Where can I correct the print time calculation ?

edited October 2020 in Questions & Answers
short question:
The real printing  time is quicker than the calculated time from Repetier-Server.
It takes 23 minutes, calculated are 31 minutes.

And yes, can and must not be exact, but where can i try to optimize the calculation time?

I change the values from: printer settings => Calculation print time:
Increase the speed (i.e. from 500 to 540) and acceleration (i.e. from 4000 to 4400) values etc. and  also the multiplication (from 1 to 0.82); (see screenshot).
Than I upload the gcode again, but get exact the same calculated print time as before (31 minutes)
(I think uploading the gcode to RepSrv will start a new print time calculation ...)

So I'm wondering, where or when have these values any effect ?
Where is the correct place to fix the calculation time ?
Thought this part (in german: "Druckzeitberechung (print time calc.)) is the correct place ....



(In Cura I must also check, the calculated  printing time is to short there (21 minutes) ...)


  • You are already on the correct position. These values are used for calculations but assume repetier firmware behaviour e.g. for jerk handling. But they are changing constantly in firmwares so real calculation is not possible to follow exactly, but normally neglectable.

    You missed one important part though that can take 10 minutes in calculation - heat up at start. In the tools tab there is a wizard to measure heating and cooling times for bed and heater. For the computed time we assume further that you start with a cold printer at 25°C. You see that when you start a print and temperature commands are passed to printer the time makes a big drop in time.

    Changing any of these relevant parameters makes the server recalculate all precomputed times.

    Also note that some slicers send acceleration limiting commands and don't use your set max speed so changing them might not change calculated time. Changing print time multiplier on the other side should.
  • Sure,
    but should not the calculated print time in the first line (second screenshot) changed when I change the values in the print-time-calculation-part ?
    This value can be still incorrect, but why is this value exact the same also I change values in the calculation-part ?

    For me it's fine when the calculated time (wherever) is multiplicand with 0.82 (what I try), than most calculations are fine (plus/minus 10 %)
  • Just tested it. Changed multiplier form 1 to 0.5 saved and did go back directly. I directly saw at bottom x open background caclucaltions. And afterwards the printing time computed was 50% of old one.

    Please try the same and see if you see it recomputing. If not go to troubleshooting and see if server hangs with a computation. You can kill that then there.
  • Thx, aater restart the times are calcalated new!
    Also for all the old print jobs ... takes time ...
  • Great. Then just one slow calculation was hung and blocking somehow.
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