Trying to make affordable metal case for custom PCB

[cmckilla44]

Hello all,

I posted on this forum a few months ago to get some technical support with a PCB I was designing. You guys really helped me out.

I'm up against another quandary, though. My PCB works perfectly; I just need to find an economic enclosure to protect it. I will upload some pictures so you guys can see exactly what I have so far.

The dimensions are as follows: Width: 183mm; length: 152.4mm. height: 25mm.

Where could I get a case for this made? Also, should I have the case maker do the cutouts or should I do them myself? Has anyone else here made a custom PCB and found a great case for it?

Thanks for your help!

Clay

[cdev]

Do you want to get a case custom designed for a project you're going to build a lot of, or just one?

Re-reading your post, I get the feeling you want to pay to have a nice case made. There I cant help you. Thinking about it its likely my answer below isnt really what you're looking for, I'm sorry. I was thinking about a case I need to build too. I am always trying to save money.

Suppose you just want one case and it needs to appropriately protect the row of rj45 jacks..

Of course there are parametric searches for cases on the major electronics vendor sites and you should be able to find a case thats larger than your device but not so large it gets lost in there. But as you said getting the panel holes (punched out of metal?) is likely not so easy. But i bet if you look around you may be able to find a ready to go panel with the holes at the proper distance.

If its a one off device, the RJ45 size square holes might also attainable by using another device, re-purposing another device.. something you got cheaply, perhaps because its obsolete and mounting your device inside of it?

Something network related (an old network switch or hub) might give you the jacks you need, but you may have to move the jacks to fit it..  That might work out well.

If that sounds right you might find such a device on ebay - maybe an old switch or hub or similar- lots of networking hardware doesnt support gigabit Ethernet and so is selling for a fraction of what it originally cost- you can discard the guts and use the box and perhaps also the jacks..

 I am in a similar situation with several projects and what I often do in the interests of getting the projects out of harms way is mock up cases using plain cardboard boxes, sometimes it works out so well I just leave them there..

However, I have a very nice paper cutter that makes cutting perfectly rectangular pieces of cardboard exactly to any given size very easy to do. That helps a lot.

The clear plastic looks nice. its a shame it broke.

[ovnr]

"Custom" and "affordable" don't really go hand in hand.

Try Protocase. Have heard good things, but never used them myself because I'm a cheap bastard.

[cmckilla44]

cdev,

Thanks for your help. Yes, I am trying to look on Aliexpress and other cheaper sites for solutions that I can adapt to my needs. Would be awesome if I could find a case maker that would go ahead and make the cutouts. I can do it if need be though.

That is a very good idea, I will have to look into that.

I would be open to using a cheaper solution like cardboard; however, my PCB will be used in a data center. So I am looking for something that protects the PCB and can be mounted to server racks.

Yeah... I tried to make a case with standoff screws and plexiglass, but it is very difficult to do. I thought it looked nice too! It's just hard to drill and mount plexiglass to racks without the plexiglass breaking.

Thanks again for your reply!

Clay

[cmckilla44]

ovnr,

Thanks for your response. Yes, that is what I have started to figure out. Just trying to see if any other makers out there have found a great solution that isn't several times the cost of the PCB itself.

I did look at using Protocase. What I found, though, is that they charge quite a bit for a very simple 3D printed case. The CNC milling cost was exorbitantly expensive, unfortunately.

I am beginning to think my only option is to adapt another case to my needs.

Thanks for your response!

Clay

[cstratton]

You need to think about what your goals are.

For example, why metal?   If it's because it feels solid or might be more durable, fine, but if you are thinking of that for shielding, it's not enough to just have some aluminum folded into a metal box with some PEM studs pressed in, you need to consider all the openings in it.

You mentioned the case cost vs. the board cost - which raises the idea of possibly re-designing the board to fit an existing generic case - what you have there looks a lot like a multi-port Ethernet switch.

[cdev]

Thinking about it, I am wondering, - a rack mounted hosting facility is also likely to have very stringent rules that whatever they put in their (locked down) co-location racks is built in a manner as to minimize risks to other equipment of fire.

ALL networking facilities especially colo facilities have very expensive fire suppression systems, and I think the chance is very high that special rules apply to whatever gets used in that setting that dont for home or even most commercial equipment.

Any large colo company also probably has their own rules and thats one of the questions that customers likely often ask so they likely hve a PDF or something laying it out they can point you to.

They may not even allow you to use something thats not "UL rated" or (insert local protection agencies) or something like that. In the EU its possible both EU and national rules might apply.

Check!

Some probably treat it on a case by case basis. But don't push your luck. If I were you before you even bring the issue up, I would put your device in a case that screamed "well made", "well fused", etc.

The issue is likely to come up, so be ready with all the data you need to show them its well made and especially, as fireproof as is possible.

[hlavac]

Most 3D printers would fit 200x200 mm (or close to).
I would totally 3D print a case on a FDM printer.
From black ABS preferably if you want it to last.
Its one of the most useful applications I have found for my 3D printers.
Find someone local with a 3D printer

[stmdude]

I've been meaning to investigate Front Panel Express myself. Maybe that'll fit your needs?

https://www.frontpanelexpress.com/

( They make entire enclosures as well )

[cmckilla44]

cstratton,

The reason I wanted to make a metal case was so that I could easily mount it to server racks. I was thinking that it would be difficult if I used plastic, especially 3D printed plastic, to mount to the racks.

You are right, redesigning the PCB may be the best option... I am still considering that. It does look a lot like a switch; I am using it as a reboot switch for 60 different servers.

Thanks for your feedback!

Clay

[suicidaleggroll]

I've been meaning to investigate Front Panel Express myself. Maybe that'll fit your needs?

https://www.frontpanelexpress.com/

( They make entire enclosures as well )

You can also go with a standard off-the-shelf enclosure from someone like Hammond, and then have FPE just make the front/back panels for you (might be cheaper than full custom).

[cmckilla44]

cdev,

That is a great idea. maybe that will be the best option for me. Thanks for bringing that up.

A fire could be a potential hazard... In all my testing of this PCB, no part of it has gotten hot enough to come close to starting a fire. But, of course, we have to prepare for the worst-case scenario. 

The visuals are important, though. It doesn't need to be perfect... just something that is solid, well-protected from the outside environment, and somewhat visually appealing. And does not cost twice as much as the PCB itself LOL.

Thanks,
Clay

[cmckilla44]

Most 3D printers would fit 200x200 mm (or close to).
I would totally 3D print a case on a FDM printer.
From black ABS preferably if you want it to last.
Its one of the most useful applications I have found for my 3D printers.
Find someone local with a 3D printer

hlavac,

I looked into the 3D printing option. Unfortunately, I could not print a simple box this size for less than $30. Is there something I am doing wrong? Could I do it for cheaper?

Thanks,
Clay

[cmckilla44]

I've been meaning to investigate Front Panel Express myself. Maybe that'll fit your needs?

https://www.frontpanelexpress.com/

( They make entire enclosures as well )

You can also go with a standard off-the-shelf enclosure from someone like Hammond, and then have FPE just make the front/back panels for you (might be cheaper than full custom).

suicidaleggroll,

Hm. That may be a good option! I was able to find a premade case on Amazon for $10. I could modify it myself with a dremel... Just want to review my options before I do so.

Thanks,
Clay

[jmelson]

Check Digi-Key, they have, LITERALLY, about 10,000 cases/cabinets/enclosures, and a parametric search engine that can winnow it down by material, size, etc.  I have found this quite useful a couple times when I had something I needed a snug box for.

Jon

[Richard Crowley]

I would think that fire/UL/certification, etc. would be covered by the wall-wart (or line-lump?) external power supply.  Your board appears to want low-voltage power input through the "inverted-phone" power connector.

As others have mentioned, if you need to have it rack-mounted, you really need an aluminum or steel rack-mount chassis.  Several manufacturers make stock items that are available off the shelf.  For example: BUD CH-14401  That style available in several different depth dimensions to suit your board.


Even available from Amazon!  (at an inflated price)  depends on how carefully you shop on Amazon.
I found them from another vendor for the same price as Mouser/Digi-Key/Allied (within a few cents)

I didn't see where you mentioned whether this was a one-off, or some production-run of several?

If this is going to be deployed elsewhere by others, and especially if it has any kind of critical dependents, I would want to at least make two of them, one for production and one as a "hot standby".

[cmckilla44]

Check Digi-Key, they have, LITERALLY, about 10,000 cases/cabinets/enclosures, and a parametric search engine that can winnow it down by material, size, etc.  I have found this quite useful a couple times when I had something I needed a snug box for.

Jon

Jon,

Thanks for your feedback! I will look through those cases!

Thanks,
Clay

[cmckilla44]

I would think that fire/UL/certification, etc. would be covered by the wall-wart (or line-lump?) external power supply.  Your board appears to want low-voltage power input through the "inverted-phone" power connector.

As others have mentioned, if you need to have it rack-mounted, you really need an aluminum or steel rack-mount chassis.  Several manufacturers make stock items that are available off the shelf.  For example: BUD CH-14401  That style available in several different depth dimensions to suit your board.


Even available from Amazon!  (at an inflated price)  depends on how carefully you shop on Amazon.
I found them from another vendor for the same price as Mouser/Digi-Key/Allied (within a few cents)

I didn't see where you mentioned whether this was a one-off, or some production-run of several?

If this is going to be deployed elsewhere by others, and especially if it has any kind of critical dependents, I would want to at least make two of them, one for production and one as a "hot standby".

Richard,

That's right. It only requires 12V DC and could run on even less voltage than that. It's simply a DC power jack.

I will be making several of these for the data center at which I work. Something that is rack mountable would be nice.

Thanks,
Clay

[Richard Crowley]

You might want to re-design the PCB with DFM in mind (Design For Manufacturability)
At least with all the external connections on the same edge.
Making a board with connectors on opposite ends severely limits your enclosure options.
As well as how it is installed/deployed.  Do you really want half the connections in the "front" and the other half in the "back"?

Consider designing it with two boards sandwiched together and half the RJ45/8P8C on each board, facing the same way (i.e. the back panel of the rack chassis)
So that all the external connections are in the same plane ("front" or "back" as the application needs)

[floobydust]

I tried Protocase but they ended up being crazy expensive once the CADD import and setup fees are included. Quality was very good but my butthole still hurts.

I found modern (CNC, laser cut) sheet-metal shops have a wide variety in terms of price. Some are older Union-based labour shops and mostly pot-heads manually bending things, like in the HVAC industry. Expensive and sloppy work, they've never heard of PCB mounting (PEM fasteners).

You have to shop around, be flexible.
Higher volumes Hammond, Hoffman, Budd will do the cutouts for you, if you use one of their off-the-shelf enclosures.

[Richard Crowley]

OTOH, I recall a photo (or YouTube video) showing some mega server-farm (Google?  Facebook?  et.al) where they had hundreds of racks with practically bare motherboards in an open chassis (or just a rack shelf with a power supply and a hard drive).  Apparently cheaper and more efficient for cooling as well.  They could replace a motherboard, power-supply or hard-drive in a matter of seconds.

[cdev]

Richard, that might have been Facebook's newish data center in Scandinavia.. (Norway, maybe?) They are building in places where there is year round cooling available.

Google, Facebook have likely built their entire rack infrastructure around their own specific high density hardware solutions, I bet.

I wonder if there are any international specifications connected to modern data center hardware.. some official specification for server rack resident hardware. There must be,

[Mechatrommer]

I looked into the 3D printing option. Unfortunately, I could not print a simple box this size for less than $30. Is there something I am doing wrong? Could I do it for cheaper?

other than one time the printer cost, 1 roll of filament is the cost of that, and 1 roll can print many many stuffs incl your enclosure... other option is you may snap some sheet metal work and screws or glue to make your one-off enclosure... other option is find the dedicated manufacturer such as takachi produces rack mount enclosures, but getting the supplier to accept your money and send the item to your doorstep can be the hardest chore... http://www.takachi-enclosure.com/data/c16-17/MSR.pdf

[hlavac]

I looked into the 3D printing option. Unfortunately, I could not print a simple box this size for less than $30. Is there something I am doing wrong? Could I do it for cheaper?

Well I have done a rough calculation. For a box with 3mm thick walls around the size you gave the volume is 0,0002308356 m^3 which gives for ABS density of 1045 kg/m^3 about 240g of filament. Let's say quarter of a 1kg spool. I can get a 1kg spool of black ABS for about 600 CZK (VAT included!) from commercial sources which is about $27.4, so quarter of that should be less than $7. In reality I have even cheaper sources (~$22 per 1kg spool) so about $5.5 on material.

Note this is for a solid 3mm thick walled hunk of plastic box. In reality you would save on filament with structured walls and there will be lots of holes for the connectors, so it should be even less.

There must be something else added in your quote - $25 profit on a $5 job?

Printing ABS is tricky so there may be some fails, I would print the enclosure in parts to minimize risk (bottom plate, top plate, front panel, rear panel, two sides).

My advice is, get a 3D printer that can print ABS. I recommend Prusa MK2 and a heating fan. Ask me for tips if you do

[cdev]

Re: fire safety in data centers..  A very little Googling brought me to this.. You should be able to do much better.

The specific code that you are more likely than not to need to meet with your equipment if its put in a colo is:

ANSI/UL 60950-1

and it's currently being revised.. (its revised every three years) so you should also ask what requirements are likely to be in place in the near future, even if they aren't yet today.