Re: Digest Number 25

> Date: Wed, 26 May 1999 19:14:08 -0700
> From: Mike Romine <mromine@...>
> Subject: Re: Digest Number 24
>
> I am going to try something semi-related to this topic. My CNC is
> fairly stiff for what I am doing, but I have a huge problem with
> vibration. I am using aluminum and steel extrusions and box channel for
> the frame. These hollow members are very underdamped in nature. 2 ways
> to decrease the amplitude of vibrations is to either increase the
> damping coefficient of the material, or increase the mass of the
> system. I was lucky to spend a day with Dan Huggins, programmer of
> Dancad, and he gave me the idea of making a precast concrete frame
> components. Then I saw a company at a trade show (Philadelphia resins)
> who make a slurry of granite particles in epoxy, and form it into a
> composite that has much of the vibration damping properties of solid
> granite. Davenport actually makes an entire lathe bed using this
> process. They also fill structural members with this goo to help damp
> vibrations in machines. Unfortunately, their stuff is too expensive for
> a hobbyist like myself. But, I think I am going to try to fill my
> hollow structural parts with a reinforced polymerized concrete. This
> will make my machine heavy as hell, but should also decrease the
> amplitude of the vibrations radically. I will let you all know how it
> works.

Taig uses this method in their Microlathe, seems to work fine.