Is there any data on Duetwifi noise factors?
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Jesus! How much does that weigh? My gantry is a smidge longer, but the bulk of the weight is from a 40x80mm aluminum C Beam spanning the distance. I have no doubt that those badboys will work well for me so I'll save that as a last step if need be, but I'm mostly just curious about how much that amount of steel weighs lol
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Couldnt tell ya, the whole machine weighs about 500lbs it comes pre-assembled on crate without electronics….
Here is my buildlog with photos:
http://www.cnczone.com/forums/fineline-automation/336056-cnc-software.html -
Ahh, that makes more sense that it's a CNC machine. I thought you had that on a 3d printer. That looks like a properly sturdy machine for sure!
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Oh I am pretty sure I see something similar in my future with clearpath motors for a multiple gauntry independant xyz axis machine If Duet3d is willing to make some improvements to the board
Check these out:
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Thats a pretty crazy setup! I'm wondering what use cases they have in mind, I might have to look further into that concept. Right now mine is just a typical side by side dual so nothing super fancy like that.
So I bumped it up to 64x microstepping and it didn't seem to do much. I got a short video jogging each axis a few times and you can hear the Y axis is noticeably louder, but you might need headphones because they're still pretty quiet lol. Ill run some tests tomorrow to get a sense of what hardware changes I can make to see if that helps.
https://youtu.be/6EDsGkZgETM -
That's an interesting printer design! Is there any artifacting caused by the upper part being tugged along once the slack in the ties is taken up? …........................
Not so far but I've only been using that particular layout for a week or so. Prior to that I had the extruders suspended above the centre of the bed, counter balanced by a container of lead shot attached via cord and pulleys. I didn't have any artefacts with that layout so don't expect any with this. The slack in the cords is deliberate to give some degree of decoupling. So with short zigzag infill moves and small circles, the flex in the bowden tubes takes up most of the carriage movement and the extruders are more or less stationary. I did consider having the extruder carriage on mirrored coreXY axes with their own motors but discounted it on the grounds of complexity and cost, as well as the fact that there would be no decoupling and all moves, no matter how small would involve the entire mass. Although it is generally best practice to keep the moving mass to a minimum, one advantage of high mass is that you don't get ringing - it's simply too heavy to resonate.
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Thats a pretty crazy setup! I'm wondering what use cases they have in mind, I might have to look further into that concept. Right now mine is just a typical side by side dual so nothing super fancy like that.
So I bumped it up to 64x microstepping and it didn't seem to do much. I got a short video jogging each axis a few times and you can hear the Y axis is noticeably louder, but you might need headphones because they're still pretty quiet lol. Ill run some tests tomorrow to get a sense of what hardware changes I can make to see if that helps.
https://youtu.be/6EDsGkZgETMSo the concept is that most large format printers have to sacrifice quality for speed using Volcano hotends etc. Having 5 independant heads you can print in good resolution in less time as well as multi material.
In the future the intent of the design is to be able to incorporate subtractive manufacturing as well as others.
Think automated tool changes, lasers, dremmel, pick and place. It opens up the ability to do some really cool stuff.
As far as your noise goes try this:
With the machine off loosen any screws\bolts that secure and align the x and y axis. Then manually move the gantry all around. Then snug them up a little but not so much that it cant be adjusted still.
Then power your machine on and jog the x and y to the minima maxima several times using the controls , then home all and slowly and evenly tighten each screw.
I am not familiar with your setup but this process smoothed out my Davinci.
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I am not familiar with your setup but this process smoothed out my Davinci.
So is the idea to try and relieve any stress from tweaked or twisted parts so everything settles? I've basically done the first part already when I assembled everything, but I did what I could to make sure everything was squared and settled before tightening everything down. I didn't do it with the controls before locking it down, but I think I achieved more or less the same thing. Is this something that should be done every now and then?
So are load/current and driver heat just not that much of a factor then? Is there no data for this? I know deckingman wasn't experiencing any of this with his setup, but I'm wondering if instead of a linear or flat trend line, if it plots more like a ramping curve and perhaps he's fortunately operating in the more straight/small change area and with the added weight, I'm on the up swing? Swapping in new motors would rule out bad steppers as a reason why the Y axis is louder than X, but I was under the impression that this is unlikely as steppers are supposed to be pretty robust.
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So are load/current and driver heat just not that much of a factor then? Is there no data for this? ....................I've just spent few minutes doing a "google" search for stepper noise vs load/heat/current and all permutations thereof and the conclusion I come to is that there is no data, probably because there is no correlation. It doesn't seem like anyone else has the problem you describe either, so I'd be inclined to rule out the electronics and concentrate on the mechanics.
Here is a tip you can try. Go to your nearest HiFi dealer or look online and purchase some thin sheets of Sorbothane. Cut some gaskets from this and fit them under your stepper motors i.e. between the motor and the mount. If you can, try and arrange it so that the motor is fitted without fully compressing the Sorbothane.
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Here is a tip you can try. Go to your nearest HiFi dealer or look online and purchase some thin sheets of Sorbothane. Cut some gaskets from this and fit them under your stepper motors i.e. between the motor and the mount. If you can, try and arrange it so that the motor is fitted without fully compressing the Sorbothane.
That was one of the first things I did. It's not the thickest but I didn't want to introduce and play in the mounts, but perhaps I'm being a bit too cautious.
https://www.amazon.com/gp/product/B004LYGHGM/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
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Ah OK. The only other thing I can suggest then is to try a different stepper motor. I recently changed my extruder motors and although the old motors seemed quite, the new ones, which are smaller and lighter have made the extruders virtually silent. A side effect that I wasn't expecting.
You said in an earlier post that you have two Nema 23s to drive the Y carriage. Given that I can drive my 6kg gantry using a single (but high torque) Nema 17, then I'd have thought that two of them would do the job in your case with your 10lb gantry. BTW, does it really weigh 10lbs or is that just a guess? Anyway, here is a link to the Nema 17s that I use http://us.omc-stepperonline.com/3d-printer-nema-17-stepper-motor-2a-45ncm64ozin-17hs162004s1-p-16.html. No guarantee they'll fix your issue but I can vouch that they are quiet on my machine (and only USD 8.90 ).
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dont post on forums when i first wake up…. check
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It could be something you need to redo based on your setup…. My y axis is now quieter than my x axis.... but thats due to petg printed bearings on x axis (igus bearings arriving today)
Before I did that my printer was noticibly loud on the y axis even after PTFE lube.
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The post to which this was a reply has subsequently been edited / retracted so I'm doing likewise.
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Ah OK. The only other thing I can suggest then is to try a different stepper motor. I recently changed my extruder motors and although the old motors seemed quite, the new ones, which are smaller and lighter have made the extruders virtually silent. A side effect that I wasn't expecting.
Well I just double checked a few things and I think the stepper on the left side is either bad or not decoupled as well as the right side because it's still loud when I remove the belts and jog that motor. Disconnecting the left stepper and running the right produces a bit less noise so there is something up with the left one.
You said in an earlier post that you have two Nema 23s to drive the Y carriage. Given that I can drive my 6kg gantry using a single (but high torque) Nema 17, then I'd have thought that two of them would do the job in your case with your 10lb gantry. BTW, does it really weigh 10lbs or is that just a guess? Anyway, here is a link to the Nema 17s that I use http://us.omc-stepperonline.com/3d-printer-nema-17-stepper-motor-2a-45ncm64ozin-17hs162004s1-p-16.html. No guarantee they'll fix your issue but I can vouch that they are quiet on my machine (and only USD 8.90 ).
Since my machine is a basic Cartesian, I'm not sure how that would work to have a single stepper on Y given given the length of my X axis. One side only would leave the other side flapping away, otherwise I'd need a long belt or something to drive both sides with one stepper. Hopefully it is the case that it's just something off about that left Y motor, much easier to deal with. If so, then Y shouldn't be much louder than X, if it's any louder at all. I moved the gantry back and forth and there is definitely a negligible amount of force needed to move it along the rails and not audible grinding of bearings so it's definitely not a resistance thing. I did double check an older post where I had a more solid estimate of how much total weight needs to be moved for Y and it's actually 18.5 pounds lol 1 NEMA 23, 1 NEMA 17 and around 1800mm of C Beam aluminum extrusion, among other parts, but those are the bulk of the weight I believe.
That being said, my choice for these steppers was made out of convenience and to make sure I had more than enough torque with a 175oz-in NEMA 23 on each side to keep everything in line. It could very well be overkill but if I'm honest, I don't know how to find the optimal stepper, so I aimed high to be on the safe side
How could I go about calculating how much torque is actually needed and what would be a good safety margin? I'm sure that's standard engineer stuff, but I'm a 3d artist so I'm figuring it out as I go lol If I can get away with much lighter, lower torque steppers, I'd be down to make that change if that got the noise to be essentially zero. I think I'd need new mounting plates and pulleys though so I'll have weight that in also.
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The post to which this was a reply has subsequently been edited / retracted so I'm doing likewise.
he he, yeah i misread too early in the morning… thought both replies were from the same person which took it out of context
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The post to which this was a reply has subsequently been edited / retracted so I'm doing likewise.
he he, yeah i misread too early in the morning… thought both replies were from the same person which took it out of context
No worries. I've done pre-caffeine posts myself, then had a rethink.
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@efficient AF. No, you've misunderstood me. I wasn't proposing that you only use a single motor. My thought processes worked like this. Mine is a coreXY, therefore for moves that have both an X and Y component, both motors are employed. However, with 45 degree diagonal moves (such as infill), only one motor is used. Now one motor is capable of accelerating 3kg at 670mm/sec^2 with no missed steps (possibly more but that is what I have my acceleration set to). So my reasoning was that two of the same motors could accelerate twice the mass - i.e 6kg or roughly 13.2 lbs which is greater than the 10lbs you said your axis weighed. So 2 of the Nema 17s that I am using on you Y axis instead of the two Nema 23s.
As for calculating torque required, well I'll have a stab at it but bear in mind that I am a 63 year old who's current career choice is to cut and screw bits of wood together. However, this is career number 5 (or 6 or 7) and I am an engineer by training and haven't forgotten everything.
I'll have to do it in metric because although it was feet and lbs when I was at school, we've been metricated in the UK for a long time and I've forgotten much of what I learned.
So, Force = Mass x Acceleration. Your 18.5 lbs is about 8.5kg. How fast do you want to accelerate it? Given that it's big and heavy, lets say 500mm/sec^2 (I'm using 660 and that's actually pretty nifty for fast non-print moves). So Force in Newtons is mass in kg x acceleration in m/s^2. which becomes 8.5 x .5 = 4.25 Newtons. Assuming you use a 20 tooth pulley, the diameter is about 12mm so the radius is about 6mm or 0.6 cm. So the torque required = 4.25/1*0.6 = 2.55N.cm. (rounded).
Sizing a stepper that will give you that is a bit tricky. There are a lot of factors involved, many of which I don't fully grasp, but taking a previous thread where I asked a similar question, and working backwards, we can make a few assumptions. Firstly, to be safe we'll probably not run the stepper at it's full rated current, more like 85% so the torque requirement becomes 2.55/0.85 = 3.0. Using micro stepping, we'll probably only get 70% of the holding torque so 3/0.7 now becomes 4.3. The torque drops off at speed so lets use a fudge factor of 50% giving us a stepper motor requirement 8.6N.cm. Now lets say we only get 20% of that for a single micro step which means we now need a motor rated at 43N.cm,
So by those calculation, to accelerate an 18.5lb mass at 500mm/sec^2 you'd need a stepper motor rated 43N.cm. If you want to accelerate it at 1,000mm/sec^2, you need a single stepper rated at 86N.cm. As you are using two motors, each motor need only be half of that (43) so two of the ones I'm using, which are rated at 40N.cm might just about accelerate it at 1,000mm/sec^2 but should easily do 500mm/sec^2.
As you can see, there are a lot of guestimates and fudge factors in the above stepper motor calculations and they could be wildly off. Also there may be things that I haven't taken into account like motor inductance or some such. Hopefully, someone far cleverer than I will step in and correct any errors. Alternatively, you could try emailing a stepper motor manufacturer and ask them which motor they would recommend to accelerate a mass of 8.5kg at 500 mm/sec^2 (or whatever acceleration you'd like to achieve).
HTH
Ian -
Ian, you've explained the torque calculation very well in your post, but I have one comment. Torque only drops off at speed if you don't have enough drive voltage. At https://duet3d.com/wiki/Choosing_stepper_motors#How_to_work_out_the_power_supply_voltage_you_need I show how to work out the drive voltage you need to maintain torque up to a target speed. So you can leave out the fudge factor if you check that your supply voltage is sufficient for the target maximum speed.
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Ahh, I thought your printer was a CoreXY, but I wasn't sure. That certainly explains a few things!
So what you're trying to say is that my 123.5N.cm steppers are a bit on the overkill side?
I have some 42N.cm NEMA 17s that I could use if need be, hopefully the extra 1N.cm won't make much of a difference. They will require new mounting plates and pulleys w/ an ID of 5mm if I do switch. I'll try that if swapping out the bad one with the same kind to see if that fixes it. Since X is plenty quiet, albeit with a single NEMA 23 I'm optimistic that this will fix it, but if not I have a suitable backup (I think)!In any event, I really appreciate your help Ian! Your "guesstimations" are far more useful than mine given your background, that's for sure
I'll see if I can take your maths and see what the max load on my steppers are just out of curiosity. If I do end up going down to NEMA 17s it'll be helpful to know what a good use for the bigger ones are for sure!
