Re: Re: Hobbyists strike again

I do a lot of etching and have had to dispose of about 8 gallons of ferric
cloride loaded with copper over the past two years. I prefer the ammonium
sulfate. It is much, much cleaner but it does weaken and you have to add
chemicals to increase it strenght. I don't like to let the liquids
evaporate into my shop area because the fumes are corrosive. And I don't
have a safe spot that my dog or grandkids could get into. I have to take it
to dispose of it legally. It is a hassel.

I have watched Bill Wainright use a $3 carbide cutter to outline the traces
on single sided pc board. The cutter was run by a $4 18000 RPM motor and
used a double bearing spindle to hold the 1/8" cutter. He was running it at
~10 ipm and it it only took about a 1/2 hour to produce a perfect board with
traces between the pads. Bill, is a very ingenious fellow and uses that
instant glue to hold the board down to mill then drill the holes. That
cutter i'm sure has lasted Bill many many hours.

Since I have several CNC machines including a dyna 2400 mill I would prefer
to mill the traces. The dyna is perfect for that kind of work.
Dan
-----Original Message-----
From: Jon Elson <jmelson@...>
To: CAD_CAM_EDM_DRO@onelist.com <CAD_CAM_EDM_DRO@onelist.com>
Date: Friday, October 29, 1999 10:36 PM
Subject: Re: [CAD_CAM_EDM_DRO] Re: Hobbyists strike again

>From: Jon Elson <jmelson@...>
>
>
>
>Andrew Werby wrote:
>
>> From: Andrew Werby <drewid@...>
>> [Even if he isn't, people keep asking me how they can do this. Is there a
>> program out there (or a combination of programs, even) that simplifies

this

>> process so someone can go from a picture of a pc board to a g-code plot
>> file? It would be nice if the hole-drilling were automated as well- am I
>> dreaming? Does anybody out there cut pc boards with a mill, or is

everybody

>> convinced that etching is the way to go?]
>
>If you never want to make two of a particular PCB, milling it may not be
>so horrible, but it eats expensive carbide cutters for lunch. A typical
>6" square board, double sided will just about use up a $20 milling tool.
>This was confided to me by someone who sold the LPKF machine.
>That didn't sound good! Plus, you have to flip the board over and
>maintain registration for the 2nd side.
>
>With etching, you develop and etch both sides of the board simultaneously.
>If you are ingenious, you can also build a double-sided exposure frame
>and print both sides of the board at the same time. Dry film resist for
>both sides of a 6" square board costs about $2 maximum, including the
>substantial waste with the big laminating machines. The initial investment
>in the film and laminator is substantial, however. I don't want to

minimize

>that! The etchant costs maybe $.25 for that board, and it won't just burn
>up suddenly like a milling bit. It will gradually slow down, so you have
>plenty of warning that you need new etchant. When I got my used Kepro
>bench-top etcher, I was horrified that it took 4 gallons of Fe2Cl3 to fill

it

>up, so I painted some bricks and plunked them into the tank.

Unfortunately,

>they only occupy a gallon of volume, so it still takes 3 gallons to fill.
>But, I've been running on those same 3 gallons for about 4 years.

Admittedly,

>that is with VERY intermittent use, but it shows the chemical waste problem
>is not so huge. When the stuff is depleted, you can just leave it exposed
>and it will slowly dry out. Then, it is SOLID waste, and easy to dispose

of.

>
>Jon
>
>>Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the

discussion of shop built systems in the above catagories.

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>List Manager
>