Page 10 - CNC Robotics

CNC Robotics

56000 U.S., but I can never convince myself to buy a too l wo rth so
much . Even if the cost of the machin e seems reasonable you still
have ship ping a nd du ties to pay, and in my case the exchange rate
between U.S. and Canadian dolla rs. All things considered, it was
going to cost me in excess of 510,000 Canadian to get a CNC
machine in my shed. I can't afford that kind of price tag! I searched
for plans or a book that described what I wanted to build. I did find
some plans on the Internet but either the machine was too small
and inaccurate or the plans were expensive and requ ired the use
of expensive components. I cou ldn't find any books in print about
a similar project. I won't buy plans that I can't get a good look at
first, so the Internet plans were out of the qu estion. I prefer books
because I ca n hold them and flip through the pages before I hand
over the cash. Books also cost less.
I decided to build my own machine us ing some off-t he-shelf
lineal motion co mpo nents and some co mponents that I salvaged
or modified to suit the project. I thou ght the most logica l thing
would be to docum ent my progress and share the inform ation
through a book . To summa rize, I decided to build my own machin e
because I love a cha llenge and I learn more when I have a practi-
cal project; also, I can keep the cost low. It's that simple.

Gantry Style

In my op inion, a gantry styled CNC machine is sim plest to imple-
ment. A few years ago, I built a band saw mill fram e and gantry,
so the design of a more accurate system didn't seem too tough a
project. I also like the idea of moving the tool over the material
rather tha n the material under the tool. A machine built to move
material would not have as large a wo rking area for a given foot-
print. Con sidering my work shed is only 22 X 12 feet , a gantry
machine is most suitable.

Motors

The first purchase to make was the stepper motor. My local
Princess Auto has a great surplus department, so I headed there

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