Snuggly's Plasma Build

About homing.

I have plan's to do homing with a component in the future. I have had 2 incident's.

1. Milling machine :
The mill was drown into the table because of user fault. Oke he restarted linuxcnc. But he needed to home first.
He had a problem, because machine can not move with mill drowned into the table. So solution is 2 separate
startup icon's. One for homing on limit switch, one for homing directly without switch.

2. Plasma machine :
My tables have a border finish, like an edge. The z-axis need to be above the border height, if not, torch will hit
the table border while homing x and y axis. So solution is 2 separate
startup icon's. One for homing on limit switch, one for homing directly without switch.

Final solution :

Component homing :
This is a button in the program that homes when you want to do. Machine will alway's move.
And we are satisfied.

I believe that both of those problems become non issues if you use the convention of having the machine home the Z axis first before it homes the other axis.

And most machines can be jogged before homing. Some gantry setups may be exceptions to that rule. But even those can usually jog the non slaved joints before homing (in other words move the Z out of the way).

Hi Todd,

I agree. But the gantry type's with homing sensor's only on X0 and X1 is one of the exeptions.
If you have homing sensor on Z. You have no problem. It stay's in the rules of linuxcnc.
Without homing on Z. You find out the solution is a custom component. Or change the linuxcnc source code.
The last option will be a great impact to merge after a few year's of separate coding between the master and the sub.

Would it not be simpler and more effective just to add a Z and Y home sensor. They would not need to take any more io points, they could share with the X1 and X2 home inputs, if you are short on io points..

Hi Todd,

Thanks for your input, i know what you pointed about.
Effective is not the word for the problem. The problem is different. It has more to do with machine size.

In point of time. It matters. If a machine each time linuxcnc startup have to be homed, customer's will think about why homing each time i startup... ?

In practical way we could say add a home sensor on Z, i agree.
Y homing for milling machine's is standard.

For plasma a home z is out of the box. Only the probe sensor is important in my case.
But it really takes time by format 2x4m or 2.5x6m if machine is stopped and closed in the middle.
So that is not a fast option. I tell only my experience so far, and provide information that is usefull to
developper's section to make Linuxcnc the most powerfull cnc application in the world.

I could do it myself, and write a component. But i also will help others, like snuggly. I like this guy and his video's.

Todd Zuercher wrote: I believe that both of those problems become non issues if you use the convention of having the machine home the Z axis first before it homes the other axis.

And most machines can be jogged before homing. Some gantry setups may be exceptions to that rule. But even those can usually jog the non slaved joints before homing (in other words move the Z out of the way).

Getting the Z axis out of the way was an early (and violent) learning for me. Yes it takes more time to home sequentially but it sure is safer!