New to Input Shaping
-
I've been working with the LC1 on my custom printhead (CoreXY) and the input shaper. I have had good results so far using zvddd. I do seem to have a rather high amplitude abrupt excursion/spike in the x axis at one small point centered around 47-59 Hz, depending on the speed (not sure the cause yet).
I am seeing an improvement in the test prints as far as reduced ringing.
I also would like to try testing with some slightly different belt tension adjustments to see if it makes any difference.
One thing I am curious about:
Would it be of more benefit the to repeat the input shaper test at various typical print speeds to get a better idea of what range of frequencies I want to try and tune out?... Or does it get all of the data it needs with the higher acceleration and max speed? I noticed on the default test that it just uses the maximum set speed and acceleration written in my config.g. The peak frequencies obviously vary in Hz based on the speed that the steppers are moving the printhead.
-
@br7408 the resonances do not depend on the print speed, however the speed and acceleration can affect how much those resonances are excited. This means that if you have more than one significant resonance, changing the speed or acceleration may affect the relative amplitudes of those resonances, but not their frequencies.
Changing the belt tension will affect the resonance frequencies, however as the frequency varies approximately with the square root of the tension, you would have to change the tension a lot to shift the frequency significantly.
-
@dc42 said in New to Input Shaping:
@br7408 the resonances do not depend on the print speed, however the speed and acceleration can affect how much those resonances are excited. This means that if you have more than one significant resonance, changing the speed or acceleration may affect the relative amplitudes of those resonances, but not their frequencies.
Changing the belt tension will affect the resonance frequencies, however as the frequency varies approximately with the square root of the tension, you would have to change the tension a lot to shift the frequency significantly.
After further testing and reading, I believe that I have determined that the issue I identified is not an input shaping issue. Its more inherant to shorter distances and speeds that are not able to be measured or cancelled by input shaping, and they are more likely unavoidable and based on physical characteristics of the printer. I am working through some more tests with longer accelerations/decellerations and radius curves to capture a transient resonance that I can truly test using input shaping. I will report back.
-
@dc42
I cannot thank you enough. Your selflessness, knowledge, and advice you've given over the last few years has helped me immensely and taught me so much. There is always a lazy answer, but you always take the time to explain. I hope Duet is paying you extremely well. I'll run into a snag or two, and I archive the forum, and its usually your advice that always leads me to a solution. Very rarely have I seen such efficient/ problem solving subject matter experts, and very few like you left anymore. Thanks. -
@br7408 thanks for the compliment!