer than the estimated print time. I understand that estimating the print time is difficult because of lots of factors involved in printing.

 

What is the algorithm that calculates this print time?

  • Link to post
    Share on other sites

    Posted · Estimated Time Algorithm

    The algorithm works incredibly well for Ultimaker printers.   It is making assumptions about the accleration and jerk settings on your particular printer.  These are pretty high on (for example) the UM2 printer - 5000mm/sec/sec is the default acceleration.  "jerk" is 20mm/sec (not true jerk - this is a weird marlin terminology).

     

    I think there *might* be a way to tell Cura what the acceleration is for your particular printer so that it calculates these print times more accurately.  I guess you have to know how long a typical retraction takes as well?  I suspect cura cheats and just has a certain amount of seconds for each retraction (versus knowing the E axis acceleration, max speed, retraction distance.

  • Link to post
    Share on other sites

    Posted · Estimated Time Algorithm

    It doesn't make assumptions; It uses the exact values the machine definition provides. In the case of Ultimaker, we set those to the correct values. The quality of contributed definitions can vary, so they quite often have (blatantly) wrong acceleration rates.

  • Link to post
    Share on other sites

    Posted · Estimated Time Algorithm

    If you want to experiment with setting these acceleration and jerk settings from Cura, you can use this plugin:

     

  • Link to post
    Share on other sites

    Posted · Estimated Time Algorithm

    I'm having this problem too with my Anet A8, I've only printed a few things so far (I've only had it 2 weeks), but print times have been up to 40% longer than the estimate, but oddly enough, material use has been as much as 25% less than the estimate...

  • Link to post
    Share on other sites

    Posted · Estimated Time Algorithm
    On 5/13/2018 at 6:17 PM, gr5 said:

    The algorithm works incredibly well for Ultimaker printers.

     

    Great. So... What is the algorithm?

  • Link to post
    Share on other sites

    Posted · Estimated Time Algorithm
    On 6/6/2018 at 11:41 PM, joshuaSmith2021 said:

    Great. So... What is the algorithm?

     

    It simply tots up how long it takes to carry out each extrusion and travel move based on the values for speed/acceleration(/jerk?) that Cura believes are right the printer. As is mentioned above, you can specify those values for the various types of move. I think Cura assumes linear acceleration (speed ramps up, constant speed, speed ramps down) for each move and so if your printer implements some fancy acceleration scheme (s-curves, or whatever) then it's not going to be right. Also, I don't think that Cura knows about extruder acceleration and so if you are using low acceleration values for your extruder that's going to make the print take longer than estimated. I find for my Kossel deltas that the estimate is very good, maybe a couple of minutes per hour optimistic but really OK.

  • 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
     Share

    • Our picks

      • New here? Get ahead with a free onboarding course
        Hi,
         
        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
        • 8 replies
    ×
    ×
    • Create New...