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Construction principles:
As I said earlier, I was inspired by "Coquery" to build
my machine. His philosophy is to use affordable material and the
tools that any handyman would have in his workshop.
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Tools:
Stand drill, saws and common tools.
The material:
The structure is made of aluminium bars available in most hardware
and hobby shops. AU4G class alloy would be preferrable. The carriages
use rollers ball bearings. They are sold in sport shops. It is reliable
and economical, even if you need a few dozens to build the machine!
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Driving system:
It is the most expensive part of the machine. I decided to use
belts for the driving system. It is more reliable than cables. The
only drawback is the price (370 Euros of equipment from HPC), unless
you can find used material for a good price. The Sanyo Denki steppers
motors were bought for 10 Euros each. Wich is very reasonable.
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Control board:
The connexion to the pc is made through the parallel port. You
can find plenty of boards to control your machine. The most known
in France are the ones designed by Bernard Baud (BB 2001 etc.) and
Laurent Fouga (CNC3AX etc.) The aeromaniacs
site lists many cards. You can also go to the cnc
links pages to get the urls for a few sites. As I don't know
a lot in electronics, I bought a CNC3A board already soldered. The
installation and the configuration didn't make any problem. You
just have to pay a lot of attention to the wiring of each components.
You will have to get a good power supply for the stepper motors
and add a radiator on the mofsets. If you are anintensive use of
your equipment, a cooling fan is recommended. The picture on the
left shows the CNC3AC board installed in a metal case. On the back
you can see the power supply forthe board. It comes from an old
hard drive. But this power supply handles only the board. The stepper
motors are fed by a separate unit.
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Spindle head and milling cutters
A Proxxon IB/E mini drill is used to do the milling work. This
model has a 20 mm collar that simplifies the installation on the
machine.
You can easily adapt another model like a dremel.
Milling cutters
If you want to achieve decent results, you must get good cutters.
Otherwise the cutter will overheat and burn the wood or melt the
foam instead of cutting. After a few tries, it seems that Aeromaniacs
suggests the best choice for this kind of use.Those cutters are
also available at Otelo
with the reference 28 913 015 (about 10 Euros /piece). They give
good results with wood as well as with foam and they last quite
long.
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