Re: [CAD_CAM_EDM_DRO] Re: EDM

From: "Ian W. Wright" <Ian@...>

>
> I am very interested in making a small wire EDM machine ....
> The main thing which prevents me doing so is
> that I don't understand how the feedback circuit works to control the

speed

> of wire electrode movement.

Some of the wires just move at a set speed. There is a chart based on the
wire size and the wire is moved slow enough so that it will touch the part.
You don't get your best cutting speed this way, but it makes things much
easer to design and in some cases gives you a better finish on the cut. The
other way is basicly the same as a ram edm. You have the gap voltage sensor,
the difference is that it tells the computer what is going on and the
computer adjusts the speed. The edm's I've been using for the last few years
have both options

> I do understand how this works in a ram-type
> machine but the 2-axis movement has me fooled. Can anyone shed any light

on

> this please - perhaps with example circuits???

The sensor is the same, except there is no motor control at the other
end, the computer controles the servo movement. The cnc sinkers also use
computer control and can burn moving in all 3 axes.

> I did look into getting the HSM magazine but it is only available over

here

> in the UK by annual subscription which, for the odd one or two issues,

isn't

> an option for me as I am retired and on a tight budget

If you go to the web site they have books covering every thing that was
published in the magizine over the past year, you just have to wait a
year....