Re: Sanity check on home switches

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Brad Eyben" <abeyben@t...>
wrote:

> Sounds OK to me although I have my Y axis home with the table

towards me

> which makes it easier to change material and clamp etc.
> Brad
> ----- Original Message -----
> From: "washcomp" <jeff@w...>
> To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> Sent: Wednesday, April 09, 2003 7:01 PM
> Subject: [CAD_CAM_EDM_DRO] Sanity check on home switches
>
>
>

Not being a commercial user I have no idea how they do it there. It
seemed logical when I setup my table that I would orient 0,0,0 at the
same place that my CAD system does which is the lower left and Z zero
was the material surface. The CAM software I use likes that
orientation as well so I can just take the g-code and run it. Call
me stupid but it's a lot easier for me to watch my machine run and
visualize the cut when it is layed out exactly like my drawing. I
know the purists define XYand Z ind different ways but for me its
easy for my non-machinist mind to accept lower left corner as 0,0.
On the mill where the table moves and the head is fixed then the
limit (home) switches would be setup so that they are actived when
the table moves (opposite) so that the spindle is over the defined
0,0 point. I don't know what the best way is to reference Z since in
my funky corridinate system it changes based on the top of the
material. I establish Z zero manually at this point before each run.
Since my CAM software spits out code based on the depth of cut from
the materials highest point it makes it easy to set things up. On the
torch table I am working on sensing the top of the material and
resetting Z automatically.

MACH1 allows you to define a switch as both limit and home
(reference) so that when you tell it to do a move to home (g28) then
it uses the switch as a zero locator then backs off of it slightly to
preserve it as a limit. The only thing I would caution you on is
letting those limit switches be your absolute safety stops. I have
rigged a second set of switches past the home switches and tied to
the other far end limts, that feeds directly back to my DC motor
control and stops everything to stop a crash.