Hello--

I am working on a custom electronics system which ultimately requires a
hand-held case design. Moreover, I would like to use Pro/Engineer to
model the electronics case for production using a rapid prototyping
system. Consequently, I am wondering if anyone would know of a good
book, paper or tutorial on electronics case design, preferably using
Pro/Engineer.

How would I align the circuit board inside the case with the outside of
the case? How do I create standoffs for the circuit board? How do I
effectively deal with the routing of wires inside of the case? Perhaps
there are more general books that are available on this type of design.
Does anyone have a suggestion?

As an aside, I am also curious as to how it might be possible to design
an enclosure for an electro-optical system. How would I integrate
lenses and an optical system into the enclosure? Are there standard
mounting parts for lenses which I can model in Pro/Engineer (and then
produce using rapid prototyping), or would I simply purchase
"ready-to-order" mounting parts?

Nicholas

Hi there,

yep, I should have written that book long ago (if I only had time).
On the other hand, I guess it would not sell by the million.

Answers to your questions require additional information:

- what does that hand-held have to look like?
- will it require some elegant industrial design?
- who´s going to use this device later on?
- does the housing allow for maintenance later?
- in which environment will it be used?
- how long is its planned lifetime?
- how many of these will be produced eventually?
- what overall production costs are allowed?
- what EMI specs will be applied?
- who is going to produce it and where?
- what materials are desirable/undesirable?
- which methods of production are considered?
- etc. pp.

You´ll need a lot of knowledge about electronics (not only housing),
and standard engineering expertise too, e. g. from sheetmetal,
plastic injection molding, power supply and thermal management...
...yes, one could very well write a book about.

You may omit some design criteria if RP is the way of choice,
but then you´re stuck with high costs and no way to ramp up numbers.

Perhaps you´d better look for some experienced consultant :-)

Through trial end error you will easily waste lots of both money
and manpower and make the product a complete failure anyway,
especially when you´re not an ace with Pro/E´s functionalities.
You will sure have to adapt design to demands that show up later on.

Walther


Nicholas Kinar schrieb:
Hello--

I am working on a custom electronics system which ultimately requires a
hand-held case design. Moreover, I would like to use Pro/Engineer to
model the electronics case for production using a rapid prototyping
system. Consequently, I am wondering if anyone would know of a good
book, paper or tutorial on electronics case design, preferably using
Pro/Engineer.

How would I align the circuit board inside the case with the outside of
the case? How do I create standoffs for the circuit board? How do I
effectively deal with the routing of wires inside of the case? Perhaps
there are more general books that are available on this type of design.
Does anyone have a suggestion?

As an aside, I am also curious as to how it might be possible to design
an enclosure for an electro-optical system. How would I integrate lenses
and an optical system into the enclosure? Are there standard mounting
parts for lenses which I can model in Pro/Engineer (and then produce
using rapid prototyping), or would I simply purchase "ready-to-order"
mounting parts?

Nicholas

yep, I should have written that book long ago (if I only had time).
On the other hand, I guess it would not sell by the million.

Answers to your questions require additional information:

- what does that hand-held have to look like?
- will it require some elegant industrial design?
- who´s going to use this device later on?
- does the housing allow for maintenance later?
- in which environment will it be used?
- how long is its planned lifetime?
- how many of these will be produced eventually?
- what overall production costs are allowed?
- what EMI specs will be applied?
- who is going to produce it and where?
- what materials are desirable/undesirable?
- which methods of production are considered?
- etc. pp.

I agree. The topic is worth a book, probably a whole degree program. The
books that Spehro Pefhany mentioned are a good place to start in getting a
handle on plastic, injection molded enclosures. But, as Walter pointed out,
sheet metal ones are also prevalent. Considering the history, extending
back
to the first radios and auto and aircraft instrument panels, the problems
and solutions have been around for a century.

A practical place to start might be project based tutorials. Consider
this site and some of its projects; it's loaded with them:
http://www.sparkfun.com/commerce/tutorials.php
Some of them make it pretty clear that a legitimate approach is to find
a commercial box and to start modifying it to fit a board, screens,
ports, plugs, switches, etc. I think they also make it pretty clear
that all enclosure issues begin with the board and its function and
requirements. The board raises questions like how will it be powered?
how will it communicate with peripherals, humans? will it generate
enough heat to require special cooling that an enclosure must
accommodate? will it generate or be effected by EMI/RFI and have to be
isolated from these effects? will the board and mounting have to
withstand vibration, shocks, dust, salt fog or other extreme
environmental effects? will it be mounted like a control box on a
machine or be hand held like a cell phone?

The answers to these questions greatly effect both board and enclosure
design. But the problem set is quite specific to application. The more
you can narrow the field, the more you gain access existing solutions
and resources.

David Janes

Thanks for your response, David!


I agree. The topic is worth a book, probably a whole degree program. The
books that Spehro Pefhany mentioned are a good place to start in
getting a
handle on plastic, injection molded enclosures. But, as Walter pointed
out,
sheet metal ones are also prevalent. Considering the history,
extending back
to the first radios and auto and aircraft instrument panels, the problems
and solutions have been around for a century.


A practical place to start might be project based tutorials. Consider
this site and some of its projects; it's loaded with them:
http://www.sparkfun.com/commerce/tutorials.php
Some of them make it pretty clear that a legitimate approach is to
find a commercial box and to start modifying it to fit a board,
screens, ports, plugs, switches, etc. I think they also make it pretty
clear that all enclosure issues begin with the board and its function
and requirements. The board raises questions like how will it be
powered? how will it communicate with peripherals, humans? will it
generate enough heat to require special cooling that an enclosure must
accommodate? will it generate or be effected by EMI/RFI and have to be
isolated from these effects? will the board and mounting have to
withstand vibration, shocks, dust, salt fog or other extreme
environmental effects? will it be mounted like a control box on a
machine or be hand held like a cell phone?


Great tutorials. I've heard of Sparkfun before, but I didn't know that
they offered all of these tutorials. I'd like the case to be hand-held.



The answers to these questions greatly effect both board and enclosure
design. But the problem set is quite specific to application. The more
you can narrow the field, the more you gain access existing solutions
and resources.

So, what does the board look like that we're building this box around.
Since you're insisting it will be hand held, you must know the size and
approximate volume, maybe even the location of most inputs and outputs?
What will power it, i.e., how much power does it require? Hand held, to
me, means anything from a battery powered cell phone to a chorded, 5
pound machine controller with 30 buttons. The cell phone has a nice
plastic case, the machine controller, plastic over sheet metal.
Handhelds come in a thousand different sizes, shapes, weights and
complexities. Again, it's a very loose definition of a requirement. You
can help us help you with something more precise, more exacting.

So, what does the board look like that we're building this box around.
Since you're insisting it will be hand held, you must know the size
and approximate volume, maybe even the location of most inputs and
outputs? What will power it, i.e., how much power does it require?
Hand held, to me, means anything from a battery powered cell phone to
a chorded, 5 pound machine controller with 30 buttons. The cell phone
has a nice plastic case, the machine controller, plastic over sheet
metal. Handhelds come in a thousand different sizes, shapes, weights
and complexities. Again, it's a very loose definition of a
requirement. You can help us help you with something more precise,
more exacting.


Hi David--

Thanks again for your response. We're looking at a PCB that is slightly
larger than 9 cm by 15 cm by 2 cm. The transducer assembly is located
at the front of the case. The inputs (power plug and USB) will be
situated near the back of the case. The circuit will be powered by a
Li-Ion battery pack placed inside of the enclosure. Preferably the
circuit will have a plastic case. I'm thinking of using a rapid
prototyping machine to produce the case.

So, it sounds like you need a couple openings in your case in the back,
some standoffs for mounting the board and some standoffs for mounting
the cover. The best method would be FDM. Find an RP outfit with a
Stratasys Dimension 'printer'. They use ABS plastic, the parts are fast
and accurate and usable out of the machine.