Over the past year or so I've been building a selling a few specialized
products where the production runs are low, and cost is an issue. I'm
generally looking at products in the $100ish and under price range, and
production runs of around 100 or so.
Unfortunately, it seems that 25-50% of the cost of these products often
end up in the enclosure (you know, $10 components+ PCB, $5 enclosure, or
$100 components+PCB, $50 enclosure).
As I've got some products coming which are even more cost sensitive
enclosure-wise I figured I'd ask the list if I'm missing some low-cost
options.
Just to get this started, let me mention what I've looked at/what I'm
looking at...
I've looked at some of the standard enclosure manufacturers (PacTek and
the like), and it always seems that the enclosures are a) too expensive
at the low end, b) not the right size, and c) a pain to modify to my
needs. I'd love to hear if someone has had good luck making these type
of enclosures work, and if so, how they went about getting holes cut
which are consistent and look professional.
Currently I'm using envision plastics, which basically takes sheets of
plastic, puts them on a CNC table and cuts them, then bends them.
Kinda like making a sheet metal box but with plastic. I've been happy,
but I still think I could do better price-wise somehow... This is my
fallback position.
I've kinda looked at epoxy potting/encapsulation with some sort of
homemade mold. I.E. build and test the circuit then turn it into a
brick of epoxy with wires/connectors coming out of it. This is
intriguing but leaves me a lot of questions I can't find the answers to
(like what components aren't compatible with this, or how do you keep
it out of connectors, etc. etc. etc). I'd love to hear of any
experiences with doing this. Regardless, there's lots of projects
which this wouldn't be useful for anywas.
The last thing I've looked at is building the enclosures myself with
vacuum forming or something like that. Again, more questions than
answers.
So maybe what I'm really looking for is some ideas/resources which I
haven't looked at yet.
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Forrest,
Exactly what quantity per:
build (or run) ?
month ?
year ?
More options as quantities rise.
Potting works the best for VERY low builds if you design pc board with all the connectors on one end.
Ray
On Sun, 01 Oct 2006 18:18:21 -0600, Forrest Christian wrote: {Quote hidden}
> Over the past year or so I've been building a selling a few
> specialized products where the production runs are low, and cost is
> an issue. I'm generally looking at products in the $100ish and
> under price range, and production runs of around 100 or so.
>
> Unfortunately, it seems that 25-50% of the cost of these products
> often end up in the enclosure (you know, $10 components+ PCB, $5
> enclosure, or $100 components+PCB, $50 enclosure).
>
> As I've got some products coming which are even more cost sensitive
> enclosure-wise I figured I'd ask the list if I'm missing some low-
> cost options.
>
> Just to get this started, let me mention what I've looked at/what
> I'm looking at...
>
> I've looked at some of the standard enclosure manufacturers (PacTek
> and the like), and it always seems that the enclosures are a) too
> expensive at the low end, b) not the right size, and c) a pain to
> modify to my needs. I'd love to hear if someone has had good luck
> making these type of enclosures work, and if so, how they went
> about getting holes cut which are consistent and look professional.
>
> Currently I'm using envision plastics, which basically takes sheets
> of plastic, puts them on a CNC table and cuts them, then bends
> them. Kinda like making a sheet metal box but with plastic. I've
> been happy, but I still think I could do better price-wise
> somehow... This is my fallback position.
>
> I've kinda looked at epoxy potting/encapsulation with some sort of
> homemade mold. I.E. build and test the circuit then turn it into
> a brick of epoxy with wires/connectors coming out of it. This is
> intriguing but leaves me a lot of questions I can't find the
> answers to (like what components aren't compatible with this, or
> how do you keep it out of connectors, etc. etc. etc). I'd love to
> hear of any experiences with doing this. Regardless, there's lots
> of projects which this wouldn't be useful for anywas.
>
> The last thing I've looked at is building the enclosures myself
> with vacuum forming or something like that. Again, more
> questions than answers.
>
> So maybe what I'm really looking for is some ideas/resources which
> I haven't looked at yet.
>
> Ideas?
>
> -forrest
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I've also had problems with enclosures. We generally use CNC punched and
bent sheet metal. It's not very cheap, but we get what we want. We also
use some plastic enclosures that support flat panel inserts. We have these
panels CNC punched, then drop them in to the plastic cabinet (see the
IQ512 at http://www.dovesystems.com). In one project, we used a standard
PacTec box and had them do the additional holes. We provided them with
drawings and they shipped the first run of something like 500 pieces with
the holes in the wrong place. They got it right on the second run (which
they did for free). The result is at http://www.brailletutor.com . I've
also done several projects for other companies where I've worked with
mechanical engineers who design custom plastic enclosures. These are
considerably larger production volumes. I've also seen a company that
specializes in custom metal panels (punching, labeling, etc.), but have
not used them. I'd be interested in hearing what others are doing to keep
enclosure costs below electronic costs.
>Forrest,
>
>Exactly what quantity per:
>build (or run) ?
>
>
Generally I build about 25-30 of any given assembly at a time, but
that's more related to how many I can easily fit on the amount of
workspace I have right now (which will be increasing shortly). I have
one unit that I do 44 of (4 rows of 11 fit in the area I work with), and
another I do 24 of (4 rows of 6).
For the most part, I'd be comfortable actually doing runs of around 100
at a time.
>month ? year ?
>
>
The unit I sell the most of do about 50/month of on average. I've got
another product coming which I expect to double or triple that.
>More options as quantities rise.
>
>
I realize that. Unfortunately I'm at the low end of the scale, or so it
seems.
>Potting works the best for VERY low builds if you design pc board with all the connectors on one end.
>
>
Is the idea that that end is "up" in the mold? I.E. you build the board
such that everything which needs to stick out is on that end, then you
dunk the board such that that end is still out of the epoxy?
My main concern about the potting/encapsulation is things like "what
happens when I have a capacitor decide to blow apart", and "will
component X fail (due to heat, or just the epoxy, etc).
I've got a couple of "wart in the middle" type of apps which the
encapsulation seems ideal for... I.E there's no displays, there's no
moving parts, just a couple of connectors (and/or cables sticking out),
assuming that the tantalum caps don't turn it into a small epoxy bomb.
That said, I've also got some stuff though which needs a bit more
interaction (buttons, leds, lcd's, etc) which makes me think that
potting isn't the end all be all answer. Not to say I don't want to
play with the potting/encapsulation since I think it's an interesting
option for many things I plan to do.
Forrest Christian wrote:
> Over the past year or so I've been building a selling a few specialized
> products where the production runs are low, and cost is an issue. I'm
> generally looking at products in the $100ish and under price range, and
> production runs of around 100 or so.
>
> Unfortunately, it seems that 25-50% of the cost of these products often
> end up in the enclosure (you know, $10 components+ PCB, $5 enclosure, or
> $100 components+PCB, $50 enclosure).
>
>
This is the real bugaboo of us small design & mfr companies. Our
products are generally the size of two-way mobile radios and must be
made of metal (aluminum) since they are used in RF environments. We
have sheet metal companies punch, drill, fold and paint our enclosures.
It seems like no matter what product we're working on, then enclosure
always costs $30 +/- 10% in qty 100-200.
I get custom folded/punched metal boxes from my friend in Thailand.
two piece
0.030" thick steel
electrostatic black epoxy paint
white silkscreen legend
13.68" x 5.35" x 1.45"
tooling about $200
unit price about $7.00
100pcs minimum purchase BUT
UPS shipping for 24 pcs is about $120 (25kg UPS shipping box)
Ray
On Sun, 01 Oct 2006 20:44:28 -0600, Forrest W Christian wrote: {Quote hidden}
> Ray Newman wrote:
>
>> Forrest,
>>
>> Exactly what quantity per:
>> build (or run) ?
>>
>>
> Generally I build about 25-30 of any given assembly at a time, but
> that's more related to how many I can easily fit on the amount of
> workspace I have right now (which will be increasing shortly). I
> have one unit that I do 44 of (4 rows of 11 fit in the area I work
> with), and another I do 24 of (4 rows of 6).
>
> For the most part, I'd be comfortable actually doing runs of around
> 100 at a time.
>
>> month ? year ?
>>
>>
> The unit I sell the most of do about 50/month of on average.
> I've got another product coming which I expect to double or triple
> that.
>
>> More options as quantities rise.
>>
>>
> I realize that. Unfortunately I'm at the low end of the scale, or
> so it seems.
>
>> Potting works the best for VERY low builds if you design pc board
>> with all the connectors on one end.
>>
>>
> Is the idea that that end is "up" in the mold? I.E. you build the
> board such that everything which needs to stick out is on that end,
> then you dunk the board such that that end is still out of the
> epoxy?
>
> My main concern about the potting/encapsulation is things like
> "what happens when I have a capacitor decide to blow apart", and
> "will component X fail (due to heat, or just the epoxy, etc).
>
> I've got a couple of "wart in the middle" type of apps which the
> encapsulation seems ideal for... I.E there's no displays, there's
> no moving parts, just a couple of connectors (and/or cables
> sticking out), assuming that the tantalum caps don't turn it into a
> small epoxy bomb.
>
> That said, I've also got some stuff though which needs a bit more
> interaction (buttons, leds, lcd's, etc) which makes me think that
> potting isn't the end all be all answer. Not to say I don't want
> to play with the potting/encapsulation since I think it's an
> interesting option for many things I plan to do.
>
> -forrest
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