[turpija]

i had an idea to make a main construction for cnc router out of square steel tubing, and for "silencing" vibrations i thought to put sand into frame. would this make any significant improvement or is this waste of time ?

[lgalla]

pozdravi,Turpija,
I am one of the guys{caknut}from the Epoxy granite machine bases thread where we a attempting vibration reduction.Hollow steel tubes will resonate like a pipe organ because of the hollow nature.Sand is a good choice to dampen resonances as it is cheap and if not suitable can be removed.The next step is epoxy and sand and not changeable.Read the posts on the epoxy granite and decide if you want to try it.Raw sand is a good starting point.
Hvala
Larry

[walter]

Great info Mr Larryard!

And speaking of pipe organ.. Where are you guys buying your steel tubing?
I need some for my project. Not really loud but some good sounding steel.
_

[lgalla]

Good sounding steel is for Steel drum bands,not for CNC machines.Steel drums go ding,ding boom,boom,sand damping is not suitable as you will get dud,dud.The various sizes and lengths of steel tubeing in a CNC machine will resonate at different frequencys hopefully in key and in concert,making a new hit single.If not you could possibly us it to cut aluinium,I understand servos are smooth,while steppers resonate possibly adding to the musical experience.Nesretan Turpiga,I kazano we are the ludovati decki.
Αποτελέσματα αναζήτησης για 'apollonius de perga': Δεν βρέθηκαν λέξεις.

AdamAnt:good sounding steel is no sounding steel

[dertsap]

i was thinking if the steel tubing will echo any noise on my system i will try spray foam (insulation) , it would be light and should dampen any vibrations

[turpija]

Pozdrav lgalla !

So sand would make a difference (improvement) considering dampening vibrations, that's nice to hear
And i've saw some of those epoxy with sand solutions, but i did't research where could i get all the supplies, and for first hand sand seems like a logical solution epoxy sand can allways be added later ...


2 derstap: that (poliurethane) foam, yellow right, would probably make it better than just tubes alone but sand is way havier, and that's also what good machine makes better

[RICHARD ZASTROW]

I over engineer everything. Lead shot in 90w gear lube with a drain hole large enough for media changes if it doesn't work. Doesn't work for the pipe organ thing however.

[cut more]

I have an 80/20 router and was thinking of trying the urethane foam in the extrusion.
Dertsap,I was wondering if you tried the foam in yours or just thinking of trying it?
I agree it should help.
Cutmore

[dertsap]

I have an 80/20 router and was thinking of trying the urethane foam in the extrusion.
Dertsap,I was wondering if you tried the foam in yours or just thinking of trying it?
I agree it should help.
Cutmore

i do plan to use it but i haven't tryed it yet , i want to make sure i'm all done with my wiring and such before i do so

[lgalla]

If one was to fill a frame with anything,depending on the size of the machine,The verticals are easy.How would you fill the horizontal tubes? Larry

[cut more]

IGALLA,
If you use something like expanding foam it would be easy to fill in any direction.
Dertsap,
Thanks for the reply.
Cutmore

[RICHARD ZASTROW]

Or try this http://www.mkprofiles.com/profile_sy...d_profiles.asp

[M30]

I thought the pipes of a pipe organ were traditionally made out of lead?

Quick Google search:
http://www.madehow.com/Volume-5/Pipe-Organ.html

Most pipes are made from metal. Metal pipes are most often made from alloys containing various amounts of tin and lead. Pipes may also be made from other metals, such as zinc and copper. The vibrating reeds inside reed pipes are usually made of brass.

I saw someone restoring a pipe organ once, and there was enough lead in the pipe it was soft enough to bend by hand.

[JerryFlyGuy]

I over engineer everything. Lead shot in 90w gear lube with a drain hole large enough for media changes if it doesn't work. Doesn't work for the pipe organ thing however.

Richard, have you actually done something like this?? I'm working on a harmonics problem in my Z axis [it's a 6 x 6 .250Hss post over 4ft long] and am wondering if this would do what I need. It's fairly straight forward, well except that a person can't buy lead shot anymore.. Would steel shot work as well in the same situation??

Can a person even buy lead anymore??

Jerry

[Geof]

..... Would steel shot work as well in the same situation??

Can a person even buy lead anymore??

Jerry

Look up a company called Metallex. I think that is the name, they refine lead from old batteries and may be able to put you onto a source for lead shot. Steel shot will work it is just not as heavy.

You should also read a bit about constrained layer damping and elastomeric damping with weights. This is based on finding the location of maximum deflection along the beam and gluing on weights via a rubber interface. The weight and rubber have a different resonant frequency so they interfere with the harmonic vibration of the structure. You are quite likely familiar with this idea in the form of crankshaft dampers which have a ring of metal bonded to a hub via soft rubber. Also I think it is applied in propeller design but this could date back a few years.

[martinw]

Can a person even buy lead anymore??

Jerry

Dear Jerry,

Over here you can get lead shot at scuba stores, but buying weight belts on ebay is usually the cheapest source. I'm not sure if the same applies in Canada.

Best wishes,

Martin

[martinw]

Can a person even buy lead anymore??

Jerry

Yes!

http://www.marsmetal.com/newpages/aaleadshot.html


Martin

[lgalla]

Hi Jerr.How are you?
Ever heard the expression"Get the lead out"A 6"X6"X48" tube is one cu/ft or 500 lbs of shot.You got big motors?Why not try the sand idea first.
Is the resonance from the steppers or the spindle?
Appears we have a parallel universe or thread happening here.
Trumpet or trumbone?Really doesn't matter.If you filled it[the musical instrument] with foam or what ever nothing is going to resonate or make any music..The main irritation of the resonance is the air in the tube.Foam filling will eliminate the irritation but I don't know if it will eliminate the vibration.
Sorbothane to the rescue?Pads between joints absorb 94% shock and provides shock absorbing.Used as gaskets in speakers,provides reduction in vibration transfer from the motor or speaker.Useful in a machine.I donut know.
Edmond scientific has sorbothane sheets 12"X12"X1/8" for $20.
Apparently you can cover your hand with a sheet of sorbohane and hit it with a hammer and not feel a thing due to the high damping visco-elastic nature.
Maybe for a million bucks I would try it,other wise I will accept the claim.
Larry

[RICHARD ZASTROW]

Jerry, Yes the shot thing works but I was being "ironical". There is a high density rubber compound available for sound and vibration dampening. I think it is rubber and lead in a heavy paste like slurry that dries on like paint or plaster. We used it to quiet down the old steel tube type bar feeders on lathes. I would think you could apply it internally to your tube and not have much of a weight problem. I'll look around and see if I can find it again. It used to be sold as a sound proofing solution to OSHA's rules.

Sorry to reply so late. Been awful busy for a retiree.

[martinw]

Trumpet or trumbone?Really doesn't matter.If you filled it[the musical instrument] with foam or what ever nothing is going to resonate or make any music..The main irritation of the resonance is the air in the tube.Foam filling will eliminate the irritation but I don't know if it will eliminate the vibration.

Larry

Dear Larry,

My limited understanding is that hollow tubes have a tendency to form standing waves acoustically if there is a length of tube in which they can form. That's how organ pipes work (I think). If you deny the airspace, the waves do not form, so stuffing tubes with anything should work on that front. Sand, lead shot or foam ought to work.

I am unsure about how to ensure that the "stuff-filled" tube performs best however.

If you go for a two part polyurethane foam (boat bouyancy type), you could fill the sections from any angle. That is not easy with sand or lead shot unless you can pour into vertical sections.

Lead shot and sand add mass to the tube which should mean that more energy is required to set up vibrations and resonance. Obviously, lead does that a lot better than sand. However, a foam fill probably does a better job of making the steel section stiffer for the simple reason that the foam links opposing faces of the tube together and therefore increases the I value, and hence reduces bending. Any thoughts on this?

This is something that loudspeaker stand designers know about.....(and I do not)

Best wishes,

Martin