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Edward's S2 Enclosure

Posted: Mon May 05, 2014 10:01 pm
by edwardrford
Building an enclosure for Shapeoko has been on my list of things to do since the beginning of the project (almost 3 years ago!). I have tried building several, maybe 3-4 different styles in all, but none of them really worked out.

The problem has always been that I wanted to enclosure to follow the same principles as the project itself: low cost, no fabrication, simple to do.

There have been quite a few enclosures on the forum that are impressive, especially recently it seems that a lot of new users have built their own rather quickly and effectively. Seeing all of them put me back in the mood to design one of my own.

This isn't finished yet, but it's very close.
20140503_001743.jpg (155.56 KiB) Viewed 5746 times

It's a simple extrusion based enclosure The only modification I made to the actual Shapeoko 2 was to use longer pieces of 20mm x 20mm extrusion across the front. instead of the stock 550mm, I used 650mm.

At a casual pace it took me about 3 hours to bolt everything together and square it up. I'm really pleased with the results. Right now, all I need to complete the main build are the panels for the sides and a couple of brackets for the top.

Instead of putting the panels into the extrusions (slot style) I am instead opting to bolt them directly to the sides via the tapped holes on the sides of the brackets. This will keep some of the frame color visible and allow me to use smaller panels to cover the gaps. I will be using 1/4" acrylic.

The front panel is made from 1/4" acrylic and slides in between the extrusions to act like a vertically sliding door. It's not a super tight fit but was surprisingly effective at blocking the sound.

For the main area inside the box, the distance works out to be 570mm from inside to inside. Which, no coincidence, will allow me to cover it with HSQN4 t-slot panels to cover it edge to edge. I already have 500mm from my current build and will be adding an additional 70mm (HFSQN4-1570) to close the gap. From there, I will need to drill an access hole through the t-slot to route the wires into the bottom section and then create / purchase some sort of tight grommet to close it back up.

I left 60mm of open space on the bottom of the machine. My though is to build, basically what bluecamel has in his controller box, right onto the front of the enclosure! So looking at the machine from the front, one will see buttons, switches, and a small joystick for jogging. The top of this control section also works out as a positive stop from the vertically sliding door. On the back of the machine, I will route out line power and USB connection.

Sound reduction:
I did some testing with 1/2" MDF panels on the sides, top and back, and with the panels on, the sound (from 5ft) was reduced from 89dB to 82dB (via a free android app). I'm not sure if that's good or not good, but to me it seemed like a huge difference. Especially when comparing with the door open and closed. I imagine that once the main platform is completely closed (with the HSQN4 t-slot) the sound will be reduced even more. I'm also not sure about how well the 1/4" acrylic will work compared to the 1/2" MDF. I picked up a box of 12"x12" panels that are supposed to reduce sound. I'm not sure where I'll use them, but figured they'd be handy to have around while working on this.

Once the whole thing is put together and I get a baseline measurement for sound (with the 1/4" acrylic) I'll start testing other materials to compare.

Right now, the BOM cost at around $150 for all of the extrusions, brackets, hardware, and even a new 3mm t-handle. All of the parts can be purchased from misumi and mcmaster. After the panels are cut and know their cost, i'll pass that information on. I wouldn't say that at this point the enclosure is low cost, but it's not *crazy* expensive either.

If the whole thing can be done for less than $250, I will consider that a win for a version 1 build. We can do a community cost reduction when the build is finished to see how low we can get it.

Re: Edward's S2 Enclosure

Posted: Tue May 06, 2014 3:01 pm
by Philip
Edward, that looks great. Soundwise I don't think you'll get much reduction because you bolted the machine to the frame which will transport the vibrations to the outside.

The advice I got on a local 'sound control' forum is to make the frame on the outside, then use 18mm plywood around to create an airtight box (I didn't ask about a window, using a door and a camera). Then use 25mm or 50mm rockwool around the inside (bottom also) to isolate the frame and plywood from the machine. Line the inside with thin PE foil and cover that with perforated board. Place the machine on the bottom layer of perforated board and make sure any tiny gaps are filled with rubber or caulk(?) to prevent high frequencies leaking through. Cables and ventilation (against heat buildup) are exchanged with the outside trough a labyrinth of which every piece of inside surface is covered in rockwool, but no PE foil over it as high frequencies may leak out. The mass of the outer layer is important; 18mm plywood should be enough for frequencies in the 2000Hz range according to this expert but if you use something lighter it works less well.

Just thought I should mention it as I spend a good deal of time trying to get an answer to the problem. I didn't build it yet as I'm waiting for my machine to arrive from Catalin.

Re: Edward's S2 Enclosure

Posted: Wed May 07, 2014 8:04 am
by Nigel K Tolley
Fastest cheapest way to improve the sound insulation is likely to be just to glue corrugated cardboard to the inside of the acrylic sheets where you can. Put it over the edges where you'll leave the cover is place so it covers the frame without touching it.
Should give you a few more dB of suppression for near zero cost and effort. If you really want more, or rockwool or the like all over them line with cardboard, but then the internal thickness is likely to become an issue.

Sent from my SM-N9005 using Tapatalk

Re: Edward's S2 Enclosure

Posted: Wed May 07, 2014 12:55 pm
by Philip
As far as I understood the mechanics involved are quite well known and there are people called 'audio engineers' who have a large set of mathematical tools they can use to generate answers on what setup would give what noise reduction. If the goal is to make a sell able housing with noise reduction I think the best way is to find someone who understands this stuff (even a student?) and get some hard facts tailored to the exact product you want to create.

Re: Edward's S2 Enclosure

Posted: Wed May 07, 2014 6:42 pm
by skipmcdonald
I also hate to bring this up but any significant vibration transferred into the 2020's during the milling process may make your panels into resonators since they are mechanically coupled together. You might look at putting some kind of mechanical dampener between anything that vibrates and the outside part as that might further enhance noise reduction.

On the bright side if that kind of noise can be heard above the rest of the noise then the enclosure is already doing a pretty good job of reducing sound.

Nice looking design.

Re: Edward's S2 Enclosure

Posted: Wed May 07, 2014 9:08 pm
by Llamas
I'll be decoupling my noisemakers from the enclosure structure using compartmentalized pneumatic shock absorption panels.

Re: Edward's S2 Enclosure

Posted: Wed May 07, 2014 10:23 pm
by skipmcdonald
Llamas wrote:I'll be decoupling my noisemakers from the enclosure structure using compartmentalized pneumatic shock absorption panels.
Sorry, Use some rubber washers to keep the outside from getting shook-up by the buzzy do-hicky inside and making more noise... :lol:

Re: Edward's S2 Enclosure

Posted: Wed May 07, 2014 10:55 pm
by Llamas
I'm still going to use bubble-wrap under the equipment, but the rubber washers just made me think of the screws and rubber washers I've seen in hard drive mounts in quiet PC cases. The screws contact the threads, but all contact with the metal on the other side is buffered by rubber washers and grommets.

Re: Edward's S2 Enclosure

Posted: Wed May 07, 2014 11:32 pm
by skipmcdonald
I was going to purchase some foam egg crate material to line mine, but bubble wrap is a great idea!! and probably a lot cheaper and easier to clean/replace.

Besides bubble wrap is cool....pop.......pop.....pop.....pop.........pop.....pop.......

Re: Edward's S2 Enclosure

Posted: Thu May 08, 2014 11:20 pm
by Brian
I actually just got a free 6x10 sheet of 1/8 red (not my choice) plex, I'm thinking about building this and adding some side panels and a top to keep it all contained. I could even add an air blast at the tool and a a vac at the top to suck out the kicked up dust, similar to a dust collector on a sandblaster. I did just buy a dust so i should prob just keep it simple and use that, hah.