Homebrew PCBs

Guys, thanks very much, I appreciate the feedback.

I can definitely see some mistakes I've been making with the transfer method...it really surprised me to find out from several of you that 8 passes are sometimes needed, it honestly didn't occur to me that additional passes would make any difference.

I have to make a fundamental decision...whether to try yet again to make the toner transfer method work....I mean, I DO have all the stuff, the special paper, the green film, the laminator, etc., etc., ...and just get CRAZY about cleaning boards, using solvent, doing a zillion passes, etc., and WORKING on the process until I finally get it to work RIGHT....

....or to go straight to the photoresist method. I realized in writing this I accidentally lied...I had forgotten that even though I did buy an exposure setup and photoresist boards, etc., I never tried using that method...because the cost of those photoresist boards seemed too high to me.

So....go crazy on the toner transfer method until I get it RIGHT, or go with photoresist and accept the higher cost of the boards....

Any consensus on this?

Very Best, Charlie


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

Consensus is off topic on this list. ;-)

If you only need single sided board with limited resolution
requirements (say 8 mil or something) toner transfer is a good option.
It is cheaper and in my opinion less work than photoprocess.

ST


On Mon, Aug 30, 2010 at 3:29 PM,
<synchronousmosfet@transformationaudio.com> wrote:

> Guys, thanks very much, I appreciate the feedback.
>
> I can definitely see some mistakes I've been making with the transfer method...it really surprised me to find out from several of you that 8 passes are sometimes needed, it honestly didn't occur to me that additional passes would make any difference.
>
> I have to make a fundamental decision...whether to try yet again to make the toner transfer method work....I mean, I DO have all the stuff, the special paper, the green film, the laminator, etc., etc., ...and just get CRAZY about cleaning boards, using solvent, doing a zillion passes, etc., and WORKING on the process until I finally get it to work RIGHT....
>
> ....or to go straight to the photoresist method. I realized in writing this I accidentally lied...I had forgotten that even though I did buy an exposure setup and photoresist boards, etc., I never tried using that method...because the cost of those photoresist boards seemed too high to me.
>
> So....go crazy on the toner transfer method until I get it RIGHT, or go with photoresist and accept the higher cost of the boards....
>
> Any consensus on this?
>
> Very Best, Charlie
>

If you use magazine paper, it is basically free to experiment.  Magazine 
paper works well for me, 8 passes through the laminator.  If an attempt 
fails, just clean the board and try again.  I DO make the occasional  
'proof of concept'  board  for  customers,  but  basically, it is a 
hobby. So even the time is free.

Kerry


synchronousmosfet@... wrote:
> Guys, thanks very much, I appreciate the feedback.
>
> I can definitely see some mistakes I've been making with the transfer method...it really surprised me to find out from several of you that 8 passes are sometimes needed, it honestly didn't occur to me that additional passes would make any difference.
>
> I have to make a fundamental decision...whether to try yet again to make the toner transfer method work....I mean, I DO have all the stuff, the special paper, the green film, the laminator, etc., etc., ...and just get CRAZY about cleaning boards, using solvent, doing a zillion passes, etc., and WORKING on the process until I finally get it to work RIGHT....
>
> ....or to go straight to the photoresist method. I realized in writing this I accidentally lied...I had forgotten that even though I did buy an exposure setup and photoresist boards, etc., I never tried using that method...because the cost of those photoresist boards seemed too high to me.
>
> So....go crazy on the toner transfer method until I get it RIGHT, or go with photoresist and accept the higher cost of the boards....
>
> Any consensus on this?
>
> Very Best, Charlie
>   



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On Mon, 30 Aug 2010 09:29:27 -0400 (EDT), you wrote:

>Guys, thanks very much, I appreciate the feedback.
>
>I can definitely see some mistakes I've been making with the transfer method...it really surprised me to find out from several of you that 8 passes are sometimes needed, it honestly didn't occur to me that additional passes would make any difference.
>
>I have to make a fundamental decision...whether to try yet again to make the toner transfer method work....I mean, I DO have all the stuff, the special paper, the green film, the laminator, etc., etc., ...and just get CRAZY about cleaning boards, using solvent, doing a zillion passes, etc., and WORKING on the process until I finally get it to work RIGHT....
>
>....or to go straight to the photoresist method. I realized in writing this I accidentally lied...I had forgotten that even though I did buy an exposure setup and photoresist boards, etc., I never tried using that method...because the cost of those photoresist boards seemed too high to me.
>
>So....go crazy on the toner transfer method until I get it RIGHT, or go with photoresist and accept the higher cost of the boards....

Photoresist, especially with pre coated boards, is more expensive,
gives better results.

Toner transfer is cheaper, and for 16 mill boards (and larger) does a
good job.  It's not indistinguishable from photoresist (always sharper
lines), but by far. cheaper.

I'd be tempted to use both, or at lease, go through your stock of
paper and blank board until you have the process in hand, making
boards that work well with the process.

For finer boards, you may want to consider the photo process.

I make boards with 10/10 (10 mil, 10 mil spacing), double sided,
non-plated through holes.  I still have some chancy results here and
there but the TT process does work.  

Photo would be better, I do have the capability of doing SS boards,
but most of mine are DS.  

Note that TT can still do such things as silk screen layers.

I may go to photoresist, but buying film and laminating my own boards.
Depends.  

I may also go to a board house for about 2 or 3 of the more
complicated boards, but those are low demand boards, very complicated.

It's a tradeoff.

Harvey

>
>Any consensus on this?
>
>Very Best, Charlie
>
>
>[Non-text portions of this message have been removed]
>
>
>
>------------------------------------
>
>Be sure to visit the group home and check for new Links, Files, and Photos:
>http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>

The fact that you are unlikely to get consensus on any of your question 
should be an indication that there is a fairly wide tolerance involved 
here. Here is my 2c:

1. Cleaning - The rule I learnt 30 years ago when I first did this is 
that you want a 'wettable' surface, i.e. when you hold the board under a 
tap, the water should evenly cover it, and not bead up. How you get to 
that point is up to you, but generally scouring powder, fine wet & dry 
sandpaper (400grit or higher) or 3M pads will all get the job done. 
Wiping down with some degreasing solvent (alcohol, acetone etc) is 
entirely optional.
2. Toner transfer is definitely the easier method *if* you have hot 
roller laminator and *if* it gets hot enough. You'll generally know when 
you have done enough passes because the paper will stick. Find a paper 
that works for you, you can get by without the specialty toner transfer 
paper. I use heavyweight brochure paper simply because I have some, but 
most glossy magazine paper will work as well.
3. If you want better resolution, go photoresist, but bear in mind, 
there a far more variables, e.g density of your transparencies, exposure 
time, developer strength etc., and if you buy presensitized pcb, your 
mistakes can be costly (though you can use your failures for toner transfer)



synchronousmosfet@... wrote:

>
> Guys, thanks very much, I appreciate the feedback.
>
> I can definitely see some mistakes I've been making with the transfer 
> method...it really surprised me to find out from several of you that 8 
> passes are sometimes needed, it honestly didn't occur to me that 
> additional passes would make any difference.
>
> I have to make a fundamental decision...whether to try yet again to 
> make the toner transfer method work....I mean, I DO have all the 
> stuff, the special paper, the green film, the laminator, etc., etc., 
> ...and just get CRAZY about cleaning boards, using solvent, doing a 
> zillion passes, etc., and WORKING on the process until I finally get 
> it to work RIGHT....
>
> ....or to go straight to the photoresist method. I realized in writing 
> this I accidentally lied...I had forgotten that even though I did buy 
> an exposure setup and photoresist boards, etc., I never tried using 
> that method...because the cost of those photoresist boards seemed too 
> high to me.
>
> So....go crazy on the toner transfer method until I get it RIGHT, or 
> go with photoresist and accept the higher cost of the boards....
>
> Any consensus on this?
>
> Very Best, Charlie
>
> [Non-text portions of this message have been removed]
>
>

synchronousmosfet@... pravi:
> Guys, thanks very much, I appreciate the feedback.
>
> I can definitely see some mistakes I've been making with the transfer method...it really surprised me to find out from several of you that 8 passes are sometimes needed, it honestly didn't occur to me that additional passes would make any difference.
>
> I have to make a fundamental decision...whether to try yet again to make the toner transfer method work....I mean, I DO have all the stuff, the special paper, the green film, the laminator, etc., etc., ...and just get CRAZY about cleaning boards, using solvent, doing a zillion passes, etc., and WORKING on the process until I finally get it to work RIGHT....
>
> ....or to go straight to the photoresist method. I realized in writing this I accidentally lied...I had forgotten that even though I did buy an exposure setup and photoresist boards, etc., I never tried using that method...because the cost of those photoresist boards seemed too high to me.
>
> So....go crazy on the toner transfer method until I get it RIGHT, or go with photoresist and accept the higher cost of the boards....
>
> Any consensus on this?
>
> Very Best, Charlie
>
>   
Photo VS Toner Transfer?

That's the question...

Do not use TT for lines under 8 mils. (I do my routing with at least 12 
mils and go thinner just where need to be - SMD chips with 0.5mm raster)
TT is NOT PRECISE. I can get TQFP44 package on board with TT. But I 
can't get 10cm long connector to fit into holes. The paper and printout 
is just skewed and not precise enougth for that job. The image is very 
hard to align(near imposible) with CNC drill.

So if you careful plan board and isn't big the TT is way to go. If you 
have big board or big component with many pads then don't use TT.
You must find where limit is. The 20cm x 30cm board and just ordinary 
chips (CD40xx, 74HC... DIP PACKAGE) is plausible. Same board with ONE 
connector run in one side is NOT.

And TT is cheap. You can transfer image and check if component's fit. If 
not You can scale image and try again. Just use one piece of 'other' 
unetched pcb and scrub all the toner from the working one. Don't use 
chemical.

I do not use photo. If board is double sided or I can't do it with TT 
then I send that to the PCB house to manufacture it.

Slavko.

When I started my last batch I was using 12.5 mill traces. I was having 
problems with the 12.5 mil traces using the TT process. I changed to 20 mil 
traces and got good transfers every time..

Bob Macklin
K5MYJ
Seattle, Wa.
"Real Radios Glow In The Dark"
----- Original Message ----- 

From: <synchronousmosfet@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, August 30, 2010 6:29 AM
Subject: [Homebrew_PCBs] from Charlie re process you would bet your life on


> Guys, thanks very much, I appreciate the feedback.
>
> I can definitely see some mistakes I've been making with the transfer 
> method...it really surprised me to find out from several of you that 8 
> passes are sometimes needed, it honestly didn't occur to me that 
> additional passes would make any difference.
>
> I have to make a fundamental decision...whether to try yet again to make 
> the toner transfer method work....I mean, I DO have all the stuff, the 
> special paper, the green film, the laminator, etc., etc., ...and just get 
> CRAZY about cleaning boards, using solvent, doing a zillion passes, etc., 
> and WORKING on the process until I finally get it to work RIGHT....
>
> ....or to go straight to the photoresist method. I realized in writing 
> this I accidentally lied...I had forgotten that even though I did buy an 
> exposure setup and photoresist boards, etc., I never tried using that 
> method...because the cost of those photoresist boards seemed too high to 
> me.
>
> So....go crazy on the toner transfer method until I get it RIGHT, or go 
> with photoresist and accept the higher cost of the boards....
>
> Any consensus on this?
>
> Very Best, Charlie
>
>
> [Non-text portions of this message have been removed]
>
>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and 
> Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>
>

I've used both, and switch back and forth occasionally.  I use the 
special TT paper, so the cost-per-board is about the same (special paper 
costs about as much as the UV film).  I've found the UV method more 
reliable, but more steps are involved too, and you need a 
temperature-controlled laminator (IMHO) to reliably put the film on the 
PCB.  Regular laminators run around 320F but that'll melt the film. 
Mine can be set to 200F or 240F for wet or dry lamination, as well as 
350F for toner transfer.

UV also needs special artwork film and printers to get a decent photo 
master for the UV exposure, which adds to the cost and time (printing 
takes far longer) but aligning DS boards is far easier (pre-drill some 
holes, you can *see* through the artwork :)

As for cleaning the boards, I use a green scrubbie and some Dawn disk 
soap, never had a problem.  UV film sticks pretty reliably with the 
laminator.  I think my toner (HP) has a very narrow window between 
"sticks" and "melts"

My "comfort zone" is 10/10 for TT and 6/6 for UV.

One other advantage of UV is you can use UV film to make 
aluminum-foil-based solder paste stencils.

I've done the photo-resist using positive boards and the results were excellent. A bit of work with exposing, developing, stopping, stripping, ect. But the boards did turn out very nice. After trying TT again over a year ago (from reading here), I haven't done a photo board since. For me TTis so easy and the boards are excellent.

I use the Hammermil office gloss paper and HP laser printers (my 1200 at home does the best job).  My board prep is simple, I use a green scrubby sponge (scotch brite pad) and Dawn dish soap. I scrub it each direction a few times and make sure the whole board has been cleaned. 1 to 2 minutes tops (file board edges first for rough spots and the sponge will last longer ;-) ). Then place the transfer on the board and I iron it. I bought a cheap $10 iron and set it on the highest setting (cotton). I iron it 3 to 4 minutes each side and press moderately hard. I like to use the rounded front part of the iron to make sure I've pressed each area but never turn the iron up on it's edge. Let the board cool a little and then soak. A couple minutes in the water and I rub off the bulk of the paper then I let it soak 10, 20 minutes (just throw it in a while) and come back and carefully rub the rest off. A little foam rubber gently rubbed will help remove between thin traces. I found it doesn't have to be 100% off, just most of the paper gone. Then into the ferric chloride for etching. I've had much better results with the ferric than with other acids, the toner seems to hold up better in ferric chloride for me.

Phil - KA0HBG


--- In Homebrew_PCBs@yahoogroups.com, synchronousmosfet@... wrote:

>
> Guys, thanks very much, I appreciate the feedback.
> 
> I can definitely see some mistakes I've been making with the transfer method...it really surprised me to find out from several of you that 8 passes are sometimes needed, it honestly didn't occur to me that additional passes would make any difference.
> 
> I have to make a fundamental decision...whether to try yet again to make the toner transfer method work....I mean, I DO have all the stuff, the special paper, the green film, the laminator, etc., etc., ...and just get CRAZY about cleaning boards, using solvent, doing a zillion passes, etc., and WORKING on the process until I finally get it to work RIGHT....
> 
> ....or to go straight to the photoresist method. I realized in writing this I accidentally lied...I had forgotten that even though I did buy an exposure setup and photoresist boards, etc., I never tried using that method...because the cost of those photoresist boards seemed too high to me.
> 
> So....go crazy on the toner transfer method until I get it RIGHT, or go with photoresist and accept the higher cost of the boards....
> 
> Any consensus on this?
> 
> Very Best, Charlie
> 
> 
> [Non-text portions of this message have been removed]
>