Making Aluminum enclosures with Box and Pan Brake

[slugrustle]

I'm very comfortable making projects where everything is on one circuit board, but I often have difficulty finding a good enclosure and connectors / switches / etc. that are easy to panel mount on the enclosure.

To overcome this problem, I am looking into making my own enclosures out of 16 gauge (~1.3mm) 3003 or 5025 type Aluminum sheet metal with a 12" box and pan brake and a throatless shear. The following links are examples of those tools, chosen only for the nice pictures---I would probably buy from different manufacturers:
http://www.eastwood.com/eastwood-12-inch-box-and-pan-sheet-metal-brake.html
http://www.eastwood.com/throatless-shear.html
 
Does anyone else have experience making enclosures this way? Are these tools appropriate for the task? And, most importantly, is there a better way to get enclosures that are convenient for mounting PCBs and panel mounting connectors/other parts? I'm thinking DC barrel jacks, micro USB ports, headphone jacks, terminal blocks, toggle switches, pushbuttons, indicator LEDs, LCD displays, and so on.

I have considered making enclosures out of stacked laser cut acrylic from an online laser cutting service. The nice part about folded aluminum is that I can afford the tools to do it myself.

[coppice]

A lot of electronics people seem to have a fear of mechanics. When you work with people who also have done some mechanical work, they tend to be very open to using tools like the ones you are interested in. Vinyl skins, and other modern coating techniques, mean its not that hard to get a nice finish over formed aluminium sheeting these days. If you are sure these tools are of adequate quality to give good results (I've been bitten by tools of this kind which were not rigid enough to be really up to the job), and you have the cash and space for them, I say go for it.

[Richard Crowley]

I like making enclosures with 1.75 inch aluminum channel.  I use it to form the front, back and sides, and then sheet stock (metal, plastic, wood, etc.) for the top and bottom.

1.75 inch is a convenient size for most of my projects and it is exactly 1 rack-unit for rack-mount projects.  I get it from Orange Aluminum:
http://www.orangealuminum.com/index.php/channel-9386m.html



U-channel like that is availlable in other sizes, of course (both more narrow and wider).

[T3sl4co1l]

0. Have you considered boxes from Hammond, Bud and others?  Prefabbed sheetmetal, diecast aluminum and plastic (usually ABS and PC) are readily available and cheap.  (And sometimes not cheap -- "you get what you pay for" isn't very true with enclosures -- your best bet is to browse around.)

0.5. Have you tried copper clad PCB stock?  Great for prototypes, it can be cut with tin snips and soldered together.  Not very strong or stiff (the foil bond is the weak point), but very convenient for electronics projects!  Cheap on eBay or any other online marketplace, you can get a few pounds for, well, almost a few pounds. Make sure it's two sided and 1 or 2oz foil.

1. You can cut plates and bolt them together with angles or channels, like Richard said.  Kind of annoying for how many screws are needed, but at least with aluminum extrusion, you can use sheet metal screws (self tapping).

2. A tiny brake may be a bit of a toy, although that particular one looks fairly feature-ful and strong, at a glance.  Definitely one of the bigger and more expensive tools you'll have in the shop (if you're just doing electronics), but it can do the job very nicely.

3. You can get by, using wood or metal beams, bolted or clamped together.  Make bends with a hammer (and some hearing protection!).  Sloppy results -- you'll end up with dents and a soft bend, but you absolutely can make a properly strong metal box with just hand tools and scraps!

4. Sheet metal, by the way: you can get thin stock at most hardware stores.  Usually, 20-30 thou aluminum and 18-30 ga. steel (galvanized or plain).  The steel is okay, but the aluminum is too thin for most things.

By the way, steel is solderable, but you'll need a big iron and lots of flux to do it.  Galvanized is also solderable, but the zinc dissolves in the solder and oxidizes, making a drossy blob no matter how much rosin you pour on -- solder it as quickly as possible.  Aluminum is famously unsolderable without extreme measures, so stick to fasteners to make connections.

For real metal, you need a metal supply store.  There's usually one within 20 miles (30 km) of a major city, or you can mail-order from many places.  You'll probably not get a very good price in small quantities, but, well, that happens.  Or if you need it now, damn near everything under the sun is available from McMaster Carr -- if you're willing to pay for it.

If it turns into an addiction, a welder may tempt you.  Don't be afraid, just let it happen...

Tim

[rhb]

Those are appropriate tools and Eastwood has a good reputation among the auto and aviation restoration crowd.  Grizzly sells a similar box and pan brake.

Another option is a 3 in 1 combination press brake, shear and slip roll such as this:

http://www.grizzly.com/products/12-Combination-3-in-1-Sheet-Metal-Machine/T21320

You should look at how deep a pan you can make on the box and pan brakes.  The press brake is likely to have more depth range.  Probably a bit more challenging to learn to use also.

Harbor Freight offers a 30" 3 in 1 unit which I inherited from Dad.  Good brakes of any type are heavy, so shipping weight is a good indication of quality.  The thicknesses quoted are for full width bends, so for smaller bends you can go a *little* thicker, but not much.  The 30" HF is heavy so you have to provide a solid base.  Dad had it on a flimsy base and it very nearly collapsed when I moved it.

If you don't mind galvanized boxes, you can probably get all the scraps you want from a HVAC shop.  That has the advantage that you can spot weld the enclosures which is not really practical with aluminum because of the complexity of spot welding aluminum.  You can also solder galvanized which is helpful if you're working with RF.

[slugrustle]

Thanks for all the replies.

coppice: I have a realized lack of knowledge about mechanics, but I would like to learn more. I respect the careful work it takes to get multiple dimensions to line up in a design.

Richard Crowley: What do you use to cut the aluminum channel stock? How do you join the corners of your box?

T3sl4co1l:
0. I've used these before and successfully, usually ABS boxes by Hammond or Serpac. I want to miniaturize the project I'm working on now, and am having difficulty finding a good standard enclosure.
0.5. Very interesting. I'll look into it.
3. I've seen this done well on hackaday: https://hackaday.com/2011/12/07/aluminum-bending-tutorial-and-a-diy-brake/
4. Thanks for the tip. I was going to start out with McMaster Carr and use blind rivets and/or threaded standoffs with low profile screws on the outside of the case. Will look around for a metal supply shop. I've always wanted a spot welder.

rhb: I went with the 12" break from woodward fab https://www.woodwardfab.com/product/wfbp1220-2/ as it had the largest max. box depth (1 + 7/8") of any similar brake. Also found good reviews for this unit on a site that sells it with free shipping.
I know that MIG welding galvanized metal puts off dangerous fumes, is the same true for spot welding?

[rhb]

Zinc fumes are only hazardous if you breathe them.  So spot welding outdoors in the upwind position has no appreciable hazard, especially if you hold your breath for the duration of the weld.  Zinc poisoning causes the shakes.  The traditional remedy is to drink lots of milk.

I have one of the larger of the two units Harbor Freight sells.  I should have a similar unit made by Hobart that Dad had, but I think it may have been stolen in a move.  The HF works quite well.  Only real complaint is the toggle switch weld activation.  I've got a microwave oven transformer I'm going to turn into a spot welder for fine work.  I'm also going to add weld time and pulse count control for both along with a foot pedal to clamp the work and another to trigger the weld cycle.

Get copies of Ron Fournier's books on metal fabrication.  In particular, look into hammer forming on a wooden mandrel.  That will let you make some very elegant two part aluminum enclosures with the only seam being the joint between the two halves.

[691175002]

Sheet metal is one of the hardest processes for a hobbyist.  Sheet metal is kind of like welding - in theory it seems easy, but getting results that don't look like amateurish slop is much harder than it looks.

You have to account for bend radius/reliefs and hit everything +-0.5mm or better otherwise there will be unsightly gaps in the finished part.  I designed my parts in solidworks then printed the flat pattern at 100% and tacked it to the sheet metal.  Cutting the part out requires a mix of shearing and dremel/file work.





I try to avoid sheet metal work whenever possible.  I'm sure its easy with CNC plasma and a press brake, but working sheet metal with hand tools is torturous.  Given a choice I'd rather start with an existing project box and drill/mill the faceplate, or 3d print something and maybe finish the exterior with bondo.

There are too many essential tools for manual sheet metal work as well; a throatless shear plus finger brake will work but aren't entirely sufficient.  You kind of need a way to do straight cuts as well as a corner notcher, and press brakes are pretty essential as well.  Everything just too damn expensive especially if you are working 16ga sheet.

[tszaboo]

A lot of electronics people seem to have a fear of mechanics. When you work with people who also have done some mechanical work, they tend to be very open to using tools like the ones you are interested in. Vinyl skins, and other modern coating techniques, mean its not that hard to get a nice finish over formed aluminium sheeting these days. If you are sure these tools are of adequate quality to give good results (I've been bitten by tools of this kind which were not rigid enough to be really up to the job), and you have the cash and space for them, I say go for it.

No, it is just... I order a PCB, it arrives in 2 days, or for 10 euros. The manufacturer will not ask any questions, they know what to do. I get the price after logging in and uploading files in 5 minutes automatically. What they do and technology limitations are clearly described.
When it comes to mechanical design? I make DXF files. Altium can do it. And then... Ask a qoute, they ask questions, and this goes on and on, and then I get something, and something will not be OK. Like they did not file the cuts or the tolerances are not acceptable, or something else.

Tell me a service, where I upload a file and I get shipped a 1.2mm aluminium panel, with silkscreen, holes shipped to my location. Or a service, which can drill some holes into the said Hammond enclosure. I dont mind paying as much as I pay for the European PCB manufacturers. There isnt a service like that, is there?

Same applies for simple stuff, like getting a plastic label. It is almost impossible to find a service like that.

[ChrisLX200]

Yes, working with sheet metal is hard going and time consuming. I had a small 12" 3 in 1 brake/shear tool but sold it about 12 months ago. Really not worth the effort. I now use pre-formed (extruded) alloy section which is available from my supplier up to 6" square which is big enough for my needs. Anything bigger I would fabricate from sheet and angles.

[T3sl4co1l]

Richard Crowley: What do you use to cut the aluminum channel stock? How do you join the corners of your box?

Ah, hacksaw, for basic starters.  Or if you have woodworking tools, any other saw (just be extra careful!).

Corners can simply be held together by the plates, or you could add angle stock to hold them, or you could partially miter the corner (into the "throat" side of the 'C', cut 90 degree triangles out of the flanges, but leave most of the web intact) and bend it that way. 

4. Thanks for the tip. I was going to start out with McMaster Carr and use blind rivets and/or threaded standoffs with low profile screws on the outside of the case. Will look around for a metal supply shop. I've always wanted a spot welder.

Also, if you're any good with SolidWorks (guessing not, haha), you can make sheetmetal sections and send the files off to a shop to have them made.  Typical shop is equipped with laser, waterjet or punch cutters, CNC benders and so on, so the cost is pretty good.

Needless to say, this shoots straight from "beginner" to "professional", but just FYI.

Once you get a feel for how to cut and form sheetmetal into useful shapes (basic geometry, folding, leaving tabs/flanges for rivets, leaving clearance for tools, etc.), you can also just do hand-sketched drawings, given that you'll either need to find someone who can turn said drawings into CAD (any ME with some free time should be able to do that for a modest price), or a shop that does it for you (in which case the cost will be rolled into your parts cost).

IIRC, a typical sheetmetal prototype run looks like 10-20 pcs, lead time 2 weeks, total cost in the low $100s.  Not exactly hobbyist fodder, but very affordable if you're starting small production, or you're a company that doesn't have a machine shop to do it in house.

Again on the note of PCBs, they can be used for structure, too.  Mikeselectricstuff has some videos on this.  PCBs are cheaper, but you have less flexibility (literally).  Creative solutions include soldering PCBs edgewise, or snapping them together (a lot of makers out there use laser cut plywood, snapped together by slots and tabs -- same idea!).

I know that MIG welding galvanized metal puts off dangerous fumes, is the same true for spot welding?

Yes, but only a small puff, since the HAZ (heat affected zone) is small.  Doing that in a well ventilated shop is no problem*.

*Unless you have metal fume hypersensitivity, in which case you might want to avoid that, too.  Zinc fume sensitivity varies by person, and by history (sensitivity tends to increase with exposure).

One catch: galv in the middle of the joint is probably not a great thing.  It should boil away as it heats up, but some will end up fused into the weld bead, some will be oxidized to slag, it might make the joint brittle or weak.  Anyway, that's physical speculation -- there'll be tons of articles about this, it's a normal industrial process.

Tim

[Andreas]

Hello,

normally I use ready made EURO-style housings like this ones:
https://www.reichelt.de/Proma-Gehaeuse/GEH-EFG-1A/3/index.html?ACTION=3&GROUPID=7728&ARTICLE=50426&SEARCH=euro%2Bflachgeh%25C3%25A4use&START=0&OFFSET=100&

https://www.reichelt.de/Proma-Gehaeuse/GEH-EG-2/3/index.html?ACTION=3&GROUPID=7728&ARTICLE=50424&SEARCH=euro%2Bflachgeh%25C3%25A4use&START=0&OFFSET=100&

perhaps etching your housings is easier than mechanical work. (same process as double sided PCBs)
here a example with 0.3 mm brass which has been chemically tinned afterwords.
Also coin cell holders can be made this way.

today I would try to do the etching job as SMD-stencil.

with best regards

Andreas

[radar_macgyver]

Tell me a service, where I upload a file and I get shipped a 1.2mm aluminium panel, with silkscreen, holes shipped to my location. Or a service, which can drill some holes into the said Hammond enclosure. I dont mind paying as much as I pay for the European PCB manufacturers. There isnt a service like that, is there?

How about Front Panel Express? Their parent company, Schaeffer AG, is EU-based. Not cheap, but they give splendid results. The other issue is the 'default' way of specifying the drawing is using their own CAD program. This can cause errors to creep in. They also have an option to work from drawings, I've never used it. They will let you send in a panel (custom material option) and machine it for you. Otherwise, they have aluminum and plastics in various thicknesses and surface finishes. They can also do post-processing (digital imaging, filling of engraved lines, etc). I've used them a lot, especially in combination with 19" enclosures from Par Metal.

[Richard Crowley]

What do you use to cut the aluminum channel stock?

A basic hacksaw and a miter box is what I used to use.  But I got a cheap cut-off saw from Harbor Freight and put a 80-tooth carbide blade on it for cutting aluminum channel.  If you are really clever, you can cut V-notches and simply fold the four sides around to make a 1-piece front, back, left, right assembly.

How do you join the corners of your box?

The front, back and sides are all separate pieces that fasten on to the top and bottom.  After machining the holes), I typically screw the front, back, and sides onto the bottom, install all the components, and then screw the top on (in the same way as the bottom)  That holds it all together. 

I sometimes use the flush side "out" (for the sides) and the "recessed" side of the channel for "inset" areas to put things like XLR connectors with those little fiddly release buttons and protect them from damage on the road.  I have made several "stage box" kinds of things using this method.  In addition to sheet aluminum, I also use textured ABS plastic sheet for the top and bottom, and sometimes even 1/4 inch or 3/8 inch plywood for really ruggedized chassis.  Sometimes I round-over the edges of the plywood and wrap it with carpet so that it looks nice, but can still take the abuse of location production. 

If I need to shield the top and bottom of plastic or wood, I simply glue a sheet of aluminum foil on the inside.  It works pretty nice.  Quite professional looking and presentable, rugged and completely customizible (length and width, and even height with different aluminum channels).  I like it a lot.

[matthuszagh]

slugrustle, hows that box and pan brake working out for you? I'm thinking of getting something similar, though I was leaning toward the eastman 3-in-1 (https://www.eastwood.com/eastwood-12-inch-3-in-1-brake-shear-and-slip-roll.html?gclid=Cj0KCQiApKagBhC1ARIsAFc7Mc553PNqexXvXmNBjWUhfkBHgDyoIhCgBEsT2pfQszcNaaSOyoVy76oaAuONEALw_wcB&wcid=18669317454&wickedid=629947574869&wickedsource=google&wv=4). I don't think I'll need anything beyond 90deg and I would use the shear.

[Martinn]

Maybe consider purchasing a plasma cutter (dirt cheap nowadays).

Even better: Have it laser cut by some local supplier. Perforate the bend lines so you can bend it by hand.
In the picture you can see my first try, next time I'll make the perforations much narrower, but longer. Closing the perforations would have been a nice aluminium tig welding exercise, but I did not feel that necessary.
Use blind rivets and press in nuts for assembly.
Having a mechanical CAD system with sheet metal capability helps (I use Alibre design).
Don't attempt this with 3 mm stainless!

For the front panels, as someone already mentioned, use a service like https://www.schaeffer-ag.de/en/front-panel-designer

Or use a aluminium PCB https://jlcpcb.com/help/newsdetail/3-New-Arrival---Aluminum-PCB-Boards,-only-$2! with silkscreen print for labeling. Currently it's only white solder mask with black silkscreen, but cheap.

[libralect]

You'll find video guides from professional alu sheet-metal folding workshops on YT.

[matthuszagh]

Maybe consider purchasing a plasma cutter (dirt cheap nowadays).

Even better: Have it laser cut by some local supplier. Perforate the bend lines so you can bend it by hand.
In the picture you can see my first try, next time I'll make the perforations much narrower, but longer. Closing the perforations would have been a nice aluminium tig welding exercise, but I did not feel that necessary.
Use blind rivets and press in nuts for assembly.
Having a mechanical CAD system with sheet metal capability helps (I use Alibre design).
Don't attempt this with 3 mm stainless!

For the front panels, as someone already mentioned, use a service like https://www.schaeffer-ag.de/en/front-panel-designer

Or use a aluminium PCB https://jlcpcb.com/help/newsdetail/3-New-Arrival---Aluminum-PCB-Boards,-only-$2! with silkscreen print for labeling. Currently it's only white solder mask with black silkscreen, but cheap.

Those results look great. What material/thickness are you using?

Unfortunately I don't really have the space for a plasma cutter at the moment, but hopefully soon - seems like a good option.

[Martinn]

A plasma cutter (hand held, not CNC!) is quite compact, at least if you have a compressor already and buy one of the cheap chinese supermarket ones:

Of course CNC would be nice, but I also don't have space for that. But I guess with guides for holes and straight cuts you could get decent hand held results as well.
Material was AlMg3 1.5 mm. For smaller desktop housings maybe 1.2 mm would be OK also, although material cost probably won't make much of a difference.
Cost was
1 pc 81 Fr.
2 pc 52 Fr.
10 pc 30 Fr.
I took two - you never know when you need another VFD...

[matthuszagh]

A plasma cutter (hand held, not CNC!) is quite compact, at least if you have a compressor already and buy one of the cheap chinese supermarket ones:

Of course CNC would be nice, but I also don't have space for that. But I guess with guides for holes and straight cuts you could get decent hand held results as well.
Material was AlMg3 1.5 mm. For smaller desktop housings maybe 1.2 mm would be OK also, although material cost probably won't make much of a difference.
Cost was
1 pc 81 Fr.
2 pc 52 Fr.
10 pc 30 Fr.
I took two - you never know when you need another VFD...

You did that without a CNC? Did you use guides? If not, your hands are steadier than mine

[Martinn]

You did that without a CNC? Did you use guides? If not, your hands are steadier than mine

No, I ordered it laser cut. I just thought that instead of hacksaw/filing a plasma cutter might be an option.
But the quality of laser cut parts is that good that you really don't want to do any more manual filing...