What is the "proper" zero origin

tommylight wrote:

Blazini is talking about a moving table mill, Rod about a moving head mill!
So both are right.
BTW, TLDNR

I'm not sure about that. I was really taking about both as they have the same geometry. On my manual mill, I was only ever interested in the movement of the tool in relation to the workpiece as I cranked the DRO to get to a position on a drawing using Cartesian coordinates. That's how I think. Thats how the preview in Linuxcnc is. The movement of the table is just a distraction, a byproduct if you will.

and I was not arguing, I just stated my thoughts, my theory as I stated..

My theory is the front of the machine should be defined from where the operator stands. The x axis should run across your chest with the positive direction running left to right. The Y axis should run away from the operator with the positive direction running front to back.

 
+1

Zeroing a mill table at the front left is the same as zeroing a gantry at the rear right.

'Gantry' does not define whether it's the head or the table that moves.

I don't get pissed on forums, but every argument has 1 of 3 outcomes. 1) I prove you wrong and you say "oops", 2) you prove me wrong and I say "oops", or 3) somebody realizes they were wrong and says "well that's what I meant". The first 2 don't bother me either way, I'm not a fan of the 3rd.

Sometimes asking the right question is more difficult than giving the right answer.

[edit]

Thats the thing. I always refer to the movement of the tool in relation to the table for any machine, not the table movement on a milling machine.

And just to be clear about this: There is nothing to 'LOL' about this statement. This is actually the standard definition of motion direction when we talk about machine tools. Whether that is a knee mill, a gantry, a hexapod, a serial manipulator or what have you. If it wasn't then you would need different Gcode for all these machines.

Aciera wrote:

Sometimes asking the right question is more difficult than giving the right answer.

Oh yes it is!

I think machine origin only really matters if you wish to use G28,G30 or G53.
And even then it's position is not that important as long as it's consistent.

g28/30 default to machine origin so having the origin somewhere safe might be nice.

If using a tool changer that requites a specific, consistent spot it might be nicer to G53 to X0y0z0 for tool changes rather then G53 x3 y1028 z1401

Chris

goodness this editor is buggy