Metal enclosure

[Steve]

I want to make a metal enclosure for an electronics product. The enclosure
will be 4" wide, 6" long, 1" high. Up till now I've been using an
off-the-shelf standard extruded aluminum case. The main cost has been the
CNC milling of the front and rear panels (they both have a few holes for
connectors/buttons/LEDs). Plus it is a real pain to assemble, since the
front panel is glued to the sides in order to avoid screws showing through
(it's a consumer item). Now I am hopefully going to make them in bigger
batches (500s or so), I've been looking at other approaches to save money
and make assembly easier. So far, the alternatives I've thought about are:

a) Stay with the extruded aluminium and face plates, but use a stick-on
overlay over the front panel, so I can have screw holes in the panel behind
it. However, on such a small unit, I am worried that registration between
overlay and panel (and bubbles?) will make this problematic or at least be
slow during assembly - the less skill/judgement decisions required during
assembly, the better

b) Use a folded aluminium enclosure, one piece for base, front and rear, and
one piece for top and sides. Although this would get rid of the screws
needed to hold the box together, I still need some way of attaching a small
PCB with buttons and LEDs behind the front panel (I'm using foam and glue
for this at the moment!). I guess I could use blind fasteners for this, but
maybe that is not the best/cheapest solution.

c) A mod of (b) that seems to be used for DVD players etc. - folded aluminum
plus a plastic clip-on front panel to make it look nice. The metal panel
behind could then have all the screw holes etc. it needed. Not sure if the
cost of making the plastic panel is feasible for my quantities (500's)

Can anyone please suggest another approach, or comment on those above.

Many thanks,
Steve

 

[Steve]

Steve, just some thoughts.....

Is using a 'c' shape extrusion with slots for the PCB to run in possible - a
single sided PCB with 'reverse mounted' leds (via a 2/3/5mm hole in the
board or use SMD 'flipside' leds so the PCB becomes the 4th side of the
enclosure. Silk screen the outside face of the PCB. Without knowing the
application this may or may not be suitable.

That's an amazing idea that I've never come near to thinking of so far. I
didn't say, but there are also three 7-seg LED digits and some 6x6 tactile
switches that currently protrude though holes in the front panel, so I don't
think it is quite suitable, but thanks for such a novel approach (to me
anyway.)

Polycarbonate or whatever decals are easy to apply without bubbles etc - use
a squirt bottle with some weak soapy water in it and spray the surface prior
to fitting the label. You can slide the label around to position it and
remove bubbles, then either by hand or with a roller or squeegee push out
any excess water.

That sounds good. I wonder what the results and costs are like when
contracted out to an assembly house? It's a real question as I have no
experience with this.

For no screws in the front panel - is it possible to mount the PCB off the
end caps or in 'slides' inside the extrusion. Could you change any of the
front panel indicators/controls to ones that have mounting threads and use
these to hold the assembled PCB in place?

The use of slides could be a very good one. The extruded aluminium already
has parallel grooves along the lengths of its sides for horizontal PCB
mounting, so I'd need some way of attaching the vertical slides to that.
Otherwise, I don't mind holes drilled in the base of the unit in order to
attached the vertical PCB in someway, if that is possible.

Can ally extrusions be laser cut??????


regards
rob

Thanks for your ideas, Rob.

Steve

 

[martin griffith]

I want to make a metal enclosure for an electronics product. The enclosure
will be 4" wide, 6" long, 1" high. Up till now I've been using an
off-the-shelf standard extruded aluminum case. The main cost has been the
CNC milling of the front and rear panels (they both have a few holes for
connectors/buttons/LEDs). snip
Can anyone please suggest another approach, or comment on those above.

Many thanks,
Steve

Hi Steve, not sure if this link helps, but the prices seem reasonable
for CNCing. But I dont think they will machine user supplied parts
http://www.emachineshop.com/faq/prices.htm




martin

Serious error.
All shortcuts have disappeared.
Screen. Mind. Both are blank.

 

[Tim Wescott]

I want to make a metal enclosure for an electronics product. The enclosure
will be 4" wide, 6" long, 1" high. Up till now I've been using an
off-the-shelf standard extruded aluminum case. The main cost has been the
CNC milling of the front and rear panels (they both have a few holes for
connectors/buttons/LEDs). Plus it is a real pain to assemble, since the
front panel is glued to the sides in order to avoid screws showing through
(it's a consumer item). Now I am hopefully going to make them in bigger
batches (500s or so), I've been looking at other approaches to save money
and make assembly easier. So far, the alternatives I've thought about are:

a) Stay with the extruded aluminium and face plates, but use a stick-on
overlay over the front panel, so I can have screw holes in the panel behind
it. However, on such a small unit, I am worried that registration between
overlay and panel (and bubbles?) will make this problematic or at least be
slow during assembly - the less skill/judgement decisions required during
assembly, the better

b) Use a folded aluminium enclosure, one piece for base, front and rear, and
one piece for top and sides. Although this would get rid of the screws
needed to hold the box together, I still need some way of attaching a small
PCB with buttons and LEDs behind the front panel (I'm using foam and glue
for this at the moment!). I guess I could use blind fasteners for this, but
maybe that is not the best/cheapest solution.

c) A mod of (b) that seems to be used for DVD players etc. - folded aluminum
plus a plastic clip-on front panel to make it look nice. The metal panel
behind could then have all the screw holes etc. it needed. Not sure if the
cost of making the plastic panel is feasible for my quantities (500's)

Can anyone please suggest another approach, or comment on those above.

Many thanks,
Steve

With those volumes unless you're cutting costs to the bone you should be
able to justify getting professional help for the packaging. I'd
consider finding a mechanical engineer who can help you out.

Alternately you can go to the enclosure manufacturers to do the work:
just call up the sales staff and say "gee, I'd buy 1000 a year of that
if only I could figure out how to make it work the way I need".

Label manufacturers will be similarly eager to help out, and you can get
polycarbonate labels with embedded switches -- they look really slick
and (to the best of my knowledge) can be quite reliable.

 

[John Larkin]

I want to make a metal enclosure for an electronics product. The enclosure
will be 4" wide, 6" long, 1" high. Up till now I've been using an
off-the-shelf standard extruded aluminum case. The main cost has been the
CNC milling of the front and rear panels (they both have a few holes for
connectors/buttons/LEDs). Plus it is a real pain to assemble, since the
front panel is glued to the sides in order to avoid screws showing through
(it's a consumer item). Now I am hopefully going to make them in bigger
batches (500s or so), I've been looking at other approaches to save money
and make assembly easier. So far, the alternatives I've thought about are:

a) Stay with the extruded aluminium and face plates, but use a stick-on
overlay over the front panel, so I can have screw holes in the panel behind
it. However, on such a small unit, I am worried that registration between
overlay and panel (and bubbles?) will make this problematic or at least be
slow during assembly - the less skill/judgement decisions required during
assembly, the better

b) Use a folded aluminium enclosure, one piece for base, front and rear, and
one piece for top and sides. Although this would get rid of the screws
needed to hold the box together, I still need some way of attaching a small
PCB with buttons and LEDs behind the front panel (I'm using foam and glue
for this at the moment!). I guess I could use blind fasteners for this, but
maybe that is not the best/cheapest solution.

c) A mod of (b) that seems to be used for DVD players etc. - folded aluminum
plus a plastic clip-on front panel to make it look nice. The metal panel
behind could then have all the screw holes etc. it needed. Not sure if the
cost of making the plastic panel is feasible for my quantities (500's)

Can anyone please suggest another approach, or comment on those above.

Many thanks,
Steve

What's wrong with letting screws show? Will that keep people from
buying it?

John

 

[Steve]

What's wrong with letting screws show? Will that keep people from
buying it?

John

Afraid it might - since the front panel is only 4" x1", a couple of even
small screws will show up quite obviously. It's an audio consumer item for
putting alongside their expensive kit, and so it will help if it looks the
part too.

Steve

 

[Steve]

With those volumes unless you're cutting costs to the bone you should be
able to justify getting professional help for the packaging. I'd
consider finding a mechanical engineer who can help you out.

Alternately you can go to the enclosure manufacturers to do the work:
just call up the sales staff and say "gee, I'd buy 1000 a year of that
if only I could figure out how to make it work the way I need".

Label manufacturers will be similarly eager to help out, and you can get
polycarbonate labels with embedded switches -- they look really slick
and (to the best of my knowledge) can be quite reliable.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Thanks Tim. Actually I am going to visit the existing metalworkers to see
what they think - I'd like some ideas to give them too so any input here
would be great. I'll give the label manufacturers a try too. It's all very
knew to me, so thanks again.

Steve

 

[Steve]

Hi Steve, not sure if this link helps, but the prices seem reasonable
for CNCing. But I dont think they will machine user supplied parts
http://www.emachineshop.com/faq/prices.htm

martin

Serious error.
All shortcuts have disappeared.
Screen. Mind. Both are blank.

Hi Martin. Thanks for the link. In fact I just remembered that site a few
minutes ago! Prices seem ok in volume, and the software is pretty
straightforward (the audio help files are worth listening to.) I tried to
create a folded aluminum lid for starters but the s/w refuses to laser cut
sheet ally despite saying it is compatible with that (I've emailled their
support).

Steve

 

[Walter Harley]

I want to make a metal enclosure for an electronics product. The enclosure
will be 4" wide, 6" long, 1" high. Up till now I've been using an
off-the-shelf standard extruded aluminum case.

I've been talking to http://www.lansing-enclosures lately; it's still
off-the-shelf extrusions, but they're nicely consumerized, I think. And
they sent me to an overlay manufacturer, http://www.polycraftinc.com.
Between those two I think you could probably get what you need at a
reasonable price.

 

[Tim Wescott]

Afraid it might - since the front panel is only 4" x1", a couple of even
small screws will show up quite obviously. It's an audio consumer item for
putting alongside their expensive kit, and so it will help if it looks the
part too.

Steve

Then use black oxide coated stainless hex socket fasteners -- that
should be equally at home in an audio equipment rack or the engine bay
of a race car.

 

[Steve]

I've been talking to http://www.lansing-enclosures lately; it's still
off-the-shelf extrusions, but they're nicely consumerized, I think. And
they sent me to an overlay manufacturer, http://www.polycraftinc.com.
Between those two I think you could probably get what you need at a
reasonable price.

Many thanks for the links Walter. The Lansing extruded enclosures could be
good for consumer items as you say. It's an excellent site too for
explaining the customisations available, fasteners etc. Bit of a shame I'm
in the UK, but I'll try them anyway (might have contacts here).

 

[John Larkin]

Then use black oxide coated stainless hex socket fasteners -- that
should be equally at home in an audio equipment rack or the engine bay
of a race car.

Actually, exposed screws - especially flathead, countersunk, black,
hex-wrench types - give gear a high-end look.

John

 

[Rich Grise]

Then use black oxide coated stainless hex socket fasteners -- that
should be equally at home in an audio equipment rack or the engine bay
of a race car.

Button head.

 

[John Larkin]

Button head.

Hey, just who are you calling a button head?

But seriously, the other cool kind are allen-drive cylindrical cap
heads recessed in in milled-out holes, black or stainless. Doesn't
work for sheet metal, of course.

John

 

[Ken Smith]

But seriously, the other cool kind are allen-drive cylindrical cap
heads recessed in in milled-out holes, black or stainless. Doesn't
work for sheet metal, of course.

Add a "finish washer"


If the product has knobs, hide the screw under the knobs skirt, or use the
controls shaft bushings to mount it.

Put blind Pem inserts into the front pannel and run a bolt through from
the back pannel.

Electron beam weld the front pannel on.

 

[John Larkin]

Add a "finish washer"

No, they're tacky.

If the product has knobs, hide the screw under the knobs skirt, or use the
controls shaft bushings to mount it.

Put blind Pem inserts into the front pannel and run a bolt through from
the back pannel.

Electron beam weld the front pannel on.

Leave the screws in plain sight. They make a statement: This Product
Is Held Together By Screws.

John

 

[Rob]

Steve, just some thoughts.....

Is using a 'c' shape extrusion with slots for the PCB to run in possible - a
single sided PCB with 'reverse mounted' leds (via a 2/3/5mm hole in the
board or use SMD 'flipside' leds so the PCB becomes the 4th side of the
enclosure. Silk screen the outside face of the PCB. Without knowing the
application this may or may not be suitable.

Polycarbonate or whatever decals are easy to apply without bubbles etc - use
a squirt bottle with some weak soapy water in it and spray the surface prior
to fitting the label. You can slide the label around to position it and
remove bubbles, then either by hand or with a roller or squeegee push out
any excess water.

For no screws in the front panel - is it possible to mount the PCB off the
end caps or in 'slides' inside the extrusion. Could you change any of the
front panel indicators/controls to ones that have mounting threads and use
these to hold the assembled PCB in place?

Can ally extrusions be laser cut??????


regards
rob

 

[Anders F]

Leave the screws in plain sight. They make a statement: This Product
Is Held Together By Screws.

I wonder if that's the message Audi wanted to send when they designed (?)
the TT (and were followed by many others)... ;-)

/A

 

[Nicholas O. Lindan]

Leave the screws in plain sight. They make a statement: This Product
Is Held Together By Screws.

The heads can be 'semi-decorative', SS hex button-head screws for
instance. Or hex cap screws for an industrial look.

Screws under an overlay make servicing a pain. And the manufacturer
is the #1 servicer, so make things easy on yourself.

 

[Steve]

The heads can be 'semi-decorative', SS hex button-head screws for
instance. Or hex cap screws for an industrial look.

Screws under an overlay make servicing a pain. And the manufacturer
is the #1 servicer, so make things easy on yourself.

Thanks for all the input. I'm finding myself being tempted to go the route
that all the DVD player/amplifier/VHS recorder manufacturers seem to use -
folded aluminum case comprising 2 pieces, with a plastic front panel that
clips on or screws to the aluminum inside. The screws holding the two peices
of aluminum together are at the sides and the rear, out of the way. The cost
of the plastic front panel will be the deciding factor if I do go this
route. Or I could use a milled piece of solid aluminum...

Steve