[Tristar500]

I'm close to completing a new 4 axis large format carving machine. (able to carve statuary from a 4footx4foot cube of foam]

Question; is it customary to set zero Z and perhaps Y axis at machine center, or the traditional way mills usually home z all thee way up?

I realize many ways would work but I'd rather get comfortable setting it up in the traditional way if there is such a thing.

Thanks in advance all!

[mactec54]

I'm close to completing a new 4 axis large format carving machine. (able to carve statuary from a 4footx4foot cube of foam]

Question; is it customary to set zero Z and perhaps Y axis at machine center, or the traditional way mills usually home z all thee way up?

I realize many ways would work but I'd rather get comfortable setting it up in the traditional way if there is such a thing.

Thanks in advance all!

Every Axis is Home normally, X Y Z A, when you set up a Tool Offset, it can still be to the Top of the part as normal, or to the center of the part, so if you can't set it to the top of the Part because you have nothing to referance off, then you would set the Tool offset to the Center of the A axis

Make sure your G-Code Program is referencing the same Tool Offset, you use for your machine.

[Tristar500]

That was my thinking as well. The homing switches are in the normal place and planned on using offsets to index y axis over the centerline of the rotary. Not sure If I'd ever have a reason for the tool tip to ever go below the centerline but I do have the Z travel to do so if necessary.

Thanks for the input.

[awerby]

Usually the long axis of a CNC machine is called X, and the one that crosses it is called Y. The Y axis is shorter and typically has the Z axis assembly traveling along it, which minimizes deflection. Z zero is generally set at the center of the rotary axis. In your machine the long axis has Z on it; are you calling that X or Y? Since the rotary table and tailstock don't seem to be in place yet, it's difficult to tell which is what, but most CAM programs assume that the A axis is parallel to X and Y crosses it. 4th axis cutting strategies include ones where Y is fixed above the center of the rotary axis and the cut increments in A as the tool moves along X varying in Z, also ones where it increments in X and the A axis revolves as Z goes up and down. Usually it's only when indexing that Y will move during the cut. It might be possible to set your home switches for Y and Z (which would have to be separate from the limit switches) at the center of the rotary axis. This would save time, since the other way to do it, if you don't have home switches, is to set up a precise cylinder there and touch off to it to establish reference points, then subtract its radius to establish Y and Z zeroes. But your way should work, as long as your home switches are precise enough.

[Tristar500]

Rotary is in place but hard to see in that pic. You are correct, the tailstock and it's linear rails have not yet been put in place.
Putting a second homing switch on center Y was something I considered. Could just use the Y limit/home and use offsets but as you said, it might save time to just set a separate Y zero. I'm using AB prox switches run through and opto relay board for my home and limits.

for Z xero I could just home fully retracted and use the known distance to set z zero. My other thought was to place a switch as the same z height near the Y home position and then just touch off it to set zero. It's important to be able to get back to zero while a piece of stock is chucked up on the rotary in the care of lost position due to some strange cause. most probably operator error.:banana: