RadioBanter - View Single Post

October 28th 04, 11:19 PM

In article ,
(Brian Kelly) writes:

(Len Over 21) wrote in message
...

Sweetums blurted out:

Who is "sweetums?" :-)

I use a combination of PDFs, BMPs (via MS Paint) to get 1:1
drill guides for PCBs and small chassis structures.

Welp, I knew there had to be somebody far enough behind the curve to
still be using goofy old MS Paint. For *anything*.

tsk, tsk, tsk...

1. MS Paint is a freebie, came with Win95, transported through
Win98 and onto XP.

2. I've used it to draw schematics, small to very big, using symbols
also developed on Paint.

3. Resolution is at least 300 DPI which equates to +/- 0.003 inch.

4. The repeatable accuracy of dot-matrix printers such as either
the HP 722c or HP PSC2110 is +/- 0.003 inch.

5. The accuracy of the printing process is greater than I can get
using ordinary hobby-type hand tools.

6. You've got to remember this hobby radio work does NOT
normally need Jo-block-checked accuracy. It is a HOBBY,
not a working machine shop.

Congratulations Sweetums, you win the annual Kill Bill Society "Last
of the Mohicans" award for 2004.

Don't mess with the Mohicans, white man. :-)

Snarl at Microsoft all you want. Bill G. will chuckle in his
mansion. :-)

With either
Corel or Adobe photo edit programs you will find that one can
do quite-exact photo reductions of 2:1 or even 3:1 by the
adjustment of pixels per inch in either Corel Photo House or
Adobe PhotoDeluxe 3. Other photo programs should be able to
do the same thing. Good for one-of-a-kind projects.

I've regularly done 2:1 scale manual PCB resist traces on a pad
of vellum (gridded 0.1"), scanned that into BMP format, cleaned
it up in MS Paint (image attributes set to B&W), dropped the
scale to 1:1, and done the etch masks on VueGraph transparent
stock. Note: Paint allows adding lettering, numbers, etc. as you
need. All without going out to any photo services. Again, good
for quick one-of-a-kind projects.

*GROAN*! I don't believe it, whatta bass-ackward, contorted heap of
nonsense.

Tsk. You should have been over at Miccolis' shack, making those
state-of-the-art chassis into something looking "professional."

And you're an "engineering professional" eh? As if.

You betcha. Everything from thin-film/thick-film (the first of the
SMD applications) to hand-painting lacquer resist for a very
quick turn-around without leaving the lab (one afternoon, start
to finish). I drew the line on compression-bonding of SAW
filter wires and left that to the thin/thick film tech who had more
experience with a micromanipulator and bonder. SAW filters
were aluminum film on quartz, about the size of fundamental
crystals in HF but were 56 to 63 MHz center frequency.

Now let me explain the right way to do quickie one-off PCB and panel
layouts Sweetums: In the first place you don't use frigging bit maps
or any of the others of it's pixel-juggling junk for engineering work,
those are for touching up photos of Aunt Minnie's birthday party.

Tsk, tsk, tsk. Did you feed your kiddies Gerber plot foods?
:-)

In the first place, you argumentative old snit, ham radio is a
HOBBY, not some profession.

As such, one has to approach homebrew projects from the hobby
standpoint...what tools are available, what processes can be
safely done at home, the experience of the hobbyist, all those
things.

Tsk. I've done L-band stripline layouts at 4:1 on rubylith for a
finished work about 10 inches long, had it photoreduced to full
scale complete with the touchups to black out blank spots for
spray etching on Duroid. Was needed to get the four
directional couplers on that board accurate. It was.

["L-band" is 1 to 2 GHz for you long-wavers of HF]

NO ONE NEEDS that kind of accuracy or QC for simple, loose
tolerance one-of-a-kind PC boards, milliameter scale overlays,
or small chassis drill guides. Try to stay focussed.

Real profesionals use vector-based graphics software which are
designed for engineering purposes. They're called CAD programs you
see.

Spoken like an UNREAL professional who does NOT do regular
electronics engineering. :-)

Real pros will use anything that WORKS and costs the company
the least amount. Ham radio isn't involved in "company"
business.

Acronym-wise, you have to get them straight. "CAD" is
computer-assisted-DRAFTING now. "CAE" is computer-
assisted-ENGINEERING. "CAD" used to be general Design
stuff but that changed about a decade ago.

Got news for you, mechanical man. "Vectored" lines depend on
the plotter being used. If you look deep into the guts that make
them work you will find those are really DIGITAL with enough
temporary storage to make the picture elements ("pixels") of
high density. If you want REAL analog lines (which is what
"vectoring" originally meant), then you cut Rubylith...something
I did about 30 years ago.

$100 at any decent computer store gets you 2-D TurboCAD which is
accurate to a millionth of an inch if one cares to get that anal about
locating holes in PCBs and it goes uphill from there.

YOU are the one getting anal about accuracy. :-)

For $100 anyone can download PCB software for FREE from
Express PC's website and order a couple of finished PCBs
with plated-thru vias or pads, foil both sides, if laid out with
their software.

Or even better
dig up Felixcad LT which is a general purpose full-featured freeware
2D CAD program and dump it in.

Why go to all that trouble for some simple one-of-a-kind PCBs
which do NOT need exceptional tolerances...or meter scale
replacements...or small drill guides? MS Paint was in the Win95
bundle, Corel Photoshop was bundled with WP8, and Adobe
Photo House was bundled with Acrobat. I had an earlier Adobe
photo program bundled with the HP 722C. One uses what one
can.

I'll put it this way: By the time you've fiddled with your pencil,
graph paper, scanner and collection of low-res dimensionally raunchy
photo editing software just to get a drilling pattern I'll have a
complete board layout including all the traces, lettering, donuts and
the drilling pattern done 100% onscreen with a single program. All I
have to do from there is load a sheet of vellum into the old LaserJet,
specify the scale (100:1? No sweat.) and hit the "print" button. Or
print just the hole pattern. Or just the traces and such for board
burning purposes, etc.

"Raunchy photo editing software?" :-)

Is that a clue on what YOU use YOUR photo editing software for?
:-)

Don't have a laserjet printer...or a Gerber plotter...or have any
need for "100:1" scaling. I know of where I CAN get those
services...for nothing. Don't need them for hobby projects.

Hobby projects don't need esthetic perfection. Electrons don't
care about human esthetics. Plated-through pads and vias are
a convenience, not a necessity. Just enough pad for the solder
to create a physical wedge (in addition to making a good solder
joint) will do it. MG Chemicals has a good "green" overspray
conformal coating; can be ordered through Allied Radio. No
silkscreen reference designations for one-of-a-kinds needed if
you have the original drawings.

Manual PCB layouts are fine for not-dense boards. Autorouters
are a help and programs for plotting with 20-thousandths wide
traces and photo etch are a must. I don't try manual resist
patterns at that kind of density...but I do try a manual layout
BEFORE going either manual or programmed resist pattern.
Some of us are good at that sort of thing and some are not; I
am towards the good side. Having been an illustrator helps in
that regard.

Just for the hell of it I checked a couple of my layouts for
dimensional errors with a Pratt & Whitney optical comparator set to
10:1 magnification and the worst error I could find was 0.003 inches
over a six inch span. Which is better than the advertised limit of the
printer accuracy. Try that with Paint.

What I actually tried was to draw a couple of dimensions (two
each of 5 inches) on a piece of vellum from a pad (Clearprint
No. 1000H-10, each pad 50 sheets 8 1/2 x 11 inches, got a
bunch of those from Staples long ago), run it through the Umax
digital scanner, then print it out. Did the same with Paint for a
second image, printed that out.

Lacking a Pratt & Whitney optical comparator (not exactly in
every ham shack or hobby workshop), I used an old single-piece
steel alloy scale and got the SAME dimensions. To be honest,
I didn't send the scale to NIST for precise calibration and I don't
have a set of Jo-blocks at home and no laser interferometer to
measure precise distances. Making simple punch marks by
naked eyeball (being near-sighted helps) for drilling by a B&D
variable-speed electric drill is what I normally do. :-) For PCBs
I use an old Dremel Moto-Tool in the old-style Dremel mini-
drill press holder (there's a new model Dremel that works more
like the standard drill press). A Powerstat is used to slow down
the Dremel's speed to suit the work material (Superior Electric,
comparable to the GR Variac, does the same function). The
trick for hobby purposes and ordinary workshops is to allow
for sloppy location of holes with slightly over-size ones and
manuevering room.

Electrons, fields, and waves don't much give a snit what fancy
instrument you use to make the supports or enclosures for
their circuits. They don't care how much you make, how much
you brag about income, job title, or ham class. You work by
THEIR rules not by your shouting and snarling. Same for
professional or amateur. Try to remember that.

Len