--- milwiron@... wrote: At 08:12 AM 04/05/2002 -0800, you wrote in part:
So the only issues are paint that will scratch away cleanly and
that it leaves a wide enough opening after etching. Very interesting idea.
You could use layout fluid for metal working. Most are a lacquer
type base
and scratch very cleanly since that's exactly what they're
designed for.
Dykem is one manufacturer, it's available in a couple of colors,
spray or
brush.
Denny Great idea. Anyone here have some and some etchant and want to try it and report back here? Nothing fancy, just coat a scrap of board and then scratch the surface with the scratching device held at 90 degrees with only its own weight holding it down. Steve Greenfield __________________________________________________ Do You Yahoo!? Yahoo! Tax Center - online filing with TurboTax
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Steve,
In most software you can set the width of the milled
area or Isolation. When using a plotter, there will be less
drag if the point is fine.
Hey Steve! Thanks for this conference! I am having fun!
John
toggle quoted message
Show quoted text
--- In Homebrew_PCBs@y..., Steve Greenfield <alienrelics@y...> wrote: This might be a wierd idea, just say so if it is-
How about a pointed bit used in your PCB milling machine, with the
laquer coating and a bath in the etchant after? That guarantees a
wider swath but with less cutting.
I'm thinking of a guy who sells pictures etched into stone. His
bits are just carbide shafts ground to a slightly faceted point.
The idea being that this gives you a wider path through the copper,
and you can resharpen the bits. It does require the CNC milling
machine and etching afterwards, though, so perhaps complexity would
outweigh any cost savings.
I've gotta try your scratch and etch idea.
Steve Greenfield
--- crankorgan <john@k...> wrote:
Hi Denny,
The acid will also stay strong because there
is less copper etched when doing isolation. I use the
Think and Tinker bits. They only last a little while
longer if you hit just the copper. I did all kinds
of tests trying to reduce my costs so I could see
circuit boards to the public. Hopefully someone
gives the Scratch and Etch a real test!
John
--- In Homebrew_PCBs@y..., milwiron@t... wrote:
I'm finding John's idea pretty intriguing.
Just to take the brainstorming another step:
One big problem with PCB routers is tool life and their cost.
But using a CNC router with a cutter to just cut through the
surface of the
resist and a thou or two in to the copper would prolong the life of
a
carbide tool immensely... and produce a board that should etch quickly and
cleanly.
Yes it would be better do away with etching all together but a marriage of
the two technologies for some applications could be useful.
Denny
At 02:35 PM 04/05/2002 -0000, you wrote:
Hi,
Nobody liked my light on a plotter idea. I was told the
light source would have to move too slow. The board would take
way to long. Ok, I use Mechanical Etching bits myself. But what
if you coated the whole board with resist. Then you put a
sharp
point in the plotter. Have the plotter do isolation paths.
Then
the board goes to the acid.
John
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This might be a wierd idea, just say so if it is- How about a pointed bit used in your PCB milling machine, with the laquer coating and a bath in the etchant after? That guarantees a wider swath but with less cutting. I'm thinking of a guy who sells pictures etched into stone. His bits are just carbide shafts ground to a slightly faceted point. The idea being that this gives you a wider path through the copper, and you can resharpen the bits. It does require the CNC milling machine and etching afterwards, though, so perhaps complexity would outweigh any cost savings. I've gotta try your scratch and etch idea. Steve Greenfield --- crankorgan <john@...> wrote: Hi Denny,
The acid will also stay strong because there
is less copper etched when doing isolation. I use the
Think and Tinker bits. They only last a little while
longer if you hit just the copper. I did all kinds
of tests trying to reduce my costs so I could see
circuit boards to the public. Hopefully someone
gives the Scratch and Etch a real test!
John
--- In Homebrew_PCBs@y..., milwiron@t... wrote:
I'm finding John's idea pretty intriguing.
Just to take the brainstorming another step:
One big problem with PCB routers is tool life and their cost.
But using a CNC router with a cutter to just cut through the
surface of the
resist and a thou or two in to the copper would prolong the life of
a
carbide tool immensely... and produce a board that should etch quickly and
cleanly.
Yes it would be better do away with etching all together but a marriage of
the two technologies for some applications could be useful.
Denny
At 02:35 PM 04/05/2002 -0000, you wrote:
Hi,
Nobody liked my light on a plotter idea. I was told the
light source would have to move too slow. The board would take
way to long. Ok, I use Mechanical Etching bits myself. But what
if you coated the whole board with resist. Then you put a
sharp
point in the plotter. Have the plotter do isolation paths.
Then
the board goes to the acid.
John
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Hi Denny, The acid will also stay strong because there is less copper etched when doing isolation. I use the Think and Tinker bits. They only last a little while longer if you hit just the copper. I did all kinds of tests trying to reduce my costs so I could see circuit boards to the public. Hopefully someone gives the Scratch and Etch a real test! John --- In Homebrew_PCBs@y..., milwiron@t... wrote:
I'm finding John's idea pretty intriguing.
Just to take the brainstorming another step:
One big problem with PCB routers is tool life and their cost.
But using a CNC router with a cutter to just cut through the
surface of the resist and a thou or two in to the copper would prolong the life of a carbide tool immensely... and produce a board that should etch quickly and cleanly.
Yes it would be better do away with etching all together but a marriage of the two technologies for some applications could be useful.
Denny
At 02:35 PM 04/05/2002 -0000, you wrote:
Hi,
Nobody liked my light on a plotter idea. I was told the
light source would have to move too slow. The board would take
way to long. Ok, I use Mechanical Etching bits myself. But what
if you coated the whole board with resist. Then you put a sharp
point in the plotter. Have the plotter do isolation paths. Then
the board goes to the acid.
John
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Hi Steve,
I feel by using the Scratch and Etch method, pen speed
and flow will be out of the picture. Most software will allow the
outlining to be done. I don't acid etch here! But I got into it
trying to help someone else. I even bought a plotter. I bought the
plotter to see how it is made. I want to create a really cheap
PCBMill next. The one I sell plans for works great. I am looking
to cut the building time and cost way down. While working on the
new PCBMill the Light bulb idea hit. Then the Scratch and Etch
idea! I hope somebody will try it and report back.
John
toggle quoted message
Show quoted text
--- In Homebrew_PCBs@y..., Steve Greenfield <alienrelics@y...> wrote: Yep, far too long to expose, and the problem of "blooming". UV
laser, anyone?
That sounds do-able! It would just require modifying a pen with one
of those carbide point marking pens. I think you could probably
just spray something like one coat of black fast drying laquer to
scratch through.
And one of the things I've always liked doing to boards I make is
sign them. Couldn't do that when I made some with the vinyl cutter.
So the only issues are paint that will scratch away cleanly and
that it leaves a wide enough opening after etching.
Steve Greenfield
--- crankorgan <john@k...> wrote:
Hi,
Nobody liked my light on a plotter idea. I was told the
light source would have to move too slow. The board would take
way to long. Ok, I use Mechanical Etching bits myself. But what
if you coated the whole board with resist. Then you put a sharp
point in the plotter. Have the plotter do isolation paths. Then
the board goes to the acid.
John
__________________________________________________
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I'm finding John's idea pretty intriguing.
Just to take the brainstorming another step:
One big problem with PCB routers is tool life and their cost.
But using a CNC router with a cutter to just cut through the surface of the
resist and a thou or two in to the copper would prolong the life of a
carbide tool immensely... and produce a board that should etch quickly and
cleanly.
Yes it would be better do away with etching all together but a marriage of
the two technologies for some applications could be useful.
Denny
toggle quoted message
Show quoted text
At 02:35 PM 04/05/2002 -0000, you wrote: Hi,
Nobody liked my light on a plotter idea. I was told the
light source would have to move too slow. The board would take
way to long. Ok, I use Mechanical Etching bits myself. But what
if you coated the whole board with resist. Then you put a sharp
point in the plotter. Have the plotter do isolation paths. Then
the board goes to the acid.
John
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At 08:12 AM 04/05/2002 -0800, you wrote in part: So the only issues are paint that will scratch away cleanly and
that it leaves a wide enough opening after etching. Very interesting idea. You could use layout fluid for metal working. Most are a lacquer type base and scratch very cleanly since that's exactly what they're designed for. Dykem is one manufacturer, it's available in a couple of colors, spray or brush. Denny
|
Yep, far too long to expose, and the problem of "blooming". UV laser, anyone? That sounds do-able! It would just require modifying a pen with one of those carbide point marking pens. I think you could probably just spray something like one coat of black fast drying laquer to scratch through. And one of the things I've always liked doing to boards I make is sign them. Couldn't do that when I made some with the vinyl cutter. So the only issues are paint that will scratch away cleanly and that it leaves a wide enough opening after etching. Steve Greenfield --- crankorgan <john@...> wrote: Hi,
Nobody liked my light on a plotter idea. I was told the
light source would have to move too slow. The board would take
way to long. Ok, I use Mechanical Etching bits myself. But what
if you coated the whole board with resist. Then you put a sharp
point in the plotter. Have the plotter do isolation paths. Then
the board goes to the acid.
John __________________________________________________ Do You Yahoo!? Yahoo! Tax Center - online filing with TurboTax
|
Hi,
Nobody liked my light on a plotter idea. I was told the
light source would have to move too slow. The board would take
way to long. Ok, I use Mechanical Etching bits myself. But what
if you coated the whole board with resist. Then you put a sharp
point in the plotter. Have the plotter do isolation paths. Then
the board goes to the acid.
John
|
Re: UV Light Source for Exposing PCB's
Hi Dave,
Yeah, my kids are grown up! In fact, the oldest is in grad school, and
borrowed my "eraser", and my PIC programmer! I got my lamp in '77, so I
think it's paid for it's self!
Your box sounds good. I'll get around to it!
Alan KM6VV
Dave King wrote:
toggle quoted message
Show quoted text
And for others reading, just operate the lamp in a box, or in a spare
bathroom/photolab (I hang a warning sign on the door!). As has been
noted, it's dangerous to expose your eyes to the light, and no doubt
will also cause severe sunburns.
Alan KM6VV Gotta chirp in the middle here ;-]
I purchased a metal tool box, a germ light, and a electric timer a few years
back. I wired the whole thing up inside so that when close the lamp
is located just above the removable tray which has some contact foam
glued in place. I put the parts to be exposed/erased on the foam, close the lid
(which still has the padlock hasp on it if needed), plug it into the socket,
give the timer a twist and wait till it goes ding.
The lid seals well enough that no light escapes but a strip of door seal would
fix a toolbox with a poor fit. Other than the timer knob and the cord
everything
fits inside the box and is protected. When done with it will easily stuff
into a
closet. If you are doing stuff at home and have prying little fingers about
aka
mutant rugrats aka kids you can put a lock on the hasp walk away from it
and not worry about them getting hurt or exposed.
I can't rem what the timer was from but it went to 45 or 60 minutes. Anyway
this
has worked quite well for big and small batches for 11 years (getting old)
Dave
|
Re: UV Light Source for Exposing PCB's
And for others reading, just operate the lamp in a box, or in a spare
bathroom/photolab (I hang a warning sign on the door!). As has been
noted, it's dangerous to expose your eyes to the light, and no doubt
will also cause severe sunburns.
Alan KM6VV Gotta chirp in the middle here ;-] I purchased a metal tool box, a germ light, and a electric timer a few years back. I wired the whole thing up inside so that when close the lamp is located just above the removable tray which has some contact foam glued in place. I put the parts to be exposed/erased on the foam, close the lid (which still has the padlock hasp on it if needed), plug it into the socket, give the timer a twist and wait till it goes ding. The lid seals well enough that no light escapes but a strip of door seal would fix a toolbox with a poor fit. Other than the timer knob and the cord everything fits inside the box and is protected. When done with it will easily stuff into a closet. If you are doing stuff at home and have prying little fingers about aka mutant rugrats aka kids you can put a lock on the hasp walk away from it and not worry about them getting hurt or exposed. I can't rem what the timer was from but it went to 45 or 60 minutes. Anyway this has worked quite well for big and small batches for 11 years (getting old) Dave
|
Re: UV Light Source for Exposing PCB's
Hi Hugh,
Yes, quite true! I'd forgotten about that! and I'm with you on the
Altair's too. I have a pair still stashed in the garage. I've used my
lamp for erasing EPROMS for years, and recently for erasing PIC's.
And for others reading, just operate the lamp in a box, or in a spare
bathroom/photolab (I hang a warning sign on the door!). As has been
noted, it's dangerous to expose your eyes to the light, and no doubt
will also cause severe sunburns.
Alan KM6VV
Hugh Prescott wrote:
toggle quoted message
Show quoted text
Actualy the germicidal lamp tube is made of quartz not glass and thats why
the cost so much.
Glass in general is not very transparent to UV.
Had mine since the days of th PROM burner for the Altair 8800.
Hugh
----- Original Message -----
From: "Alan Marconett KM6VV" <KM6VV@...>
To: <Homebrew_PCBs@...>
Sent: Thursday, April 04, 2002 12:23 PM
Subject: Re: [Homebrew_PCBs] UV Light Source for Exposing PCB's
Hi John,
What you want is called a "germicidal lamp". It is a clear glass
fluorescent lamp. Mine is about 14 inches long. I bought it and a
holder for about $20 (quite some time ago). Ask for one at an
electrical supply house.
HTH
Alan KM6VV
johnman9146 wrote:
<SNIP>
I do not have a UV light source. I didn't buy one as I didn't want
to spend the money. Some of you have told me that you made a light
box. What types of lights/lamps work for exposure? I saw somewhere
that a blacklight works. Is this true?
<SNIP>
So please, if you could help me build a UV light source to expose
small PCB's, I would appreciate it.
Thanks
|
At 05:49 AM 4/4/02 +0000, johnman9146 wrote: I'm not looking for ink for an ink-jet, I am looking for ink that one
would use for silk-screen type printing. The stuff we used to use was called "Circuit Black" but I don't remember the manufacturer's name. Check your local Silk Screen supply house - they should be able to search that name for you. If I get a chance tomorrow, I call around and see what I can find out. dwayne Dwayne Reid <dwayner@...> Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 18 years of Engineering Innovation (1984 - 2002) .-. .-. .-. .-. .-. .-. .-. .-. .-. .- `-' `-' `-' `-' `-' `-' `-' `-' `-' Do NOT send unsolicited commercial email to this email address. This message neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email.
|
Re: UV Light Source for Exposing PCB's
Actualy the germicidal lamp tube is made of quartz not glass and thats why
the cost so much.
Glass in general is not very transparent to UV.
Had mine since the days of th PROM burner for the Altair 8800.
Hugh
toggle quoted message
Show quoted text
----- Original Message ----- From: "Alan Marconett KM6VV" <KM6VV@...> To: <Homebrew_PCBs@...> Sent: Thursday, April 04, 2002 12:23 PM Subject: Re: [Homebrew_PCBs] UV Light Source for Exposing PCB's Hi John,
What you want is called a "germicidal lamp". It is a clear glass
fluorescent lamp. Mine is about 14 inches long. I bought it and a
holder for about $20 (quite some time ago). Ask for one at an
electrical supply house.
HTH
Alan KM6VV
johnman9146 wrote:
<SNIP>
I do not have a UV light source. I didn't buy one as I didn't want
to spend the money. Some of you have told me that you made a light
box. What types of lights/lamps work for exposure? I saw somewhere
that a blacklight works. Is this true?
<SNIP>
So please, if you could help me build a UV light source to expose
small PCB's, I would appreciate it.
Thanks
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Re: UV Light Source for Exposing PCB's
So please, if you could help me build a UV light source to expose small PCB's, I would appreciate it.
Thanks
there was a recent thread on aus.electronics USENET group about this. search subject "UV Light Box Plans" in For my UV source I use 400W standard HID mercury vapor flood lamp. Exposure is 90 sec at 400 mm distance from the lamp. 175 W would be more suitable.
|
Re: If you do buy an HP G/L plotter
1)You can't use the HP pen's they aren't waterproof. Others have suggested using modified Staedler waterproof pens. 2) The plotter speed can be explicitly controlled in software. 3) Mount the board on a mylar overhead transparency film -- this is plenty rigid. 4)the original post dealt with repurposing the HP7475a as an XY pen plotter. I wrote some code if anyone cares to take two 0-5V inputs and convert them to the XY coordinates. Jack --- In Homebrew_PCBs@y..., "johnman9146" <johnman@d...> wrote: I already own one. I tried using it before, but didn't like the
results. I even modified a couple of pens as I thought this might be an easy way to "draw" boards to etch. I have owned this plotter
since new a long time ago.....
The main problems I had with trying the plotter were:
1. The ink would not last through the etch. At the time I think I
had tried to use a OHT marker (cut it off and used one of the plotter pen bodies).
2. When the pen would "land" on the copper, tiny ink droplets would
splatter and make a mess of the fine traces.
3. The speed seemed WAY too fast to get nice dark lines that you
could get by hand with the same pen.
4. Securing the board to backing paper. As the plotter requires
paper to "grip". (The paper movement also seemed WAY too fast and
would sometimes move the board out of registration.)
5. The process seemed slow, and since I never got a decent board to
etch with this method, I abandoned it.
The plotter now once again collects dust in the closet :(
If you have any ideas to try, or like you said, software to try I
would be game to try it once again as I would like to get some more
use out of this practically new plotter.
--- In Homebrew_PCBs@y..., "caveteursus" <j.walton@a...> wrote:
like the HP7475a which I own, I've written some code to also use it as an XY pen-plotter.
|
Hi.
What if, you took a surplus plotter. Put a sensitized board
on the plotter in a dark room. Replaced the pen with a focused
light source that turned on and off with the pen-up and pen-down
signal. I used to do Radio FAX pictures like this until I found
that metalized paper that burned when a current went through it.
John
|
Re: UV Light Source for Exposing PCB's
Hello crankorgan,
Thursday, April 04, 2002, 2:57:25 PM, you wrote:
c> Hi,
c> Years ago I tried to locate a UV light to erase Eproms. I
c> got alot of bad info. The Blacklight for posters is not
c> the right wavelength. UV bulbs look like a clear florescent
c> light bulb. They used to come with a drop of mercury in them. After
c> trying to buy one, I found one in a Tropical Fish store. They
c> are used in a Sterilizer. Water passes past the bulb and the
c> germs in the water are killed. Do not look at the light while
c> it is on!!! It may look like it is not bright but it can give
c> you welders flash! You will wake up 2 o'clock in the morning with
c> the feeling sand is in your eyes. Be careful!
c> John
And I replied:
And much worse things can happen if your tiny grey cells are on vacation:
A nurse in one hospital thaught that she could gain some sun-tan under the
germicidal lamp, so she went to a room where some of the laundry was
stored and layed down for about half hour, intremittantly observing the
'not so intense' blue light which in fact is almost pure UV-C (peak for
germicidal lamps is arround 237nm - ideal for UV-EPROM erasing).
She was severe burnt and her staring to the lamp gaved her 60% sight loss
(permanent).
--
Best Regards,
Zoran A. Scepanovic
mailto:zasto@...
|
Re: UV Light Source for Exposing PCB's
Hello Tim,
Thursday, April 04, 2002, 5:25:55 PM, you wrote:
TG> Even better is to get some real flourescent UV bulbs. I got mine from a
TG> local lighting supply house. I just looked for light bulbs in the yellow
TG> pages. The bulbs are F20T12/BL and cost me about $10 per tube when I bought
TG> them last year. They are a 2' long bulb and go into a standard fixture that
TG> I got at Home Depot. I added a 5 minute mechanical timer to control the
TG> exposure.
TG> Tim
TG> [Denver, CO]
And I replied:
Just my ??? 0.02.
Take a trip to the www.thinktink.com
There are a lot of info on PCB making. I've made the axposure unit using 2
Philips TL20/09N 20W tubes that are quite radiating in the UV spectrum.
Peek output is somwhere arround 340-360nm range. the /09 type of tubes
have more UV radiated than /05 type. The tubes are rised approx 20cm from
the board covered with the artwork, and the exposure time that I use is 8
minutes (still have to obtain the Stoufer gauge to determine the correct
time), but nevertheless, the boards that I make are always well exposed
(covered with 2mm thick ordihary glass).
The whole unit costed me arround $ 20 (DM 50.-) as follows:
* Philips TL20/09N DM 10.-
* Balasts 20W DM 10.-
* Chipwood for box DM 10.-
* Various screws, nuts, washers DM 4.-
* Starters for fluorescent lamps DM 2.-
* Power cable DM 2.-
* PVC pipe 110mm dia 1m length DM 3.-
* Al foil for reflectors DM 1.-
TOTAL DM 42.-
--
Best Regards,
Zoran A. Scepanovic
mailto:zasto@...
|
Re: UV Light Source for Exposing PCB's
You may be able to get uv lamps from catering suppliers as we use them in uv
fly killers.
Ian
toggle quoted message
Show quoted text
----- Original Message ----- From: "Tony Jeffree" <tony@...> To: <Homebrew_PCBs@...> Sent: Thursday, April 04, 2002 7:19 PM Subject: Re: [Homebrew_PCBs] UV Light Source for Exposing PCB's I guess the other obvious place to look for these lamps is the supplier you use to purchase other PCB-making goods (board, developer, etc.). The
suppliers I use in the UK for such materials (RS Components, Farnel, Rapid
Electronics...) sell suitable lamps, and complete exposure units designed
for the job too.
Regards,
Tony
At 10:23 04/04/2002 -0800, you wrote:
Hi John,
What you want is called a "germicidal lamp". It is a clear glass
fluorescent lamp. Mine is about 14 inches long. I bought it and a
holder for about $20 (quite some time ago). Ask for one at an
electrical supply house.
HTH
Alan KM6VV
johnman9146 wrote:
<SNIP>
I do not have a UV light source. I didn't buy one as I didn't want
to spend the money. Some of you have told me that you made a light
box. What types of lights/lamps work for exposure? I saw somewhere
that a blacklight works. Is this true?
<SNIP>
So please, if you could help me build a UV light source to expose
small PCB's, I would appreciate it.
Thanks
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Steven Greenfield AE7HD