Anti-vibration feet and misconceptions (Vibration Tip)

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21

Many thanks for the compliment :slightly_smiling_face: I remember the concepts, but I would not have a chance to pass even the most elementary exam in the topic anymore. It’s just a reasonably rare specialization.

The same here. My printer is currently busy with a print profile with fans set at 100% Part, 70% Aux and 100% Chamber and the main noise is clearly exiting from the Chamber fan exhaust. Fortunately, it is only raising the chamber temp by 1° and when I bring it down to 70%, it is no longer the loudest fan. I did make a minor change to the air path though since I added a cut-up FFP2 mask underneath the coal filter. Not sure if that is effective in any way, but it was an easy mod without observable detrimental effects. And I feel better in case I ever get around to printing CF filaments.
If the chamber fan itself was placed further away from the exhaust, then the air/wave guide to the exit could be designed to contain a muffler tuned to the blade passing frequency/ies. But that would be something for an X2.
Of course, a muffler could also be added flush at the exhaust, but to be honest, lowering the chamber fan speed is much, much easier! And as long as heat creep is avoided, that is the definetively by far the most efficient and effective method. :+1:
Doing something about the part cooling fan would be much more challenging. In principle, having two or more air paths of different lengths could be used to cancel out the main frequencies, but that’d influence part cooling. And we want all the cooling we can get while keeping the print head light and small. I am not sure if oversizing the part fan in order to use it at lower power for the vast majority of prints would be an option for Bambu for an X2.

Many thanks for those. I do not have the feet but am intrigued.

While the squishing is clearly visible, I am surprised that this affects primarily the lower part while the upper part seems not to take part in the deformation. Without seeing the inside, I can only speculate that there’s either a solid member insides (at least solid in z) or, what I regard as much more likely, the wall thickness of the feet is actually changing. I draw that conclusion from Bambu’s picture with the feet underneath a P1P where the same behavior is seen but to a slightly lesser extent.
That would be rather clever as it would turn a single frequency spring-dampener into a bandwidth spring-dampener capable of being effective over a (slightly) changing range of frequencies depending on the load placed on it. With the uppermost part not actually squished, that would mean that they do their job in your set-up. :+1: :smiley:
I like your approach with the foam under the paver :smiley: Although the system is not tuned, I can imagine soft foam to be quite effective in this set-up :smiley: :+1:

The one thing I am a bit uncertain about however is about the best position in the system for the paver. Usually, vibration absorbers tend to be much lighter than the excited system (think earthquake stabilization pendulums in skyscrapers). From a conservation of momentum point of view, it may be even more effective to add the pavers mass to the printer directly.
It could be an interesting experiment to replace the anti-vibration feet under the printer with the original feet, and then secure 8-12 Bambu anti-vibration feet underneath the paver.
A big word of warning though:

:warning: This could be entirely and absolutely wrong! :warning:
:grimacing: My wife has a few stories about my “smart” reasoning :grimacing:
And of course, since that very nice addition of the active noise control in the motors, the biggest source of noise is now the chamber fan.

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LOL…wifes have always something to say (or complain) , most of the time, when such “actions” suits them… (I could add quite a “few stories” myself, next to yours. :smile:.
Other than that (and to the point), like @HotFix above, I also add my thanks to you for the extent and comprehensiveness of the information you’re sharing with us. I’m learning quite a few new things myself on this forum, lessons (or, if you like, teachings) for which I’m really grateful, having started my 3D printing journey just a few months back (and enjoying every bit of it). :+1:

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Interesting discussion!

Both Tom and Stefan have posted on this topic (links below). At least with Cartesian 3D printers, anti-vibration feet seemed to help reduce ringing and thus improve print quality. Perhaps the physics of CoreXY printers are different?

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I bought the anti vibration feet for the X1C and can confirm what most already know, the feet don’t like to stay in the machine (they fall out easily but once in place they seem okay).

As for shaking, the printer shakes more now than with the normal feet but the table it is on shakes far less. So, as already stated, it’s more about not shaking the surface you put it on I would say.

I think the idea of concrete pavers (or whatever) on a thick rubber mat is probably the better solution.

Now, I did move my printer directly to the floor (second story of my house) and CAN SAY that the anti vibration feet DO help in transmitting less vibration (and noise) through the floor. So there is that bonus at least. It’s only a temporary move for me but a nice bonus while it’s on the ground.

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Many thanks for these links @Tarrant1702 :smiley:

Fortunately, physics are the same this side of the event horizon :wink:

Stefan made a really nice explanation of the basic principles and supports that really nicely through his experiments. He nailed it when he wrote that the de-coupling provided by the vibration insulation reduces the stresses on the printer frame’s, thereby improving print performance. That would also apply to a Core XY, but with a somewhat higher internal stiffness.
Tom’s observations are (almost) also in line with Stefans.
My very simple modelling only considers the printer as a single rigid block, as I was focussing on the vibrations transmitted to the supporting surface. Same thing and principle, but they both also assessed the internal system response very nicely.

The reason Tom’s hanging printer did not work as intended is that he inadvertently did not build a vibration isolator. By hanging the printer from the top, rather than hanging a platform on which the printer stood, he actually built a double pendulum. That is also called a Chaos Pendulum. :flushed:
It may at first be surprising that his paver experiment did not achieve the same kind of results as Stefan’s. However, Stefan nicely worked out that thick pads are needed. Tom’s set-up with the paver and thin feet looked rather rigid, so only a small difference can be expected due to lack of moveability of the entire system against the surface.

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Hi Hotfix,

When fleshing out my last answer, I realized that there would be more to be said in order to provide some more meaningful assistance. For that to be effective I needed to invest a little bit more thought. Fortunately, @Tarrant1702 also posted some very nice links which got me thinking and @matcoland and @drakko confirmed that there was some wider interest. Of course, the recent sharp increase on vibration insulator models (some more, some less effective) on MakerWorld showed me that some further insights may also be helpful to the wider community.

Three main items came to mind:

  • Although @julie777 very nicely explained the importance of mass, the reason why seems to be easily forgotten
  • The importance of spring stiffness does not seem to be so well understood
  • At a certain point, considerations narrow down on damping rather than thinking more freely about energy conversion
    => The general discussion seems to be stuck at Vibration Isolators: It is only a very small step to true Vibration Absorbers.

My very simple design is not a be-all and end-all. It is only of a very first, self-teaching step: Hopefully the needed push to go to true Vibration Absorbers from better designers than myself.
The pads can be printed in TPU purely for supervised experimentation and I provided a more detailed insight in the description. That should be able to take you all the way from double checking your Vibration Insulators, see why to place the paver where and to being able to play around with a very simple but true Vibration Absorption. Regarding vibrations: Feeling is believing.
It also gave me a chance to make a first experience with MakerWorld myself. Not being much of a designer, I have wanted to try it out for a while. Let’s see how that goes.

I do hope that you find it useful or at least interesting. Furthermore, it may actually help us in getting better vibration insulators and of course that we do get actual vibration absorber solutions from the community.

Merry Christmas,
Eno

PS: Please do not feel obliged to actually run through the experiment just because my post is adressed to you. You got me thinking and I needed to work that out this far for my own well being.

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Wow, super impressive read here and on the link you gave. Bonus points for all of the white board drawings! I saved it and when I get some TPU I think I’ll print some to see how it goes. Will be interesting to see how well it works for you over time as well.

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Well. I don’t often use forums, but the sheer quality of the discussion here has made me rethink my stance! Thank you @EnoTheThracian for some superb technical insight and @julie777 for starting the topic in the first place.

I had been planning on putting my P1S on a paving slab - I’d modified my Ender 3 to within an inch of its life to be as quiet as possible, and I knew I wouldn’t be able to do as much with the P1S, so I fell back on my 1992 Physics qualification and started thinking about the mass.

What I’m wondering about is the foam that tends to go between it and a work surface though. What properties would be most beneficial (preferably that’s easy to get hold of, ideally from around the house)? My initial thought was some spare 12mm foam insulation board (although that might not provide enough grip to my desk) or an EVA foam floor mat from my garage, but is there something better that I might already have?

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Hi irregularshed,

I agree that there are some really helpful and fascinating threads here :smiley:

As for you question on foam, when I delved a bit deeper I found that key are first mass, second spring stiffness (as they determine the natural frequency) and then damping while of giving sufficient movement capability to ensure that the energy is not just passed through.

For an ideal isolator, mass, stiffness and damping would need to be tuned which can either be done by measurement and calculation or by trial and error. My very simple tutorial part linked above supports in particular trial-and-error.
However, it is perfectly feasible to just use what you have and experiment a little until you are satisfied.

You could for example just use the 12mm foam and stack two sheets above each other to try to find a compromise between movement, spring stiffness and damping until you are satisfied. You could also cut foam into four smaller patches and use them as individual feet with your paver. That increases contact pressure and changes spring stiffness (non-linear in this case) and damping.

You could also use this to try to turn a vibration isolator into a true vibration absorber like seen in my tutorial with an additional board of wood. I have tried that with my parts and it does indeed absorb vibrations at the cost of increasing overall height. However, foam is not a good solution for that as it needs tuning of the spring stiffnesses.

Best wishes and :crossed_fingers:
Eno

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Thank you for taking the time to explain these points. I’m on a anti-vibration mission myself though in my case it’s more for noise rather than print quality reasons.

I’m running a Bambu A1, I don’t have any issues with print quality, however I need to minimise as much noise transference as possible. I live in an apartment and my neighbour below me is VERY sensitive to noise, and a bit of a psycho.

I have my printer on a pedestal (a drawer unit that typically goes under an office desk), it’s fairly solid and doesn’t really flex at all but it does tend to transfer vibrations to the floor which I need to avoid as much as possible. I’m thinking of getting a 20mm thick steel slab instead of a paver (cleaner appearance = higher “wife approval factor”) and was planning to use some anti vibration feet with this, do you think it would work to stop the transference of sound to the floor?

Since getting my printer I’m desperate to do some longer all-night prints, but I can’t risk a complaint from my witch of a neighbour down below :joy:

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That’ll probably do it. But I’d also consider a thin/dense sheet of foam between the steel plate and whatever the plate sits on.

Heavier will be better. You want to be really sure, spec a steel plate in a thickness that results in a part you can barely lift.

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@julie777 - great article, I have a follow-up question … BTW, thanks to you my X1C is sitting on two pavers on the garage floor and works great.
Q: It’s pretty clear that “putting a paver” on the top of the machine would considerably reduce remaining vibration when the head is moving fast - problem is that the top is made of glass except at the edges, which aren’t perfectly flush. I’m guessing the top is tempered glass and very flat, as is the paver, but I’m not confident in the C_static between the two surfaces …
Do you have any thoughts on an expedient solution? LoL, I’m obligated to take full responsibility if anything goes horribly wrong because I have a BSME that I never used much until I got the printer :sweat_smile: (did EE/CS in grad school).

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My old printer was a rattling box…
But without any engineering degrees or such to rely on I reverted to using logic and common sense to address the issue.

The machine came with the standard round pads, not too hard, not too soft.
Just good enough to prevent slipping.
When I was younger I had a passion for music and good DIY speakers.
Living in a multi storey building meant those base speakers transmitted the sound not just into my living space.
The solution to the problem was the same I applied to my printer…

Mechanical movement, vibrations, are transferred through the mating surfaces.
The more surface area the easier the transmission, the better the flatness the louder the the noise will be.
Thing with physics from the viewpoint of someone blissfully unaware of the stuff is that you can do things those who know would just ignore…
I learned from other audio enthusiast of the old days that the feet of the audio equipment are as vital as the equipment itself.
Like why does this vintage vinyl play use such flimsy and long screws for the feet ?
Or why does this old tube radio need those long legs and these half moon shaped metal caps at the end ?

The answer might surprise you: PRESSURE.
Some countries prefer BAR but basically all tyres come with a number in PSI - Pressure Per Square Inch !
Goes like this:
If you try blow up one of those rubber bottles to keep you bed warm you have a high chance it backfires and pops you lungs.
But if you try to blow up a weather balloon you feel next to no resistance.
The huge surface area means it takes a lot to build up and meaningful pressure and since the weather balloon also expands freely you have a hard time building up pressure.
Like it or not: The little pressure those tablets for vitamin drinks and such provide would be enough to blow the walls out of a room if the room is fully sealed…

How does this translated now from speakers and audio equipment to our printers ?
Try this for a change:
Print a cone with a sharp point as the feet and also a matching plate for the resting surface, e.g. table, with concave top - like an hourglass.
Now do some basic math - only if you want!
How heavy if your printer you said?
What is the combined surface area of the tips of these feet you said ?
No problem for the first but the second would be a very tiny number.
Translated that to PSI and you are in for a shock LOL
It can be a few hundred PSI working on those tiny points…
Now: WHY would this matter ?

SOUNDWAVES really struggle to make it trough very thin things like those points.
A bit like a filter if you like as the wavelength is usually longer than the diameter of the mating surface.
And with this intense weight transferred through those tips these feet are more like bolted connections with a bolt so thin that it can’t exist.
Why did I highlight the sound part you wonder …
Well…

Our printers not only created vibrations but also a lot of movement through the abuse of these laws of physics…
You know… For every action there has to be an equal and opposite reaction…
If you use firearms you know all about it - recoil…
The moving head makes the entire box RE-ACT in kind.
It is only how unflexible the box is and how heavy it is that compensates for this unwanted jerking around.
Using those pointy feet will eliminate a lot of the noise transferred and also helps a lot to keep the bottom stable and in place.
But it WON’T prevent the flexing and moving of the entire machine’s framework.
On the other hand those pointy feet REDUCE the TRANSFER of these motion but quite a bit.
Meaning that only the movements with the lowest frequency and highest amplitude will e transferred.
IF you have a very HEAVY and UNFLEXIBLE base than those movements can’t really be transferred :wink:
For other things I do this by adding a heavy top, like from a discarded marble bench top of board.
You will find that, for example, on a concrete floor using pointy feet the machine housing does not really move and flex much at all.
Well, that is if you ignore that the housing itself is not THAT solid…

A neat way to cheat is to use a good sized table in a corner of the room and to use angle brackets or such to fix it to the wall.
With the table unable to move in the XY direction you only have to worry about those feet :wink:

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34

I got an email from Voxel PLA about their new anti-vibration feet.

" VOXEL x HULA is the world’s first seismic isolator-inspired anti-vibration damper for the Bambu Lab P1P / P1S / X1 / X1C printer designed by Thrutheframe. HULA’s innovative damping method decouples the printer from the desk, minimizing table shakes, improving print quality, and reducing stress on the printer. Unlike the Bambu Lab Anti-Vibration damper, HULA is self-aligning and doesn’t sway/rock when printing, ensuring superior print quality and stability."

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thank you for the insight on the argument, i’ve been struggling with the issue of vibration too

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I don’t see too much of a difference.
I would like to see the prints with a side by side comparison.

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Watch closely the video and you’ll definitely see the difference between the two… although, I wouldn’t say no to having access to their stp files.

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I would like to see the end result differences.

Shaking more/less doesn’t matter to me unless one produces cleaner prints.

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You’ll get it free of charge here: HULA Anti-Vibration Feet for Bambu Lab X1 and P1 by thrutheframe - MakerWorld

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Yeah, but at only 13 dollars for all for all 4 feet, and not having to order the rest of the parts, I’ll take convenience and order the prebuilt ones.