Shake 'n' Tune: belts, input shaping and vibrations

Brief introduction to Shake 'n' Tune (original author of SnT is Frix)

This guide is based on this tool: https://github.com/Frix-x/klippain-shaketune

The RESULTS will be stored under MACHINE in mainsail in KShakeTune_Results

Order of events

(Do all of this cold; apart from your final measurement of your axes (input shaping) which should be done hot with fans going at normal rates to test correct resonances).

1. Do your belts

2. Do your input shaping

2a) Remove unwanted resonances seen in input shaping graphs

2b) Rinse and repeat input shaping until resonances disappear that you do not want

3. Run vibrations graph generator

BELTS

Mounting the belts...

Lay both of your belts on the floor (a flat surface not a carpet) and ensure that both are EXACTLY the same length.

Then, using a sharpie, (red works well), mark a tooth on both sides 20cm vertically on both belts (this assumes a 350 printer, consider 15cm for a 300, maybe 12cm for a 250).

Next loosen up both idlers completely.

Then mount the belts. You want to be able to see when mounting that the red lines line up vertically on the front of the printer, left and right sides.

Note, to clarify, the sharpie marks are NOT to align the frayed bits; they are to align the belts once mounted in an easy way and the sharpie marks will be somewhere on the x gantry.

Pull the belts to reasonable tension on both sides (as tight as possible without overdoing it; you'll struggle to get them overtight unless you are pulling them towards you).

Then once you've mounted both belts successfully to the carriage using whatever mounting mechanism you use and tightened up the belt mounts, tighten up the idlers.

1 First off we need to get your belts tuned to be 110Hz on each belts

Methods include (all require that you turn off motors and move the gantry to 15cm/150mm from the front idlers):

a) Use a 3D printed and constructed GT2 tension meter; this:

• https://github.com/Diyshift/3D-Printer/blob/main/GT2%20Belt%20Tension%20Meter/Manual/GT2_Tensiometer_Manual.pdf

b) Use Spectroid (available on Android phones) and tune to 110Hz on left and right belt.

c) Use Gates carbon drive (available on apple and android phones)

d) Use a guitar tuning app and tune to the tone that is 110Hz

e) Use this online tone generator and use your ears if they are good enough: https://onlinetonegenerator.com/

2 Now that you've done that, home your printer and run the macro: COMPARE BELTS RESPONSES.

DEEP DIVE HERE: https://github.com/Frix-x/klippain-shaketune/blob/main/docs/macros/compare_belts_responses.md

a) You should be able to see (if you have a good starting point and tuned to 110Hz on each belt well) that you are almost getting two peaks which need to align (in purple and orange) or potentially two double peaks which need to align.

What you are after is the purple and orange peaks to be aligned and at the same height in an ideal world but if the amplitude differences are not completely aligned it's not the end of the world. Furthermore, in an ideal world you are after 90%+ similarity on the belts;

When tuning the belts, you want to tighten by about 1/4 to 1/8th of a turn each time you adjust on either the B or A idler.

The B idler is on the left and the A idler is on the right. Think of looking at your printer as like looking at a sheep; a sheep goes BAAAAAA, hence BA left to right.

Now, ignore the peak labels on the graphs, they are labelled with Greek lettering - they are NOT your belts. Your A belt is the orange graph, the purple one is your B belt. ACTUALLY, Frix swaps the colours on an almost weekly basis so you can't trust this; read it from the graph top left.

My belts graph isn't perfect but it's all in the green belt and the A/B belts are almost aligned in the peaks as you can see in my most recent run here:

3 Now run the AXES SHAPER CALIBRATION macro. This will perform your input shaping.

DEEP DIVE HERE: https://github.com/Frix-x/klippain-shaketune/blob/main/docs/macros/axes_shaper_calibrations.md

Once you see the results for input shaping as a graph, typically if you see peaks starting around 0Hz this might be caused by binding (i.e. a low frequency signal) so check your idlers and pulleys for too much tension and you may need to redo your belts at this point if you adjust tension here.

Other peaks that are unwanted can be tested by hand; what you need to do is insert the frequency, the time of run (I choose about 60 seconds) and the axis that is resonating on the input shaping graph that is producing said peak or peaks; you may need to excite multiple frequencies.

The macro to run is called: EXCITE AXIS AT FREQ; use the DROPDOWN. Touch all the things on your printer including your toolhead and tighten up anything that moves at that resonant frequency.

Once you're done, take the recommended shaper for either performance or vibrations (I always take the best vibrations one; preferably 0.0% or 0.something%), frequency and damping ratio and add it to your printer.cfg (or at the base in the commented section if you have already saved one to replace that.

If you have greater than 5% vibrations on either IS graph (x or y) then you may want to worry about your hardware a little. The recommended shaper is a combination of vibrations and smoothing at the recommended acceleration and most of the time smoothing is more important according to Frix. You can always check and validate with a test print.

I've spoken to Frix and he says that the filter recommendation (performance) will be suitable for most scenarios in future and the vibrations shaper will be much more of a last resort choice.

You want to choose the lower of the two max recommended accels (x and y) for your outer walls on your slicer profile for printer with.

I'm not particularly proud of my x shaper result so I won't post it here but my y is pretty nice and what you're aiming for on both so here is that as a good example:

(This was run with ADXL v3 Cartographer FYI)

4 Once you've tuned everything

DEEP DIVE HERE: https://github.com/Frix-x/klippain-shaketune/blob/main/docs/macros/create_vibrations_profile.md

Run the macro CREATE VIBRATIONS PROFILE.

This will produce a set of useful graphs that you can study to improve your slicer settings. Generally speaking you might want to choose a minimum speed (usually around 10-25mm/s) to avoid vibrations in your slicer; this is the top middle graph.

Then ensure that none of your print speeds are in the white areas; always in the green areas. The bottom middle graph indicates high orange colours for where resonances are occurring in the heat map. The bottom right and top right graphs should ideally look like a set of clean peaks. This is my most recent run, it's not perfect but it's also pretty good (running with TMC autotune):

You ideally want close to 90%+ on the polar angle energy profile.