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Making
your own PCB
I have nothing
against anyone making their own PC boards for a particular project but
firstly I want to make a number of points clear.
Many schools and courses get their students to make the PC board for a project to simply
"waste time." They etch a board or drill one that has been
previously etched. What this is supposed to achieve, I don't know.
The end result is a board with no overlay.
This is the type of board I
totally object to.
When I started producing projects 25 years ago, we were the only hobby
magazine to insist on delivering PC boards with an overlay. My reasoning has
remained stead-fast and now most hobby magazines have caught up with this
essential requirement and supply boards with a legend.
The reason is simple.
The legend contains a lot of information such as "ID" for the
inputs and outputs, the name of the project, component values, ON/OFF switch
identification, etc and this adds enormously to the ease and pleasure of
using the board.
Most of our boards are designed to be exposed (such as for experimentation) and
the overlay is essential.
If you you have a blank PC board it will take a lot of interpretation to
work out what project it applies to.
When you have hundreds of boards in your inventory, you
will appreciate our approach.
Secondly, many readers will be using a board of this complexity for the
first time and we want the chances of success to be maximum.
Many readers in the past have sent emails to say a project does not work and
after lots of discussion, it was realised the board was home-made with a
"dalo pen" or "resist" and acid.
This is now the first
question we ask. We suggest the reader makes the project on one of our PC
boards and resubmits the enquiry.
Invariably the problem is a short-circuit between tracks or a cut in a track and this is
something we cannot diagnose over the web.
Thirdly, PC board manufacture has really "flown out of the hands"
of the hobbyist. Producing fine track-work, overlays, masking and tinning
are not steps that can easily be achieved in the workshop.
The availability of chemicals is also restricted and their disposal also
causes problems.
It all comes down to economics.
Since the manufacture of PC boards is not a requirement for entry to an
electronics profession, we suggest you leave the manufacture to the experts
and concentrate on the aspects you need to study.
We provide PC boards at a cost well-below that of a "one-off" and
this is only possible by us making them 100 or 1,000 at a time. In fact
the whole kit is sold below the cost of the individual components. We
challenge you to produce the project cheaper yourself.
Out of 300,000 kits, we have not had a challenge.
Our primary goal is education.
As we have said in all our introductory articles, we take you though a topic
by approaching it in a very simple way. Once you see how interesting and
inviting it can be, it will be much easier to understand the complex
elements.
Of course things have complexities, but it's totally unnecessary to
introduce them at the beginning.
Our approach is new and it is SUCCESSFUL. We are streamlining
everything to cover as much as possible in the minimum time and at the least
expense.
PC board manufacturing does not enter the picture. However "PCB
design" does come into our area of involvement and if you want to
design your own board and send it to a manufacturer, ExpressPCB
will deliver three PC boards (of the SAME board): 3.8inches x 2.5inches for a fixed price of
$62.00 The boards do not have an overlay or solder-mask but they can
be double-sided or single-sided and all holes are plate-through.
To get two boards equal to the size of PIC LAB-1, with solder mask and
overlay will cost about $100, but you will have to find out the actual price
by referring to a number of PCB manufacturers.
ExpressPCB also has a
very easy to use
FREE
PCB design program. You can download
it from their site (3.66MB). It allows you to create your own trackwork on a single or
double-sided board and send it in to them by email. The boards are ready the
next day and "fast-tracked" to you at the all-inclusive price
mentioned above. 
This is a great service and the CAD program is very easy to use. It's
something you will definitely need once you get though the early stages of
working through the experiments of PIC LAB-1.
At Talking Electronics, we design 10 - 15 boards at the same time and send
them to the manufacturers on a full size panel. We certainly could not
afford to get boards manufactured on a one-off basis. When the project is
operational, we get 100 PANELS manufactured, that's why we can offer boards
for 10% of the cost of prototyping them yourself.
We will be covering this topic again, later.
Colin
Mitchell.
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