Machine Z Zero Setting?

[mlinder]

Well,

Here I am, late on a Sunday night. Sittin' on the sofa.

Naturally, I am thinking about my machine zero setting - what else???

Anyway, all of my routing work for the past 14 years has been simple 2 D stuff. Drill - rout - drill - rout. Occasionally I mill out a pocket into the material to some depth - no big deal.

However, now that I own OneCNC Mill Expert, I am entering the world of 3 D machining. It got me to thinking..

My questions is this. Do you set YOUR machine zero to the bottom of the stock (table top) or from the top of the material stock?

Which way is better, and why?

I look forward to your answers. Good night all.

Mark Linder

[wjbzone]

I like to set my machine Z zero 1 inch above the table. That way I can use a 123 block to slide under the tool while measuring the length. Dont have to worry about hitting the table with the tool while measuring.

Program zero can then be set by measuring from the top of the 123 block to the top of the work.

Bill

[Klaus]

Your Zero position should preferably always be set above the workpiece. That way there is a minimal risk of hitting your workpiece by accident. You would always have to enter a "-" dimension for the cutter to come in contact with your workpiece.

[HuFlungDung]

Edit: oh he said "machine zero"

I would set this near the top Z limit. A little bit below is good, so it is not working the limit switch mechanism when returning to home.

Part zero at the most relevant top surface of the part. Some like to set part zero at fixture height. I can see their reason for this, but I'm not used to working that way. Like Klaus said, I always know that any Z- movement is most likely into the workpiece stock.

[HomeCNC]

There are many ways to do this, I like the one below.

Your "machine" Z zero should be set all the way up until you hit your limit/home switch. This is also true for the X and Y. You then set a offset to your stock corner and Z on top of the material. Then you use a G54 offset command before cutting.