Well... I've tested it.
The flywheels did allow the printer to move and print faster. No effect on acceleration (motors have lots of torque).
They do not eliminate the midband resonance - although they may shift it to a frequency you do not want. Getting the flywheel mass just right for a given frequency is nearly impossible, we tried. A delta printer will hit every frequency, so now it sounds like it's stepping on a pile of cats.

Re: Gearing down the steppers - I think there will still be the issue of needing to get through the mid-band resonance, perhaps more so.

Mark, you've got DSP drivers on your printer, do they tame the midband?
I'm checking out some DSP drivers like the KL-4042D or KL-4022D. Perhaps the smaller one might work?

Edited 1 time(s). Last edit at 03/03/2015 02:27AM by Paul Wanamaker.

I'm not entirely sure. When I switched to the DSP driver + 32V supply on the belt driven X axis it became weirdly quiet, so I guess the answer is yes. I never operated the Y axis motor without the DSP driver so I don't know how it would behave with a chopper driver- the pololu drivers I have can't handle the current that the motor needs. I did some earlier tests on the Y axis screw drive with a smaller motor driven by the pololu driver and 12V supply and it vibrated a lot, but it's not a good comparison to the bigger motor plus DSP driver and higher voltage supply.

Mark,
Thanks for that info.
I struggled with which way to go, continue developing dampers (which I do not have any more time to do) or purchase DSP drivers - and have time to do my day job... I wish there was an open source solution to these drivers,but for now there is not.

We purchased 3 " KL-4042D Digital Bipolar Stepper Motor Driver-32 bit DSP Based", a few $ more than the cheapest but should be reliable. The extruder doesn't need one.

Good luck to those pursuing other methods of taming the vibrations!

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My printer: Raptosaur - Large Format Delta - [www.paulwanamaker.wordpress.com]
Can you answer questions about Calibration, Printing issues, Mechanics? Write it up and improve the Wiki!

I seem to recall from working with Steppers of a few decades ago (Coil Winding application at a Utility Transformer manufacturer),you can get some vibration reduction with those mounting hole brackets, but a large portion of the vibration is translated via the actual shaft and that vibration is highly related to the micro-stepping settings and the current being driven to the motors coils. The mention above of vibrations going away with the use of other motor drivers seems to give my fuzzy memory some validation. .I would imagine the tension of the belts (and at some point, the length of the belt spans) would factor into any vibrations being generated from the motor shafts.

Just some random thoughts from an old engineer.....

Edited 1 time(s). Last edit at 03/04/2015 11:32AM by dclarkm.

I know this is not exactly on topic, but I wanted to give some feedback based on my experience with the KL-4042D Digital Bipolar Stepper Motor Driver (32 bit DSP Based).
My review is mixed: They work, and I can't recommend them!

They did cut down the resonance a lot, and this is easily visible on the surface of prints, and achievable speeds.

However... tuning them is a real pain, and Kellig / automationtechnologies states on their website they do not support the software!
... and the software is really old
... and you have to find an old computer with a serial port to use the cable
... it doesn't run on Win 7 - can't find the port
... and the software does not match the model of the driver
... and the instructions are very very very poor and hard to find
... and Kellig does not appear to even make the driver or the software themselves
... it appears it is actually a re-branded Leadshine driver, it uses their software.

So I had to download a newer Protuner software from Leadshine and guess at the comparable model number, and find an old laptop to run it on, and experiment...

This was not a great experience. It did cut down on the resonance a lot, but not completely. When I have time I may experiment with some dampers also.

I was able to separately set safe max speeds for X,Y,Z in the Smoothie config of 12000 mm/min, and the Alpha/Beta/Gamma max rates to 11000 mm/min. The first gives speed limits for the effector movement, and the second gives speed limits for each motor - so that when a delta arm is extended closer to horizontal it does not over-speed the motor - as it must move faster to achieve the same effector speed. This has been very reliable - I love Smoothie!

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My printer: Raptosaur - Large Format Delta - [www.paulwanamaker.wordpress.com]
Can you answer questions about Calibration, Printing issues, Mechanics? Write it up and improve the Wiki!