How to reduce noise on my G&C CoreXY?

My G&C CoreXY printer has always been a little noisy, but since fitting a direct extruder and its stepper motor to the carriage, the noise has become more obvious. I think the increased carriage mass has affected everything, resulting in a lot more resonance and buzzing. I have been making some parts for this printer on my Prusa i3 and the difference in noise levels is very noticeable!

If I move the carriage by direct commands at any speed it's fairly quiet, but it's far noisier when printing. Any move that involves both X-Y motors - e.g. a straight line in only the X or Y direction - results in quite a bit more noise. The noise when printing circles is especially loud and annoying. It's as if the 2 motors are resonating with each other, or interacting in some way.

All fasteners are tight, and the belts have enough tension to 'bong' when plucked - it think the belt tensions are equal, as far as I can tell.

So now I'm looking for some help and guidance:

1. Can anyone suggest some diagnostics to help narrow down the cause of this noise?

2. Can anyone suggest some solutions? People have spoken in the past about using 0.9 degree steppers instead of 1.8 degree ones - would this help? And is changing over simply a case of swapping the X-Y motors and doubling their steps per millimetre values?

3. Are there any changes I could make to the configuration of my Duet 0.6 board to reduce noise? I have attached a copy of my config.g file, if that helps (ignore the 'M92 E600' line - this file was copied from my backup - it's now 'M92 E102').

Also, I said above that my drive belts are tight - could I have them too tight? When I first built the printer I used those rubber mountings to reduce vibration, but the belts pulled the motors over at an angle, so I had to remove them and use the thin cork dampers. How can I tell whether the belts have the proper tension?

All helpful suggestions appreciated!

Edited 1 time(s). Last edit at 11/18/2016 05:03AM by David J.

Is it possible to mount one of these between your extruder/stepper? It will absorb quite a lot of the vibrations and should make a noticeable difference.

Those are the things I've tried on the X-Y motors - they distorted too much to be useful, due to belt tension. The noise isn't coming from the extruder though - it's a combination of the X-Y motors and everything around them.

Some additional info: I have also played with motor currents, acceleration values and max instant speed changes values. none had much effect on the noise.

I have those vibration dampeners on my Fusebox X and Y motors and I guess it helps reduce vibration when running at higher speeds, but my printers are still noisy just like you mentioned in the first comment.

First I would check to make sure all the axis' are square, so that it's not binding a little bit causing noise. Second i would guess, and what I suspect is my issue also, is that we're using bearings, and the cheaper the bearing the more notorious the noise.

Also a video helps a lot too!

I'm starting to think that it's the cheap bearings in the carriage... the extra mass of the extruder and its motor was a step too far, maybe. I have tried Igus bearings, but they were getting deformed by the printed components - the hole they fit in has to be precisely dimensioned, and getting a perfectly round hole with the correct dimensions is not easy at our level of 3D printing, no matter how well the part is designed.

I might take another look at zelogik's original metal design to see if I can use his carriage on this printer - I have a lathe and I know that I can ream a 15mm diameter round hole on that. It will probably require changes for it to be a 1-to-1 replacement though.

Alternatively, does anyone know a source of genuine LM8UU bearings? I'm prepared to pay the premium price if it means that I don't have to start making stuff in the workshop, much as I enjoy that. I don't want to go to linear bearings, as that's a step too far for me; what I've got is working well for me, apart from the noise problem.

Misumi has some, but they are expensive. If you live in the US you can have them ship to you directly.

pretty sure is the linear bearing.
You can upgrade with better bearing and rods too. They are rods better that orthers.

you can shop goods bearings and rodds where:
[smalltec.de]

you can go with igus bearings too, they have one made of plastic and with a metal case, this remove the problem you have before.

If you are going to replace the rods i have a two pretty good upgrade you can do:
1- change the two Y rodds of 8mm rodds with 10mm rodds.
2- buy two smaller X 8mm rodds, them apply a better printed pieaces that not alow theses rods to move on the side. this was a problem i found later when i was adding tension on the belts.

In case you go with one of both upgrades i can help you and redesign the new parts that need to be printed.

Edited 4 time(s). Last edit at 11/18/2016 12:35PM by filipeCampos.

Hi Filipe,

First of all, I must say that the reason I didn't post this in the G&C topic is that I thought it was a general problem, rather than a design one - it could just as easily been a problem with my Duet's configuration. I wanted to get a general response, instead of a printer-specific one. It's not a criticism of your design!

Do you have a reference for the igus bearings with a shell? I'd like to check the specifications.

I'll leave your design changes for a while, but I would like to know what the differences are.

Thanks,
David

Well, I've got rid of most of the objectionable noise (the buzzes and other horrible sounds). I have replaced all of the bearings in the X and Y axes with Igus equivalents. This wasn't a direct swap - in fact it turned out to be quite a mammoth task.

I won't go into details here - once I've got a few pictures organised I'll tell all in the G&C Printer topic.

(The only remaining problem is that one of my axial print cooling fans has a very annoying vibrating buzz when it's not turning - the vibration in the X-Y belts is obviously hitting the fan's resonant frequency. But that's a different problem!)