Sound proof box construction???

[jaydee]

Got some questions for you all. I need to construct a box for my CNC mill that silences the noise it makes when running and milling. What type of materials should I consider? Only way i will be able to make any new blocks and stuff with it is to make it quiet or I will get kicked out of here.

[bigben2k]

If I haven't typed it a zillion times, I never typed it!

A solid object blocks high frequency noises.
A low-density object blocks low frequency noise.

I suspect that in your case, you want to isolate the 60Hz hum that the motor makes, and that means mounting the whole she-bang on rubber.

You've probably got high freq noise at the gearbox (if you have one) or around the motor, but that should already be wrapped, so if you need to, wrap it again. Aluminium should do, and is easy (relatively) to work with (you just can't get away from that stuff, can you?).

Your other source would be the bit hitting the workpiece, but here you need to see it, and you may even need to get your hands in there, so I'd recoment and Alu frame, with an acrylic top.


Ok, that's the best of the advice I can give you.

[jaydee]

Originally posted by bigben2k
If I haven't typed it a zillion times, I never typed it!

A solid object blocks high frequency noises.
A low-density object blocks low frequency noise.

I suspect that in your case, you want to isolate the 60Hz hum that the motor makes, and that means mounting the whole she-bang on rubber.

You've probably got high freq noise at the gearbox (if you have one) or around the motor, but that should already be wrapped, so if you need to, wrap it again. Aluminium should do, and is easy (relatively) to work with (you just can't get away from that stuff, can you?).

Your other source would be the bit hitting the workpiece, but here you need to see it, and you may even need to get your hands in there, so I'd recoment and Alu frame, with an acrylic top.


Ok, that's the best of the advice I can give you.

it is a high tourque DC motor which is plenty quite. What is loud is the belt that drives the pully. It screaches quite loudly. And then the endmill actually cutting is the worst part. I need this box to be take-apart-able, light, and easy to move. Metal is out as it doesn't absorb sound. I am thinking about 3/4"Particle board with an acrylic lineing on the inside. It also has to be liquid proof in the inside which is why I say acrylic lining. I need material that absorbs sound and doesn't just echo it like metal does. An aluminum angle frame maybe good.

measurements: 24" wide, 35" long, 30" high. Those are the minumums. that will leave enough room to use the all the hand wheels.

Here is the mill. http://www.acumotion.com/pro_mill.htm

[bigben2k]

I think that you can put some kind of dressing on the belt, to quiet it down, not sure.

I like your acrylic box idea: you'll need the light, to see what's going on. I don't think that the particle board is going to do anything for you, but the Alu angle frame sounds pretty good.

Go for it.

[jaydee]

The belt is not a standard rubber belt. It is ment to run dry. Can't be allowed to slip at all either. Very very important that it doesn't. I am actully not to sure yet if it is the belt itself or the housing around it. I have to look closer as I don't remember it being loud when I bought it. I need to make a good mounting base for the mill aswell. It has 4 bolt holes to hold it down. I think if I get some type of rubber lining under it and then bolt it to a good thick base is should remove a lot of the vibration noise. It actually doesn't make a lot of noise when cutting as long as the endmill is sharp and the feed rate is not going to fast.

Wish I wasn't on the top floor of my apartment building. Luckily I am on the end of the building and there is no more apts next to me on one side which is the same side the mill is in. Just have to worry about noise getting below. I will get working on it.

[Blackeagle]

It would seem to me you could also line at least the top of the inclosure with egg carton foam material as sold by McMasters. Could also add a layer of foam between the floor and the mill's base. I know the foam would be compressed in many areas of contact but will add some sound reduction.

A last thought is to look over some of the materials here.

www.b-quiet.com

They have a selection of materials made just for killing sound. Not cheap, but then moving isn't a low cost option it's self.

Looks to me like you have a tough job to kill the noise of a mill compared to most here trying to reduce the sound of a PC.

Good luck man.

[JSimmons]

That stuff seems a bit pricey. I notice that you don't have any computer cases in your installation gallery.

[Blackeagle]

Yes it is pricey, but it's sound deadening rates for it's thickness are the best I've found. And the thickness of the materials are important in a computer usage.

I have no connection with that site, I found it while doing searches for good sound deadening solutions for the next build I have in mind.

The thin and much lower priced stuff often sold for computer sound deadening usage is not very effective, just cheap, by comparison.

BE

edit:

McMasters sells some sound deadening materials that will also outperform the Akassa sound mat or Magic fleece that are most often sold for computer sound control. While the McMasters materials are better and a bit lower cost they are also thicker, which would be a problem in most computer cases.

[bigben2k]

Here's an example of the belt dressing stuff I mentionned. You'd have to check your belt material, for compatibility, but this particular product is Kerosene free (which unfortunately usually means that it's been substituted with "something", and good luck finding out what the "something is"! MSDSs help).

[hara]

If money is no object you could isolate all the room with sound deadening material, just like a studio.

[Balinju]

It would seem to me you could also line at least the top of the inclosure with egg carton foam material

this is what they use for sound prooving a room and to eliminate the echos (in sound studios i mean). you can't for sure use it in you belt but if you are going to build a small wall which could be folded easily, that is the way in which you would fill the middle of your wall

[hara]

Slightly out of topic. Is g-code compatible with all cnc mills?

[jaydee]

Belt dressing will not work with my belt. it is nothing like a cars belt. Also don't think it is the best itself making the noise. Looks like the pully is rubbing the plastic housing.

Money is an object and I use the room to live in aswell so I am not going to sound proof the whole room. Apartment managers probably would like that much anyway.

And no, G-Code is machine spacific. Some G-Code will work with some mills while some will not on others. There is a set of commands that need to be known for each mill because if a command is used that that mill doesn't support it will either stop or mess something up. You need to know the mill that will be used and understand how it works, or just submit the drawing to the machinist and he can convert it. But that is rather expensive.

[Fixittt]

Jay,

I made a rather large box for mine out out stainless steel sheets. Then cut windows in the sides for plexi. it really quiets the machine down, heavy as hell, but its on an old photo copier stand with wheels. Wood would work, if your not using coolant. If you do use coolant, then paint the inside a light color, but makesure you seal the joints.

[Fixittt]

JAY, JOIN THIS GROUP, THEN GO UNDER PICTURES SECTION AND LOOK FOR THE FOLDER "ROBERTS SETUP" SO SEE MY BOX.


http://groups.yahoo.com/group/MaxNC-users/

[Axly]

I've used MDF with thick plexi windows, lined with 10 mm neoprene (wetsuite stuff) though not for mills, but for noisy machines and large matrix printers.

[jaydee]

Well I am scraping the idea. I am going to set the mill up at my Grandparents shop. There I can use it the way it should be used. Problem with that is it is a 120mile one way drive. So I will not be able to use it much, but that is still better than not at all.

[JSimmons]

Why don't you rent a 1-car garage from someone locally?

[jaydee]

Originally posted by JSimmons
Why don't you rent a 1-car garage from someone locally?

That takes money. Which is not available anytime soon.

[hara]

Screw the neighbors, just use it in the apartment.
They SHOULD understand how important the milling of waterblocks is.

[jaydee]

Originally posted by hara
Screw the neighbors, just use it in the apartment.
They SHOULD understand how important the milling of waterblocks is.

Hehe, well the manager already told me not to use it anymore.... So appearently the neighbors like quiet over waterblocks. I also might be moving here shortly. Back with the EX and the kid into another Apt.... So I need to set it up elsewhere. Will give me an excuse to get out of there on the weekends.

[Cova]

This will likely exceed your weight requirement, but many theaters sound-proof each theater with just drywall. Just going by memory from what my dad told me quite a while ago (he used to install drywall for a living, now he sells it) I believe they use about 12 1/2" layers of various densities, each density blocking/absorbing a certain range of frequencies. Now you don't need anywhere near as much sound-deadening as a theater does, so if you can find 1/4" thick drywall of a few various densities you should be able to build yourself a fairly good sound killing box.