VzBoT gets Aluminum Y gantry!
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- Опубліковано 28 вер 2024
- If you wish to support me: ko-fi.com/vez3d
-Really happy to announce a collab with Mellow! These parts were manufactured by them and will continue to collab for more VzBoT parts, and maybe a full Kit soon. Stay tuned !
(Credits to Diemex for the Aluminum gantry design)
Mellow Store: mellow.aliexpr...
CAD files: grabcad.com/li....
or from the full VzBoT: grabcad.com/li...
Always looking forward to improve 3D printing performance.
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Re: frequencies - I believe that the increase in resonance is coming from the added rigidity of aluminum vs plastic -- plastic can act as a damper for the vibrations, so it wasn't transferring to other axes before. But now that it's more rigid, the vibrations are being transferred directly into the X (&Z) axes.
I think if you only look at your Y axis, it's more or less fine and expected. But now you have to worry about transferring to X. I know some of the industrial printers put rubber washers on the bolts for the carriage, probably for this reason. Very interesting though -- I definitely wouldn't have expected this going in, but it makes sense now seeing your graphs :)
Iv'e machined all my mounting hardwear from cnc milled aluminium and found i had significant resonance untill i had all of my linear rails and frame perectly aligned, was very frustrating at first but now it's all dialed in it prints wonderfully. Not a VZBot but my own design. 35 years as a designer/cnc machinist.
@@roscoe3dp470 Yeah that lines up with the thoughts - any minor deviance in alignment would cause resonance with a rigid frame. In this case, it can either be solved by perfect alignment (as you did - I believe this would be more important in a cnc mill for example), or by adding some dampening to the axes connections (which should be more than good for 3D printing molten plastic tolerances)
Also note that the order of magnitude on the charts is different when put next to each other. (i.e 1e3 vs 1e5 for the x chart) The amplitude of the resonance is 100x greater in the x-direction and 10x in the y. This may be because this design isn't very robust along the x axis. The CF tube mounted to thin cantilevers on either side. It also may have a lot to do with the misalignment of the belts.
@@shawnwilhem4171 When he first changed to the CF tube with no other changes, it also increased resonance by a few orders of magnitude. I think the increase in amplitude mostly comes from reduced weight (lower inertia) and only a little bit from mechanicals.
But yeah having weight on the outsides of the X axis certainly would help keep alignment/dampen as well (though also add weight and inertia). Alas, it's always a game of balance and tradeoffs :)
Adding rubber is a good idea
Instead of titanium bolts you can always consider aluminium ones. They're 33% lighter with a higher strenght to weight ratio (unless hardened titanium is used). I don't know what the forces are on your gantry but an M3 screw can take up to 100kg of pure shear force before it yields. All in theory of course, but it's a lot cheaper to test
I can't get enough of this printer. It really makes me want to start my own corexy project, but for now I feel it would be too hard to do.
Me too it's seems so difficult and i'm french so it didn't help with the technique vocabulary
Dive in , you'll learn as you go and then be hooked like the rest of us..
you can skeletonize in a reticulated fashion the carbon square tube too, top and bottom cause the big forces are lateral and not vertical but being carbon fiber i think you can cut the sides too without losing stiffness.
you can experiment gluing the linear guide to the tube saving all the bolts
keep going this project is so cool, an aluminum mount for all the extruder part gona save a lot
I would think glue is going to weigh close to the same as 5x m3 bolts and nuts. The bolts also being less permant and heat resistant also a bonus for a enclosure.
@@Side85Winder how a less than paper thin layer of glue can weigh more than five screw +nuts?, there are special adhesives for where ever you want to do high temp etc . And yes is kinda permanente but is a possibility ja
@@francomaccaroni795 because 5 screws and nuts will be titanium and are about 8-10mm long so they will be even lighter than before. Glue covers the entire surface area can't be adjusted once set. I use epoxy a lot of them are rated to 150°c i got some expensive stuff for us here in aus jb weld (american brand) it claims 500°f. The glue is heavier than a gram per ml it will take close to 10ml to cover/ hold a rail. Glue isn't the answer ti bolts to be honest costs a little more than the glue but its a way better option.
@@Side85Winder yes i know that is permanent and you can't adjust but if you have the time to diale in before it cures you can do it, it a possibility but obviously any bolt, and of course, Ti bolt are the way to go in this state of rapid changing.
and 9mm wide by 350mm long have an area of 3150mm^2, with a very imposible thick layer of 0.2mm you have a volume of 630mm^3
density of epoxy resin 1.1g/cm^3
you have the total mass of 0.69g
with that a DIN912 M3x8 screw wight 0.8g in steel and 0.46g in Ti, so the super thick 0.2mm strip of glue are equivalent to 1 + half bolt (without nuts) so you are saving a lot but yes is a lot of preparation and more complicated but if you go for the stupid minimum weight possible that's the way jaja
If you tap the bottom of the holes in the bracket you can reduce the need for a nut on the idlers.
I think they are thru holes because it is easier to machine.
A couple of years ago I read an article that asymmetry in your design is a good thing. Nasa wanted a super rigid antenna boom for a disc transmitter/receiver. Engineers thought well: make it a symmetrical design. And low and behold whatever they did there was always a frequency where the boom started to resonate. Then some clever guy used a genetic algorithm to 'evolutionize' a boom that was not resonating. That worked. The engineers saw the result and thought why didn't we came up with that.
To reduce resonance in your design you could redesign the gantry pieces with this wisdom in mind. Do not make it symmetrical: the holes that are cut etc. The left part could be slightly different than the right part. Maybe this wil solve part of the resonance...
I can't tell the magnitude so well on the video. But it looks like the vibrations increased substantially.
its possible cheaper to make it out of lasercut and bended alu sheet metal i think that it would cost less then $5 a piece @20pcs MOQ
Was actually about to say in scale cheaper(20), 1 off less so. Plus if done by a friend in a large shop. They are probably small enough to be from scrap or drops
As magamac125 mentioned the more stiffer and rigid build causes the vibrations - as you can read from graphics: they are way more "spiky" then before. There you also notice that there is no constant kind of damping it looks to me that vibration "flows" though the other axes, The main connector between X and Y axis is the belt so my suggestion is to rubber-mount the bearing axis at X/Y crossing.
As soon as he went to put those screws in I could tell he made a major engineer move 😂
Which screws? Haha I'm far from being an engineer. I'm a hobbyists having fun thats all
Where they didn’t quite fit in the slot, Thats a move right up my alley haha.
@@AT_Automation haha ok that. Yes the design has been fixed for that.
You can use mushroom head M3s on the carriages the clearance required is lower, so you may be able to get away with the existing spacing
I tried with the ones I had, and same issue applies but its a bit better. The spacing has been redesigned anyway so that part is taken care of :)
Those parts looks awesome!!!!!!!
Nice project, what is precision of carbon tube, it straight enough to be guide rail?
You could use button head screws for the rail block
I'm interested in the methodology you use fine tune the belt tensions. I googled and found Gate's tension calculator for their micro v-belts. The spec for a new 6mm belt is 187.5 lbs and suggested (broken in?) is 90-125 lbs. The only problem is lbs/per what??? ft. in. mm. etc... so that it can be converted into hertz.
Now I know why you answered that to my titanium comment joke the other day XD.
Design related have you and mellow considered a 2 part or 3 part design? Maybe top and bottom plates separated by a "cage"? That would allow for easier mounting. Like cage to carriages, cage to X rails. And then plates with rollers. And everything sandwiched by the screws ( just an example) that would increase parts but assembly and manufacturing would be easier and cheaper. That part seems milled from a big block in 2 directions but may be wrong as I looked the video on my phone.
As another person commented out you make it more rigid frequency also goes higher (if to make it rigid you don't increase weight to much) but also that means that other parts vibrations can't travel up to the head and are not dampered/dissipated on the way.
Increasing frequency also it's not linear si going from 60 to 70 is not as difficult as going from 80 to 90. As resonance frequency is, simplifying, the square root of rigidity Vs mass. So with a material of same density but twice rigidity you don't get twice the frequency. Just the square root of 2.
It would be interesting to see the graphs out of UA-cam. Those peaks after the X axis first natural mode makes me curious jeje.
Also think of mounting the accelerometer out of the X axis maybe into the middle of the y axis extrusion. If y resonance is structure related you will see it clearly. If it's gantry (belts or whatever) related you will see a really smaller peak.
Keep it going!
Is that your Magnum+ hotend? what insulation do you have onit?
Custom made out silicone tube
😃
just use good grade stainless hardware nice job on the aluminum xy part
Hello, I want to build the y-gantry yesterday, but I can't find your tube end pieces for the cnc alu brackets. I insert the wrong one from the newest CAD Model from github but these end pieces doesn't work. Where can I find the one, shown in this video?
The one in cad should fit. Might need a bit of sanding depending on your cf tube . Where doesnt it fit?
@@Vez3D Hey thank you for your quick response. :) I got this Github Version: NEW-VzBoT Official v1.1-CU4. There are only screws wholes, I couldn't the one from the video with insert nuts. Thanks and regards
@@julian4061 ahh ok.. thats because its been changed. Screw goes all the way through now. Please chek here github.com/VzBoT3D/VzBoT-Vz330/tree/master/Assemblies%20BOM%20and%20STL/Gantry/Y%20gantry/Aluminum%20Y%20Gantry/BOM
@@Vez3D thanks 🙂
9:50 is your zoom-in gesture anecdotal or does your camera feature gesture control?
I am sorry my friend, I have no idea anecdotal means here. I googled it, and still dont understand. Sorry for my not so good english here. The camera is a Galaxy S21 Ultra.
Plese notice the change of the scales in the charts...
yes I did :) the amplitudes changes a lot with belt tension from my testings. so I found that I can really rely on that to make observation because its really hard to give it the exact same tension that it had before. I am more looking at what hz it happens, unless there is huge cap between the 2 amplitude.
@@Vez3D Does the magnitude also change? on the left it is 1e3 and on the right 1e4-5
@@Hajtosek you made me realize I never saw those numbers. I was looking only at the numbers on the left. I'll check
@@Vez3D Yup. 950 (x left) vs 130 000 (x right) is a big difference whatever the spectral power is.
@@Hajtosek now which one is better?
If you are going to the trouble of shaving weight off everywhere you can, even the bolts, would there be any benefit to changing to mgn9 on the Y?
yes.. the slider is smaller.. but with the current design, belts would not pass between the m3 bolts that bolts to the slider. However, we can possibly redesign a bit and have the belt passing in front of the aluminum gantry. We will check that option
Yeah the weight savings of using MGN9 over MGN12 is major. Carriage weight MGN12H 54g, MGN12C 34g, MGN9H 26g, MGN9C 16g. So if one goes to the limit one could save 40g per side by using MGN9C
The problem is the bolt spacing of MGN9 is too narrow. So the belt cannot pass inbetween the bolts at the back. It has to pass in front of the bolts. I made a design for MGN9 too.
@@D1emex @Vez3D Very nice. Ah that certainly complicates matter, will be interesting to see how it works out if you decided to explore this option further because that weight saving is pretty nuts!
How much did these cost you?
for now.. nothing. Mellow was kind enough to provide them to me for testing.
I hate the opening theme music :(
thanks for the feedback my friend. Its hard to please everyone I guess. At least its just music :)
@@Vez3D I can help you pick a less gangsta-style rap opening if you like :)
@@slimanus8m feel free to suggest. But I personally like my opening :)
No need for titanium. Just use aluminum screws (proper ones with rolled threads o/c).
You could even go up one thread size and still get the same weight and load capacity of the (smaller) titanium bolt but at a much lower price.
I should mention that sometimes adding more weight while also increasing studiness reduces ringing. So weight isn't everything!
This looks cool, but looks like you should have a washer between the Idler pulley and the bracket so the it doesn't rub.. washer needs to be only the diameter of the inner race of the pulley bearing. otherwise you might as well just have a bushing instead of the bearing.
You should give that linear rail to your grinder of choice to grind it to an 'H' shape, a slot down the top side to the plane where the boltheads sit, and same thing from the bottom but to leave you enough meat in the middle, i'd go 3 mm probably ? Remove heavy steel if you have the chance to, you gain more than changing light plastic to light Aluminum 😀
Looking at your acceleration data I would check belts arrangement and ODrive system tuning. It looks like move in one axis sometimes causes move on another. Basically having acceleration in both axes at the same time means your printer is somehow making a compound move i.e. the head moves right at the same time it moves back.
My very loose guess is that at high acceleration moves one of the motors ends up out of position (overshoots ?). This will cause the print head to move at slight angle instead straight along the X or Y axis. I think its also related to the "cogging" issue you had earlier.
good thinking. In my new tuning, I tuned it just on the edge right before it has overshoot. But maybe im too close on the edge. Ill if reducing pos gain will help
This seems about right. The im curious, if it happens the same again, if you repeat the test. Do the cross-vibrations change for each run?
@@Vez3D Did you tune it attached to whole motion system? Additional mass (Y gantry and print head) will affect performance. If you wrote somewhere your old tuning values, you could check if the issue is tuning related by running the test back to back with old and new settings. Perhaps we could devise a method of checking how good the ODrive settings are, by using accelerometer. But for that we probably require plot of acceleration vs time.
@@Doktoreq this time I did yes. Thats why the artifacts are almost gone now and it prints good
Button head screws should fit better than the socket heads you’re using.
Your plastic parts were elastic by comparison to the aluminium and so provided some damping effect. Rigid light weight components ring, tap the edge of a crystal glass for a good example. In CNC machines structural members are very rigid but also very massive, that mass acts as a damper. This is why small CNC machines are inevitably shitty, not enough beef, they flex, vibrate and snap tooling . Composite material sandwiches are a good way to reduce vibration as each material has a different resonant frequency, you mix them up and so produce lots of widely spread anti nodes.
I like that you keep on getting things further and further. Keep on going :)
40grams is amazing for the speed you're about to hit lmao
Why make it simple when complicating it is so easy. What is wrong with the solid rod? Can you provide data to support the vibration problem you were having to suggest this setup is necessary?
I had no problem to solve. Not sure what you mean. What do you mean by solid rod?
You might be able to change the holes for the sliding block from clearance fit to a slightly oversized clearance and help reduce the issues
i believe that if you'd move to 9mm XY belts, you'd get even better results with plastic parts. Also, this parts looks the way that they could be just stomped from sheet metal instead of hours of machining :)
it was designed based on U shape parts.. but mellow did it with full machining. 9mm belts would not work on my printer unless a full redesign
Mellow bad service.
Could adding expanding foam inside the carbon tube help strength/dampening? But would add additional mass to the gantry
how many cool diy 3d printer channels are canadian. first miragec then vez3d
The French mafia!! Haha
I bought some from mellow store! Thank you! The CAD file for the Y-Gantry brings back an error 404.
Which cad file? Can you show me where you see that
The last few parts of my vzbot build arrive on Friday, can’t wait!
please post up links to the parts if Mellow does end up selling them on their store. id love a pair.
finally
This is why I did not go for any aluminium part in my Voron. The added resonance would be counter-productive in the end.
Why do you say added resonance ? I'm curious. I might not be reading the graph correctly
forstest