Centroid Community CNC Support Forum

Hello
I am writing for the second time about this problem because it remained unresolved. I am converting an old Isel GFM4433 and ran into a problem that I have never had before and I have over 20 years of experience with stepper machines.
The motors don't run smoothly and you can hear and feel all the steps very clearly almost on every speed but at low is so bad. Vibrations are more than they should be even on bench tests without the resonances of the aluminum machine. I installed Stepperonline drivers to start with and was surprised how noisy and vibrating everything was. the power supply was 36V 11A. The motors are 2.18A and I tried powering them with 2.2A, 2.0A and 1.8A. At 1.8A it's a bit smoother, but still unacceptably noisy at low speeds. I changed and tried other new Stepperonline motors. Again I reduced the load below the motor current and still no success.
I bought and installed a Gecko G540 hoping they have smooth running potentiometers. The result is the same. Maybe a bit better but still bad. I even changed the power supply to 48V. Now I'm exhausted and don't know what else to try. I tried 2 power supplies, different motor current, two type stepper drivers and two different brand motors. According to the rejection theory, the only thing left to do now is replace the Acorn and try another controller and also closed loop but I don't have one available at the moment.
If anyone has had a similar problem and solution, please help with any ideas.

You don't mention most of the specs that would be relevant to the problem. For example, motors with high inductance would, in my opinion have much higher low speed resonance when run from DC drives. (vs AC). Microstep settings can also contribute greatly.

With over 6000 Acorn4 units sold and running machines it's unlikely that unless you inadvertently smoked some components that it could be the cause of your issues. You also may have some erroneous settings that could also contribute. Have you previously posted a system report with pics and specs of the system?

Thanks for your reply. By no means am I saying that the problem is with Acorn for the problem. Before I bought it, I researched all the new controllers and this one is the only one that meets all the criteria for a DIY machine. I'm just ruling out the possible causes one by one.
On the G540, I can't run more than 2000 microsteps.
I've watched a lot of videos of Isel machines and none run as quiet and smooth when equipped with stepper motors. There is a possibility that this comes from the construction with aluminum hollow profiles that resonate noises, but I am more concerned about the vibrations.
I ordered to try with a closed loop stepper now. Next week I hope it will be delivered and I can do some test runs.
Yes, I uploaded pictures and a system report about 2 weeks ago in a previous post.

I have a stepper based milling machine that I converted from Mach 3 to acorn. The first time the machine moved I was amazed at how much smoother it was.

You didn't mention in your original post what your steps are per revolution. If set to coarse this could cause vibration, I can look on my mill and see what I have mine set at. It worked for me on the first try I just used the original settings from Mach 3. Have you played around with different steps per revolution?

Edit: I just looked mine is set at 2000 steps per revolution and it's smooth.

Yes, I uploaded pictures and a system report about 2 weeks ago in a previous post.

Thats great, if you wish someone to look over those settings in relation to this question, post a current report

I looked at his old report and he's metric but if my conversion is correct his settings are certainly not correct. He also has his encoder counts set to 10,000 in Acorn but he says he has the G540 set at 2000. I'd suggest setting the Acorn to 2000 and give it a go. He's gonna have to recalculate his turns ratio but that's the easy part. Stepper are going to resonate on an aluminum extruded frame.

He should also read this topic start to finish.
https://centroidcncforum.com/viewtopic.php?f=63&t=1801

I'm sorry but the previous report was with the Stepperonline DM542T drivers. They have been replaced with the G540 and today's report is attached.

I'm sorry you replaced the DM542T drives with a G540, that a downgrade in my opinion.

I also wouldn't use 2000 step/rev, set everything to 1600 and see what happens. Did you look over the link I posted on setting your overall turns ratio?

Also change your "Step Rate" in the wizard to 100,000. You currently have it set at 200,000. This is under the "Axis" section on the "Advanced" page.

The G540 has a native pulse per rev of 2000. Also, you will likely need to "tune" each of the drivers to provide the smoothest/quietest sound from the motors by adjusting the trimpots.

From Gecko's site...

STEP 7: ADJUST TRIMPOT
The G540 is composed of four individual G250 motor controls, each of which has a designated pin outputting the smoothness adjust trimpot to the G540 motherboard. In your CNC program set the axis being adjusted to move at 2 revolutions per second and use a screwdriver to turn the trimpot in the ADJUST hole on the top of the drive. The trimpot has 270 degrees of motion and will have an audible “sweet spot” when it is in proper position. This position will change with each motor so be sure to readjust if you change motors.

And a video that covers it at about the 10 minute mark.

https://www.geckodrive.com/support/g540 ... and-tuning