[Mr.Chips]

Electronics is my profession. CNCing and molding with resins/silicons is something growing from the DIY side.

Well you are certainly using the right fertilizer. Do you have a web site of your other work?

Hager

[RomanLini]

You can invert the design. if you use a simple flatter disk with 9 holes and instead of 9 balls or rods just use 9 short bolts with nylock nuts (or locktited nuts).

That would be an extremely simple construction suitable for those who just have a drill press and a hacksaw.

[Eclipze]

In case anyone was interested in way I chose 8 balls. It gives slightly more flexibility with symmetrical loading patterns. As you may find you don't need all the weights and want to leave some out.

For example...
9 spots gives: 0, 3, 6, 9.
8 spots gives: 0, 2, 4, 6, 8

[ger21]

Hmmm. I wonder if I can take 3 slugs out, and possible increase acceleration?

[the.sniper]

All,
here is my take on the Damper.
The body is aluminum and made a plexiglass cover. I made 1 unit.
I think Ill try plastic next time its quite noisy. Also, instead of bearings used 1/4 nuts. pretty straight forward. Also I used 8 holes instead of 9
I got at least 10ipm more instantly for about 25ipm, I thing I need to loosen my ways, gibs or something my X Axis is horrible so bad in fact it only wants to go one direction no matter what way I tell it to go.

My Config is
Taig Mill
Xylotex 4 axis controller
and 269oz steppers

[the.sniper]

All,
here is my take on the Damper.
instead of bearings used 1/4 nuts. pretty straight forward. Also I used 8 holes instead of 9

Just to update. The 1/4 nuts though worked ok, I replaced them with bearings.
and the difference was off the charts. I guess the Nuts could not roll smoothly
and created some vibration of their own. where as the bearings roll smoothly.

[Lynn Livings]

Just to update. The 1/4 nuts though worked ok, I replaced them with bearings.
and the difference was off the charts. I guess the Nuts could not roll smoothly
and created some vibration of their own. where as the bearings roll smoothly.

Thanks for the update!

[.xXACEXx.]

I replaced them with bearings.
and the difference was off the charts.

you said the one with nuts instead of bearings gave you 10 more i.p.m. , i was just curious what "the difference was off the charts" meant ??

didnt know there was a chart

had you changed any thing else besides the bearings? if so what? and if not ...how many i.p.m. more did you get from the bearings instead of the nuts?

do you think the bearings have more clearance around them ,that may have been what helped them to cancel out the resonance ?? or do the bearings have less clearance around them ?

thanks..

[the.sniper]

you said the one with nuts instead of bearings gave you 10 more i.p.m. , i was just curious what "the difference was off the charts" meant ??

didnt know there was a chart

had you changed any thing else besides the bearings? if so what? and if not ...how many i.p.m. more did you get from the bearings instead of the nuts?

do you think the bearings have more clearance around them ,that may have been what helped them to cancel out the resonance ?? or do the bearings have less clearance around them ?

thanks..

I tried the Nuts I was getting no more than 15ipm dependably. the real reason for low ipm was due in part to 2 things.
1: I had the screw/stepper couplers tightend down to much putting excessive pressure on the screw bearings. And 2: my Xylotex card was having issues. these 2 things were unknown before I had decided to embark on building my resonance dampers. I would not know about the 2 prior issues until after building the dampers. All that being said. once I had built the Aluminum ones I didnt have any bearings so I used nuts. I was able to go from 15+/- to about 30 but not reliably.but at high speeds it was ok. but any reversal of direction sent the axis in to mayhem. even at low speeds. so I had to get some bearings.
this all but eliminated the mayhem at low speeds. and I was able to up my speeds to +/- 45 triple my 15ipm's and stable at low speeds. for me "Off the charts"

I since have built the same unit out of acrylic with the same ball bearing scheme. I cut .5x.5 holes and used a .375 bearing. I would have preferred
a 15/32 ball bearing but my local supplier did not have any in stock
So Ill order some and post results. I know i could have cut a smaller hole but I intentionally cut it .5 so I could try different size bearings. I just didnt realize how hard it would be to get them locally.

As far as the final results. I have yet to compile them.
I will say that the Acrylic is half the noise at best. and they look cool too.

I did not spend much time polishing them as the sides were best left a little rough this way they can be turned by hand while in "Manual mode""
the fronts are pretty much clear.

I have not tested the speed differences yet. also i have the Gcode if anyone is interested. I cut them at avg of 10ipm total time to cut each one was
give or take 1 hour.
Sam

[daman]

How about using a rubber insert in the holes to keep the noise down?
Like a piece of rubber hose.

[.xXACEXx.]

i was sorta curious about cutting some (old) shotgun shells in two to get the shot out...after all something similar to that is what a dead blow hammer does ,absorbs the shock and doesn't allow the hammer to bounce back

you could even put the shot in the holes that are already made for an existing damper to test speed differences


ideally you would go to a good friend who happens to reload shot gun shells and say "hey ill make you a nice house number sign if ya will let me have some shot for a project"

to me it makes perfect sense ,but ive lost count of how many times i was wrong

(bet my wife can tell ya tho)

[Mr.Chips]

Or just buy a small pack of BB's there easy to get and pretty round and harder than shotgun shot.

Hager

[the.sniper]

All,
I just ordered some 15/32 bearings. this should give me 1/32 of clearance
over my existing 1/8 of play. I think the less clearance will result in better
axis reversal at speeds. Ill soon know.
Also, I have an arsenal of bb's and some lead shot. Ill post the results of each
I suspect before i even try them all the bearings will be superior.

And for the noise aspect. even the aluminum version i built as loud as it was...
it was really secondary to the noise the mill it self can generate. it renders the dampers un noticeable and now that i have plastic based one Im sure ill soon forget they even make noise to begin with. I guess what I a suggesting is unless you WANT noise. Even the loudest of them is of something I wouldnt put much time or effort into. imho.

[andrzej144]

Hallo sniper.
I just got an idea of milling a groove around the hole for ball and putting an O-ring in it.
The hole will be filled with thin oil before dropping a ball in it. The ball will displace oil and consume a part of energy. The operating noise would be reduced to nil.
What is your opinion ?

[the.sniper]

Hallo sniper.
I just got an idea of milling a groove around the hole for ball and putting an O-ring in it.
The hole will be filled with thin oil before dropping a ball in it. The ball will displace oil and consume a part of energy. The operating noise would be reduced to nil.
What is your opinion ?

Sounds like a great idea. But would have to try it to confirm that it would still absorb the unwanted energy if you do try it post some pics. we all move pics!

I will say though that since I made my last units from "Plastic" the noise is so little that compared to the rest of the machine running you dont even notice it.

[davidmb]

Hi all,

I built on of these dampers about a year ago, everything has been ok, but when I was pushing the system earlier this week I managed to find the resonant node on a 3.5 hour run, twice! ( two parts, one a complete writeoff, the second only managed one finishing pass in x axis ), after much headscratching, I took the damper apart and re-assembled with sealer and before putting the lid on filled the cavity around each slug with transmission oil, I have just re completed running the full finishing program both x & y at without hitting any resonance problems at all. And it's much much quiter, all I need now is a quite spindle.

Here's the best of the scrapped parts.

[Mogal]

Well, I sit here beside myself tonight.
I finally completed my own dampeners tonight.

Lets just say, I struggled at a (reliable) 60ipm to over 160ipm!!

WOW.

Thanks to everyone here that provided info on thier dampeners.
And to those who are still contemplating making them... DO IT!

Cheers!
Chris

[joeoancea]

hi, i know this is a very old post, but maybe you can answer me at a question: do yot think it is possible to use metal balls inside the damper? beaucouse i think is easy to find some balls and introduce them inside the disk, rather the cylinder forms.
sorry for my english.

[davidmb]

I believe these dampers work by absorbing the stray oscilations, the larger or more pronounced these oscilations are, the more mass will be needed, you can start with ball bearings but if there is not enough free mass, then get some steel bar and cut pieces with a saw to fit the holes, I have since filled the holes on mine with oil so the metal cylinders have to move the oil, makes it much quieter & I believe it works better. ( not sure what effect viscosity will have but will find out when the weather warms up! )

[vger]

Balls should work OK in that type of damper. Here are a couple of links that followers of this thread my find of interest....

http://www.pump-zone.com/articles/459.pdf

I know that one relates to putting the damper on the side of the motor to stop vibration at resonance, but the principal is about the same.

http://www.earsc.com/pdfs/engineerin...ietwhtpper.pdf

Take a look at page 7 on that one.

Steve