commercial (ie mass-produced) PCBs question

[coffyrock]

Anyone know the manufacturing process for a large company like boss or digitech when they make (millions of) pcbs for pedals? Do they use chemical echant and transfer methods similar (albeit more advanced) to DIYers? Or do they cut the traces out with lasers? Or just print the traces directly on blank boards?

I couldn't find much via searching... Any links you could provide would help me understand better...

[Paul Perry (Frostwave)]

The resist is screenprinted onto the board. And if you are making numbers small boards you make a whole bunch on the one big piece of board & cut them up later.
the interesting part is making "plated through holes". And another interesting part is where you have  a whole bunch of drills all automatically drilling in the right place at the same time.
The etching tank is pretty big too.

but don't take my word for it - there is this thing called Google & if you put
PCB manufacture steps
into it, you get a whole bunch of photo essays on commercial PCB production. Here's the one at the top of the list: http://www.sunstone.com/id/36/PCB+Manufacturing+Tutorial.aspx

[R.G.]

More to the point, companies like Boss and Digitech don't make PCBs at all. They prepare industry standard fabrication files and send them to a company that does nothing but make PCBs - like Sunstone, as Paul mentions.

The PCB companies themselves usually use either silkscreen resists or photo resist techniques. Silkscreen is going the way of the dodo. Photo techniques are the most common. This is partly because the vast majority of all PCB work is now too fine a pitch (i.e. the traces and spaces between the traces are too small) to do reliably with silkscreen.

There is a movement toward direct photoresist, if it's not already here. Old-style photoresist is done by exposing sensitized board through a photonegative. This is fast, but you have to make a photonegative. If you were to use a laser which could directly "write" on the photoresist, you could just pass a stream of sensitized boards under your laser "writer" and into the etch tank. It's at least conceptually possible to make a fully automated line.

And this is where the industry WAS headed until humans in the form of cheap third world labor became competitive with automated machines. I'm not sure where the volumes are now.

Chemical etchants are universal.

People have been trying to directly place copper traces onto a substrate ever since the idea of a "printed" circuit came up. It's never been possible to do this both well and economically. Subtractive processes which remove excess copper from an entire surface is are universal.

Removal with lasers is an idea that I'm sure gets tried. It's very seductive - just turn up the power on the "writing" laser and remove the copper directly. Shoot, for that matter, drill the holes, too. The problem is that a laser that can do all that is quite expensive. Chemical means done by low cost humans is much cheaper, and the laws of economics are much more pervasive than most people realize.

[coffyrock]

Thanks for the input. The reason I ask is that I actually have access to a laser that I hope will do the trick (after I figure out what I want to make some PCBs for that is). I know someone who runs the lasers for a small trophy/awards shop, the type they do acrylic/metal/wood awards with. That sucker is wicked! The literature for the laser says it's possible to do circuit boards with it, so we're going to try it. I'll post some pics of my success/failure in a week or two.

[Paul Perry (Frostwave)]

I'd be very suprised if one of those trophy lasers would cut PCB material, but what they WOULD shine at, is artwork for stompboxes (and even more so, synthesiser panels). I'd like to hear what is available in the way of permanently adhesive metal that can be lasered & stuck to stmpboxes. And what is available as panel aluminum that is pretreated so it can be used with the laser.

[R.G.]

I did this a while back. There are two substrates that are readily available, shiny aluminum and copper/goldish/brassish metal. These two come coated with a variety of gloss plastic colors. The laser removes the plastic coating cleanly wherever you want. You can get black on metal or the reverse.

The panel material is thin, perhaps 0.035"/ 1mm or thinner. It's designed for exactly what you want - letters and artwork on a thin bit of metal to be stuck to another object, usually trophies.

Go to your local tropy shop.

I had them do control panels for a tube amp. I took in PDF artwork files, picked up 2.5" by 22" control panels a day later.

[Paul Perry (Frostwave)]

IThe panel material is thin, perhaps 0.035"/ 1mm or thinner. It's designed for exactly what you want - letters and artwork on a thin bit of metal to be stuck to another object, usually trophies.
I had them do control panels for a tube amp. I took in PDF artwork files, picked up 2.5" by 22" control panels a day later.

And the price was???

[coffyrock]

sooooo. total failure. Laser didn't even make a mark on the copper so that's a big negatory on lasering my pcbs!
C'est la vie. I'm going to do some laser enclosures though, possibly with clear acrylic insets if I can decide on a design. I guess I'll just have to try etching chemically for the boards (been avoiding it.)

[Pushtone]

I asked both a trophy shop and an anozidizer if they could laser etch my 1590 boxes with artwork/labels.

They both said, too tall. Has to be thin.

I'm not as thrilled with the idea of laser etched art if its in the form of a thin metal laminate.
But I bet there are some ways to make it look neat and not peel up on a stompbox.

I was thinking about running my router with a flat bit over a box top to remove a narrow strip from one side to the other at a 1mm depth.
This was to seat a strip of thick photo paper flush with the box top but it could be applied to the trophy laminate.

[coffyrock]

the thin material with some coats of clear on top might be pretty durable if properly trimmed so no edges were obvious... ?

I'm not sure the depth they can do at this place but i know they can do 2" thick stratocaster bodies

[R.G.]

I had them do control panels for a tube amp. I took in PDF artwork files, picked up 2.5" by 22" control panels a day later.

And the price was???

About US$30 per panel as I remember.

I'm not as thrilled with the idea of laser etched art if its in the form of a thin metal laminate.
But I bet there are some ways to make it look neat and not peel up on a stompbox.

How about epoxy? Laser etch the artwork onto a think sheet to be glued to the top.

If you were mechanically inclined, you could mill a thin recess into the top of the box that would sink the thin metal applique into the box and hide the edges.

How about making a "drill template" out of the thin aluminum material that folded down the sides of the box with cutouts on the corners to make it lie flat, plus epoxy?

[Pushtone]

How about making a "drill template" out of the thin aluminum material that folded down the sides of the box with cutouts on the corners to make it lie flat, plus epoxy?

I get it. Cut the metal laminate into the shape of the drill template like
when its ready to tape to a box, with the corners cut out.
That might be a cool look. You could paint the box black first and have gold top/sides with black corners.

I was thinking the same thing could be done with thin acrylic plastic sheet.
Except I wanted to pop it in the oven and let the acrylic melt over the sides.
Well not melt, get warm enough to bend around the box.  For that "i" look ya know.