@@theomoons As they say... If you want help, don't ask a question, simply suggest doing it a certain way, and someone will surely explain a better one. ;)
I still feel like the sand in the frame might marginally helps, but adding the "sand containers" to all of the moving parts really just serves to add weight and increase the problems.
Although sand in the frame really is a poor-mans version of just using better aluminum extrusion profiles - i.e. the heavy-duty type instead of light-weight.
In the machine tool world, "epoxy granite" is used to fill machine frames to increase rigidity and dampening ability. It's basically just epoxy resin and sand. What the epoxy adds is it connects the mass of the sand to the structure, making it one. The aluminum extrusion with sand in it will ring nearly as much as without the sand as the sand is able to just move and allow the aluminum to move (ring).
True, however cast iron also has significantly different characteristics to aluminum extrusions. Plus, the lighter the machine then the slower / shallower you need to go. Even a mini lathe weights 40+kg.
@@arthurmoore9488 So you add mass to non moving parts only. If you're fairly certain you're not going to fiddle about with your design, you could even fill in the outer moldings.
There's an amazing technique called "Motion Amplification" which uses special cameras and DSP to visually exaggerate imperceptible movements in video. It's used largely for identifying sources of resonance in structures and industrial machinery. I'd be fascinated to see it used on a 3D printer. I predict the main source of resonance is the belts.
Wow that sounds so cool. i remember a similar tech where a camera was used to observe a human face and detect imperceptible changes in color of the skin due to blood being pumped and amplify it to detect the heart beat.
@@BerraLilltroll I saw that video (or a similar one) recently and was impressed with his technique and results. As I recall he was balancing a rotating mass with weights, but the technique could be used to identify resonate frequencies and test various damping solutions without wasting filament or waiting for test prints to finish.
FYI: I put a FDM printer on a $20K active dampening vibration table we use for laser alignment and it made no difference. I think the issue is amplitude and frequency is not consistent. What about hanging the printer from a pivot point, with a mass dampener at the other end of the pivot point? A sort of Foucalt's pendulum with a mass dampener.
I think this is the comment closest to identifying the fundamental challenge. There must be multiple resonances in the printer structure and there are certainly a multitude of stimuli when you consider acceleration and vector forces. For a Cartesian system, it is probably a problem constrained to two planes; XY and ZX. I think it’s a lot harder than it looks. The analysis would be fairly involved, I think.
Aren't vibration damping tables mostly about preventing vibration from the environment from reaching equipment? Or is it designed for vibrating equipment as well? Ultimately, I think the problem is that most of the vibration is coming from the carriage itself, which is only loosely coupled to the rest of the system, and by definition needs degrees of freedom.
The sand on a rapid-moving part was totally a mistake on my opinion. Getting down the rabit hole you could try with some mineral oil, like the ones that are inside car/bike suspensions...?
Not documenting "failures" is a huge problem in the medical industry b/c peeps don't want to embarrass themselves. Props to you for posting this. It helps inspire new hypotheses to come and still makes good content 👌
Hmm, makes sense that you shouldn't put weight on the moving parts. So I'd try the same sand setup but excluding the print bed since it's moving quickly and weighting it gives more inertia so a higher probability of skips.
I’ve put my printer on a square of *memory foam* . Using tick square of plywood on top so the printer doesn’t just sink into the memory foam. It works great & definitely makes the printer quieter.
Tom, this is such a great video! No meaningful results are still results, just as you said. Only you would build a Suspensorium Love it! I'm chasing resonance reduction as well and would be interested in how different belts affect things. You are both thorough and entertaining and it is always a pleasure watching your videos.
I wouldn't describe the results as non-meaningful. They were not 'positive' in the sense that there was no improvement in the printing artifacts due to 'ringing.' But it provided some evidence that some of the 'simple' fixes do not appear to work as miracle cures, and in some cases actually made things worse.
tuned mass damper are also commonly used in skyscrapers to absorb vibrations from swaying in the wind. there's one in Taiwan where the architects famously decided to make it a tourist attraction - instead of tucking a concrete block away in some utility room they made the main damper a large shiny decorated sphere hanging in the middle of a big atrium.
I would recommend removing the sand from the print bed. Then, run the tests again: With Feet, without feet, and then suspended. This series is great, and your willingness to be honest is appreciated.
@@brianfhunter actually the suspended test could be coupled with and earthquake reader and it can plot the sine wave of the vibrations. Then with the total mass of the 3D printer known, plus it's rought moment of inertia, you can calculate how much damping it needs
Another great video Tom. This is just a collection of thoughts. Sand alone isn't great at dampening. It's coarse and rough and irritating and it gets everywhere. Solution Epoxy "Granit" (a with Epoxy damped mixture of sand that is filled and compresses in forms or extrusions to minimize resonances and vibrations on Professional Machines like Kern cnc mills) Weight alone helps a bit but Weight and a Dampener works great. I would love to see the printer mounted to the paver and than placed on a 2 to 5 inch think piece of upholstery foam. Oh and i think stifer belts will make a noticabal difrence (steel cored belts, heard that there are some out there in the wild) Keep up the great work and i cant wait to see the next episode in this series and the escalation that it could bring with it.
Stop hidiing Anakiin, we all know it's you. Although you bring a fair pont about the resin but it defeats the purpose of dampening. What makes sand such a great dampener is the fact that it's loose particles that have thousands of points of friction for the energy to dissipate into heat, having it all merge with the resin just make's one solid mass that, albeit having greater inertia and therefore harder to get moving, has a single natural frequencey that it can resonate with.
@@coolbionicle I disagree unfortunately. Having a Mass that not solid makes it very hard to predict the result and I cant find a mechanical loss coefficient for loose sand. Besides that, the “granit” part of the epoxy graint its mostly a filler too minimize the amount of epoxy needed (epoxy = expensive). The epoxy provides the dampening, the Aluminum frame the needed stiffens for the machine and the Sand is just a filler. If you don't trust me go over to Adam bender her on you tube and watch his How to Build Epoxy Granite Machine Base video. He goes in more detail with Loss Coefficient vs. Young's Modulus and how to find the right ratios of sand to epoxy.
Love your honesty one of the reasons why we come to you you always keep it honest so we all don't go out to the store and buy lumber and try to make what you made lol I can only imagine how many people be trying to pull out their hair cuz they couldn't get what you have thanks again for keeping it honest and real
Lol, you seemed so tired & disappointed by the end of the video, but you make a good point that even the failures are useful information! This has taught me that if I want to deal with vibration, I'm better off putting my time into brushing up on my old engineering courses rather than on messy, half-baked quick-fixes. Thanks for that!
Or you could try Input Shaper, I sure hope that's where this is going, try a bunch of physical solutions, show they don't really work, then show the absolute magic of Input Shaper tuned with an ADXL.
Less initial vibrations for Input Shaper to negate would lead to sharper prints as it'll apply less smoothing. So removing as much resonance before using Input Shaper is the way to go. It's a shame this test wasn't shown without the sand containers on the bed axis, as that's somewhere you should be trying to remove weight on this style of printer.
Yes definitely do a video on the belts please ...... Since I starting playing around with 3d printing and my velleman k8200 many years ago you have taught me so much, and are normally the go to videos when I have a problem or just want to improve something. Keep them coming and hope to see you around for many more years to come THANK YOU Tom
So I am not the only one that got hurt playing with the k8200. Still got mine. But I don't use it since I got my Ender3 original. I since replaced to pcb on the Ender. I could maybe use the old pcb into the K8200 and try to have it run better.
@@pierremartel3552 My 8200 was a good printer even thou I have done a lot of upgrades, it was working fine up to a few months ago when I parted it out to build a bigger n better printer from scratch. It was the 8400 that I scraped after a few prints when the MB froze up putting the hot end into a thermal run away ..... after a hard reset it was still showing the hot end at almost 400c
Interesting ideas! It might work better to put the 3d printer on legs that stick into a bucket of sand, so that there is lots of sand to absorb vibrations in the base. I am curious to see the result of a test like that!
I was going to comment with the exact same thing - this feels intuitively like a good move. If you had a large, square container filled with sand and just sat the printer in it, I think you might see a difference. (Probably too slight for it to be worth it, but at least it would be cheap to try.)
Need stiffness + weight everywhere in the frame to shift the frequencies higher. That being said most ringing is due to how stepper motors work. Throw an oscilloscope on the stepper motor, then run Input shaper and compare.
I just bought some motor bike gel pads, cut them to roughly 5x5x2cm and put them under the printer. They have the advantage of being able to move in all directions and completely removed all ringing. The printers still stand on massive, 5cm thick sandstone slabs and those are on rubber mats, which results in an de-coupled, non resonating table and a still free moving printer While moving fast, you can see the gel visibly shaking and shifting the printer as it absorbs the energy, but the printer never moves on the gel itself. this might be worth a try if you have ringing and/or noise issues printer: prusa i3 mk3s
Have had a similar plans. Was thinking of using a section of 1-2cm thick exercise mat under a large concrete paver with gel on top. Do the feet of the printer dig into the 2cm gel pads? Thomas should test this.
@@Trevellian I removed the feat for this exact reason, didn't even try it out. One thing I found out is that the size of the gelpad has a direct influence on the movement of the printer, the smaller the pad the more it moved. I sliced them down from 5x10cm to 5x5cm and the change was noticeable when pushing the printer to one direction it is important that you enforce the table you put the stone on since it weighs a ton and it will bend your (possibly cheap) table. I enforced mine by placing a solid 3cm thick wooden board on top (no screws required)
I think the best solution would be to have a counter weight on the same belt as the X or Y. The top of the belt moves the opposite direction as the bottom of the belt.. Let's say you have a weight on the X that weighs the same as the head.. They would move opposite directions, and hence when they stop, should vibrate the machine. Just a thought.
Very cool video. Not vibration or resonance related, but one thing i have been curious about for a long time is how flipping the printer upside down would affect overhangs and bridges. Since any sagging will be pushed back up by the next pass of the nozzle, I would expect it to improve the results. And now you have the perfect "printer enclosure" to test it 😄 Also seeing the effect of different belts would be very interesting.
@@robertbyrnes7075 I don't think so. The molten plastic is probably viscous and sticky enough to stay in place wherever it is fully supported by the previous layer. And in areas along slanted edges where it is not fully supported it will sag towards the nozzle. Which means that on the pass for the next layer the nozzle will lift the sagging but now much cooler plastic up again. As opposed to pushing it further down when printing with the nozzle pointing downwards. I find it hard to predict the end result of this interaction, but I think it might make it possible to print steeper overhangs with better quality.
Back in the late 1980s, some of the scientific equipment vendors, such Edmund Scientific, sold rubber ball kits for physics demonstrations. One ball would be a standard rubber ball and would bounce as such. The other ball would sometimes be called a dead ball as it wouldn't bounce. The idea was to show how energy could transferred in one direction (bounce) or dispersed in multiple simultaneous directions (dead). At that time, the dead balls were of particular interest in the amateur holography scene as lasers weren't very powerful and the holographic process was extremely sensitive to vibrations. I don't know if the dead balls or material are still available but if still available, that could be an interesting test.
Thank you for going through everything that didn't work. I've been really curious about sand on smaller machines. I'd love to see a video on the different belts. If you could please have one cheaper belt case using an old piece belt that would be great. I honestly wonder about my belts every time I see ringing.
I think you may get some interesting results if you modified the springs on the tesseract. What it is now is a vibration isolator not a damper. All of the vibrations made by the printer stay within the system. If you think about vibration dampers on cars there are two parts, the spring and the actual damper or shock absorber. The tesseract set up is only spring and does not have the best damping qualities.
I have a lot of respect for what you said here at 11:10. Knowing what doesn't work is super important; thank you for sharing with us! Also good luck with the sand lol
TH-cam in parts seems to be more honest than most the research journals - also presenting what did not work, or what did not make the greatest WOW !!! effect. thanks so much
You could try small dampers from RC trucks. They are sprung and oil filled. This will actually adjust the frequencies instead of just adjusting the amplitudes. You need to absorb some energy, elastic straps provide almost no damping effect. I dont understand the fascination with optimizing single variables. It would be far more effective to increase the stiffness of the frame by putting braces on it or adding gussets at the connection. Damping a wet noodle is pointless. Brace it until it is rigid the dampen it. Otherwise you are finding ways to dampen a frequency that is irrelevant and ineffective. At least the oil filled damper would effect a far wider spectrum of frequencies and it is tunable using different weight oils.
Small dampers for belt tensioners, shouldnt help with skips but maybe will with resonanses. For skips you decrease moving mass or increase motor power.
@@Gebsfrom404 Wasnt thinking for belts. The exercise in the video is about dampening the vibration of the frame. I was thinking if they wanted to put the frames on an elastic base then could mount the dampers to the table. This way the elastics or flexible bases allow movement but the oil filled dampers absorb vibration. As for belt tensioners I ended up using a small coil spring from a brake drum hardware kit (had a lot of them)... it is used as a retention spring to hold the brake shoes to the backing plate... around 19mm diameter and 25mm tall compression spring... pretty stiff. Then I preloaded it with a threaded rod running through it to a yoke holding the belt pulley. Any compression spring would work as long as it is stiff enough to maintain control of the belt.
Sand filled feet are a good, cheap and decently working solution. There are many different sand filled balls you can use with a printed holder to keep them in place below the printer
I love your Sciency thinking. Please keep valuing it as this sets you greatly apart from typical TH-cam content we all got used to! - You briefly mentioned the additional mass on the printbed might harm the print quality. I totally agree. I would have tried again withouout those printbed Santainers, maybe even adding them elsewhere… - I highly value the additional mass on the printer. The bigger the mass difference between bed and printer body, the more recoil you can convert into printbed acceleration. - A tip from back in the days (experience with laser interferometry in physics lab): For effective (nearly critical) dampening of alu extrusion profiles instead of pure frequency shifting fill the profiles with silicone (not silicon - Fugensilikon, nicht Silizium ;-) This also greatly assists survivability of your mechanical components when compared to sand… I would love to know the frequency range of problematic ringing. This would hugely narrow down the root of the evil (profile bending, profile ringing, belt stiffness etc.) okok, I’m getting to scientific. Looking forward to the engineering way of life: try it out! :-D
This was fantastic. And thank you so much for testing things out. I was very curious as to the outcome, especially the sand damped tests. It also makes sense that BMW used such a complicated series of dampers. But in the industrial and aerospace worlds, there is a simpler solution - avoid the areas of operation that induce harmful resonances! In a light aircraft, this could be as simple as a plaque that says "Do not run propeller at RPM between 2500 and 2550 for more than 5 minutes". Or for a larger aircraft, a redesign of the vibration causing components, to shift their resonances rather than compensate in other areas. Where the moving masses are controlled by stepper motors, that's the obvious place to control vibrations. Match the speeds and accelerations to avoid areas of resonance. That's not cheating or a hack! That's proper design. Love your channel and the work that you do...not intended as a slight at all. That I learned that a printer will work upside down is worth more than the price of admission. To me that means it's just a matter of time before there's a 3d printer in space.
Keep this series going please. Super enternaining and gets everybody's gears going. What about non-symetric dampening setup? It could help with reducing resonation of the dampening system itself. For instance - your tesseract cube with some cables tensioned way more? Or usual dampening rubber feet but with one odd, softer/stiffer foot?
Any experiment that contributes to knowledge is always welcome. Whether the output is positive or negative, it is still knowkedge that can used in future endevours. Please continue with the belt swaps to see if there is any improvement to be gained on the prints at high speeds/accelerations. Thank you Tom.
Considering the small amount of sand you used, you could've just bought play sand, ran it though a sieve and blender. That would give you sand as fine as flour.
Thomas, I have a couple suggestions for the next video in the series... First of all, thanks for showing us what doesn't work. The early rocket scientists had a saying, "Fail big, fail fast" so they wouldn't waste time and efforts that wouldn't be ultimately productive. Please try making these quick checks on the system - they may point you (and us) in a better direction. Try tightening and loosening the belts when repeating test models. This might give us an indication of wether we need to absorb vibration being transmitted to the print or if the belts are a source of the oscillations. Then, you could compare different types of belts and look for different results. This might be done scientifically off the printer... If the print head velocity is known, measuring the ringing in the print could determine it's frequency. You could then suspend varying weights from belts and vibrate them at that frequency to see what belts might oscillate or dampen that movement. I suspect that CNC machines benefit from sand dampening because the multi-flute tools are turning and hundreds of rpms, creating chatter at several khz. Printers are operating at much slower resonances, so I expect that most problems are within the motion system itself. However, I will look forward to your next videos and learning what you discover. Keep up the great work!
Just a piece of advice for measuring squares, you can do the triangle method. 3:4:5, is the ratio your sides should be at and the distance between them. Its a commonly used carpentry trick for getting perfect 90 degree angles.
Big companies make for there products Physik simulations so they don’t have any vibration. If you find such software and explain it too us i would look it
Very interested in the belt comparison video. I found early on in continuous belt platforms (CoreXY) that there are parametric resonances that crosstalk in abrupt vector changes, leading to ringing artifacts. I used accelerometers and a 35670a dynamic signal analyzer to capture the response of the gantry vs the head. Data is on e3d's forum. I came to believe, but did not follow up on the idea of tuned dashpots that the belts can ride on... (shock absorbing idler pulleys)... might be a trick to try. Thanks for the hard work, Tom!
Just wanted to say thank you for all that you have done and continue to do to help the community improve our printers and skills. You and a couple other content creators out there are doing amazing things for the community that are just as important, if not more than what companies like Prusa do to continually advance all aspects of 3D printing. Again, I would like to convey a sincere whole hearted thank you!!!
You went through all that effort to add the sand to the moving bed, found out that the extra weight on the bed cause problems, and then didn’t test without bed weights on the Cartesian printer. Wowza.
I have observed quite a bit of NVH testing. The bottom rails likely didnt harm much, but the vertical supports having sand added was the main issue making prints worse. Adding mass to cantilevered components will just shift the frequency of the resonance. More mass generally = more resonance at lower frequencies (greater deflection distance). Adding reinforcement to the gantry along with soft mounts that absorb energy will help most. A support rod run from the top of each vertical support, to lower frame would mitigate the motion of the gantry. Soft materials used under the machine would help absorb vibrations from print head motion.
I am an electrical engineer so I haven't studied this topic, but I would first attach vibration sensors all over the frame and heating bed and do frequency analysis and then designed springs with resonant frequencies matching the strongest frequencies from the analysis.
On the UH60 BlackHawk Helicopter, we have tuned masses on springs that we test and tune to the aircraft to dampen unwanted vibrations, on the new model, there are counter rotating electromechanical vibration dampers that actively cancel unwanted frequencies.
Since the idea is to apply dampening to counter the moving parts, and you already have the suspension rig, try loading two printers one facing upright and the upside down one facing the opposite direction... you want to load the same program into both and start them running (the bottom one does not need to be actually printing). The bottom printer will be moving in the opposite direction to the top one and should mostly cancel out the movements of the top one. Might be a relatively easy experiment to try out.
With that many skipping steps, I'd start looking into bumping up the stepper motor voltage via the driver pots. I'm curious whether fixing those skipped steps make the 'sandtainer' approach work at all, if only because stuffing them wherever they fit just kinda looks cool. But also, resonance tuning in software is way easier and very effective.
Really. Really. REALLY. Respect your sincerity in this review. 100% Correct that you could fake it for the views, and seriously appreciate you bringing us these honest comparisons and tests.
Beside motion damping feet, the most efficient loss mechanism available to you on a filament printer is actually the molten plastic. It will have a resonance at a few Hz an typically a 1/f fall off for its transfer function (basically how much can you shake your printer before it turns into movement in your nozzle head, ie. ringing). It takes a lot more motion to ring at higher frequencies. This is also why ringing is less obvious on larger nozzles: there is more plastic to absorb the motion. The vibration damping feet are going to be resonant in the few Hz range just like the plastic. But there is a lot more mass to the feet so they can absorb a lot more energy than the molten plastic. The sand containers were never going to add much damping to the system. The resonant frequency of your frame is going to be 100+ MHz. Molten plastic already damps this motion out really well. The belts and cables, however are going to be resonant in audible frequencies (100-10,000 Hz). Assuming the ringing on your prints is roughly 0.5 mm between peaks and you are printing at 300 mm/s, your ringing is at 600 Hz. These resonances can be tuned by tightening the belts and cables as must as possible. The added tension will bring the frequency up. The whole point of having a rigid system is two-fold: dimensional accuracy and bringing the resonant frequencies up. The mass of a bed-slinger means that one axis will have a lower resonant frequency than the other and ultimately appear worse. There isn't a lot you can do about that other than not use a bed-slinger. There is one more tuning knob available to you, the viscosity of the molten plastic. This will largely be material dependent. Higher temperatures could increase the effective damping mass for a lower resonant frequency, but will decrease the viscosity and therefore your damping. Lower temperatures can increase the viscosity but negatively affects your layer adhesion, increases the probability you clog, and increases the force your drive needs to exert on the filament which can cause stripping. The suspension system was also never going to help. It sets up isolation where energy is only allowed to transfer out of the printer at the resonant frequencies of the bungie cables. If your wooden frame isn't very lossy at those frequencies it doesn't even matter. All of the vibrations either have to be absorbed by your plastic or radiated out as sound. Now if your floor was vibrating at your ringing frequency it would have helped over no-feet, but the feet would still have been the better option for all frequencies.
One thing that I found to minimize vibration and stepper sounds is to add a bearing to the other side of the motor. I used a v slot wheel that just happened to fit my set up.
I got a Creality CR-6 SE and I haven’t ever gotten it to work, and I found out that both the extruder and the printing bed are completely different temperatures than what it says on the screen so I’ve been searching for videos to try to help me and I click on this video thinking I might find something, only to find you filling your 3-D printer with sand and hanging it upside down from bungee cords 😂 although your video didn’t help me with my printer, it did lift my spirit, so thank you.👍
Thomas, you didn’t fail. You simply helped identify several options that don’t work and reduced the list of remaining options for others to test going forward. The effects from resonance appear to be most pronounced along the X and Y axes since we rarely move and change directions rapidly along the Z axis ( unless one starts slicing and printing diagonally at some point ). That said, I think effects from the X axis resonance might be reduced by two things 1) making the X-Z frame one solid piece (welding the corners, for example) and 2) dampening or stiffening the print head assembly itself. The Y axis requires something more robust to prevent additional forward movement when shifting direction due to the increased inertia involved. Perhaps some type of electromagnetic braking along the direction of the current force Y vector ( picture a magnet attached to the bed which whose strength of attraction to the base could be varied to match the force Y, but in the opposite direction of the force Y vector). Just sanding thoughts while drinking coffee….
If you're chasing after resonances, tuning the structure will get you into diminishing returns fairly quickly. What you want to do is ramp all of your steppers up and down so that resonance never has time to build. Remember, one movement of the printer is easy to dampen out, it becomes a problem when you have many movements happening rhythmically that case resonance to build to the point where they cause significant movement. The other thing to do is to decrease the mass of your moving elements. The ender 3 is a poor platform to perform that modification on, however, something like a voron build gives ample opportunity to drill out 'speed holes' while maintaining rigidity.
A damping mechanism can reduce high frequency vibrations, but it also enhance low frequency ones. Most of the vibrations coming from the moving nozzle are low frequency ones, so the dampener could make things worse.
12:28 - 12:32 aren't vibration dampeners. They are CV (constant velocity) joints. Like Universal Joints but more linear. They allow rotation across an angle. The rubber bits on the rear differential are dampeners though, sure. I would really like to see the experiment again but with the sand weights removed from the Y (and X?) axis, just leaving the sand in the frame. Also comparison at a higher print speed perhaps.
I did the sand earlier this year. You need to tamp the tube until the sand settles. You can add a significantly more amount of sand when you do. All it takes is tapping the sides of the extrusion to make it vibrate.
I went through the trouble of getting Klipper working on my Ender 3 V2 for resonance tuning using an accelerometer (and Klipper's implementation of pressure advance works with the stepper drivers hardwired into legacy mode on a stock V2). It worked incredibly well and the Ender's frame and motion system is surprisingly stiff, allowing the use of the better dampening algorithms that provide compensation without excessive smoothing of corners.
Putting a printer in the air is awesome, and its the same concept as the metronomes on a wood plank with wheels. All 3 will eventually sync up making the settling time and steady state different than the original. Adding mass to the system like the sand is a good idea, it could help balance it, like a washer with clothes, or it might not. it is hard to tell. If you add mass to the bed, you change the MMI al together making it have more ringing. My current professor worked for BMW and Ford here in the states designing those mass dampers you speak off :) we had this discussion in our linear systems and controls class. each class is 6 months long of nothing more than studying the system response of natural frequency and damping effects. When they add those small little weights to your tires on your car to "balance" them, they are adding mass because in the equation for transient response, the mass influences the omea^2 portion. Same reason you adjust the clothes in a washer, your literally adding interrail dampers to the system. Actual dampers have a fluid in them, such as the dampers on a screen door that help it close softly. Mass has alot to do with damping. In our vibrations lab today we went over this concept. i am thinking of testing out a large piece of rubber that the entire printer will be on .
I actually have done similar experiments (although with much less effort) and found that rubber pipes that are supposed to be used on milking machines work surprisingly well.
Echoing what others have said, take the excess weight off the print bed and other moving parts. Might be an easy thing to test to see if it helps, but as of right now, it looks to me like you may be partially cancelling out any gains you otherwise would have made. That said, my printer is bolted to a heavy MDF slab in my shop with zero dampening, and while ringing does occur, it's barely noticeable. I think mechanical tuning will only get you so far in this case, especially if your feeds and speeds are maxed out. It's definitely an art, and I love it. Thanks for the vid, and your "3D" tesseract did look pretty awesome!
Should have used lead shot as is used in speaker pedestals - more mass and less leaky than sand. Ultimately the problem is with elasticity within the printer frame and mechanism. The lab robots I work on use large stiff belts that don't stretch to achieve precision. If I could be bothered to do it , I would reproduce the printer frame in welded steel RHS. That would eliminate a lot of the flex. Then the only thing to deal with is the flex in the mechanical drives. You could try wider belts. Most modern motorcycles have vibration dampers in the handlebar ends and often on other parts of the frame
Best place to add damping is directly to the motion components, in this case the stepper (moving mass), the belt (spring component) or the head (moving mass). Easiest is probably to the belt, at the tensioner or with another idler wheel that has dome resistive (to motion) mounting. Sorbothane, memory foam, felt clutch - like a brake in a car or some other friction mount. Large buildings use dynamic systems, moving a mass in the opposite direction, even water that gets pumped around. This is a fun topic, am enjoying it.
Sand was common for audiophiles for a short time to deaden platforms and it did work but then things like soundproofing sheets ended that. One thing I am testing is turntable spikes/isolators. They are little 2 part metal pucks that either have a spike that fits In a cup foot or use a steel ball between 2 metal plates. They work well and so far are stopping a lot of transfer from the printer to the table.
It is all about the mass of the stationary parts. The more mass, the better. I went from a 1000lb vertical bench top milling machine to a Bridgeport-style vertical mill weighing around 3000 lbs, and the difference in the surface finish was astounding during cuts in steel. The same principle applies to a 3D printer. More mass in the stationary frame will help tremendously. Sand is not dense enough. The little sand containers aren't even close to having enough mass. Some solid steel bolted to the extrusions would be a possibility. Another option is to plug all of the holes in the extrusions and pour that big container of mercury you have sitting on the shelf into the machine ;)
I have really enjoyed these videos. Short of software resonance compensation, there are a lot of things people try, and an honest look at some of them was nice to see. Great content as always. Thank you!
What worked well for my Ender 3 Pro: Get a concrete paver (approx 18x18x1.5in), wash it, dry it, then spray it with FlexSeal to stop dust. Put the paver on 4 small pads of some of the soft dense foam you see in some shipping packages. Then put the printer on the paver. The printer will shake the "ground" (paver) and the mass of the paver acts as a damper and disipates through the foam pads. It makes the printer much more quiet too.
Steel belts, ditch the weights on the bed, and then build flextures that constrain in one axis and allow the printer to oscillate in the other axis. Then test both X and Y axes to see which is better for ringing. Also seeing some models available that have 2 axis suspension feet on top of squash and tennis balls. You really do have the perfect filament to test this stuff with.
Had a good time watching this, thanks. I found vibration dampening a bit annoying too, especially when you have a wide range of excitation. Nvmd, white steel belts on heavy beds vs cheap or kevlar would be interesting indeed.
Tom, dumb question as I haven't checked through all of your other experiments, yet - what have you done with the bed springs? Stock Ender 3 springs are woeful, I use the regular yellow upgrade springs on all of my printers, with a LOT of compression to eliminate some print bed wobble, these springs are better finished than ones fitted to cars - the ends are ground flat - [N.B. car springs break BECAUSE the ends are not finished properly so it transfers all the stress to the end of the first coil, saves the maker money, costs us for replacements] The other thing I do is fix the M4 countersunk [flat head] screws to the print surface from below, using M4 nylon nuts - this fixes the screws to the print bed, don't use metal nuts without nylon washers - you will damage the insulation surface or worse, short the bed to the frame, not unlike what happened with the early CR6SE's. Finally, after fixing the screws to the bed, putting the bed back onto the frame becomes difficult because the clearances on the screws are tight, so I enlarge three of the four holes with a 5mm drill.
The sand will add more mass to the printer, making it still vibrate, but because of the mass, the amplitude will be much less. You should add lots of weight to the top crossbar of the printer. This should greatly decrease the amplitude of vibrations. Also, locate the filament spool somewhere else. If the spool rocks on the printer that could translate to the print quality. I've got a delta printer and this video has got me thinking I should just load up the top of the printer with something to keep it from moving around as much.
I worked in the computer chip industry and this is what they do to print computer chips at 0.25 microns and less. XYZ stage is on granite slab. That slab is on air bladders and sits on another granite slabs. All cables are mounted with vibration dampening hardware. All motors are mounted with vibration damping hardware. To check for vibration we put accelerometer on each axis ( use one accelerometer 3 times). My touch was so tuned in after 16 years I could put my hand on the stage close my eyes and tell you where the vibration was coming from. Most 3D printers don’t isolate the motors or cables. I recommend silicon dampeners for the motors and cables and for 3D use a tile or concrete tile on silicone dampeners on top of another tile. Air bladder maybe overkill
With that suspended setup, you're making it work like a washing machine. I think you can try to make it smaller and add some suspension to slow down the movement, like in a washing machine: there are springs to absorb vibrations and small pistons to add friction and reduce the resonance effects. Nice project.
man thank you for doing this so I didnt have to, saved me from filling my printer with sand. I think if you dont add sand to the build plate itself, adding mass to the moving part will just increase the force it puts out.
Accelerometer works if your reference doesn't move at all. In the case of a 3D printer, where both the bed and the toolhead can move, you actually need to measure the delta between the motion of the nozzle and the motion of the bed, requiring some quite custom solutions to record.
Thick silicone pads are the best. They absorb just the kind of vibrations that 3D printers create. You can DIY them from dried up silicone caulk tube. Just be very careful when slicing, the silicone sausage is difficult to handle. They also hold their shape very well under a load, just let them cure fully if you DIY, a week after slicing so they are properly hardened. Even a dried up silicone caulk can be soft in places..
I used a sandwich of rubber-plywood-rubber as feet between the printer and a sturdy table. This worked great for me because vibration doesn't go through different densities well.
I remember an old episode of Ave where he used a variable speed controller to remove resonances from a lathe. The way it worked was to just change the speed of the lathe randomly between a certain range, e.g., between 11,200 and 11,300 rpm. This way the resonances couldn't build up as the resonating frequencies were always shifting. Now I get this would be much harder to do on closed hardware but it would be interesting.
Might be worth noting that springs do not dampen shocks or movement, they only absorb it, and if not dampened by a shock absorber, they can make the effect more pronounced. Try driving a car with blown shock absorbers. The springs still work, they just keep bouncing after you've hit the bump, and your car will be all over the road. The shock absorber is there to slow and halt the movement of the spring, after the bump has past.
Thank you for exploring the sand in frame idea but can you please test without added sand to the bed? You even pointed out that extra weight on the bed is an issue at 10:23.
Those sand containers are a great solution. Did you try adding the sand only to the static portions of the frame?
Sandtainers*
I was going to ask the same question. Leave those heated bead sand containers out.
Surprised he didn't try it without, first, to begin with...
Same question from me too. I'd love to see it only attached to the static frame parts
The ones on the bottom. Of the bed can't be a good idea
Try removing the sand blocks from the moving parts. Keep them on the non-moving parts.
He has to generate comments. That helps getting the clip prompted all over the interwebs.
I was wondering that as well
@@theomoons As they say... If you want help, don't ask a question, simply suggest doing it a certain way, and someone will surely explain a better one. ;)
I still feel like the sand in the frame might marginally helps, but adding the "sand containers" to all of the moving parts really just serves to add weight and increase the problems.
Not sand. It should be ie. lead to even have marginal difference.
Yes. I would have liked to see what would happen if sand was added to just the non moving parts.
Although sand in the frame really is a poor-mans version of just using better aluminum extrusion profiles - i.e. the heavy-duty type instead of light-weight.
@@alexbaeza4370 mhmm mm
@@graealex its not the same… one adds strengths and the other absorbs vibration energyyy
In the machine tool world, "epoxy granite" is used to fill machine frames to increase rigidity and dampening ability. It's basically just epoxy resin and sand. What the epoxy adds is it connects the mass of the sand to the structure, making it one. The aluminum extrusion with sand in it will ring nearly as much as without the sand as the sand is able to just move and allow the aluminum to move (ring).
True, however cast iron also has significantly different characteristics to aluminum extrusions. Plus, the lighter the machine then the slower / shallower you need to go. Even a mini lathe weights 40+kg.
@@arthurmoore9488 So you add mass to non moving parts only. If you're fairly certain you're not going to fiddle about with your design, you could even fill in the outer moldings.
There's an amazing technique called "Motion Amplification" which uses special cameras and DSP to visually exaggerate imperceptible movements in video. It's used largely for identifying sources of resonance in structures and industrial machinery. I'd be fascinated to see it used on a 3D printer. I predict the main source of resonance is the belts.
Wow that sounds so cool. i remember a similar tech where a camera was used to observe a human face and detect imperceptible changes in color of the skin due to blood being pumped and amplify it to detect the heart beat.
@@wizardOfRobots it's the same, it's called Eulerian Video Magnification
Ot watch Mathias Wandel checking vibrations with a loudspeaker and oscilloscope. Wandel is the master.
U,u
@@BerraLilltroll I saw that video (or a similar one) recently and was impressed with his technique and results. As I recall he was balancing a rotating mass with weights, but the technique could be used to identify resonate frequencies and test various damping solutions without wasting filament or waiting for test prints to finish.
FYI: I put a FDM printer on a $20K active dampening vibration table we use for laser alignment and it made no difference. I think the issue is amplitude and frequency is not consistent.
What about hanging the printer from a pivot point, with a mass dampener at the other end of the pivot point? A sort of Foucalt's pendulum with a mass dampener.
What do you mean by a pivot point in printer?
I think this is the comment closest to identifying the fundamental challenge. There must be multiple resonances in the printer structure and there are certainly a multitude of stimuli when you consider acceleration and vector forces. For a Cartesian system, it is probably a problem constrained to two planes; XY and ZX. I think it’s a lot harder than it looks. The analysis would be fairly involved, I think.
Shouldn't input shaper be able to cancel out all frequencies?
Aren't vibration damping tables mostly about preventing vibration from the environment from reaching equipment? Or is it designed for vibrating equipment as well?
Ultimately, I think the problem is that most of the vibration is coming from the carriage itself, which is only loosely coupled to the rest of the system, and by definition needs degrees of freedom.
The stepper and belt is the culprit.
And this time alot driver help eliminate example trinamic.
The sand on a rapid-moving part was totally a mistake on my opinion. Getting down the rabit hole you could try with some mineral oil, like the ones that are inside car/bike suspensions...?
Those dampeners only work at high amplitude, low frequency vibration.
The oil in dampers only works because it gets pushed through a valve. How would you install such a valve in a 3D printer.
Yes the increase weight on the bed destroy the test.
Moving parts = as light as possible
Frame = as heavy as possible
@@VanDerPol watercooling tubing...?
Filled with oil it would still act like a solid.
Not documenting "failures" is a huge problem in the medical industry b/c peeps don't want to embarrass themselves. Props to you for posting this. It helps inspire new hypotheses to come and still makes good content 👌
I think we all need to be more supportive of each other making mistakes.
Hmm, makes sense that you shouldn't put weight on the moving parts. So I'd try the same sand setup but excluding the print bed since it's moving quickly and weighting it gives more inertia so a higher probability of skips.
This for sure. I think that will help alot.
I had the same thought. Direct drive units are intentionally light weight to avoid inducing ringing.
Also makes sense that you should put weight on the moving parts to generate a lot of comments and viewer engagement for the algorithm.
I’ve put my printer on a square of *memory foam* . Using tick square of plywood on top so the printer doesn’t just sink into the memory foam. It works great & definitely makes the printer quieter.
I do the same, except I use a concrete tile instead of plywood and some cheap mattress foam from Amazon underneath
Tom, this is such a great video! No meaningful results are still results, just as you said. Only you would build a Suspensorium Love it! I'm chasing resonance reduction as well and would be interested in how different belts affect things. You are both thorough and entertaining and it is always a pleasure watching your videos.
How about input shaper?
"No meaningful results are still results" now i know its a bad idea to fill my printer with sand.
I wouldn't describe the results as non-meaningful. They were not 'positive' in the sense that there was no improvement in the printing artifacts due to 'ringing.' But it provided some evidence that some of the 'simple' fixes do not appear to work as miracle cures, and in some cases actually made things worse.
tuned mass damper are also commonly used in skyscrapers to absorb vibrations from swaying in the wind. there's one in Taiwan where the architects famously decided to make it a tourist attraction - instead of tucking a concrete block away in some utility room they made the main damper a large shiny decorated sphere hanging in the middle of a big atrium.
I would recommend removing the sand from the print bed. Then, run the tests again: With Feet, without feet, and then suspended.
This series is great, and your willingness to be honest is appreciated.
Agree, but the suspended one is just for fun, there is no logic on continuing that other than entertainment.
@@brianfhunter actually the suspended test could be coupled with and earthquake reader and it can plot the sine wave of the vibrations.
Then with the total mass of the 3D printer known, plus it's rought moment of inertia, you can calculate how much damping it needs
Another great video Tom.
This is just a collection of thoughts.
Sand alone isn't great at dampening. It's coarse and rough and irritating and it gets everywhere. Solution Epoxy "Granit" (a with Epoxy damped mixture of sand that is filled and compresses in forms or extrusions to minimize resonances and vibrations on Professional Machines like Kern cnc mills)
Weight alone helps a bit but Weight and a Dampener works great. I would love to see the printer mounted to the paver and than placed on a 2 to 5 inch think piece of upholstery foam.
Oh and i think stifer belts will make a noticabal difrence (steel cored belts, heard that there are some out there in the wild)
Keep up the great work and i cant wait to see the next episode in this series and the escalation that it could bring with it.
Stop hidiing Anakiin, we all know it's you. Although you bring a fair pont about the resin but it defeats the purpose of dampening. What makes sand such a great dampener is the fact that it's loose particles that have thousands of points of friction for the energy to dissipate into heat, having it all merge with the resin just make's one solid mass that, albeit having greater inertia and therefore harder to get moving, has a single natural frequencey that it can resonate with.
@@coolbionicle I disagree unfortunately. Having a Mass that not solid makes it very hard to predict the result and I cant find a mechanical loss coefficient for loose sand.
Besides that, the “granit” part of the epoxy graint its mostly a filler too minimize the amount of epoxy needed (epoxy = expensive).
The epoxy provides the dampening, the Aluminum frame the needed stiffens for the machine and the Sand is just a filler.
If you don't trust me go over to Adam bender her on you tube and watch his How to Build Epoxy Granite Machine Base video. He goes in more detail with Loss Coefficient vs. Young's Modulus and how to find the right ratios of sand to epoxy.
Love your honesty one of the reasons why we come to you you always keep it honest so we all don't go out to the store and buy lumber and try to make what you made lol I can only imagine how many people be trying to pull out their hair cuz they couldn't get what you have thanks again for keeping it honest and real
Lol, you seemed so tired & disappointed by the end of the video, but you make a good point that even the failures are useful information! This has taught me that if I want to deal with vibration, I'm better off putting my time into brushing up on my old engineering courses rather than on messy, half-baked quick-fixes. Thanks for that!
Or you could try Input Shaper, I sure hope that's where this is going, try a bunch of physical solutions, show they don't really work, then show the absolute magic of Input Shaper tuned with an ADXL.
Less initial vibrations for Input Shaper to negate would lead to sharper prints as it'll apply less smoothing. So removing as much resonance before using Input Shaper is the way to go.
It's a shame this test wasn't shown without the sand containers on the bed axis, as that's somewhere you should be trying to remove weight on this style of printer.
@@howaboutbecause686 Exactly, the GiGo principal still applies no matter how good your software compensation, garbage in garbage out.
@@m3chanist How dare you insult the best 3D printer to ever see the light?
Yes definitely do a video on the belts please ...... Since I starting playing around with 3d printing and my velleman k8200 many years ago you have taught me so much, and are normally the go to videos when I have a problem or just want to improve something. Keep them coming and hope to see you around for many more years to come
THANK YOU Tom
So I am not the only one that got hurt playing with the k8200. Still got mine. But I don't use it since I got my Ender3 original. I since replaced to pcb on the Ender. I could maybe use the old pcb into the K8200 and try to have it run better.
@@pierremartel3552 My 8200 was a good printer even thou I have done a lot of upgrades, it was working fine up to a few months ago when I parted it out to build a bigger n better printer from scratch.
It was the 8400 that I scraped after a few prints when the MB froze up putting the hot end into a thermal run away ..... after a hard reset it was still showing the hot end at almost 400c
Interesting ideas! It might work better to put the 3d printer on legs that stick into a bucket of sand, so that there is lots of sand to absorb vibrations in the base. I am curious to see the result of a test like that!
I was going to suggest the same thing. Just place the printer in a sand box and see what happens. Hopefully it won't dig itself in. :-)
I was going to comment with the exact same thing - this feels intuitively like a good move. If you had a large, square container filled with sand and just sat the printer in it, I think you might see a difference.
(Probably too slight for it to be worth it, but at least it would be cheap to try.)
Need stiffness + weight everywhere in the frame to shift the frequencies higher. That being said most ringing is due to how stepper motors work. Throw an oscilloscope on the stepper motor, then run Input shaper and compare.
More weight shifts frequencies to lower
I find most of the ringing comes from motor, belts, pulleys. Just lubricating and stabilising makes a huge difference.
Would absolutely love to see the belt comparisons
Great video as always, always learning from your content. Keep it up
I agree. I would love to see the belt comparisons too.
@@AntiVaganza I'm fine with feeding the algorithm to help a channel that is good
That look of concern at 3:37 XD
I just bought some motor bike gel pads, cut them to roughly 5x5x2cm and put them under the printer. They have the advantage of being able to move in all directions and completely removed all ringing.
The printers still stand on massive, 5cm thick sandstone slabs and those are on rubber mats, which results in an de-coupled, non resonating table and a still free moving printer
While moving fast, you can see the gel visibly shaking and shifting the printer as it absorbs the energy, but the printer never moves on the gel itself.
this might be worth a try if you have ringing and/or noise issues
printer: prusa i3 mk3s
Have had a similar plans. Was thinking of using a section of 1-2cm thick exercise mat under a large concrete paver with gel on top. Do the feet of the printer dig into the 2cm gel pads?
Thomas should test this.
@@Trevellian I removed the feat for this exact reason, didn't even try it out.
One thing I found out is that the size of the gelpad has a direct influence on the movement of the printer, the smaller the pad the more it moved. I sliced them down from 5x10cm to 5x5cm and the change was noticeable when pushing the printer to one direction
it is important that you enforce the table you put the stone on since it weighs a ton and it will bend your (possibly cheap) table.
I enforced mine by placing a solid 3cm thick wooden board on top (no screws required)
I think the best solution would be to have a counter weight on the same belt as the X or Y.
The top of the belt moves the opposite direction as the bottom of the belt.. Let's say you have a weight on the X that weighs the same as the head.. They would move opposite directions, and hence when they stop, should vibrate the machine.
Just a thought.
Very cool video. Not vibration or resonance related, but one thing i have been curious about for a long time is how flipping the printer upside down would affect overhangs and bridges. Since any sagging will be pushed back up by the next pass of the nozzle, I would expect it to improve the results. And now you have the perfect "printer enclosure" to test it 😄 Also seeing the effect of different belts would be very interesting.
Wouldn't you literally just have the overhang problem on every layer?
@@robertbyrnes7075 I don't think so. The molten plastic is probably viscous and sticky enough to stay in place wherever it is fully supported by the previous layer. And in areas along slanted edges where it is not fully supported it will sag towards the nozzle. Which means that on the pass for the next layer the nozzle will lift the sagging but now much cooler plastic up again. As opposed to pushing it further down when printing with the nozzle pointing downwards. I find it hard to predict the end result of this interaction, but I think it might make it possible to print steeper overhangs with better quality.
Need a way to measure resonances and their vector/directions. Then matching those with damping would be clearer.
Back in the late 1980s, some of the scientific equipment vendors, such Edmund Scientific, sold rubber ball kits for physics demonstrations. One ball would be a standard rubber ball and would bounce as such. The other ball would sometimes be called a dead ball as it wouldn't bounce. The idea was to show how energy could transferred in one direction (bounce) or dispersed in multiple simultaneous directions (dead). At that time, the dead balls were of particular interest in the amateur holography scene as lasers weren't very powerful and the holographic process was extremely sensitive to vibrations. I don't know if the dead balls or material are still available but if still available, that could be an interesting test.
They are called squash balls and are available from most sports shops
Thank you for going through everything that didn't work. I've been really curious about sand on smaller machines. I'd love to see a video on the different belts. If you could please have one cheaper belt case using an old piece belt that would be great. I honestly wonder about my belts every time I see ringing.
I think you may get some interesting results if you modified the springs on the tesseract. What it is now is a vibration isolator not a damper. All of the vibrations made by the printer stay within the system. If you think about vibration dampers on cars there are two parts, the spring and the actual damper or shock absorber. The tesseract set up is only spring and does not have the best damping qualities.
Wow!
I really thank you soooo much for showing all this and still be so sympathetic! Cheers a lot!
Great ideas, Thomas. The super hero prison made me laugh out loud, very accurate description of how it looks lol
I have a lot of respect for what you said here at 11:10. Knowing what doesn't work is super important; thank you for sharing with us! Also good luck with the sand lol
Anakin hates this video so much
TH-cam in parts seems to be more honest than most the research journals - also presenting what did not work, or what did not make the greatest WOW !!! effect. thanks so much
You could try small dampers from RC trucks. They are sprung and oil filled. This will actually adjust the frequencies instead of just adjusting the amplitudes. You need to absorb some energy, elastic straps provide almost no damping effect.
I dont understand the fascination with optimizing single variables. It would be far more effective to increase the stiffness of the frame by putting braces on it or adding gussets at the connection. Damping a wet noodle is pointless. Brace it until it is rigid the dampen it. Otherwise you are finding ways to dampen a frequency that is irrelevant and ineffective.
At least the oil filled damper would effect a far wider spectrum of frequencies and it is tunable using different weight oils.
Small dampers for belt tensioners, shouldnt help with skips but maybe will with resonanses. For skips you decrease moving mass or increase motor power.
@@Gebsfrom404 Wasnt thinking for belts. The exercise in the video is about dampening the vibration of the frame. I was thinking if they wanted to put the frames on an elastic base then could mount the dampers to the table. This way the elastics or flexible bases allow movement but the oil filled dampers absorb vibration. As for belt tensioners I ended up using a small coil spring from a brake drum hardware kit (had a lot of them)... it is used as a retention spring to hold the brake shoes to the backing plate... around 19mm diameter and 25mm tall compression spring... pretty stiff. Then I preloaded it with a threaded rod running through it to a yoke holding the belt pulley. Any compression spring would work as long as it is stiff enough to maintain control of the belt.
Sand filled feet are a good, cheap and decently working solution. There are many different sand filled balls you can use with a printed holder to keep them in place below the printer
Why did you add weight to the moving parts?
Obviously that wouldn't work.
The question was if sand in the *non*-moving parts would make a difference.
I love your Sciency thinking. Please keep valuing it as this sets you greatly apart from typical TH-cam content we all got used to!
- You briefly mentioned the additional mass on the printbed might harm the print quality. I totally agree. I would have tried again withouout those printbed Santainers, maybe even adding them elsewhere…
- I highly value the additional mass on the printer. The bigger the mass difference between bed and printer body, the more recoil you can convert into printbed acceleration.
- A tip from back in the days (experience with laser interferometry in physics lab): For effective (nearly critical) dampening of alu extrusion profiles instead of pure frequency shifting fill the profiles with silicone (not silicon - Fugensilikon, nicht Silizium ;-) This also greatly assists survivability of your mechanical components when compared to sand…
I would love to know the frequency range of problematic ringing. This would hugely narrow down the root of the evil (profile bending, profile ringing, belt stiffness etc.) okok, I’m getting to scientific. Looking forward to the engineering way of life: try it out! :-D
Thanks for the attempt Thomas! I know I appreciate all the effort you put in these videos!
This was fantastic. And thank you so much for testing things out. I was very curious as to the outcome, especially the sand damped tests. It also makes sense that BMW used such a complicated series of dampers. But in the industrial and aerospace worlds, there is a simpler solution - avoid the areas of operation that induce harmful resonances! In a light aircraft, this could be as simple as a plaque that says "Do not run propeller at RPM between 2500 and 2550 for more than 5 minutes". Or for a larger aircraft, a redesign of the vibration causing components, to shift their resonances rather than compensate in other areas. Where the moving masses are controlled by stepper motors, that's the obvious place to control vibrations. Match the speeds and accelerations to avoid areas of resonance. That's not cheating or a hack! That's proper design. Love your channel and the work that you do...not intended as a slight at all. That I learned that a printer will work upside down is worth more than the price of admission. To me that means it's just a matter of time before there's a 3d printer in space.
Keep this series going please. Super enternaining and gets everybody's gears going. What about non-symetric dampening setup? It could help with reducing resonation of the dampening system itself. For instance - your tesseract cube with some cables tensioned way more? Or usual dampening rubber feet but with one odd, softer/stiffer foot?
Any experiment that contributes to knowledge is always welcome. Whether the output is positive or negative, it is still knowkedge that can used in future endevours. Please continue with the belt swaps to see if there is any improvement to be gained on the prints at high speeds/accelerations. Thank you Tom.
Considering the small amount of sand you used, you could've just bought play sand, ran it though a sieve and blender. That would give you sand as fine as flour.
Geile Ideen, geiler Typ, weiter so...!
Thomas, I have a couple suggestions for the next video in the series...
First of all, thanks for showing us what doesn't work. The early rocket scientists had a saying, "Fail big, fail fast" so they wouldn't waste time and efforts that wouldn't be ultimately productive.
Please try making these quick checks on the system - they may point you (and us) in a better direction.
Try tightening and loosening the belts when repeating test models. This might give us an indication of wether we need to absorb vibration being transmitted to the print or if the belts are a source of the oscillations.
Then, you could compare different types of belts and look for different results.
This might be done scientifically off the printer... If the print head velocity is known, measuring the ringing in the print could determine it's frequency.
You could then suspend varying weights from belts and vibrate them at that frequency to see what belts might oscillate or dampen that movement.
I suspect that CNC machines benefit from sand dampening because the multi-flute tools are turning and hundreds of rpms, creating chatter at several khz. Printers are operating at much slower resonances, so I expect that most problems are within the motion system itself. However, I will look forward to your next videos and learning what you discover.
Keep up the great work!
Just a piece of advice for measuring squares, you can do the triangle method. 3:4:5, is the ratio your sides should be at and the distance between them. Its a commonly used carpentry trick for getting perfect 90 degree angles.
Big companies make for there products Physik simulations so they don’t have any vibration. If you find such software and explain it too us i would look it
Very interested in the belt comparison video. I found early on in continuous belt platforms (CoreXY) that there are parametric resonances that crosstalk in abrupt vector changes, leading to ringing artifacts. I used accelerometers and a 35670a dynamic signal analyzer to capture the response of the gantry vs the head. Data is on e3d's forum. I came to believe, but did not follow up on the idea of tuned dashpots that the belts can ride on... (shock absorbing idler pulleys)... might be a trick to try. Thanks for the hard work, Tom!
You can take a osci with a piezo and messure the frequency and than buy a right piece
What doesn't work is almost more useful and helpful than what does work. If nothing else, this is an interesting and fun series!
Have you considered adding tags or a series name behind the titles to make it easier for people to find via search in the future?
Just wanted to say thank you for all that you have done and continue to do to help the community improve our printers and skills. You and a couple other content creators out there are doing amazing things for the community that are just as important, if not more than what companies like Prusa do to continually advance all aspects of 3D printing. Again, I would like to convey a sincere whole hearted thank you!!!
thank you so much, I really appreciate your words!
You went through all that effort to add the sand to the moving bed, found out that the extra weight on the bed cause problems, and then didn’t test without bed weights on the Cartesian printer. Wowza.
I have observed quite a bit of NVH testing. The bottom rails likely didnt harm much, but the vertical supports having sand added was the main issue making prints worse. Adding mass to cantilevered components will just shift the frequency of the resonance. More mass generally = more resonance at lower frequencies (greater deflection distance). Adding reinforcement to the gantry along with soft mounts that absorb energy will help most. A support rod run from the top of each vertical support, to lower frame would mitigate the motion of the gantry. Soft materials used under the machine would help absorb vibrations from print head motion.
I am an electrical engineer so I haven't studied this topic, but I would first attach vibration sensors all over the frame and heating bed and do frequency analysis and then designed springs with resonant frequencies matching the strongest frequencies from the analysis.
On the UH60 BlackHawk Helicopter, we have tuned masses on springs that we test and tune to the aircraft to dampen unwanted vibrations, on the new model, there are counter rotating electromechanical vibration dampers that actively cancel unwanted frequencies.
Since the idea is to apply dampening to counter the moving parts, and you already have the suspension rig, try loading two printers one facing upright and the upside down one facing the opposite direction... you want to load the same program into both and start them running (the bottom one does not need to be actually printing). The bottom printer will be moving in the opposite direction to the top one and should mostly cancel out the movements of the top one. Might be a relatively easy experiment to try out.
With that many skipping steps, I'd start looking into bumping up the stepper motor voltage via the driver pots. I'm curious whether fixing those skipped steps make the 'sandtainer' approach work at all, if only because stuffing them wherever they fit just kinda looks cool.
But also, resonance tuning in software is way easier and very effective.
Really. Really. REALLY. Respect your sincerity in this review. 100% Correct that you could fake it for the views, and seriously appreciate you bringing us these honest comparisons and tests.
subscribed just because of your honesty about the results. GOOD VID
Beside motion damping feet, the most efficient loss mechanism available to you on a filament printer is actually the molten plastic. It will have a resonance at a few Hz an typically a 1/f fall off for its transfer function (basically how much can you shake your printer before it turns into movement in your nozzle head, ie. ringing). It takes a lot more motion to ring at higher frequencies. This is also why ringing is less obvious on larger nozzles: there is more plastic to absorb the motion. The vibration damping feet are going to be resonant in the few Hz range just like the plastic. But there is a lot more mass to the feet so they can absorb a lot more energy than the molten plastic.
The sand containers were never going to add much damping to the system. The resonant frequency of your frame is going to be 100+ MHz. Molten plastic already damps this motion out really well.
The belts and cables, however are going to be resonant in audible frequencies (100-10,000 Hz). Assuming the ringing on your prints is roughly 0.5 mm between peaks and you are printing at 300 mm/s, your ringing is at 600 Hz. These resonances can be tuned by tightening the belts and cables as must as possible. The added tension will bring the frequency up. The whole point of having a rigid system is two-fold: dimensional accuracy and bringing the resonant frequencies up. The mass of a bed-slinger means that one axis will have a lower resonant frequency than the other and ultimately appear worse. There isn't a lot you can do about that other than not use a bed-slinger.
There is one more tuning knob available to you, the viscosity of the molten plastic. This will largely be material dependent. Higher temperatures could increase the effective damping mass for a lower resonant frequency, but will decrease the viscosity and therefore your damping. Lower temperatures can increase the viscosity but negatively affects your layer adhesion, increases the probability you clog, and increases the force your drive needs to exert on the filament which can cause stripping.
The suspension system was also never going to help. It sets up isolation where energy is only allowed to transfer out of the printer at the resonant frequencies of the bungie cables. If your wooden frame isn't very lossy at those frequencies it doesn't even matter. All of the vibrations either have to be absorbed by your plastic or radiated out as sound. Now if your floor was vibrating at your ringing frequency it would have helped over no-feet, but the feet would still have been the better option for all frequencies.
One thing that I found to minimize vibration and stepper sounds is to add a bearing to the other side of the motor. I used a v slot wheel that just happened to fit my set up.
Those all seemed like good ideas. Thanks for letting us know they don't work!
You saved a lot of people a lot of time!
I got a Creality CR-6 SE and I haven’t ever gotten it to work, and I found out that both the extruder and the printing bed are completely different temperatures than what it says on the screen so I’ve been searching for videos to try to help me and I click on this video thinking I might find something, only to find you filling your 3-D printer with sand and hanging it upside down from bungee cords 😂 although your video didn’t help me with my printer, it did lift my spirit, so thank you.👍
Maybe a bad thermistor or not fitted right. Sometimes it also helps to add thermal paste.
Thanks for the help I’ll try that
Thomas, you didn’t fail. You simply helped identify several options that don’t work and reduced the list of remaining options for others to test going forward. The effects from resonance appear to be most pronounced along the X and Y axes since we rarely move and change directions rapidly along the Z axis ( unless one starts slicing and printing diagonally at some point ).
That said, I think effects from the X axis resonance might be reduced by two things 1) making the X-Z frame one solid piece (welding the corners, for example) and 2) dampening or stiffening the print head assembly itself.
The Y axis requires something more robust to prevent additional forward movement when shifting direction due to the increased inertia involved. Perhaps some type of electromagnetic braking along the direction of the current force Y vector ( picture a magnet attached to the bed which whose strength of attraction to the base could be varied to match the force Y, but in the opposite direction of the force Y vector).
Just sanding thoughts while drinking coffee….
If you're chasing after resonances, tuning the structure will get you into diminishing returns fairly quickly. What you want to do is ramp all of your steppers up and down so that resonance never has time to build. Remember, one movement of the printer is easy to dampen out, it becomes a problem when you have many movements happening rhythmically that case resonance to build to the point where they cause significant movement.
The other thing to do is to decrease the mass of your moving elements. The ender 3 is a poor platform to perform that modification on, however, something like a voron build gives ample opportunity to drill out 'speed holes' while maintaining rigidity.
Großartiges Video! Wie immer hast Du sehr Mühe gegeben, dass machen nur wenige TH-camr.
A damping mechanism can reduce high frequency vibrations, but it also enhance low frequency ones. Most of the vibrations coming from the moving nozzle are low frequency ones, so the dampener could make things worse.
12:28 - 12:32 aren't vibration dampeners. They are CV (constant velocity) joints. Like Universal Joints but more linear. They allow rotation across an angle.
The rubber bits on the rear differential are dampeners though, sure.
I would really like to see the experiment again but with the sand weights removed from the Y (and X?) axis, just leaving the sand in the frame. Also comparison at a higher print speed perhaps.
I did the sand earlier this year. You need to tamp the tube until the sand settles. You can add a significantly more amount of sand when you do. All it takes is tapping the sides of the extrusion to make it vibrate.
I went through the trouble of getting Klipper working on my Ender 3 V2 for resonance tuning using an accelerometer (and Klipper's implementation of pressure advance works with the stepper drivers hardwired into legacy mode on a stock V2). It worked incredibly well and the Ender's frame and motion system is surprisingly stiff, allowing the use of the better dampening algorithms that provide compensation without excessive smoothing of corners.
You got lots of points! Sometimes involving plastics or other absorbent material. Thanks for making this video.
Putting a printer in the air is awesome, and its the same concept as the metronomes on a wood plank with wheels. All 3 will eventually sync up making the settling time and steady state different than the original. Adding mass to the system like the sand is a good idea, it could help balance it, like a washer with clothes, or it might not. it is hard to tell. If you add mass to the bed, you change the MMI al together making it have more ringing.
My current professor worked for BMW and Ford here in the states designing those mass dampers you speak off :)
we had this discussion in our linear systems and controls class. each class is 6 months long of nothing more than studying the system response of natural frequency and damping effects. When they add those small little weights to your tires on your car to "balance" them, they are adding mass because in the equation for transient response, the mass influences the omea^2 portion. Same reason you adjust the clothes in a washer, your literally adding interrail dampers to the system.
Actual dampers have a fluid in them, such as the dampers on a screen door that help it close softly. Mass has alot to do with damping. In our vibrations lab today we went over this concept.
i am thinking of testing out a large piece of rubber that the entire printer will be on .
I actually have done similar experiments (although with much less effort) and found that rubber pipes that are supposed to be used on milking machines work surprisingly well.
Echoing what others have said, take the excess weight off the print bed and other moving parts. Might be an easy thing to test to see if it helps, but as of right now, it looks to me like you may be partially cancelling out any gains you otherwise would have made.
That said, my printer is bolted to a heavy MDF slab in my shop with zero dampening, and while ringing does occur, it's barely noticeable. I think mechanical tuning will only get you so far in this case, especially if your feeds and speeds are maxed out. It's definitely an art, and I love it. Thanks for the vid, and your "3D" tesseract did look pretty awesome!
Should have used lead shot as is used in speaker pedestals - more mass and less leaky than sand.
Ultimately the problem is with elasticity within the printer frame and mechanism.
The lab robots I work on use large stiff belts that don't stretch to achieve precision.
If I could be bothered to do it , I would reproduce the printer frame in welded steel RHS. That would eliminate a lot of the flex. Then the only thing to deal with is the flex in the mechanical drives. You could try wider belts.
Most modern motorcycles have vibration dampers in the handlebar ends and often on other parts of the frame
Best place to add damping is directly to the motion components, in this case the stepper (moving mass), the belt (spring component) or the head (moving mass). Easiest is probably to the belt, at the tensioner or with another idler wheel that has dome resistive (to motion) mounting. Sorbothane, memory foam, felt clutch - like a brake in a car or some other friction mount. Large buildings use dynamic systems, moving a mass in the opposite direction, even water that gets pumped around. This is a fun topic, am enjoying it.
a rule of thumb for elastic dampening materials is that their size are about 70% when put under compression for a more effective absorption.
Sand was common for audiophiles for a short time to deaden platforms and it did work but then things like soundproofing sheets ended that.
One thing I am testing is turntable spikes/isolators. They are little 2 part metal pucks that either have a spike that fits In a cup foot or use a steel ball between 2 metal plates. They work well and so far are stopping a lot of transfer from the printer to the table.
It is all about the mass of the stationary parts. The more mass, the better. I went from a 1000lb vertical bench top milling machine to a Bridgeport-style vertical mill weighing around 3000 lbs, and the difference in the surface finish was astounding during cuts in steel. The same principle applies to a 3D printer. More mass in the stationary frame will help tremendously. Sand is not dense enough. The little sand containers aren't even close to having enough mass. Some solid steel bolted to the extrusions would be a possibility. Another option is to plug all of the holes in the extrusions and pour that big container of mercury you have sitting on the shelf into the machine ;)
I have really enjoyed these videos. Short of software resonance compensation, there are a lot of things people try, and an honest look at some of them was nice to see. Great content as always. Thank you!
What worked well for my Ender 3 Pro: Get a concrete paver (approx 18x18x1.5in), wash it, dry it, then spray it with FlexSeal to stop dust. Put the paver on 4 small pads of some of the soft dense foam you see in some shipping packages. Then put the printer on the paver. The printer will shake the "ground" (paver) and the mass of the paver acts as a damper and disipates through the foam pads. It makes the printer much more quiet too.
Righty and balance are key. Add rigid supports, and balance moving parts.
Steel belts, ditch the weights on the bed, and then build flextures that constrain in one axis and allow the printer to oscillate in the other axis. Then test both X and Y axes to see which is better for ringing. Also seeing some models available that have 2 axis suspension feet on top of squash and tennis balls. You really do have the perfect filament to test this stuff with.
This one of your best videos, thank you
Had a good time watching this, thanks. I found vibration dampening a bit annoying too, especially when you have a wide range of excitation.
Nvmd, white steel belts on heavy beds vs cheap or kevlar would be interesting indeed.
Tom, dumb question as I haven't checked through all of your other experiments, yet - what have you done with the bed springs?
Stock Ender 3 springs are woeful, I use the regular yellow upgrade springs on all of my printers, with a LOT of compression to eliminate some print bed wobble, these springs are better finished than ones fitted to cars - the ends are ground flat - [N.B. car springs break BECAUSE the ends are not finished properly so it transfers all the stress to the end of the first coil, saves the maker money, costs us for replacements]
The other thing I do is fix the M4 countersunk [flat head] screws to the print surface from below, using M4 nylon nuts - this fixes the screws to the print bed, don't use metal nuts without nylon washers - you will damage the insulation surface or worse, short the bed to the frame, not unlike what happened with the early CR6SE's.
Finally, after fixing the screws to the bed, putting the bed back onto the frame becomes difficult because the clearances on the screws are tight, so I enlarge three of the four holes with a 5mm drill.
The sand will add more mass to the printer, making it still vibrate, but because of the mass, the amplitude will be much less. You should add lots of weight to the top crossbar of the printer. This should greatly decrease the amplitude of vibrations.
Also, locate the filament spool somewhere else. If the spool rocks on the printer that could translate to the print quality.
I've got a delta printer and this video has got me thinking I should just load up the top of the printer with something to keep it from moving around as much.
I worked in the computer chip industry and this is what they do to print computer chips at 0.25 microns and less. XYZ stage is on granite slab. That slab is on air bladders and sits on another granite slabs. All cables are mounted with vibration dampening hardware. All motors are mounted with vibration damping hardware. To check for vibration we put accelerometer on each axis ( use one accelerometer 3 times). My touch was so tuned in after 16 years I could put my hand on the stage close my eyes and tell you where the vibration was coming from. Most 3D printers don’t isolate the motors or cables. I recommend silicon dampeners for the motors and cables and for 3D use a tile or concrete tile on silicone dampeners on top of another tile. Air bladder maybe overkill
I appreciate your content and the help it's given me in my 3D printing journey.
I'd love to see the difference the belts make.
With that suspended setup, you're making it work like a washing machine.
I think you can try to make it smaller and add some suspension to slow down the movement, like in a washing machine: there are springs to absorb vibrations and small pistons to add friction and reduce the resonance effects.
Nice project.
man thank you for doing this so I didnt have to, saved me from filling my printer with sand. I think if you dont add sand to the build plate itself, adding mass to the moving part will just increase the force it puts out.
Good science is showing the failures as much as the successes! (Thus a huge issue with publishing bias in the modern age) Good video, Tom!
Small lead shot instead of sand apparently is the best- used in higher end audiophile equipment/cabinets to dampen vibrations
Why no use an accelerometer to check the vibration frequency of the machine? Then add/remove the weights at points and observe each effect.
Accelerometer works if your reference doesn't move at all. In the case of a 3D printer, where both the bed and the toolhead can move, you actually need to measure the delta between the motion of the nozzle and the motion of the bed, requiring some quite custom solutions to record.
@@MadeWithLayers Looks like a job for cnc kitchen. Lol
I cut the molded foam and box my E3V3KE came in and placed it in that. No problems so far. Not sure even if it helps but it's peace of mind.
Thick silicone pads are the best. They absorb just the kind of vibrations that 3D printers create. You can DIY them from dried up silicone caulk tube. Just be very careful when slicing, the silicone sausage is difficult to handle. They also hold their shape very well under a load, just let them cure fully if you DIY, a week after slicing so they are properly hardened. Even a dried up silicone caulk can be soft in places..
I used a sandwich of rubber-plywood-rubber as feet between the printer and a sturdy table. This worked great for me because vibration doesn't go through different densities well.
I remember an old episode of Ave where he used a variable speed controller to remove resonances from a lathe. The way it worked was to just change the speed of the lathe randomly between a certain range, e.g., between 11,200 and 11,300 rpm. This way the resonances couldn't build up as the resonating frequencies were always shifting. Now I get this would be much harder to do on closed hardware but it would be interesting.
Might be worth noting that springs do not dampen shocks or movement, they only absorb it, and if not dampened by a shock absorber, they can make the effect more pronounced.
Try driving a car with blown shock absorbers. The springs still work, they just keep bouncing after you've hit the bump, and your car will be all over the road. The shock absorber is there to slow and halt the movement of the spring, after the bump has past.
Thank you for exploring the sand in frame idea but can you please test without added sand to the bed? You even pointed out that extra weight on the bed is an issue at 10:23.