Print estimation is wrong (too short) (Custom Delta Printer)

[theliadir 0]

Hello

 

I use Cura 4.6 for slicing my stl's for my custom delta (kossel like) delta 3D printer.

The time estimation of cura is wrong. The estimation is too quick, or the printer needs more time to print than predicted by cura. (If it estimate 8h it can be that it prints 12h)

I tried also 4.4 and 4.7 which I had the same problem.

Although its not a crucial problem it's still unconvienent not to know when the print finish more or less.

 

The printer runs with marlin 1.1.9 and as I said for now I use cura 4.6.

I activated acceleration and jerk control in the cura profile and used the numbers which I use in marlin. 

But the time estimation is still wrong.

 

Is there anything I could try to improve the time estimation?

Any help or hints are highly appreciated.

 

[gr5 2,167]

Marlin should have two accelerations in it: "acceleration" or "xy acceleration" and the other is "max acceleration".  You need to enter both of these into the printer settings (not the cura settings).  The printer settings are tricky to find.  I recommend you install this plugin:

 

Click "marketplace" in upper right of cura, make sure you are on "plugins", scroll down and alphabetically among the "P"s is "printer settings" plugin.  After installing, restart cura.

 

[theliadir 0]

I tried this plugin. When I insert the numbers more or less correctly it changes from 4h13min to 4h19min.

When I remember correctly I had more problem with this plugin in failing prints than actually solving my problem.

[GregValiant 1,246]

I've had this one for a while.  It displays the remaining time on the LCD (do you have one on the printer?) and has a fudge factor you can adjust.  Because it's a post-processor you have to save the gcode and then check the file lines with M117 to see how the fudge factor adjusted it.  I haven't played with that part but I think if you see that Cura wants 2 hours to print and you know the print takes 4 hours then you would enter .50 as the fudge factor.  Cura is displaying 1/2 as long as it will actually take.  It will not change the Cura estimate in the slicer, but the gcode M117 commands will display the adjusted time on the LCD.

It goes into plugins\postprocessingplugin\scripts and will show up in Cura when you restart.

ShowProgress.zip

[theliadir 0]

Thank you for your suggestion. (Yes it does have a display)

I dont see how that should help or solve my problem.

I dont care about the time on the display. I just need to know when I have to set an alarm to go and retrieve my 3D print.

 

Would there a time estimation on the display like: Print estimation time: 8h34min ?

Because the printer is already showing the remaining time and shows in the end how long it took to print and I'd like to match this time better with the time estimation in cura.

 

I assume that the time on the display is correct. So when it says 5h28min on the dispaly, it took that amount of time.

So why should I want to change that number in the printer?

 

I will make a test and run a timer at the same and check if my assumption is correct.

 

 

Edited December 19, 2020 by theliadir

[GregValiant 1,246]

I would guess it depends on how your firmware is determining the time.  The print time is expressed differently in various slicers.

Cura:             ;TIME:62183 seconds

Simplify3D:  ;Build time: 3 hours 29 minutes

Craftware:   ; Time:13.9775 min

KISS:             ; Estimated Build Time:   40.67 minutes

In Cura and Craftware the time estimates are at the front of the file.  In the cases of Simplify3d and KISS, the lines are at the very end of the file so it appears unlikely that the printer is reading time estimates from the file but rather extrapolating the time from the file size, and the bytes/second it's processing.  It's in real time and so is correct especially at the end of a print when it just needs to display "here's how long I've been running".

The ShowProgress plugin adds this to every layer:

;LAYER:0
M117 1/254 | ETA 5H13M

The M117 line updates the projected ETA on the bottom line of the LCD at the beginning of every layer.  (It has no effect on the internal time that the printer is keeping.)  With a close fudge factor the ETA would be something approaching reality.  If you change the feed rate by making an adjustment on the LCD then of course the gcode would not compensate.  On my Creality printer the estimated time as expressed by that M117 line with a fudge factor of "1" is very close to how long a print takes to complete at 100% feed rate.  The response to M31 on my Marlin firmware is "echo:Print time: 5245s" which at least implies that it's simply reporting the time since a print started.

 

How about putting an M300 and an M240 at the start of the last layer.  The M240 could trigger an alarm rather than a camera.  Or at the end of a print have the table move to MAX Y and hit a switch that triggers a relay and rings a bell?  Or maybe triggers a blue-tooth device (or something) to send a message to your phone?

 

That's what I have sir.  I'm going to stop now before I start bouncing laser signals off the moon.

 

[theliadir 0]

Ok I understand you now.

So you suggest to let the printer make an estimation of the printing time instead of the slicer.

I will check it out. thx.

 

 

[GregValiant 1,246]

12 minutes ago, theliadir said:

Ok I understand you now.

Thank You.  Not many people say that to me.

 

Cura makes pretty good time estimates based on accel, jerk, and printing speed but every printer is different.  I like the "fudge factor" of that plugin because it allows a user to account for their particular printer.

Play with it.  Who knows, you might find it useful.  It has to be worth at least what you paid for it.

[theliadir 0]

well thank you for your time and effort explaining it to me. 🙂