Homebrew PCBs

I'm convinced now that I should give the photographic method a try and 
even try pre-sensitized boards.  I'd like to do things the Right Way 
instead of going sloppo like I have been so far.  That might explain my 
previous problems.  Anyhow, I'll start with constructing a UV exposure 
box.  The box and timer stuff seems straightforward enough, but what I'd 
really like is to make a gizmo that sandwiches the PCB and films between 
two sheets of glass or lexan.  The idea is to put the things in this 
frame, adjust for registration, clamp it closed, and that's it.  Insert 
into the UV box for exposure.  I saw a page a couple years ago discussing 
something like this, but I can't find it anymore.  Does anyone here smell 
what I'm cooking?

I keep the boards small and one-sided, would a UV EPROM eraser work?

-- 
David Griffith
dgriffi@...

A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?

On Mon, Jan 25, 2010 at 4:35 PM, David Griffith <dgriffi@...>wrote:

>  The box and timer stuff seems straightforward enough, but what I'd really
> like is to make a gizmo that sandwiches the PCB and films between two sheets
> of glass or lexan.
>
>
> I keep the boards small and one-sided, would a UV EPROM eraser work?
>

David,
You might want to go to Instructables.com and search for "UV Led."    They
have plans for an exposure box for two sided PCBs that sounds like it's just
what you're looking for.

Hal

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

David Griffith <dgriffi@...> writes:

> Anyhow, I'll start with constructing a UV exposure box.  The box and
> timer stuff seems straightforward enough, but what I'd really like

http://www.delorie.com/pcb/uvled/

> is to make a gizmo that sandwiches the PCB and films between two
> sheets of glass or lexan.

I put rubber gasket around the edge of the bottom shelf (wood), and
used a vacuum to suck the glass down.  Not a full vacuum, but a
venturi setup off a shop vac (just stuck a poly tube into the end,
it's enough).  A couple of inches of vacuum is enough to hold the film
tight against the copper.  I also stack up card stock under the pcb to
get it all to the right height for an even squish.

Of course, I only expose one side at a time, using a few small
pre-drilled holes for alignment.

On Mon, Jan 25, 2010 at 7:35 PM, David Griffith <dgriffi@...>wrote:


> I'm convinced now that I should give the photographic method a try and
> even try pre-sensitized boards. I'd like to do things the Right Way
> instead of going sloppo like I have been so far. That might explain my
> previous problems. Anyhow, I'll start with constructing a UV exposure
> box. The box and timer stuff seems straightforward enough, but what I'd
> really like is to make a gizmo that sandwiches the PCB and films between
> two sheets of glass or lexan. The idea is to put the things in this
> frame, adjust for registration, clamp it closed, and that's it. Insert
> into the UV box for exposure. I saw a page a couple years ago discussing
> something like this, but I can't find it anymore. Does anyone here smell
> what I'm cooking?
>
> I keep the boards small and one-sided, would a UV EPROM eraser work?
>
>
Get one or two "bug zapper" U-shaped lights and a ballast for T-40 lights
(and a AC plug and wire) and you're in business.  I've been doing it that
way for years and I use kids "mega blox" stacked up 2 high on either side of
the board I've mounted the lights on (1/4-inch fiber board).  I drilled
holes around the edges of the lights then gently zip-tied them to the board,
ballast and all, plus wire nuts for all the connections except for the
lights which I soldered onto the ballasts since the way I use them I'll die
before they do.  It only takes about 3-4 minutes of exposure time with the
film people buy and I've also had success with the spray-on negative
photoresist that smells and looks the same when dry.  It allows me to do
boards larger and thicker than my small laminator can handle and works well
once you get the trick of air-brushing on the resist and then drying in the
oven for a couple minutes.
Finally, I wouldn't worry too much about trying to get a setup that
sandwiches the board and artwork.  Get a food vacuum sealer and put the
artwork with the printed side facing down onto the board and seal it up!  It
works perfectly every time and there is zero gap between the board and
artwork, regardless of whether the board is a little warped from cutting or
whatever.  You can usually get several exposures out of one bag before it
gets too small to keep your board out from under the logo and crap they
print on the bottom of the bag.  Just make sure you seal using the clear
side of the bag up, not the matte side.

HTH,
Larry


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

David Griffith wrote:
> I'll start with constructing a UV exposure box. I saw a page a couple
> years ago discussing something like this, but I can't find it anymore.
> A: Top-posting.
> Q: What is the most annoying thing in e-mail?
> 

http://translate.google.pt/translate?u=http%3A%2F%2Fwww.chirio.com%
2Fbromografo_uv.htm&sl=it&tl=en&hl=&ie=UTF-8
Or for you guys.

http://www.chirio.com/bromografo_uv.htm

This Italian guy has a nice one built with a old scanner box. And he
point to the use of compact fluorescent starters like i built mine years
ago in a wood box. These days there are UV leds, but this can still be
easier to build. 
 

Ohhh, top posting give you first the answer i would normally put last :>

I found that an old overhead projector worked. It needs to have a mercury
lamp (they are the more 'modern' version, with whiter light, mine is 3M
brand). About 1 minute exposed my boards pretty well.

I used it because it has a convenient flat glass surface, and the light
seems to be evenly distributed, and it exposes quickly. I'm not totally sure
about the 'collimation' or angle of the light, but it seemed to work fine
for my purposes and i used it for a 0.5mm pitch chip.

If I was going to build an exposure box, I would consider re-purposing on
old overhead projector, or even a broken digital projector - I think those
have mercury lamps.

On Tue, Jan 26, 2010 at 11:35 AM, David Griffith <dgriffi@...>wrote:

>
>
>
> I'm convinced now that I should give the photographic method a try and
> even try pre-sensitized boards. I'd like to do things the Right Way
> instead of going sloppo like I have been so far. That might explain my
> previous problems. Anyhow, I'll start with constructing a UV exposure
> box. The box and timer stuff seems straightforward enough, but what I'd
> really like is to make a gizmo that sandwiches the PCB and films between
> two sheets of glass or lexan. The idea is to put the things in this
> frame, adjust for registration, clamp it closed, and that's it. Insert
> into the UV box for exposure. I saw a page a couple years ago discussing
> something like this, but I can't find it anymore. Does anyone here smell
> what I'm cooking?
>
> I keep the boards small and one-sided, would a UV EPROM eraser work?
>
> --
> David Griffith
> dgriffi@... <dgriffi%40cs.csubak.edu>
>
> A: Because it fouls the order in which people normally read text.
> Q: Why is top-posting such a bad thing?
> A: Top-posting.
> Q: What is the most annoying thing in e-mail?
>  
>


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

On 26/01/2010 00:35, David Griffith wrote:
>
> I'm convinced now that I should give the photographic method a try and
> even try pre-sensitized boards.  I'd like to do things the Right Way
> instead of going sloppo like I have been so far.  That might explain my
> previous problems.  Anyhow, I'll start with constructing a UV exposure
> box.  The box and timer stuff seems straightforward enough, but what I'd
> really like is to make a gizmo that sandwiches the PCB and films between
> two sheets of glass or lexan.  The idea is to put the things in this
> frame, adjust for registration, clamp it closed, and that's it.  Insert
> into the UV box for exposure.  I saw a page a couple years ago discussing
> something like this, but I can't find it anymore.  Does anyone here smell
> what I'm cooking?
>
> I keep the boards small and one-sided, would a UV EPROM eraser work?
>

Here is my UV exposure unit:

http://www.leonheller.com/www/Photos/UV%20unit.jpg

It's made from MDF and some strips of wood, screwed tofether and glued. 
I had a sheet of glass cut to size. A heavy book on top of the PCB keeps 
it in contact with the transperency.

Leon
-- 
G1HSM
http://webspace.webring.com/people/jl/leon_heller/

Sorry, URL was wrong.

On 26/01/2010 00:35, David Griffith wrote:
>
> I'm convinced now that I should give the photographic method a try and
> even try pre-sensitized boards.  I'd like to do things the Right Way
> instead of going sloppo like I have been so far.  That might explain my
> previous problems.  Anyhow, I'll start with constructing a UV exposure
> box.  The box and timer stuff seems straightforward enough, but what I'd
> really like is to make a gizmo that sandwiches the PCB and films between
> two sheets of glass or lexan.  The idea is to put the things in this
> frame, adjust for registration, clamp it closed, and that's it.  Insert
> into the UV box for exposure.  I saw a page a couple years ago discussing
> something like this, but I can't find it anymore.  Does anyone here smell
> what I'm cooking?
>
> I keep the boards small and one-sided, would a UV EPROM eraser work?
>

Here is my UV exposure unit:

http://www.leonheller.com/Photos/UV%20unit.jpg

It's made from MDF and some strips of wood, screwed tofether and glued. 
I had a sheet of glass cut to size. A heavy book on top of the PCB keeps 
it in contact with the transperency.

Leon
-- 
G1HSM
http://webspace.webring.com/people/jl/leon_heller/

David,
Back in the 70's and 80's I did a lot of 2 sided boards using photographic methods, it worked very well.  Back then you hand taped you master artwork at 2x and sent it to the photo house for reduction to net size.  I was using Shipley AZ111 positive photo resist that was spin coated on the boards and etched in hot ammonium persulfate.  The results were very good but the hand taping of the artwork was the major drawback.

To keep undercut to a minimum I had to make sure the emulsion of the film was in direct contact with the coated boards.  Had to add a big note on the master artwork about which side of the artwrok was to face the lense of the camera to be sure they got it correct and the emulsion was on the correct side of the final film.  I had a DYI exposure box using 3 18" VU fluorescent tubes for each side of the board.  The board was clamped between two pieces of 1/4" glass.  Exposure times were about 5 minutes.  Looking back I am sure the glass absorbed a lot of the UV but it still worked fine.   There was a local shop in Mountain View, that did much of the photo work for the electronics companies here in the valley and I could get 8x10 negatives for about $10 each.  Because I was using positive resist I had to make a contact print of the negatives to reverse the image beforer exposing the board.  For two sided boards, you just align the two films and scotch tape them together aroung the edge making a pocket and slip the board inside.  Etching in fresh ammonium persulfate took 20 to 40 seconds then a dip in the electroless tin.

Drilling was a pain, I had a small 1.25" dia by 2" surplus DC motor that was attached to a small chuck salvaged from an old flex shaft tool. Powered it from my bench supply with a foot switch. The key here was to use DC braking on the motor by shorting out the motor leads with the foot switch to stop the motor before positioning the bit in the next hole. Used HHS drills that had to be frequently sharpened on a small carborundum stone.  Tried carbide but they were too brittle for had use. I think the it was a 20V motor I ran on 40V so it turned a good RPM.  Had to let it cool every once in a while.

Seems its hard to get good UV opaque artwork out of todays lasers or inkjet printers, lots of pin holes etc.  I think one could print 2:1 artwork on a laser, then have it photo reduced 2:1.  Print shops were a good source for camera work.  Or even make a 2:1 camera from some plywood and a lense. I think front lighting the master would solve the opaque problem, if not go at it with a black sharpie.

Once you set up and get you process going its easy to make boards. Lately I have done a few simple PCBs with the Toner method, with mixed results, partly due to my Brother laser printer.

Craig



--- In Homebrew_PCBs@yahoogroups.com, David Griffith <dgriffi@...> wrote:

>
> 
> I'm convinced now that I should give the photographic method a try and 
> even try pre-sensitized boards.  I'd like to do things the Right Way 
> instead of going sloppo like I have been so far.  That might explain my 
> previous problems.  Anyhow, I'll start with constructing a UV exposure 
> box.  The box and timer stuff seems straightforward enough, but what I'd 
> really like is to make a gizmo that sandwiches the PCB and films between 
> two sheets of glass or lexan.  The idea is to put the things in this 
> frame, adjust for registration, clamp it closed, and that's it.  Insert 
> into the UV box for exposure.  I saw a page a couple years ago discussing 
> something like this, but I can't find it anymore.  Does anyone here smell 
> what I'm cooking?
> 
> I keep the boards small and one-sided, would a UV EPROM eraser work?
> 
> -- 
> David Griffith
> dgriffi@...
> 
> A: Because it fouls the order in which people normally read text.
> Q: Why is top-posting such a bad thing?
> A: Top-posting.
> Q: What is the most annoying thing in e-mail?
>

I use a sun lamp in one of those aluminum reflector/clip on bulb holders as a uv source. At a foot away the exposure time is about 1 1/2 minutes for negative dry film. You don't have to build anything. Lay a piece of glass over the film and board for some weight.

RD 

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

--- In Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:
>
> 
> David Griffith <dgriffi@...> writes:
> 
> > Anyhow, I'll start with constructing a UV exposure box.  The box and
> > timer stuff seems straightforward enough, but what I'd really like
> 
> http://www.delorie.com/pcb/uvled/
> 
>


The 99 LEDs look like quite a hassle. I use a 15W U shaped bug zapper fluorescent tube, they work fine with a ballast for an ordinary F15T8, which if you're not very electrically inclined the whole setup can be pulled from a cheap under cabinet fixture.

No, EPROM erasers do not work with the spectrum of liquid, dry-film, and pre-sensitized PCBs.

You do not explain exactly why are you going to do things "Right Way". If you only need a hobby PCB once a week you could do things same as you do now. If you want to do one (or 100) professional PCBs in the same week, maybe with real soldermask, you will need a good UV imaging exposure box. So the first thing is to avoid all those new fancy UV LEDs units. The reason is simple: no professional PCB shop use that. Period. You only have two alternatives, high-pressure mercury lamp, which is a hassle to operate when you only intend to image a single PCB, since you have to wait until UV energy become estable, or flourescent tubes, which is very simple and efficient to work on.

Also, you will need real vacuum if you want perfect results every time. You could built that at very low-cost with a modified fridge compressor. And you will need to CNC-machining some kind of fixture for registry of your PCBs fast.

I know that maybe all of this sounds excessive for doing a few PCBs, but it is the only way to do it "Right Way". Any other way you could end frustrated re-inventing the wheel.

David,

I have tried other methods and came back to the photographic method too, overall cheaper, more reliable and faster.

I don't think you need specialized lamps or  UV lamps to make this work. I use a full spectrum daylight fluorescent lamp, 15W, 16in long in a standard enclosure. This is held above a desk surface about 6inches. I have metal feet that MG Chemicals sell for this purpose, but I suspect two piles of books or a couple of pieces of 2X4 would be just as good. 

For artwork, I use standard over head transparency sheets available at Office Max, Staples or similar and print direct from Eagle to my HP Laser jet. I use a small piece of acrylic sheet to hold the artwork against the board... This works just fine.

With this setup it takes between 8 and 12 minutes to expose, and is very forgiving in terms of small alignment adjustments at the start of the exposure.

I have used both positive pre-sensitised copper clad boards and negative film that is then laminated onto a blank board (slightly longer exposure needed). I use MG Chemicals products and they habve given consistent results so far.

Both methods have been extremely successful, with the pre-sensitized having slightly better results, but higher costs.

Eagle has print settings that ensure that the toner is on the right side (ie the side that touches the coating) and can also print negative artwork.

I have successfully built double sided and 6mil trace boards.

Good luck!

Mat


--- In Homebrew_PCBs@yahoogroups.com, David Griffith <dgriffi@...> wrote:

>
> 
> I'm convinced now that I should give the photographic method a try and 
> even try pre-sensitized boards.  I'd like to do things the Right Way 
> instead of going sloppo like I have been so far.  That might explain my 
> previous problems.  Anyhow, I'll start with constructing a UV exposure 
> box.  The box and timer stuff seems straightforward enough, but what I'd 
> really like is to make a gizmo that sandwiches the PCB and films between 
> two sheets of glass or lexan.  The idea is to put the things in this 
> frame, adjust for registration, clamp it closed, and that's it.  Insert 
> into the UV box for exposure.  I saw a page a couple years ago discussing 
> something like this, but I can't find it anymore.  Does anyone here smell 
> what I'm cooking?
> 
> I keep the boards small and one-sided, would a UV EPROM eraser work?
> 
> -- 
> David Griffith
> dgriffi@...
> 
> A: Because it fouls the order in which people normally read text.
> Q: Why is top-posting such a bad thing?
> A: Top-posting.
> Q: What is the most annoying thing in e-mail?
>

I made a few photographic resist boards long ago, some in positive presensitized boards, some were sprayed by me with negative resist. I didn't have to spin the boards, just sprayed an even spray in a couple of thin coats.

I used an incandescent 75W "Gro" light, sounds like just what you describe. Takes a little longer than a brighter UV source, but that just makes the timing less critical, too.

I found the proper timing the old fashioned way - cover all but 1/10th of the board, expose for 40 seconds, move the cover to expose another 1/10th, after 10 seconds move it again, etc so I have 40, 50, 60, 70, 80, 90, 100, 110, 120, and 130 second exposure times. Then I used that info to refine and then shot for the center.

Hand-taped using drafting tape and rub-on patterns for positives. For negatives, I drew the outlines in drafting pen and filled in by hand.

Boards looked great. Made a few dozen that way. I often avoided drilling by using the semi-SMD method, clip DIP leads off just a little proud of the bottom, same with resistor leads and solder to the copper side. A few boards I used real SMDs.

Steve Greenfield

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

>
> I use a sun lamp in one of those aluminum reflector/clip on bulb holders as a uv source. At a foot away the exposure time is about 1 1/2 minutes for negative dry film. You don't have to build anything. Lay a piece of glass over the film and board for some weight.
> 
> RD 
> 
> [Non-text portions of this message have been removed]
>

On Tue, 26 Jan 2010, jcarlosmor wrote:

> No, EPROM erasers do not work with the spectrum of liquid, dry-film, and 
> pre-sensitized PCBs.

There goes that bright idea.

> You do not explain exactly why are you going to do things "Right Way". 
> If you only need a hobby PCB once a week you could do things same as you 
> do now. If you want to do one (or 100) professional PCBs in the same 
> week, maybe with real soldermask, you will need a good UV imaging 
> exposure box. So the first thing is to avoid all those new fancy UV LEDs 
> units. The reason is simple: no professional PCB shop use that. Period. 
> You only have two alternatives, high-pressure mercury lamp, which is a 
> hassle to operate when you only intend to image a single PCB, since you 
> have to wait until UV energy become estable, or flourescent tubes, which 
> is very simple and efficient to work on.

By the Right Way, I mean to have a mostly self-contained kit of equipment 
that's simple, effective, and not fiddly.  Fluorescent tubes seemed like 
the best approach from a simplicity perspective.  UV LEDs seem harder to 
diffuse.  The sort of box I'm considering goes something like this:

Two shells, each 4 inches deep with UVA fluorescent tubes in their 
bottoms.  These are fastened together with a piano hinge.  A lip just 
inside the edges of the shells holds a .25" glass slab upon which the 
pouched stencil with PCB inside is placed.  Strips of scrap PCB lightly 
sprayed with rubber paint are laid along the edges and another glass slab 
is laid on top.  Once the top glass is laid down, it weight against the 
scraps should prevent movement.  Close the lid and latch.  Rubber coating 
on the shell lips tightly clamp the whole thing together.  The thickness 
of the glass prevents significant bowing.

> Also, you will need real vacuum if you want perfect results every time. 
> You could built that at very low-cost with a modified fridge compressor. 
> And you will need to CNC-machining some kind of fixture for registry of 
> your PCBs fast.

I'm told that taping the stencils face-to-face to create a pouch makes for 
good registration.  Any opinions on this?

> I know that maybe all of this sounds excessive for doing a few PCBs, but 
> it is the only way to do it "Right Way". Any other way you could end 
> frustrated re-inventing the wheel.

What I'm after right now is a light box that exposes two sides at the same 
time, is relatively inexpensive, and convenient to quickly pack up and 
stick on a shelf when I'm done.


-- 
David Griffith
dgriffi@...

A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?

The problem with this is the non-zero width of the PCB. Depending on
how you hold things together the films can shift one side relative to
the other. A better method is to stick the films to PCB cutoff strips,
or an L-shape. Insert a piece of clear acrylic or glass while aligning
the two sides instead of the PCB. This gives very exact results,
probably the best you can get without alignment pegs.

Vacuum holddown is highly recommended, it is easy to make by covering
the film/artwork stack with a framed sheet of flexible clear plastic
and applying vauum to that.

ST


A: Automated signatures containing views and opinions nobody asked for.
Q: What is the most annoying thing in e-mail?

On Tue, Jan 26, 2010 at 7:29 PM, David Griffith <dgriffi@cs.csubak.edu> wrote:

> I'm told that taping the stencils face-to-face to create a pouch makes for
> good registration.  Any opinions on this?
>

Is it possible to pre-drill some of the holes and align the artwork overlay against them?

Peter Harrison

On 26 Jan 2010, at 18:44, Stefan Trethan wrote:

> The problem with this is the non-zero width of the PCB. Depending on
> how you hold things together the films can shift one side relative to
> the other. A better method is to stick the films to PCB cutoff strips,
> or an L-shape. Insert a piece of clear acrylic or glass while aligning
> the two sides instead of the PCB. This gives very exact results,
> probably the best you can get without alignment pegs.
> 
> Vacuum holddown is highly recommended, it is easy to make by covering
> the film/artwork stack with a framed sheet of flexible clear plastic
> and applying vauum to that.
> 
> ST

Sure is.

The drilled holes will expose the edge there to under-etching, might
want to use mounting hole locations or something. Also, if you raise a
burr it will lift the film there, not ideal. And you need to drill the
holes in just the right place. I haven't found that method to be
particularly practical.

I very rarely do two-sided boards at home, although most of my board
stock would be double sided. So I have never perfected the process and
it doesn't come easily to me. I usually check two hole locations with
a caliper after transfer to make sure the sides are aligned before
etching.

ST


On Tue, Jan 26, 2010 at 8:02 PM, Peter Harrison
<peter.harrison@helicron.net> wrote:

> Is it possible to pre-drill some of the holes and align the artwork overlay against them?
>
> Peter Harrison
>
>
>
>
> On 26 Jan 2010, at 18:44, Stefan Trethan wrote:
>
>> The problem with this is the non-zero width of the PCB. Depending on
>> how you hold things together the films can shift one side relative to
>> the other. A better method is to stick the films to PCB cutoff strips,
>> or an L-shape. Insert a piece of clear acrylic or glass while aligning
>> the two sides instead of the PCB. This gives very exact results,
>> probably the best you can get without alignment pegs.
>>
>> Vacuum holddown is highly recommended, it is easy to make by covering
>> the film/artwork stack with a framed sheet of flexible clear plastic
>> and applying vauum to that.
>>
>> ST
>
>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>
>

On Tue, 26 Jan 2010, Stefan Trethan wrote:
>> I'm told that taping the stencils face-to-face to create a pouch makes for
>> good registration.  Any opinions on this?

> The problem with this is the non-zero width of the PCB. Depending on
> how you hold things together the films can shift one side relative to
> the other. A better method is to stick the films to PCB cutoff strips,
> or an L-shape. Insert a piece of clear acrylic or glass while aligning
> the two sides instead of the PCB. This gives very exact results,
> probably the best you can get without alignment pegs.
>
> Vacuum holddown is highly recommended, it is easy to make by covering
> the film/artwork stack with a framed sheet of flexible clear plastic
> and applying vauum to that.

I see.  The L-shape sounds like a good idea.  My reasoning is that if you 
leave enough space beyond the edge of the board, that space will bow out 
slightly thus allowing the very edges to be fastened together.

-- 
David Griffith
dgriffi@...

A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?

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

Peter Harrison <peter.harrison@...> writes:
> Is it possible to pre-drill some of the holes and align the artwork
> overlay against them?

That's what I do, but I have separate registration holes I add to the
board just for that purpose (see my other post).  Also, I do this
before cleaning the board so the hole gets de-burred too (also means I
can get my fingerprints and tape marks on the board while drilling :)

Making your own PCB's is time consuming with questionable quality of the results. I've been using Express PCB (expresspcb.com) for quite a while.

Their software is free and you can get 3 - 3x5 drilled, doublesided boards for $51. I have designed a board that was 8.5" by 3.5" double sided and ordered 2 for $110.

Their quality was great and the boards were recieved in 3 days. The smallest trace was .007" and  with many plated through holes.

 I have made my own PCB's before and the time, experimentation for results, drlling holes and fixing etch problems could not compete with this commercial process.

       Ron Shaul

 



________________________________

From: jcarlosmor <jcarlosmor@...>
To: Homebrew_PCBs@yahoogroups.com
Sent: Tue, January 26, 2010 11:56:54 AM
Subject: [Homebrew_PCBs] Re: setting up the Right Way

  
No, EPROM erasers do not work with the spectrum of liquid, dry-film, and pre-sensitized PCBs.

You do not explain exactly why are you going to do things "Right Way". If you only need a hobby PCB once a week you could do things same as you do now. If you want to do one (or 100) professional PCBs in the same week, maybe with real soldermask, you will need a good UV imaging exposure box. So the first thing is to avoid all those new fancy UV LEDs units. The reason is simple: no professional PCB shop use that. Period. You only have two alternatives, high-pressure mercury lamp, which is a hassle to operate when you only intend to image a single PCB, since you have to wait until UV energy become estable, or flourescent tubes, which is very simple and efficient to work on.

Also, you will need real vacuum if you want perfect results every time. You could built that at very low-cost with a modified fridge compressor. And you will need to CNC-machining some kind of fixture for registry of your PCBs fast.

I know that maybe all of this sounds excessive for doing a few PCBs, but it is the only way to do it "Right Way". Any other way you could end frustrated re-inventing the wheel. 





      

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

Ronald Shaul wrote:
> Making your own PCB's is time consuming with questionable quality of the results. I've been using Express PCB (expresspcb.com) for quite a while.
> 
> Their software is free and you can get 3 - 3x5 drilled, doublesided boards for $51. I have designed a board that was 8.5" by 3.5" double sided and ordered 2 for $110.
> 
> Their quality was great and the boards were recieved in 3 days. The smallest trace was .007" and  with many plated through holes.
> 
>  I have made my own PCB's before and the time, experimentation for results, drlling holes and fixing etch problems could not compete with this commercial process.

Spamming the list with commercial ads might get you banned.

Can i get the source code to Express PCB ?

Thought not. It's not "free".

--- In Homebrew_PCBs@yahoogroups.com, Ronald Shaul <ronaldshaul@...> wrote:
>
> Making your own PCB's is time consuming with questionable quality of the results. I've been using Express PCB (expresspcb.com) for quite a while.
> 
> Their software is free and you can get 3 - 3x5 drilled, doublesided boards for $51. I have designed a board that was 8.5" by 3.5" double sided and ordered 2 for $110.
> 
> Their quality was great and the boards were recieved in 3 days. The smallest trace was .007" and  with many plated through holes.
> 
> Â I have made my own PCB's before and the time, experimentation for results, drlling holes and fixing etch problems could not compete with this commercial process.
> 
> Â Â Â Â Â Â  Ron Shaul
> 
>


The software is nice, and can be used to make your own boards, but for a one-off or two of a simple circuit, the price is exorbitant. I just made three toner transfer PCBs tonight in about an hour and that includes tin plating and it cost me about $2 in materials. It'll probably take me another 30 minutes tomorrow to drill them, but given it's an enjoyable process I don't mind. 

If I were making 10+ of the same board, or complex double sided stuff I'd have the boards professionally made, but otherwise I like doing it myself, if I want to make a revision or need an extra board, I can have it finished and working the same evening. This is homebrew PCBs afterall.

--- In Homebrew_PCBs@yahoogroups.com, James Bishop <bishopaj@...> wrote:
>
> I found that an old overhead projector worked. It needs to have a mercury
> lamp (they are the more 'modern' version, with whiter light, mine is 3M
> brand). About 1 minute exposed my boards pretty well.
> 
> I used it because it has a convenient flat glass surface, and the light
> seems to be evenly distributed, and it exposes quickly. I'm not totally sure
> about the 'collimation' or angle of the light, but it seemed to work fine
> for my purposes and i used it for a 0.5mm pitch chip.
> 
> If I was going to build an exposure box, I would consider re-purposing on
> old overhead projector, or even a broken digital projector - I think those
> have mercury lamps.
> 



Those are UHP mercury, or occasionally metal halide lamps. The lamps themselves are expensive, most are over $100 for a replacement bulb. It would work fine, but you can get bug zapper fluorescent tubes pretty inexpensively and they will work off the ballast and starter from one of those $10 under cabinet lights. If you want to use a mercury lamp, just buy a cheap yard light if you can still find the mercury ones. The manufacture of mercury ballasts was banned in the US but they are still plentiful. You'll want a clear lamp too, the coated ones put out much less UV. Bug zapper fluorescent tube is the best choice though IMO, you can get them at any hardware store or on ebay. Sometimes they're also called unfiltered blacklights, the suffix will be /BL as opposed to /BLB of the traditional dark purple blacklight tubes.

> For artwork, I use standard over head transparency sheets available at Office Max, Staples or similar and print direct from Eagle to my HP Laser jet. I use a small piece of acrylic sheet to hold the artwork against the board... This works just fine.
> 


Try some vellum paper from an office supply store. It's easier to print on than the transparencies and works really well, it's less likely to have pinholes in the print. Just make sure you put the printed side against the board.

> 
> Spamming the list with commercial ads might get you banned.
> 
> Can i get the source code to Express PCB ?
> 
> Thought not. It's not "free".
>



I'm not sure that was spam, perhaps just a satisfied customer?

I have no affiliation with the company and have never used them for boards, but what do you need the source code for? The software is freely available, it's not open source but that doesn't mean it's not free. You can download it and use it free of charge, with no obligation to have your boards made by them. It lets you print out the artwork so you can make your own boards using whatever process you like and actually looks pretty good from what little I've seen.  When I've got some time I intend to give it a go, the software I've been using is a pain but there's always the dilemma of do I take the time to learn a new package, or do I just make my project with what I already know.

Quoting Russell Shaw <rjshaw@...>:

> > Making your own PCB's is time consuming with questionable quality of the
> results. I've been using Express PCB (expresspcb.com) for quite a while.
> >
> > Their software is free and you can get 3 - 3x5 drilled, doublesided boards
> for $51. I have designed a board that was 8.5" by 3.5" double sided and
> ordered 2 for $110.
>
>
> Spamming the list with commercial ads might get you banned.
>
> Can i get the source code to Express PCB ?
>
> Thought not. It's not "free".


How is this spam?

Not "free"?  F'ing hell, you know it is in the context most people think.

I suppose if I give you you an iPhone you'll give it back, saying 'It's not
free'.  Where's the schematic, gerbers, specifications, code, IC masks etc etc.
 How dare I give you something for nothing.

Express PCB should now charge $100 for their software, then you'll have nothing
to complain about, (except 'how dare they raise the price $100!!')

If you want to promote open source, you're not doing a good job.  How about you
do all of our boards for us, since you're so keen on "free".

Tony


A: Open source wankers.
Q: What's the most annoying thing on the internet?

Tony Smith wrote:
> Quoting Russell Shaw <rjshaw@...>:
> 
>>> Making your own PCB's is time consuming with questionable quality of the
>> results. I've been using Express PCB (expresspcb.com) for quite a while.
>>> Their software is free and you can get 3 - 3x5 drilled, doublesided boards
>> for $51. I have designed a board that was 8.5" by 3.5" double sided and
>> ordered 2 for $110.
>>
>>
>> Spamming the list with commercial ads might get you banned.
>>
>> Can i get the source code to Express PCB ?
>>
>> Thought not. It's not "free".
> 
> 
> How is this spam?

How does:

   "Making your own PCB's is time consuming with questionable quality of the
    results."

align with the very existance of Homebrew_PCBs ?

> Not "free"?  F'ing hell, you know it is in the context most people think.

It's how micro$oft windoze users think is free.

Even if micro$oft came "free" with the computer, you'll be forced to upgrade
and pay for the OS when the "free" software no longer runs on that version
of windoze.

I don't have micro$hite anywhere on the premises, and i'm not going to pay
to have it either.

Is the Express PCB file format documented or exportable to an open format?

If not, you're stuck with non-free options.

> I suppose if I give you you an iPhone you'll give it back, saying 'It's not
> free'.  Where's the schematic, gerbers, specifications, code, IC masks etc etc.
>  How dare I give you something for nothing.

I don't need to to buy anything extra to use the phone.

With Express PCB, i'd be locked into a proprietory file format on a
proprietory operating system.

That's windoze users idea of free.

> Express PCB should now charge $100 for their software, then you'll have nothing
> to complain about, (except 'how dare they raise the price $100!!')

I'd be glad if they did.

> If you want to promote open source, you're not doing a good job.  How about you
> do all of our boards for us, since you're so keen on "free".

I've explained enough times how to make decent boards.

Atleast i put all my effort into software engineering instead of
throwing money away.

> A: Open source wankers.
> Q: What's the most annoying thing on the internet?

A: Virus incubators
Q: What's windoze good for?

I don't try to promote open-source and i don't/can't recommend it to
anyone because of the generally inferior quality/architecture of most
of the graphical applications i find. That said, i don't have those
problems myself. Maybe you should learn to create something of value?

Russell Shaw wrote:
> Tony Smith wrote:
>> Quoting Russell Shaw <rjshaw@...>:
>>

>> Express PCB should now charge $100 for their software, then you'll 
>> have nothing
>> to complain about, (except 'how dare they raise the price $100!!')
> 
> I'd be glad if they did.

Maybe i was a little harsh, because it is still free in terms of
immediate price.

My only problem is that the original message was dissing making
PCBs yourself, and looked definitely like commercial spam.

> How does:
>
>    "Making your own PCB's is time consuming with questionable quality of the
>     results."
>
> align with the very existance of Homebrew_PCBs ?


Well, he's right.  I still make my own though.  But not doubled-sided stuff with
teeny weeny traces, sod that.


> > Not "free"?  F'ing hell, you know it is in the context most people think.
>
> It's how micro$oft windoze users think is free.


Snipped irrelavent Blah blah windoze blah blah windoze blah f'ing blah crap


> throwing money away.
>
> > A: Open source wankers.
> > Q: What's the most annoying thing on the internet?
>
> A: Virus incubators
> Q: What's windoze good for?


...and I've got a Linux box too.  I don't see what all the windoze crap was
about.  The post was 'here's some $0 software to get $$$ boards make if it gets
all too hard for you.'  I seriously doubt the OP gets a kickback.

Wanker.

Tony


A: Not much.
Q: What are rabid open source zealots who complain about windoze at the drop of
a hat good for?

On 27/01/2010 00:59, Ronald Shaul wrote:
> Making your own PCB's is time consuming with questionable quality of the results. I've been using Express PCB (expresspcb.com) for quite a while.
>
> Their software is free and you can get 3 - 3x5 drilled, doublesided boards for $51. I have designed a board that was 8.5" by 3.5" double sided and ordered 2 for $110.
>
> Their quality was great and the boards were recieved in 3 days. The smallest trace was .007" and  with many plated through holes.
>
>   I have made my own PCB's before and the time, experimentation for results, drlling holes and fixing etch problems could not compete with this commercial process.

The photoetch process I use is very reliable and repeatable. The big 
advantage over getting boards fabricated is that I can make a board, 
assemble it and have it working in a couple of hours. PCB Train has a 24 
hour service that I use if I need a double-sided board (�30 a board with 
no solder mask or silk) but it actually takes three days before I have a 
board in my hands.

Leon

I believe that when someone ask for help about DIY PCB making using professional methods (LPI or dry-film), the last thing he(she) wants to hear is "...give it up and make your boards with XYZ manufacturer...".

In this context, any advise about your experiences using not reliable procedures like toner-transfer, etc. is of little value too.

Although this is homebrew site, many members have years of professional expertise -some of them worked in the industry also for many years- so the idea of making double-sided soldermasked PTH in home (with the correct setup not matter if it is DIY) is totally viable.

Of course that everyone in this forum thanks so much for every piece of information/post/reply that occurs, but if for example, I would ask about where to buy LPISM (for the beginner Liquid Photoimageable Solder Mask), and I receive dozens of answers like "you could spray the PCB with automotive green laquer...", "use Pulsar green-foil product...", "it can not be do it at home...", "make your boards in a PCB shop...", etc., I would be very disappointed.