Re: [CAD_CAM_EDM_DRO] Re: CNC router build

Kidharris,
 
Thanks, very useful info and I will look into sound barrier which would be most useful!
 
Jack

--- On Thu, 4/2/09, kidharris <kidharris@...> wrote:


From: kidharris <kidharris@...>
Subject: [CAD_CAM_EDM_DRO] Re: CNC router build
To: CAD_CAM_EDM_DRO@yahoogroups.com
Date: Thursday, April 2, 2009, 8:56 PM






For noise: Quit worrying about the noise of the spindle and cutters. Build a box around the entire table and soundproof the box. Make the walls so that they swing or slide open as space allows. put your controls outside the box. If you use a vacuum cleaner put it inside the box. Fiberglass insulation is a good sound deadener. Multiple walls work better than thicker single walls. The box must be made so that it is totally sealed when closed. Sound travels well through any air leak. There are also a lot of coatings that can be applied to the inner and outer walls of the box to help stop sound, some of these can be expensive. Generally speaking gummy types of coatings work well. Mass loaded vinyl can be used for a curtain or strips used to allow a window that you can reach thru, not as good as a moveable window/wall. Glass windows should be double paned and slope it backwards. There is a tutorial on Youtube about building a sound recording room that gives
details on how to build a window. You can also buy sound barrier board at Homedepot fairly cheap, but it is heavy. Check the STC value of any materials used in the construction of the box, higher is better. Even putting curtains around the table will help. Again different materials work better. Buy a cheap sound meter and test different materials. If you reduce the sound pressure by 50 db (say from 110 db to 60 db) you will probably be happy.

Sound is caused by vibrations. Building a heavier table and structure using some form of constrained damping will also help prevent some sound. In general, adding mass helps. You will also get improved accuracy and longer cutting bit life by stopping vibrations. Thats why so many industrial tools are so heavy. You may try putting a thin rubber pad (inner tube rubber glued in?) or coating between the router mount and the z axis mount to give it some constrained damping. Maybe the same treatment where the gantry mounts on the 2 ends? These, of course, should not allow flexing. Making the mounting plate out of 2 layers and epoxying them together might also afford some constrained damping. Maybe make one layer out of steel and one of aluminum? Different harmonics? Maybe just make the mounts out of steel - heavier generally means less vibration transmitted.

You can also line the walls in the shop to absorb sound (stop reflections/ echos, check the NRC rating for this, again higher is better). Many ceiling tiles are good for this, reduces the sound level in the whole shop.

Do some research on sound proofing. Stopping sound and absorbing sound are not the same thing. Stopping sound (sound barrier) prevents it being heard on the other side of the wall. Absorbing sound helps make the area inside the walls less loud.

--- In CAD_CAM_EDM_ DRO@yahoogroups. com, "Jack Mc Kie" <freshwatermodels@ ....> wrote:
>
>
> I just posted the first picture of the cnc rouoter I am starting to
> build. It is designed primarily for routing model boat hulls and hull
> patterns. I'm sure it will be used for a myriad of other model parts.
>
> It is based on a piece of 1/2" X 24" X 48.5" tooling plate. Linear
> bearings will be used with ball screws/nuts from McMaster Carr.
>
> The X axis will be powered by two steppers that will be linked together
> in Mach 3. Y and Z axis will be typical. I will be using 269oz
> steppers I got from Xylotex and a cheap controller from eBay.
>
> I have a router and a Dremel tool that could be used but I am
> considering some alternative hopeing to keep noise level down. Noise
> is a concern I'm not sure how to deal with. I'm considering making a
> box of some sort to house the router in and line it with some sort of
> noise absorbing material. Any cost effective suggestions on how to
> deal with noise supression would be welcome!
>
> Jack
>



















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