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francesco.s
(@francesco-s)
Eminent Member
Slow printing with default settings

Hi forum!

Sorry in advance for the n00b question. 🙂 I tried googling and searching the forum but with not much luck.

I've been printing a bit (not as much as I would like) with my Mk3, with an Octoprint setup, and I noticed that all the models are waaaaay slow at printing. I've been slicing with the prusa Slic3r and default settings, and usually the actual print takes double the time as the prediction (and all the gcode analyzers I tried agree on the predictions). This is in contrast with my previous experience with an older 3D printer (a solidoodle), where the predictions were quite accurate.

Anybody has the same experience? Any idea why and how to fix it? Would printing from SD card help?

Otherwise, do you have any idea on how to optimize the settings? I am thinking that the Z-Lift is slowing things down quite a lot, do you think it's necessary?

I'm using the latest firmware and normal (not stealth) printing mode.

Posted : 14/02/2018 9:14 pm
hiElvis
(@hielvis)
Eminent Member
Re: Slow printing with default settings

if your prints contain small perimeters or e.g. many circular elements which cause lots of gcode commands per print area the serial connection from octoprint to the einsy might be a bottleneck, furthermore if you are using weaker hardware for the octoprint server (e.g. rpi zero with camera/other background tasks) that might also cause some slow down.

To verify this, just print the same gcode from SD for comparison, if its faster, either one of the two above is/are the culprit.

Posted : 14/02/2018 10:17 pm
Peter L
(@peter-l)
Honorable Member
Re: Slow printing with default settings


I've been printing a bit (not as much as I would like) with my Mk3, with an Octoprint setup, and I noticed that all the models are waaaaay slow at printing. I've been slicing with the prusa Slic3r and default settings, and usually the actual print takes double the time as the prediction (and all the gcode analyzers I tried agree on the predictions). This is in contrast with my previous experience with an older 3D printer (a solidoodle), where the predictions were quite accurate.

Is the problem that the model is printing slow relative to the slicer's prediction?

Or that the model is printing slower than you would expect from the speed of your other printer?

If it's the former, this is a known issue with the gcode analyzer in Slic3r. I believe it's supposed to be fixed in a future release.

If it's the latter, it might be helpful to know the settings you're using and how long your other printer takes with similar print quality.

Posted : 14/02/2018 11:06 pm
francesco.s
(@francesco-s)
Eminent Member
Topic starter answered:
Re: Slow printing with default settings



Is the problem that the model is printing slow relative to the slicer's prediction?

Or that the model is printing slower than you would expect from the speed of your other printer?

If it's the former, this is a known issue with the gcode analyzer in Slic3r. I believe it's supposed to be fixed in a future release.

If it's the latter, it might be helpful to know the settings you're using and how long your other printer takes with similar print quality.

Well kind of both, meaning that by experience, I would guess the print time of some parts as 1.5 hours, not three (as an example). However, I cannot do a direct comparison between the two printers because I don't have the old one anymore. So I am relying on print predictions, and I tried different gcode analyzers: the print always takes double the time (more or less) than predicted.

Between the old and the new settings, the only difference (in my eyes) that could explain this discrepancy is the lift Z setting, which I did not enable on the old printer (otherwise, speeds are higher now). This would make sense since so far I've been printing plates with many small objects, so it's a lot of up and down of the X carriage. Do you guys use lift Z always?

Posted : 15/02/2018 7:23 am
Peter L
(@peter-l)
Honorable Member
Re: Slow printing with default settings


Well kind of both, meaning that by experience, I would guess the print time of some parts as 1.5 hours, not three (as an example). However, I cannot do a direct comparison between the two printers because I don't have the old one anymore. So I am relying on print predictions, and I tried different gcode analyzers: the print always takes double the time (more or less) than predicted.

When I compare my new MK3 to my older printers, one thing that jumps out at me as a big difference is the acceleration in the MK3. The MK3 uses much gentler acceleration than my old printer. This is a good thing because it lets you print at better quality with higher speeds.

But IIRC the acceleration is handled in the firmware, not the gcode (someone correct me if I'm wrong). So a gcode analyzer won't see it and has trouble predicting how long each move will take.

This might be the discrepancy. I believe better print time prediction is planned for a future Slic3r release.

In the meanwhile, I've found that slicing with Prusacontrol gives very good time estimates, though it lacks a lot of the settings available in Slic3r.

Posted : 15/02/2018 2:32 pm
francesco.s
(@francesco-s)
Eminent Member
Topic starter answered:
Re: Slow printing with default settings



When I compare my new MK3 to my older printers, one thing that jumps out at me as a big difference is the acceleration in the MK3. The MK3 uses much gentler acceleration than my old printer. This is a good thing because it lets you print at better quality with higher speeds.

But IIRC the acceleration is handled in the firmware, not the gcode (someone correct me if I'm wrong). So a gcode analyzer won't see it and has trouble predicting how long each move will take.

This might be the discrepancy. I believe better print time prediction is planned for a future Slic3r release.

In the meanwhile, I've found that slicing with Prusacontrol gives very good time estimates, though it lacks a lot of the settings available in Slic3r.

Thank you very much Peter, it turns out you were right. I tried estimating the time with the new beta version of Slic3r, which takes acceleration into account, and it is indeed much more accurate. In addition, for a part that I printed yesterday (composed of many small subparts), lift Z added a very significant amount of time, raising it from 2:30 to 3:00 hours.

Now I can go and optimize my settings!

Posted : 15/02/2018 9:16 pm
ben.t7
(@ben-t7)
Trusted Member
Re: Slow printing with default settings

I just got my printer last night and I agree it felt a little slow overall on the newer firmware though I don't have anything to compare it to the original firmwares but even the stock files that prusa slices where slower then what they claimed they would be. For example I made that whistle and it said it would take 25 minutes and total print time was closer to a hour maybe a little over. Theres a few other little elements that I am unsure about but I am sure ill figure it out over time hopefully just have to get use to prusacontrol and slicer.

Posted : 16/02/2018 3:30 pm
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