Can someone with a typical knee mill take a photo of machine X0 Y0 for me?

[slodat]

As the subject says.. can someone with a knee mill take a photo of the table at the machine X0 Y0 position for me? Despite the best effort of the very kind gentlemen trying to help me in my mill retrofit thread, I'm not clear on where the table would be in the machine X0 Y0 position. Once I know this, the rest falls into place. I apologize in advance for my ignorance. I want to get the machine setup correctly.

Thank you so much!

[cnckeith]

I assume you mean Machine Coordinate X0 Y0 as in the Home position? (as a WCS (Word Coordinate System X0 Y0 could be any where)

Knee Mills typically home the X axis in the Negative direction (table all the way to the right if you are standing in front of the machine)
and Y axis in the positive direction (table all the way closest to you)

(this is the best way to go for beginners but, this is not fixed in stone. you could actually home the X and Y axis in the middle of the travel if you wanted as CNC12 supports positive and negative software travel limits.)

[slodat]

Thank you, Keith! That helps me a bit.

I still have no idea how to set this up. Is there a sketch or something anywhere that says where the following should be for a typical knee mill setup?

• X- limit position on table (left or right end).
• Y- limit position on table (toward operator or toward column).
• X home switch position (left or right end of table).
• Y home switch position (toward operator or toward column).
• direction to home toward home switch in X
• direction to home toward home switch in Y
• correct direction of table movement for X+ button press on VCP
• correct direction of table movement for Y+ button press on VCP

[Muzzer]

On my Shizuoka, the home switches for X0 and Y0 are with the table furthest away from you in Y and to the far right in X. From that position, every possible machine coordinate position of the table (in G53) is positive in X and Y.

On the Z axis (it's a knee mill with about 6" of quill movement), Z0 is with the quill at the top of travel, to avoid the quill fully descending when looking for the home switch, as that might not end well. Any moves after the homing procedure will then result in negative Z machine coordinates.

When setting up the work coordinates (typically G54), you typically choose a position for X0, Y0 and Z0 at a point on the stock or the CAD model.

In CNC12, Pressing Alt-D toggles the DRO display between MCS (machine coords, G53) and WCS (work coords, G54 etc). That's helpful when trying to figure out what's going on.

When it comes time to swap between tools, probes etc for acquiring WCS coordinates, you will need to know how to tell CNC12 which tool is in the spindle. That requires typing G43 Tx Hx into the MDI interface, where x is the active tool number. It then uses the tool lengths table to adjust where it expects the WCS to be, relative to the tool, taking into account the different tool length offset specified by the Hx term.

It's good to keep things simple but you also need to understand what is happening with MCS, WCS and tool lengths. It took me a while to figure it out.

[cnckeith]

you got to think in TOOL motion.. NOT table motion.... X+ jog key moves the TOOL in the positive direction.

you can put the home switches where ever you want.. just so they trigger when the machine is in the home position.

[cnckeith]

page 12 https://www.centroidcnc.com/centroid_di ... -v4.14.pdf

[Richards]

Keith,
Thanks. I had my Y axis going the wrong way. Since I've only used hand-written code, it has worked. I changed the axis direction in Wizard. Now the mill moves in the proper direction on all axes.

[cnckeith]

Muzzer, check out upcoming mini Machine Coordinates DRO.. no need to press Alt D if you want to see Machine Coordinates in the next release!

[slodat]

Muzzer, check out upcoming mini Machine Coordinates DRO.. no need to press Alt D if you want to see Machine Coordinates in the next release!

That is awesome! I find myself toggling back and forth a lot as I learn all of this stuff.

[slodat]

On my Shizuoka, the home switches for X0 and Y0 are with the table furthest away from you in Y and to the far right in X. From that position, every possible machine coordinate position of the table (in G53) is positive in X and Y.

On the Z axis (it's a knee mill with about 6" of quill movement), Z0 is with the quill at the top of travel, to avoid the quill fully descending when looking for the home switch, as that might not end well. Any moves after the homing procedure will then result in negative Z machine coordinates.

When setting up the work coordinates (typically G54), you typically choose a position for X0, Y0 and Z0 at a point on the stock or the CAD model.

In CNC12, Pressing Alt-D toggles the DRO display between MCS (machine coords, G53) and WCS (work coords, G54 etc). That's helpful when trying to figure out what's going on.

When it comes time to swap between tools, probes etc for acquiring WCS coordinates, you will need to know how to tell CNC12 which tool is in the spindle. That requires typing G43 Tx Hx into the MDI interface, where x is the active tool number. It then uses the tool lengths table to adjust where it expects the WCS to be, relative to the tool, taking into account the different tool length offset specified by the Hx term.

It's good to keep things simple but you also need to understand what is happening with MCS, WCS and tool lengths. It took me a while to figure it out.

Thank you for the info. This got me where I needed to be! I decided to home my table the same way. Took a test cut and all looks good thus far.