"HOME" position on a CNC Mill, switch locations?

[manofgresley]

Hi
Just thought i would try to gather some thoughts on where on a CNC Mill you would mount proximity switches, some say "HOME" should be in the centre of the X&Y Axis, some say at the extreme + end of each Axis, i would like to hear your thoughts.

Ray

[C_Bubba]

I have my XY homes at the extreme of the table. You have to tell your controller which direction to go in the setup for home. If your position is on the wrong side of home if you have it in the middle, the controller will go off in the wrong direction until it hits the end of travel and not find the home switch!
On the other hand, work coordinates can be any place.

[cropwell]

I have my XY homes set to the 0,0 on the X,Y coordinates and top of travel on the Z axis. It is just a personal preference, as I suspect a lot of set-ups are.
When I was considering CNC'ing my little Clarke CMD10 (which never happened) I thought about having a toggle switch on the centre of each of the X and Y, with spring loaded flaps to operate them. The idea was that you then had some input to say which part of the table you were on and could home accordingly to the centre.

Many great inventors start off with what other people rate as stupid ideas. My end point seems to be the stupid idea.

[manofgresley]

Hi, where would your table be when at "0" ?

I have my XY homes set to the 0,0 on the X,Y coordinates and top of travel on the Z axis. It is just a personal preference, as I suspect a lot of set-ups are.
When I was considering CNC'ing my little Clarke CMD10 (which never happened) I thought about having a toggle switch on the centre of each of the X and Y, with spring loaded flaps to operate them. The idea was that you then had some input to say which part of the table you were on and could home accordingly to the centre.

Many great inventors start off with what other people rate as stupid ideas. My end point seems to be the stupid idea.

[cropwell]

As I look at the table, 0,0 is nearest me and to the left, just as though it were a graph on a piece of paper. I have a gantry machine BTW.

[EddyCurrent]

I can't see how it matters in reality, the home position is just a datum point that is repeatable. If you want to use the centre as zero then just apply an offset in your CAM software.