Homebrew PCBs

how i can to make pcb overlay ? 
to show element electronic of the pcb ? 
thank you

----- Original Message ----- 

From: "goodsurfer2000" <goodsurfer2000@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, September 09, 2009 9:40 AM
Subject: [Homebrew_PCBs] pcb overlay ?


> how i can to make pcb overlay ?
> to show element electronic of the pcb ?

I print the silk screen layer and use that for reference when I'm assembling 
the board, or display it on the PC.

Leon

--- In Homebrew_PCBs@yahoogroups.com, "leon Heller" <leon355@...> wrote:
>
> ----- Original Message ----- 
> From: "goodsurfer2000" <goodsurfer2000@...>
> To: <Homebrew_PCBs@yahoogroups.com>
> Sent: Wednesday, September 09, 2009 9:40 AM
> Subject: [Homebrew_PCBs] pcb overlay ?
> 
> 
> > how i can to make pcb overlay ?
> > to show element electronic of the pcb ?
> 
> I print the silk screen layer and use that for reference when I'm assembling 
> the board, or display it on the PC.
> 
> Leon
>
helo thank , can you give one method or i use laser toner too ?

how i can to make silk screen layer someone have a method for that .. 
to print in the pcb ...

I have heard of some people using toner transfer to etch and then
after they clean off the board and use the toner transfer method again
to "print" the silk screen layer onto the circuit board.

On Thu, Sep 10, 2009 at 8:50 AM, goodsurfer2000 <goodsurfer2000@...> wrote:
> how i can to make silk screen layer someone have a method for that ..
> to print in the pcb ...
>


-- 
Erik L. Knise
Pacific Shipping Company
Seattle, WA

I've made a silk screen, but haven't found an ink or method to apply it.  

I've tried a couple of water based inks with no luck.  

I'm thinking of using Testers modeling paint via a spray can through the silk screen.

Would love to get some other ideas.




________________________________

From: goodsurfer2000 <goodsurfer2000@...>
To: Homebrew_PCBs@yahoogroups.com
Sent: Thursday, September 10, 2009 11:50:44 AM
Subject: [Homebrew_PCBs] Re: pcb overlay ?

  
how i can to make silk screen layer someone have a method for that .. 
to print in the pcb ...





      

[Non-text portions of this message have been removed]

I've made a silk screen, but haven't found an ink or method to apply it.  

I've tried a couple of water based inks with no luck.  
 
I'm thinking of using Testers modeling paint via a spray can through the silk screen.
 
Would love to get some other ideas.

--- In Homebrew_PCBs@yahoogroups.com, "goodsurfer2000" <goodsurfer2000@...> wrote:

>
> how i can to make silk screen layer someone have a method for that .. 
> to print in the pcb ...
>

That, indeed, is the one and only method I've heard of (short of  
actually silk screening it on).

On a 1-layer board you TT the copper side and then TT the components  
on the top.

PG

On 11/09/2009, at 3:09 AM, Erik Knise wrote:

> I have heard of some people using toner transfer to etch and then
> after they clean off the board and use the toner transfer method again
> to "print" the silk screen layer onto the circuit board.
>

My brother just bought a silk screen setup to do shirts. Has anyone
ever screen printed onto a circuit board? I figured the only
difference would be the ink and I would need to build a fixture to
hold the board. It also looks like it would be nice to hold a frame
for a solder paste stencil.

On 9/10/09, Piers Goodhew <piers@...> wrote:
> That, indeed, is the one and only method I've heard of (short of
> actually silk screening it on).
>
> On a 1-layer board you TT the copper side and then TT the components
> on the top.
>
> PG
>
> On 11/09/2009, at 3:09 AM, Erik Knise wrote:
>
>> I have heard of some people using toner transfer to etch and then
>> after they clean off the board and use the toner transfer method again
>> to "print" the silk screen layer onto the circuit board.
>>
>
>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>
>


-- 
Erik L. Knise
Pacific Shipping Company
Seattle, WA

On Thu, 10 Sep 2009 15:50:44 -0000, you wrote:

>how i can to make silk screen layer someone have a method for that .. 
>to print in the pcb ...
>

One way works only on single sided boards, the other works on both
single and double sided boards.

Method #1, single sided only.  Print on a transparency the reverse of
your silk screen layer.  Try a contrasting color with the board (black
on light boards, dark boards you might try red or yellow ink). Reverse
the board, cement to the top of the board (or use double sided carpet
tape) and you have a silk screen layer.

method #2, use a toner transfer to the board.  If the board is light
colored, you can use black or perhaps a color laser.  Haven't tried
that.

Method #2b, use toner transfer and black for the silk screen layer,
then use white film to transfer.  www.pulsar.gs sells this though
various distributors.

Harvey

>
>

Sure, that will work, just use acrylic paint thinned with water to the 
proper consistency.

But, setup is a big deal.  Paint the screen with Diazo and let dry in a 
dark room.  Print pattern on transparency.  Expose in sunlight for 1 
minute.  Wash out unexposed Diazo. Mount board and screen and adjust for 
proper spacing.  Put 'ink' in screen and print.  Recover left over 
'ink'.  Clean pattern from screen.
By the time you're done, you've got half a day into it, and some fairly 
pricey chemicals  That's fine if you're doing 30 boards, not so fine if 
you're doing 1.  Personally, I do 1 board, not 30.  I use a board house 
if I'm making a lot of boards.

Kerry


Erik Knise wrote:

> My brother just bought a silk screen setup to do shirts. Has anyone
> ever screen printed onto a circuit board? I figured the only
> difference would be the ink and I would need to build a fixture to
> hold the board. It also looks like it would be nice to hold a frame
> for a solder paste stencil.
>
> On 9/10/09, Piers Goodhew <piers@...> wrote:
>   
>> That, indeed, is the one and only method I've heard of (short of
>> actually silk screening it on).
>>
>> On a 1-layer board you TT the copper side and then TT the components
>> on the top.
>>
>> PG
>>
>> On 11/09/2009, at 3:09 AM, Erik Knise wrote:
>>
>>     
>>> I have heard of some people using toner transfer to etch and then
>>> after they clean off the board and use the toner transfer method again
>>> to "print" the silk screen layer onto the circuit board.
>>>
>>>       
>>
>> ------------------------------------
>>
>> Be sure to visit the group home and check for new Links, Files, and Photos:
>> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>>
>>
>>
>>
>>     
>
>
>

--- In Homebrew_PCBs@yahoogroups.com, Erik Knise <elknise@...> wrote:
>
> My brother just bought a silk screen setup to do shirts. Has anyone
> ever screen printed onto a circuit board? I figured the only
> difference would be the ink

Silkscreening is used widely in PCB industry. Yes, the ink is special and it is thermaly cured.

The most advanced and useful method for overlays (which is named "legend ink" in the business) is LPI. The same as soldermask. You just silkscreen you PCB with a mesh without any artwork in it. That is, a blank mesh. You get a PCB silkscreened entire in white ink. You bake the PCB for a determined time, and then you place your legend/overlay artwork above the blanked PCB and image with UV. You then develop and only the overlay patterns end on the PCB. You bake again and there is your finished PCB.

The company that sells the AQ-3000 also sell LPI green soldermask and white legend ink.

I have - it works great

-----Original Message-----
Date: Thursday, September 10, 2009 7:58 pm
To: Homebrew_PCBs@yahoogroups.com
Subject: Re: [Homebrew_PCBs] Re: pcb overlay ?
From: "Erik Knise" <elknise@...>

My brother just bought a silk screen setup to do shirts. Has anyone
ever screen printed onto a circuit board? I figured the only
difference would be the ink and I would need to build a fixture to
hold the board. It also looks like it would be nice to hold a frame
for a solder paste stencil.

On 9/10/09, Piers Goodhew <piers@...> wrote:
> That, indeed, is the one and only method I've heard of (short of
> actually silk screening it on).
>
> On a 1-layer board you TT the copper side and then TT the components
> on the top.
>
> PG
>
> On 11/09/2009, at 3:09 AM, Erik Knise wrote:
>
>> I have heard of some people using toner transfer to etch and then
>> after they clean off the board and use the toner transfer method again
>> to "print" the silk screen layer onto the circuit board.
>>
>
>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>
>


-- 
Erik L. Knise
Pacific Shipping Company
Seattle, WA

Hello

Please can you tell me how many mj/cm2 does the Black Lights provide for exposure the PCB using the LPI inks as the AQ 3000 RC ?

And What's the difference Between the AQ3000 RC (Roller coating) And AQ3000 DC (dip coating) for applications for double sided PCBs?

Thanks for your Help.
 
Ingeniero Andres F. Hernandez
Pontificia Universidad Javeriana
 
Celular    (300)7825582
Casa       (572) 5572655




________________________________

From: jcarlosmor <jcarlosmor@...>
To: Homebrew_PCBs@yahoogroups.com
Sent: Thu, September 10, 2009 9:24:09 PM
Subject: [Homebrew_PCBs] Re: pcb overlay ?

  
--- In Homebrew_PCBs@ yahoogroups. com, Erik Knise <elknise@... > wrote:
>
> My brother just bought a silk screen setup to do shirts. Has anyone
> ever screen printed onto a circuit board? I figured the only
> difference would be the ink

Silkscreening is used widely in PCB industry. Yes, the ink is special and it is thermaly cured.

The most advanced and useful method for overlays (which is named "legend ink" in the business) is LPI. The same as soldermask. You just silkscreen you PCB with a mesh without any artwork in it. That is, a blank mesh. You get a PCB silkscreened entire in white ink. You bake the PCB for a determined time, and then you place your legend/overlay artwork above the blanked PCB and image with UV. You then develop and only the overlay patterns end on the PCB. You bake again and there is your finished PCB.

The company that sells the AQ-3000 also sell LPI green soldermask and white legend ink.





      

[Non-text portions of this message have been removed]

--- In Homebrew_PCBs@yahoogroups.com, Andres Hernandez <afhernandez79@...> wrote:
>
> Hello
> 
> Please can you tell me how many mj/cm2 does the Black Lights provide for exposure the PCB using the LPI inks as the AQ 3000 RC ?
> 
> And What's the difference Between the AQ3000 RC (Roller coating) And AQ3000 DC (dip coating) for applications for double sided PCBs?
> 
> Thanks for your Help.
>  
> Ingeniero Andres F. Hernandez
> Pontificia Universidad Javeriana

The difference between RC and DC is the viscosity and the solids composition of the liquid. You just cannot use one for another. The most simple way is to use DC since you can build a dip coating machine with relative simplicity. However, you must control the release of the PCB out of the tank with a microcontroller to obtain the required thickness of the photoresist.

With respect to how to measure the uv energy the solutions are very expensive, but also you do not need to do any measure. With the help of a Stouffer guide you can calculate exactly your exposition time for any kind of LPI. If your question is about how many black light tubes are acceptable, I can tell you that I use 4 tubes (model F15T8BL, 15 watts, termination BL, not BLB) for exposing AQ3000 DC at a distance of 5 centimeters and the exposition time is only 58 seconds.
However, for final curing of LPI soldermask and legend ink 4 tubes have few effect and maybe you need a mercury-arc lamp.

Thank you for your information.


But I said several days before that is possible to apply the photoresist by using blank screen mesh and I though was better using the RC reference. Am I right ?.

By the way...

How do you do to match the trasnparencies for expossing a double sided PCB.. do you have any web site where It is explained using pictures or something ?


Thanks for your help

Sincerely
 
Ingeniero Andres F. Hernandez
Pontificia Universidad Javeriana
 
Celular    (300)7825582
Casa       (572) 5572655




________________________________

From: jcarlosmor <jcarlosmor@...>
To: Homebrew_PCBs@yahoogroups.com
Sent: Sat, October 24, 2009 6:22:13 PM
Subject: [Homebrew_PCBs] Re: pcb overlay ?

  


--- In Homebrew_PCBs@ yahoogroups. com, Andres Hernandez <afhernandez79@ ...> wrote:
>
> Hello
> 
> Please can you tell me how many mj/cm2 does the Black Lights provide for exposure the PCB using the LPI inks as the AQ 3000 RC ?
> 
> And What's the difference Between the AQ3000 RC (Roller coating) And AQ3000 DC (dip coating) for applications for double sided PCBs?
> 
> Thanks for your Help.
>  
> Ingeniero Andres F. Hernandez
> Pontificia Universidad Javeriana

The difference between RC and DC is the viscosity and the solids composition of the liquid. You just cannot use one for another. The most simple way is to use DC since you can build a dip coating machine with relative simplicity. However, you must control the release of the PCB out of the tank with a microcontroller to obtain the required thickness of the photoresist.

With respect to how to measure the uv energy the solutions are very expensive, but also you do not need to do any measure. With the help of a Stouffer guide you can calculate exactly your exposition time for any kind of LPI. If your question is about how many black light tubes are acceptable, I can tell you that I use 4 tubes (model F15T8BL, 15 watts, termination BL, not BLB) for exposing AQ3000 DC at a distance of 5 centimeters and the exposition time is only 58 seconds.
However, for final curing of LPI soldermask and legend ink 4 tubes have few effect and maybe you need a mercury-arc lamp.





      

[Non-text portions of this message have been removed]

> But I said several days before that is possible to apply the photoresist by using blank screen mesh and I though was better using the RC reference. Am I right ?.
> 
> By the way...
> 
> How do you do to match the trasnparencies for expossing a double sided PCB.. do you have any web site where It is explained using pictures or something ?
> 
> 
> Thanks for your help
> 
> Sincerely
>  
> Ingeniero Andres F. Hernandez
> Pontificia Universidad Javeriana

We were talking about solder mask and legend ink for the blank screen mesh. However, someone sended me an email just a few days ago to tell me that AQ3000 is available now and ready for sale in SP composition (screen printing). I did not verified that information, but in that case, yes, you can apply photoresist with a blank screen mesh (but better to read the product datasheet first). I still feel that DC has more consistent results and yields than screen printing for photoresist only (not for solder mask and legend ink).

To match transparencies in a double sided board is a big problem, since normally you are matching not two, but five transparencies (top overlay, top soldermask, top layer, bottom layer, bottom soldermask).
I am assuming that you are talking about real phototools (laser photoplotted film) and no laser-printing over paper. You can build some punch and die device trimmed with cnc-machining which punch the phototools where the pcb-guides are (an area of the pcb that is not used for artwork, just only for adjustment drilled holes). You can see the process in the Bungard site video sections. Look for "laser plotting or photoplotter" and the look for "punch device" or so.