Newbie needs help getting my setup working

andypugh wrote:

Hypnotoad wrote: N20 G53 G0 Z0.

Advice?

Set the Axis limits in the INI to 0 at the top and a negative number at the bottom.

CAM systems seem to assume that G53 Z0 will always take the machine to the the top of travel, and your machine is set up differently.

Ok, so I've been playing with this all night and I'm confused. Which way should a positive jog move the milling machine head? Up? I set the Z axis up as below.

When I move the head to the top and press home on the Z axis and then issue a g0 z0 it takes the head down toward the table, as if HOME=-11.0. I'm super confused.

Well I sort of got things in working order and cut my test piece into a 2x4. Worked pretty well. I think what was confusing me before was I needed to enter G53 G0 Z0 to move in machine coordinate system -- I'm slowly picking up this stuff.

Something is still off about the coordinates. I think I need to flip both X and Y axes, I had to touch off on the wrong corner of the part. But that's for another night.

I needed to enter G53 G0 Z0 to move in machine coordinate system

2. Machine Coordinate System

Regardless of any offsets that may be in effect, putting a G53 in a block of code tells the interpreter to go to the real or absolute axis positions commanded in the block and ignore any offsets in effect. In the following example the machine will move to the machine coordinates set when the axes were homed and will ignore any coordianate system and global offsets in effect.

G53 G0 X0 Y0 Z0

G53 is not a modal command. It must be used on each line where motion based upon absolute machine position is desired.

linuxcnc.org/docs/html/gcode/coordinates.html

Which way should a positive jog move the milling machine head? Up?

After you touch off say in G54 at the top of the work piece at 0 then a positive move in the G54 coordinate system or a positive jog will move Z up and away from the work.

Rick G