Re: zero, home, offsets

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Damon" <damonfg@y...> wrote:

>
> Hey folks, new to CNC machining. Just got Y on my bridgeport
> converted, X to complete tonight or tomorrow.
>
> What I'd like to know is the proper, conventional way to
> zero/home/offset the table.
>
> What I am doing now (probably really wrong) is to manually jog
> the table to some location, then G92 X0 Y0 and force it to zero.
> I putter around a bit and want to pick another zero, offset by
> a couple inches or whatever. "home" will just shift the displays
> by an offset (base on readings before the first G92) so then I
> have to do another G92 X0.
>
> That's brutishly ugly. What's the conventional way to home a
> machine (no home switches yet, can ballpark by eye though),
> then zero in another place (like over the left rear edge of the

vice)

> and if I wanted to temporarilly offset to work outside the vice
> (on the table 8" to the left for example)?
>
> Since Gcodes allow like 9 coordinate systems I figure I am REALLY
> doing this the hard/awkward/ugly way!
> Any help greatly appreciated!
>
> -d

Home position could be any position within the travel envelope
of your machine.
It is a position pertinent to the machine with the main function
of been repeatable in day to day operation.
You could have a location that you manualy dial in every morning
as you start your machine.
As this is time consuming and tedious to do it is often automated
by mounting a positionary sensor switch on each slide.
Now that your machine has a repeatable location you can
simply use a offset from this location to zero in the location
for your parts.
The next morning after homing the machine this same offset will
reliably locate your part again.
This is basicly what homing is all about.
Good Luck