Homebrew PCBs

hi,
hope some1 can help me with this.  i've been trying the old toner 
transfer method.  i've tried it with a couple of transparencies.  i 
think 1 from 3m one from a generic producer and some other. couldnt 
find the hp transparency.  some even had a rough surface on one side 
like i read in some post.  i tried with photocopied transparencies and 
with laser printed ones.  the printed ones were much sharper though.  

what happens is when i iron the transparency on the board it shrinks 
slightly and the design gets smudged. i i mean really smudged at some 
places.  i tried it with epson glossy paper too. same thing happened. 
when i ironed it the paper shrunk mostly from the middle section and 
the design got smudged beyond recognition.

i'm fairly new to this. and i need serious help.  what am i doing 
wrong?

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

From: "chroniclz" <chroniclz@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, May 17, 2006 3:15 PM
Subject: [Homebrew_PCBs] unsuccesful attempts to transfer on board :(


> hi,
> hope some1 can help me with this.  i've been trying the old toner 
> transfer method.  i've tried it with a couple of transparencies.  i 
> think 1 from 3m one from a generic producer and some other. couldnt 
> find the hp transparency.  some even had a rough surface on one side 
> like i read in some post.  i tried with photocopied transparencies and 
> with laser printed ones.  the printed ones were much sharper though.  
> 
> what happens is when i iron the transparency on the board it shrinks 
> slightly and the design gets smudged. i i mean really smudged at some 
> places.  i tried it with epson glossy paper too. same thing happened. 
> when i ironed it the paper shrunk mostly from the middle section and 
> the design got smudged beyond recognition.
> 
> i'm fairly new to this. and i need serious help.  what am i doing 
> wrong?

What printer?

Leon

Hi,

You're mixing 2 techniques; photo-sensitive and toner transfer.

The transparencies are used to project an image of a circuit onto a special
photo-sensitive PCB using fluorescent light.

Toner transfer uses special paper, much like what they use to transfer
iron-on decals onto t-shirts.

Check up on the group links or search Google for "pcb toner transfer
method".

Robert
:)

> -----Message d'origine-----
> De : Homebrew_PCBs@yahoogroups.com 
> [mailto:Homebrew_PCBs@yahoogroups.com] De la part de chroniclz
> Envoyé : mai 17 2006 10:15
> À : Homebrew_PCBs@yahoogroups.com
> Objet : [Homebrew_PCBs] unsuccesful attempts to transfer on board :(
> 
> 
> hi,
> hope some1 can help me with this.  i've been trying the old toner 
> transfer method.  i've tried it with a couple of transparencies.  i 
> think 1 from 3m one from a generic producer and some other. couldnt 
> find the hp transparency.  some even had a rough surface on one side 
> like i read in some post.  i tried with photocopied 
> transparencies and 
> with laser printed ones.  the printed ones were much sharper though.  
> 
> what happens is when i iron the transparency on the board it shrinks 
> slightly and the design gets smudged. i i mean really smudged at some 
> places.  i tried it with epson glossy paper too. same thing happened. 
> when i ironed it the paper shrunk mostly from the middle section and 
> the design got smudged beyond recognition.
> 
> i'm fairly new to this. and i need serious help.  what am i doing 
> wrong?
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
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First, more people report good success with inkjet papers than they do  
with transparencies, so try those.

If you have shrinkage problems you should probably use another paper, but  
you may try to preheat the paper before printing. This works if it shrinks  
by drying out the moisture. So basically you would iron the blank paper  
before printing on it to drive all the moisture out. This will usually  
help when you have distortion problems because of the shrinkage. If the  
shrinking is really bad it might not help, then try another paper.

ST

On Wed, 17 May 2006 16:15:23 +0200, chroniclz <chroniclz@...> wrote:

> hi,
> hope some1 can help me with this.  i've been trying the old toner
> transfer method.  i've tried it with a couple of transparencies.  i
> think 1 from 3m one from a generic producer and some other. couldnt
> find the hp transparency.  some even had a rough surface on one side
> like i read in some post.  i tried with photocopied transparencies and
> with laser printed ones.  the printed ones were much sharper though.
> what happens is when i iron the transparency on the board it shrinks
> slightly and the design gets smudged. i i mean really smudged at some
> places.  i tried it with epson glossy paper too. same thing happened.
> when i ironed it the paper shrunk mostly from the middle section and
> the design got smudged beyond recognition.
> i'm fairly new to this. and i need serious help.  what am i doing
> wrong?
>

> Robert Wrote:
> 
> You're mixing 2 techniques; photo-sensitive
> and toner transfer.  The transparencies are
> used to project an image of a circuit onto
> a special photo-sensitive PCB using
> fluorescent light.
> 
> Toner transfer uses special paper, much like
> what they use to transfer iron-on decals
> onto t-shirts.

The funny thing about this statement is that
transperancies work very well for Toner-
Transfer but are quite hopeless for UV-Photo
etching with most laser printers. In UV photo
etching people generaly use vellum if they
can't make a real photo-tool.  The vellum does
not leave pin holes for the UV light to get
through as badly.

Over Head Transperancies work very well for
toner transfer with the right set up.  In fact
I was using OHTs for toner transfer long
before Press-n-Peel blue paper was around.
(I also kept using them after press-n-peel
became available as I think they worked better
in some respects)

I first heard of the concept in a "news"
article saying someone was doing toner transfer
at PARC.  I thought it sounded Fabulous 'cause
at the time I hated the negative photo-resist
process I was using.

I tried paper, the fibers stuck.
I tried scrubbing the fibers.  Stuffed toner.
I tried Clay paper - clay stuck to bare copper
I tried all sorts of different papers.

(nb - this was the days before real colour ink
jets - glossy "photo" paper didn't exist.  Clay
paper for B&W inkjets was new and fandangled)

I was getting better results with "glossy"
papers.  I tried some magazine covers that
I beleive are coated with a thin film of
mylar.  It worked fabulously.  Only problem
now was I had a limited supply of penthouse
magazines to rip the covers off :P

Search continued and I eventually after many
weeks of experimenting found Faber-Castle
OHTs worked fabulously with my HP laserjet.

Unfortunatly They seemed to stop making
those brand trannys on me and I had to switch.
I tried 3m GC3300 for a while - but they
where not as good.  Then I found another
brand called "Highland" which I think are
only in OZ.  They worked almost as good as
the faber-castle ones.

Some people with different laser printers say
3m GC3300 trannys are great.  Maybe with
another laser printer faber-castle might
suck. So your mileage may vary there.

To answer the question from the original
poster.  _YES_ the tranny will shrink with
too much heat.  You have to experiment
with just the right amount of heat.  It
should be JUST below the threshold of where
shrinkage happens.  This is the disadvantage
of using OHTs over the press-n-peel or
photo paper.

Also - when using trannys rather than TTS
paper - there is a knack to removing the
tranny and still leaving the toner on the
copper.  It's about pulling either side of
the tranny to put it under "tension" as it
lifts off.  If you find that large areas of
toner are sticking to the tranny - I will
take some photos and draw some diagrams to
explain what to do (too hard with words).

Good luck - but I will suggest - if you
are serious about PCBs with small* features
or you are going to be doing a lot of them -
have a look at photographic methods.



*small = leadless packages like MLFs - 0.5mm
pins that are 0.23mm wide and 0.5mm from
center to center. YES I know that is 9 thou
track and 10 thou spacing which you can 
produce with TTS - but it's just not that
much fun touching up voids and errors by
hand on stuff that small.

> -----Message d'origine-----
> De : Homebrew_PCBs@yahoogroups.com 
> [mailto:Homebrew_PCBs@yahoogroups.com] De la part de Andrew
> Envoyé : mai 17 2006 18:24
> À : Homebrew_PCBs@yahoogroups.com
> Objet : [Homebrew_PCBs] Re: RE : unsuccesful attempts to 
> transfer on board :(
> 
> The funny thing about this statement is that
> transperancies work very well for Toner-
> Transfer but are quite hopeless for UV-Photo
> etching with most laser printers. In UV photo
> etching people generaly use vellum if they
> can't make a real photo-tool.  The vellum does
> not leave pin holes for the UV light to get
> through as badly.

Before doing toner-transfer with Pulsar paper, I started by using
transparencies with photo-sensitive PCBs with excellent results.  I could
make 10mil traces quite easily.

Robert
:)

> Robert wrote:
> Before doing toner-transfer with Pulsar
> paper, I started by using transparencies
> with photo-sensitive PCBs with excellent
> results.  I could make 10mil traces
> quite easily.

Yep - some printes do a good job on OHTs.

Many laser printers leave nasty pinholes
on them and things don't work out as well.

I know my laserjet 4xxx does a bad job -
but I have used a fancy laser printer that
does a great job.

That is why generally accepted practice
it to use vellum.  It seems to work out
well on any laser printer.

k i tried different papers.  left the trannys.  will probaqbly 
experiment with achieving the right temprature for trannys later.  
they do seem to leave very dark traces on the pcb and come of really 
easay.so if i can figure out how to use them properly it'll be 
great :)
meanwhile i've been busy trying out techniques.experimenting 
basically.  spent all night on it yesterday.  i got this really 
cheap generic glossy paper for laser printers. cost me $0.03 per 
sheet.  i dont think it gets any cheaper than that :P  the toner 
sticks really well if i heat it properly.about 5-10 minutes per 
board. the down side is the paper sticks to the pcb.  i left it 
overnight in room temp soapy water.  the upper layer peeled of 
rather easily, used my thumb.  the last layer was a bit stubborn but 
i got most of it off with a medium toothbrush.  made 10 boards about 
40% came out absolutely perfect.  with some a lil toner flaked of 
cause it didnt stick.more heat should solve that.  one thing that 
got me bothered was some really thin traces merged.  i think i can 
use a sharp blade to separate the traces.is that rite?
also, if i leave the boards to dry n then etch them tomorrow would 
that make any difference? as in would the oxidization of naked 
copper cause any problems in the etching process?or am i just 
worrying to much? :P read somewhere to keep them in water untill i 
need them for etching. somehow that doesnt seem rite.

and thanks for all the help guys!!!!u've all been great!!!! :D


--- In Homebrew_PCBs@yahoogroups.com, "chroniclz" <chroniclz@...> 
wrote:
>
> hi,
> hope some1 can help me with this.  i've been trying the old toner 
> transfer method.  i've tried it with a couple of transparencies.  
i 
> think 1 from 3m one from a generic producer and some other. 
couldnt 
> find the hp transparency.  some even had a rough surface on one 
side 
> like i read in some post.  i tried with photocopied transparencies 
and 
> with laser printed ones.  the printed ones were much sharper 
though.  
> 
> what happens is when i iron the transparency on the board it 
shrinks 
> slightly and the design gets smudged. i i mean really smudged at 
some 
> places.  i tried it with epson glossy paper too. same thing 
happened. 
> when i ironed it the paper shrunk mostly from the middle section 
and 

> the design got smudged beyond recognition.
> 
> i'm fairly new to this. and i need serious help.  what am i doing 
> wrong?
>