SO3: XXL Mega-Enclosure and Dust Collection


(Mark Bellon) #21

That’s exactly how some semiconductor foundries are done! The building is literally suspended from a frame above it. The building basically moves on (high tech) springs (very fancy decoupling mechanisms). This reduces the vibrations on the chip production dramatically.

It’s fairly easy to kill noise above 400 Hz. 200 Hz isn’t that hard. Below that things get hairy. Sooner or later the vibration couples with something - the enclosure, the table, the floor, etc. - and one has seriously magnification in the sound.

Good decoupling kills all of that. You’re taking decoupling to the max.

For table mounted designs were the table is really good, I would check out some of the commercial super decouplers. Four of those under the feet of an enclosure are amazing… cheap too. The floor of my enclosures are thick HDPE, well supported underneath. The machines rest on the HDPE 0.25" of decoupling sheet. The enclosure has decouplers under the feet.

mark


(Tony) #22

I could get a 1000%+ attenuation [through the mounts) for anything over 10 Hz with a simple suspended design. With a more expensive design I could do that down to 2Hz. That doesn’t really matter though since the frame is acting like a speaker before it gets to the feet.

Once I add the sound absobing material, seal up some gaps and put foot isolators on the feet the noise level will probably drop to less than half of what it is right now.

I’m working on the dust collection setup now and it’s kicking my butt. I thought I wanted the head to stay at a fixed height (after manually adjusted), but I’m not so sure about that now. There are pros and cons of doing it either way.


(Mark Bellon) #23

I don’t doubt it. The hanging designs work well.

The other technique I’ve seem in super expensive CNC machines is exactly the opposite - they float the mill on a bed of air from underneath. Tons floating on air over a table weighing tons (it has to hold everything when the air is off).

A good table, enclosure, and several layers of decouplers should kill vibrations pretty far down too… the traditional solution.

mark


(Mark Bellon) #24

That is one way to solve things. I’ve seen those on machines that process sheet goods… the stock rarely changes and is always sheets. My friend Tim does his this way.

The dust head moving up and down with the spindle is more common. I prefer this as I can do machining with more 3D aspects with better pick up. I also like not having to adjust the height… I might forget and crash something. YMMV.

Yup, tradeoffs.

mark


(Craig) #25

Great design Tony. Do you have any sound reduction measurements using a dB meter or phone app?


(Tony) #26

I have a dB meter but haven’t taken any measurements yet. I will post the numbers when I finish all of the details. Here’s a video that will give you a pretty good idea. …https://youtu.be/mmNA96REfB8


(Chris Sader) #27

What’re you planning to use to plug the hole for wiring? What hydraulics did you use?


(Tony) #28

I covered the cable port with my hand to see if it made any difference and it didn’t make any noticeable difference so I may not do anything.

I used 50 lb gas springs from McMaster Carr. I think they are about 19" long extended. They were left over from a previous project. I put holes every inch in two one by boards and tested different mounting locations for the ends until I got it close to what I needed then I played with different positions of the ends until I got it balanced very well.


(Tony) #29

For those who have asked, these are the dimensions I used. I would suggest just making the top 48x48x25 just to give some margin inside the box.

TIP Cut all your panels as shown and assemble the box… THEN cut out the door. That way everything will stay aligned when the door is cut out. Its also much easier than trying to cut all angles for the door individually.

I just rabbited all of the joints halfway through the 3/4" sheets using a dado blade on my table saw. The top, sides and top side of the torsion box are 3/4" maple plywood. The slats and base of the torsion box are 3/4" MDF. The window is 3/8" acrylic but I would suggest using polycarbonate so it can’t shatter. The Torsion box may not be necessary but I wanted to have some extra assurance that it wouldn’t twist over time. We’ll see if that works out or not. I left the outside edge open so I could use the bottom sheet of the torsion box base as a shelf to hold tools and parts.

I used Franklin International 2892 Sound Sealant to bond all of the box joints. It acts as a damper but I don’t know if it helped or not since I don’t have anything to compare it to. I then clamped the box panels together and used finish nails to hold it. Nothing fancy.

The windows are held in with the sealant also.

Like I said, I would use the full 48x48" size for the top panel just to give some breathing room. Making it taller inside wouldn’t hurt anything either.

I just got a piano hinge from Home Depot to secure the door and I used a very strong magnet and a piece of steel tube to hold it shut when its closed.

The gas springs were left over from another project but I know they are 50 lb gas springs from McMaster.com. I think they are about 19" long when extended but I’m not sure. I played with the positioning until I was able to get the door balanced through most of its motion. I can give some dimensions for the mounting points for the springs. Feel free to ask.


(Tony) #30

Another view with the control board and gas springs installed…

The control board is mounted to an aluminum plate for heat dissipation so I spaced it off of the wall a little to allow air flow so it doesn’t overheat.


(Mark Bellon) #31

Can you comment on where you plan the vacuum inlet and your dust head ideas?

mark


(Tony) #32

Vac inlet is in the front left bottom corner. I’ll post the vacuum boot design when I have it debugged. It’s working well but I think I can improve it a good bit.


(Roger Newmon) #33

I went another way, I am using a blower to blow everything from the rear to the front so it’s easy to clean up,

Blower on top pushes air through a small duct work into the rear of the machine where I made a slot for the air to scoot across the top of the waste board.

Duct on rear:

Rail chip deflector from duct tape:

Vacuum attachment in front:

Could easily add a boot as well but the air flow seems pretty good. I test cut a few and it works fairly well. No solution is perfect but I like this one a little better, it’s quiet because the blower is one from a bounce house. The air pushed through the vacuum tube in the front where I plan to build a 5 gallon bucket dust collector type thing to capture it all.

You can see the slot in the rear:

Case opened:


(Tony) #34

One thing to think about with this setup (if I understand it correctly) is that your leaf blower puts out about 3x more flow than your shop vac can remove. That creates a positive pressure inside the cabinet. That will cause the finest dust to be forced out through the seams. The dust that you can’t even see (5 microns and smaller) is the dust that poses the most health risks.

It may be better to throttle down the flow rate of the blower and focus it using a nozzle that moves with the x-axis. That way you can still blow with a lot of force without putting out more flow than the vacuum can remove which will maintain a negative pressure in the enclosure. It takes very little flow to blow the chips to the front of the enclosure as long as you concentrate it into a very small area with a high velocity.

Ball park flow rates for shop vacs with a clean filter range from 50-180 CFM. I would imagine that leaf blower runs at around 200 CFM, plus or minus…


(Roger Newmon) #35

Good point but I actually have a negative pressure. My home build dust collector, actually pulls more then the leaf blower. So it actually speeds up the leaf blower when I turn it on! I tried it without the leaf blower and decided I need some direction of the air floe and the leaf blower ensures a uniform air right across the top of the waste board. The cool thing is that all the debris just shoots to the front and down, it’s pretty cool to watch actually.

I just got finished building a control switch panel with emergency stop button. I’m working on a joystick next followed by a new g-code sender program.


(Tony) #36

I missed the part about your home built dust collector. That’s great. Do you have any pictures or posts about it anywhere? I’d love to see it.

Regarding the EStop… do you just have to short the EStop pins on the board for that function to work? I saw EStop inputs on the board but wasn’t sure exactly how they work.


(Roger Newmon) #37

Here is the control panel: (Each switch connects to a separate outlet, and the each side is separate plug so that I can keep electronics on a different breaker from the router and vacuum)

Button available here:
http://www.amazon.com/iExcell-Mushroom-Emergency-Button-Switch/dp/B01BLJ6ES0/ref=sr_1_2?ie=UTF8&qid=1462137979&sr=8-2&keywords=Emergency+Stop+button+2pcs

The button (top left) has 1 side Normally Open and one side Normally Closed. This works well, so the normally closed one connects in between the router switch and the router electrical outlet. The Normally Open one connects to the E-Stop pins on the SO3 so when i push it it kills the router, and grounds the e-stop pin causing the CNC to halt.

The plugs, I put them on the bottom, I was contemplating the rear, but it worked out better on the bottom as all the wires go straight down, since I mounted the side to my enclosure it could have gone either way.

Here is the e-stop connection:

Hope that helps some one with a few ideas.


(Tony) #38

I updated the first post in this thread to include all of the latest info. Here’s one of the new bits… see the first post for the rest…


(Dave Miner) #39

Any good suggestions for labeling the switches…

If only you had something that could engrave the words into a hard substrate. :grin:


(Tony) #40

Ha ha :slight_smile: I knew I would get that comment eventually :-). I have the switches pretty close together with very limited room for plates. My first thought is just printing stickers would look more professional but I’m open to suggestions. I haven’t engraved anything on my CNC yet and have only done a couple carvings so I don’t have a good feel for what would look good in terms of materials, bits, sizes, etc…