Custom electronics case design

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Hi--

I'm looking for a good reference guide on how to design custom plastic cases for mounting a PCB. I'm about to design a sonar beam-forming system using AVR32, and the project requires a custom case.

Does anyone know of a good book or online tutorial for this type of thing? I have access to SolidWorks 2007 software, but I would be open to other software options (such as ProEngineer) if there is sufficient information available.

Has anyone constructed a custom case? Does anyone know of a production company willing to produce a single prototype case for reasonable prices?

Thanks!

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BTW, the cases used for the AVR programmer/JTAG tools are really nicely designed!

:D

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If you are absolutely convinced that you need a custom case, then you might take a look at this site. Similar to PCB houses that supply schematic and layout software and then build the boards for you, this place will supply you with a nice 3D mechanical design package. You can then design your part from whatever material they support and, once you are done, the software will even give you a price quote. I've never used their service (it's pricey - as will be almost any outfit you find) but I have used their software to visualize parts in 3D.

One alternative you might try - take a look at what cases are available. Find one that looks like it would work and then design your project to the case, rather than the other way around. I've done this a few times and it's worked quite well. A LOT less expensive as well.

Dave

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I should have also mentioned that you would probably only want to use eMachineShop to make an initial prototype. If you are looking to market your product and need a number of cases, then there are a number of ways to replicate it fairly inexpensively. For example, Alumilite Corp. supplies materials that will allow you to cast the cases at home. They have online video demos of the process along with tutorials. I've used this stuff before and it worked quite well. Still not as cheap as a commercial case manufactured in volume, but you do get exactly the case you want.

Dave

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I think you need an industrial designer or design house who/that has experience with plastic case design. There are lot of little rules you need to know to get a manufacturable product for a minimal price.

I think the suggestion of designing your product around a commercially available case is a good one; sometimes it's possible to have them slightly customized.

Maybe this is interesting...

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I used eMachine shop a couple of years ago for a custom case.

I'm obviously not much of a case designer, but it met the needs for the project.

I laugh at their on line specifications and tolerances. There was about a 2 cm block of plastic extending on the end of my 4 boxes. They obviously forgot the last step, cutting off the extra block used to hold the box while machining it. :?

It was cheaper and faster to have a friend with a miter saw cut them for me, than to mail them back for re-machining...

Also, as is visible, on this one, the top front corners have divits, they are out of specification. Fortunately, the box I used did not demonstrate this flaw. But why publish your tolerances if you don't meet them?

Perhaps their quality monitoring has improved. I haven't used them recently, and I have no other alternatives to suggest. But such is my experience.

That said, I would use them again if I needed a small run of a custom case. I'd just allow time in the project for a few returns to get it right.

Spark Fun also has a case service now, but I have not used it yet.

Below is an image of the top of the box, holes for a series of push button switches along the front, and their coresponding LEDs just behind them. The left end is partial heigth, to allow for a true toggle switch, and its LED.

The other photo shows the hollow inside, viewed from the back and bottom.
JC

Attachment(s): 

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Thank you so much to everyone for the replies!

dharper: This is very informative, and I didn't know about the emachineshop.com site. This is definitely something to keep in mind if I need to have small pieces made for a project. As an aside, I might think of obtaining materials from Alumilite Corp if I want to make more than a few prototype copies.

jayjay1974: Yes, I agree. An industrial design house is perhaps the best way to proceed.

DocJC: It's a nice little case. Thank you so much for posting the pictures!

Nicholas

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Yes, I agree...Great thread! thanks guys!

John

Just some guy

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There are lots of other resources that could be used to create electronics cases:

How to make your own Plastic Vacuum Former:
http://www.instructables.com/id/...

Make a good, cheap, upgradeable sheet plastic vacuum former:
http://www.instructables.com/id/...

make plastic 3D models from CAD designs using an automated "milling machine":
http://www.instructables.com/id/...

Poor Man's (not so rapid) Prototyping Method for the Fabber-less:
http://www.instructables.com/id/...

Home injection molding:
http://www.instructables.com/id/...

An injection-molding machine:
http://www.injectionmolder.net/

3D printers:
http://www.zcorp.com/

Low-cost 3D printer
http://www.desktopfactory.com/

Build your own 3D printer:
http://fabathome.org/wiki/index....

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Make your own plastic injection molding machine:

http://www.lindsaybks.com/dgjp/d...

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Nice links:-)

John

Just some guy

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Here's another:

http://www.polycase.com/article/...

They have a really inexpensive catalog with lots of models, but I have never got them to quote a custom enclosure...

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Neat. I like the Desktop/Instrument series...

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Oh, the joy of rediscovering a thread!! I used that special 'Freaks feature, SEARCH, before posting a new thread! (lifts head proudly)

John

Just some guy

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My boss will give you a quote for a nice machined aluminum case in 10 100 1000 qty. Email dave@aircraftinstruments.com with a drawing/picture.

Imagecraft compiler user

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Interesting timing on the response. At the time I first replied to this thread, I was starting a hobby project with a main board which consists of an AT91SAM7X512 along with three ATMega164P microcontrollers. It contains a ZigBee link which communicates with 18 remote XMega32A based units. As indicated in a previous post, I guesstimated the main board area up front, picked a Polycase unit that would contain the board (their SL-64P unit) and then designed the board around the case. The project is nearing completion and, over the past week I am now at a point where the case is the primary focus. I have a CNC milling machine (a Taig unit) and am in the process of milling out the case for the numerous connector cutouts.

This is working out okay but this thread (and my early decisions) are now over four years old, which is a lot of time where technology is concerned. If I were starting the same project today, I would probably approach case design from the standpoint of a 3D printer. The advances made in this area over the past four years are awesome. Prices are cheaper, materials are better and quality (print resolution) is vastly improved. You have two choices here - you can do your design and submit it to a service house which will create your custom case for a price, or you can spring for a printer and do it yourself. Just for a check, I recently submitted my current case design to a 3D printing service house and got a quote of around $50 (US) for a single unit or $40 each for two units. Not bad, but on the other hand 3D printer costs are coming down a lot. I'm currently looking at two units that I may use for the next project. The first is MakiBox A6 (www.makible.com) which will produce a case up to 6" x 4.5" x 4.5" and has an incredibly low price of $300 (US)! The other one is the Ultimaker (www.ultimaker.com) which is a bit more expensive (~$1550 US) but has a bigger print envelope (8.25" x 8.25" x 8") and great resolution. Both use free and open source software which means you can design the case using something like Google 3D Sketchup (free and supported by a supurb video tutorial series) along with various open source translation tools that translate to the STL or gcode needed by the printer.

I truly believe that 3D printing is the wave of the future (until it's replaced by something even better). The time that I've spent taking an off-the-shelf case and writing CNC programs to mill the top and bottom parts to fit my needs could have just as easily have been spent designing a 3D model of a case that was as good or better than what I settled for. Plus, there's the advantage of getting to play with a new and exciting technology.

Dave

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3D printing - do a road trip to Round Rock, Texas (recently opened):
TechShop - Round Rock
Dallas Makerspace may have some tools:
http://dallasmakerspace.org/wiki/Tools#Crafts

"Dare to be naïve." - Buckminster Fuller

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I'm amazed nobody has mentioned protolabs yet. They can do a machined version for prototyping [or small runs] as well as the injection molded parts. They have lots of good tips/info for things to do or look out for.

I use SolidWorks, and have designed several cast enclosures [both plastic and aluminum] with it without problem, so there is no real need to move to Pro/E unless you really want to. Virtually any CAD package will work, so use whatever you're comfortable with. [Sketch-up does not count as a CAD package, despite what may DIYers will say][/url]

Writing code is like having sex.... make one little mistake, and you're supporting it for life.

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My brother has been researching 3D printers and the material cost is CRAZY high right now. Most of what we discovered thus far has ranged from 10G to 30G's.

Then he found this -

http://www.nextengine.com/products

Wow, this is amazing!! We may pull the trigger on this...depending on cost estimates for prototypes!!

John

Just some guy

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I like those Polycase options.

 

"We trained hard... but it seemed that every time we were beginning to form up into a team, we would be reorganized. I was to learn later in life that we tend to meet any new situation by reorganizing. And a wonderful method it can be of creating the illusion of progress while producing confusion, inefficiency and demoralization." Petronius Arbiter, approx. 2000 years ago.

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johnrk wrote:
My brother has been researching 3D printers and the material cost is CRAZY high right now. Most of what we discovered thus far has ranged from 10G to 30G's.

Then he found this -

http://www.nextengine.com/products

Wow, this is amazing!! We may pull the trigger on this...depending on cost estimates for prototypes!!

John

John, your link is for a 3D scanner, not a printer, or anything else.

As for 3D printers there are plenty of options that are affordable, but the output of any 3D printer is not really good as a commercial product, but is fine for prototypes. FDM/FFF printers will produce some of the most durable products, but are also one of the lowest resolution printers. Makerbot, Ultimaker, RepRap are all examples of FDM/FFF printers. There are hundreds more in the DIY'er price-range... commercial units can run it to the 10's of thousands, the DIY/Maker community ones are in the high hundreds to low thousands... the ABS & PLA filament used by those printers is not all that expensive either, but expensive when compared to plastic pellets used in injection molding]

Writing code is like having sex.... make one little mistake, and you're supporting it for life.

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Nice thing about asking Dave for a quote is that he has the Hurco VM1 in the next room and has a full time dude on staff that knows how to chuck the aluminum block in the machine and hit the Big Green Button.

Imagecraft compiler user