Large change in Input Shaping Parameters
After building my Core One and getting everything tuned I ran Input Shaping. I was a bit surprised with the results as it came out at 40Hz/40Hz (MVZ), wat below the default values in the system. I asked support and got told that this was okay as my printer is a kit and there will be some variance.
Last night I moved the Core One onto a concrete paver with a yoga mat under (I would have done it earlier, but I need to get the paver painted black to pass the spouse test). On the previous print I noticed some horrible sounding harmonics (similar to other users on the forum) so decided to run the input shaping again. This time it came out with X= 54Hz(ZVD)/, Y=62Hz(MVZ).
I'm not sure if this is something I should be concerned with? I'm less concerned with the actual values than the fact that they have changed quite significantly. I've not changed anything major on the printer, minor adjustments to the belt tuning (a +/-5Hz) being about the most extreme adjustment to the printer.
The only other thing is the paver and table. The table I performed the initial calibration on acted like a sounding board and had some wild harmonics during the input shaping. New setup was much quieter. Another option I considered is that I might have installed the input shaper backwards on the first run, but I'm not sure if orientation affects the results.
Is it normal to get such large variations in input shaping? Could the orientation of the accelerometer or the table have affected the results?
I'll be curious to see the results on noise levels as the harmonics are quite grating.
RE: Large change in Input Shaping Parameters
If the support you used initially was somewhat soft, vibrations of the whole printer on (or with) its base may well have dominated the resonance spectrum. If you are concerned whether the measurement itself is reproducible, you could go back to the no-paver setup for another test.
RE: Large change in Input Shaping Parameters
Sounds like it might have been the table then. It was surprising and unexpected. I wasn't completely sure if it was possible but if the printer and the table aren't decoupled then it makes sense that they would resonate.
I'll do some test prints and see how it behaves, partially to get more data and mostly because I don't want to move the printer again. I'll defo give it a try at some point though.
If the support you used initially was somewhat soft, vibrations of the whole printer on (or with) its base may well have dominated the resonance spectrum. If you are concerned whether the measurement itself is reproducible, you could go back to the no-paver setup for another test.
RE: Large change in Input Shaping Parameters
Just an anecdote from my side:
I recently tried the input shaping calibration.
First result i got was X ZVD 58Hz and Y MZV 40Hz.
Then just for fun I ran it again and got X ZVD 56 Hz and Y ZVD 54 Hz.
Don't know why back to back tests can be so different and am questioning the accuracy of the Accelerometer. So not sure how useful the calibration actually is...
RE: Large change in Input Shaping Parameters
I did input shaping after 14 days of print time. After everything had a time to settle down and wear a bit. Printer is sitting on concrete paver with foam mat underneath. Input shaping values are 46Hz MZV for both axes.
RE: Large change in Input Shaping Parameters
One thing I thought might affect the results is I might have put the input shaper on the wrong way round. Looking at the guide this time I thought it was odd that the cable goes to the front when it comes in the back of the unit. Habit would want the cable to to also face the back.
I would der if having the accelerometer the wrong way round would affect the results?
RE:
The tab for calibrating Y on the bed slingers might be interfering with the fan if you have it the wrong way around, actual direction shouldn't make much difference other than that I think.
RE: Large change in Input Shaping Parameters
The original setting for my kit was X:60Hz, Y:50Hz.
I receive my accelerometer 3 days ago and try it today.
I run the calibration 3 times, to see if the results look the same.
First time : 56Hz/57Hz, Second time : 56Hz/56Hz, Third time 55Hz/56Hz
I finally set it to 56Hz/56Hz.
RE: Large change in Input Shaping Parameters
You might have local peaks that are close in strenght to the global maximum peak. Tried to visualize this using chatgpt if it makes sense. Surprised that they only store one set of values, but reading more on the subject it seems you cancel a lot of the resonance by removing that one peak.
