Re: [CAD_CAM_EDM_DRO] Sound proof box

Guys,
With regard to eliminating sound transmission through the base, there
is a company, http://www.lordmpd.com/, that has been making rubber isolation
mounts, for as many years as I can remember. Try contacting their
engineering department for some of their expertise.

Marv Frankel
Los Angeles

----- Original Message -----
From: "Jon Elson" <elson@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Monday, June 02, 2003 9:36 AM
Subject: Re: [CAD_CAM_EDM_DRO] Sound proof box


>
>
> Graham Stabler wrote:
>
> >I have finally got my proxxon conversion fully up and running but and
> >the only problem with it is the noise. My house ajoins another and
> >there is no chance I can mill on an evening.
> >
> >I'd like to make a sound proof box for it and have already made a
> >2.5" thick polystyrene cover for it that now just requires a "double
> >glazed" door. However after trying it last night with some foam
> >jammed in as a door it was anything but sound proof. Sitting the
> >mill on some foam did help a little but is not ideal.
> >
> >Has anyone built such an enclosure? Would it be worth lining it with
> >egg box foam? Should it be clad with a hard material like MDF as
> >well? Is there a way of making a decent base for the mill that will
> >not turn my bench into a sound box?
> >
> >
> padding alone will only cut the highest frequency noise. For lower
> frequencies, you need something stiff to "contain" the sound pressure
> waves. A box made out of 2 x 4s and at least 1/2" plywood would
> work much better. I made a "muffler" for an extremely loud oilless air
> compressor that way, and it helped enough that I could run it in the
> basement without driving the family out of the upstairs, screaming.
>
> The most effective approach is a stiff barrier with some type of energy
> absorbing padding that will damp the vibrations that will otherwise
> turn the plywood into a sounding board. This can be tested by building
> the box first, and observing the resonance by thumping on the box with
> a hammer. You then add damping (one commercial material is lead
> sheet with a material like sorbothane bonded to it - you then bond the
> sorbothane to the wall to be damped) until the resonance disappears,
> and all the sound that remains is a very dull thud. If the machine
> makes a lot of high frequency noise, small openings at door hinges
> and for wires, etc. will allow a lot of sound to escape.
>
> If the problem is transmitted sound, foam or other isolation from
> tables, etc. may be needed. No solid material, other than a ton of
> granite, will prevent vibrations of the machine from being transmitted
> into a bench or table. So, if the real problem is the machine vibrates
> the bench, you have to use some compressible material to isolate the
> vibrations. Placing the machine on a big sheet of plywood, and supporting
> that with 3 or 4 small inner tubes is one way this is done. That may lead
> to the machine dancing around, however. There may be a compressible
> foam that works almost as well. I had some stuff a few years ago that
> was sold for placing under typewriters and printers. It was a dense
> black foam about 1.5" thick. 4 pieces about 6" square, each, would
> probably support a minimill. (I'm not sure a Proxxon is that size, I'm
> just guessing.)
>
> Jon
>
>
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