muti-color silkscreens

[westfw]

Are there any PCB companies that will do multiple layers of silkscreen (each in a different color)? (or "soldermask", I guess.  Essentially the same thing, isn't it?)   In "small quantity" runs?

[Alex Eisenhut]

Are there any PCB companies that will do multiple layers of silkscreen (each in a different color)? (or "soldermask", I guess.  Essentially the same thing, isn't it?)   In "small quantity" runs?

Soldermask and silkscreen are two different things, for one thing the accuracy of soldermask is higher.
Extra silkscreen colors just means extra money since they have to flush the nozzle for each change of color, that's what I've been told.
Simply make a separate layer for each color you want. Bring money.
Ask first.

[vzoole]

There is a multi color solder mask:
http://www.eurocircuits.com/blog/171-PCB-PIXture-launched

[mikeselectricstuff]

Most PCB companies will do whatever you want in whatever quantity - the difference is how much they charge for it.
But forget the low poolling prices we've seen in recent years. Expect a couple of hundred £/$ "get out of bed" charge, and probably a not insignificant cost per colour for cleaning, and remember that below a single panel, cost won't reduce much with size.

[Kalvin]

Could the laser printer toner transfer method be used for the DIY multi-color silk screen printing?

[MicroBlocks]

For small quantities a hand operated pad printer might be an option.

[janekm]

Well silk-screen printing is a pretty simple process anyway, it could be done "DIY". Very cheap to buy the silk stencils.
Though it'll take some practice to get good at it...

[westfw]

Well silk-screen printing is a pretty simple process anyway, it could be done "DIY".

My impression is that I can't easily get the high-temp-tolerant inks used on PCBs (and if I could, they'd be expensive, require special equipment, have poor shelf life, and cause cancer.)

OTOH, I was also under the impression that actual silkscreening isn't used much in the low-volume PCB industry these days, having given way to dry-film and/or photo-sensitive inks similar to the resist layer used prior to etching.  Or inkjets.

I was sort-of hoping that one of the pooling places that has multiple soldermask colors would have separate machines for each color, and be able to run it through multiple machines at relatively small effort and moderate cost increase.  (Alas: "Pooling."  Good point about needing to fill a whole panel...  Sigh.)

[apelly]

Google released some product or giveaway or something ages ago. The specifics escape me sorry. It was a pcb with white silk over printed with a full colour google logo. Can't find anything by searching right now either.

Anyway, everyone laughed at them for wasting money on it. Wish I could remember what it was now.

[janekm]

Google released some product or giveaway or something ages ago. The specifics escape me sorry. It was a pcb with white silk over printed with a full colour google logo. Can't find anything by searching right now either.

Anyway, everyone laughed at them for wasting money on it. Wish I could remember what it was now.

Well, for that the best approach would be actually to just give the PCB to a standard "promotional item" printshop for printing after assembly is done... that would get around the issues of high temperature resistant ink...

[janekm]

Well silk-screen printing is a pretty simple process anyway, it could be done "DIY".

My impression is that I can't easily get the high-temp-tolerant inks used on PCBs (and if I could, they'd be expensive, require special equipment, have poor shelf life, and cause cancer.)

OTOH, I was also under the impression that actual silkscreening isn't used much in the low-volume PCB industry these days, having given way to dry-film and/or photo-sensitive inks similar to the resist layer used prior to etching.  Or inkjets.

I was sort-of hoping that one of the pooling places that has multiple soldermask colors would have separate machines for each color, and be able to run it through multiple machines at relatively small effort and moderate cost increase.  (Alas: "Pooling."  Good point about needing to fill a whole panel...  Sigh.)

I hadn't considered the temperature issue... if you want to put the PCB through a reflow process that could be an issue indeed. It could be worth a try though... a lot of inks are designed to cope with a moderate amount of heating.
You're right that most of the low-volume PCB factories now use "ink jet" process for silkscreen (as evident by the dot pattern). In fact, looking through my piles of recent PCBs I struggle to find any with "traditional" silkscreen.

Multiple solder mask colours has been done: http://www.seeedstudio.com/blog/2009/11/28/life-is-so-colorful-as-rainbow-how-about-pcbs/
And so has multiple silkscreen colours apparently: https://www.eevblog.com/forum/chat/poll-what-colour-pcb-do-you-like-best/