Synth-DIY Yahoo! Groups Archives

Thread

Minimum track widths

2005-06-03 by Philip Pemberton

Hi folks,
Has anyone done any testing to see if it's possible to go down to 12/12
track width/spacing with the Staples photo paper (or PnP Blue)?

I've got a double-sided PCB here that won't route (without a stupid number
of vias) in anything above 12mils. If it's not possible to go down that far
with the Staples paper and a 600dpi laser, I'll send the boardfiles off to
Olimex. Otherwise, I'll try and make the board myself :)

While I'm at it.. has anyone got any tips for aligning the two transfers
for top copper and bottom copper?
Also, does anyone know if toner is conductive - I was planning to put a
placement guide on the top layer, but not if it'll end up shorting everything
out.

Thanks.
--
Phil. | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB,
philpem@... | ViewFinder, 10BaseT Ethernet, 2-slice,
http://www.philpem.me.uk/ | 48xCD, ARCINv6c IDE, SCSI
... Clairvoyant meeting cancelled due to unforeseen events.

Re: [Homebrew_PCBs] Minimum track widths

2005-06-03 by Leon Heller

----- Original Message -----
From: "Philip Pemberton" <philpem@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Friday, June 03, 2005 3:12 PM
Subject: [Homebrew_PCBs] Minimum track widths

> Hi folks,
> Has anyone done any testing to see if it's possible to go down to 12/12
> track width/spacing with the Staples photo paper (or PnP Blue)?
>
> I've got a double-sided PCB here that won't route (without a stupid
> number
> of vias) in anything above 12mils. If it's not possible to go down that
> far
> with the Staples paper and a 600dpi laser, I'll send the boardfiles off to
> Olimex. Otherwise, I'll try and make the board myself :)
>
> While I'm at it.. has anyone got any tips for aligning the two transfers
> for top copper and bottom copper?
> Also, does anyone know if toner is conductive - I was planning to put a
> placement guide on the top layer, but not if it'll end up shorting
> everything
> out.

I can do 12/12 without problems using the standard UV exposure processs.

Toner contains carbon black, so it might be slightly conductive. The
resistance will probably be too high to cause problems, though.

Leon
--
Leon Heller, G1HSM
http://www.geocities.com/leon_heller

Re: [Homebrew_PCBs] Minimum track widths

2005-06-03 by Stefan Trethan

On Fri, 03 Jun 2005 16:12:36 +0200, Philip Pemberton
<philpem@...> wrote:

> Hi folks,
> Has anyone done any testing to see if it's possible to go down to 12/12
> track width/spacing with the Staples photo paper (or PnP Blue)?
> I've got a double-sided PCB here that won't route (without a stupid
> number
> of vias) in anything above 12mils. If it's not possible to go down that
> far
> with the Staples paper and a 600dpi laser, I'll send the boardfiles off
> to
> Olimex. Otherwise, I'll try and make the board myself
> While I'm at it.. has anyone got any tips for aligning the two transfers
> for top copper and bottom copper?
> Also, does anyone know if toner is conductive - I was planning to put a
> placement guide on the top layer, but not if it'll end up shorting
> everything
> out.
> Thanks.

12/12 should be no problem. maybe route 8/14 'cause of spreading.
The problem is to get the paper residue out of the small gap. I'm glad
that task is avoided with silicone paper.

Aligning, see recent posts, use a folded sheet of thick paper / thin
cardboard, align papers, slide PCB in, slide in cardboard, feed folded
edge first.

I often use toner for legend, and so far i was not able to measure the
resistance. might try harder one day...
pretty isolating. I think developer would be more conductive.

ST

Re: [Homebrew_PCBs] Minimum track widths

2005-06-03 by JanRwl@AOL.COM

In a message dated 6/3/2005 9:14:31 A.M. Central Daylight Time,
philpem@... writes:

While I'm at it.. has anyone got any tips for aligning the two transfers
for top copper and bottom copper?

For onesy-twosy work, I just tape the negatives (transfers?) together along
two adjacent edges. Assuming they are at least translucent, and you can SEE
the points you want to align.

I have heard SOME folks drill "spotting holes" or "targets" before
sensitizing the blanks, and with those, you can "lay down" the transfer with those
"spots" aligned. Takes some planning!

Professional houses do it with MONEY!!!!!!!!!!!

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

Re: Minimum track widths

2005-06-03 by Phil

I regularly do 12 mil traces with TT. I can get good results with 10
mil traces but I prefer a little safety margin, especially if I get a
slow etch.

I align my top and bottom artwork on a homemade light table. I use a
double sided tape dispenser from Scotch to stick them together once
aligned. cut off the excess paper (leave a 1-2 inch margin for the
tape), slide the blank in and align it on the light table. Then its
into the laminator inside a carrier. I use children's construction
paper for that as it is soft and becomes conformal after the first pass.

--- In Homebrew_PCBs@yahoogroups.com, Philip Pemberton <philpem@d...>
wrote:

> Hi folks,
> Has anyone done any testing to see if it's possible to go down to

12/12

> track width/spacing with the Staples photo paper (or PnP Blue)?
>
> I've got a double-sided PCB here that won't route (without a

stupid number

> of vias) in anything above 12mils. If it's not possible to go down

that far

> with the Staples paper and a 600dpi laser, I'll send the boardfiles

off to

> Olimex. Otherwise, I'll try and make the board myself :)
>
> While I'm at it.. has anyone got any tips for aligning the two

transfers

> for top copper and bottom copper?
> Also, does anyone know if toner is conductive - I was planning to

put a

> placement guide on the top layer, but not if it'll end up shorting

everything

> out.
>
> Thanks.
> --
> Phil. | Acorn Risc PC600 Mk3, SA202,

64MB, 6GB,

> philpem@p... | ViewFinder, 10BaseT Ethernet, 2-slice,
> http://www.philpem.me.uk/ | 48xCD, ARCINv6c IDE, SCSI
> ... Clairvoyant meeting cancelled due to unforeseen events.