slicer printing time vs real printing time
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@T3P3Tony said in slicer printing time vs real printing time:
do you have a min layer time set in the "cooling" settings (that may be different)?
Yes, but even so, the slicer would include that in its estimate, it knows what it did. But I'm going to disable it for this test because its irrelevant.
@Phaedrux said in slicer printing time vs real printing time:
Not sure if you've tested this yet, but can you try using firmware retraction instead to see if it changes the outcome?
I can tell you from prior experience it wont but I will go one better, lets eliminate all retracts from the test print. We can do that with spiral vase mode. No retracts the whole way up, no travel moves other pauses, just plain circles. This is simple enough that we can make an estimate of print time based on the radius (50mm), height (100mm) and print speed of 35mm/s:
2π * 50 = 314.2 circumference
100mm / 0.2 = 500 layers
500 * 314.2 = 160600 mm traveled
160600 / 35mm/s = 1h 16m approximatelyThe slicers estimate is 1 hour 24 minutes which is pretty close to our estimate. You can also see see the slicer is emitting moves for a 35mm/s speed (this is the configured outer perimeter speed):
Then simulate it on the Duet:
We can then estimate the Duets actual achieved speed as 160600 / 1h 46m 58s = 25.02mm/s
That's a loss of 10mm/s from the desired speed.And just out of curiosity, what happens if the outer wall speed were a lot faster? Say 100mm/s? Is the effect linear or constant?
This is where my Jaw hit the floor. Its not a constant effect, going faster makes it worse:
So that's 160600 / 1h 22m 11s = 32.5mm/s
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Oh and here is a cube for comparison, same vase mode, 100mm/s perimeters etc:
The printer is happy to do 100mm/s and take square corners that fast. Its not a printer settings issue. My computed speed estimate for that is 88.6mm/s.
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I tried printing the 100mm/s test and the printer prints at the requested speed.
Also note that the time for individual layers in perfectly consistent as expected. Its the simulation that is wrong in this case.
My guess is my real speed issue is related to Z or E as I originally suspected but I'm unable to see that from the simulation.
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garethky - do you have solved this issue?
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No, I gave up the investigation. Something about the simulation isn't accurate. Something about the real print time isn't right either.
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We've been investigating and I think we've identified something but I'm not sure of the specifics.