Floating Z Head

[tulsaturbo]

I read this on another website:

The floating head works like this.. The Z lowers untill it hits the plate and keeps going untill it hits your floating head limit switch then comes up to 0 plus your pierce height. In your g-code you tell it the switch travle so it adds that to your Z. The purpose of the floating head is to tell Mach3 where the top of the metal is before the pierce

Can anyone explain with more detail on how to set this up with mach3 settings / configuration? I have tried looking all over the net for an explanation on how to set this up and can't find one! It would be greatly appreciated!

TIA

[lowpull]

Its not setup in mach , it is setup in your post processor. In sheetcam my post processor has a place for me to put my offset which is .26

This is the code it then produces for every pierce.
N0110 G28.1 Z0.12
N0120 G92 Z0.0
N0130 G00 Z0.2600
N0140 G92 Z0.0
N0150 G00 Z0.1300
N0160 M03
It makes the z go down until the switch is tripped. It sets the z axis dro to 0. It raises the z the offset number (.26 in my case). It again sets the z axis to 0. Now the top of the metal is at 0 and the the tip of the torch is at 0. It raises the z axis to the pierce height. ( I use .13 in this case) and starts cutting.
Hope this helps.

[tulsaturbo]

Its not setup in mach , it is setup in your post processor. In sheetcam my post processor has a place for me to put my offset which is .26

This is the code it then produces for every pierce.
N0110 G28.1 Z0.12
N0120 G92 Z0.0
N0130 G00 Z0.2600
N0140 G92 Z0.0
N0150 G00 Z0.1300
N0160 M03
It makes the z go down until the switch is tripped. It sets the z axis dro to 0. It raises the z the offset number (.26 in my case). It again sets the z axis to 0. Now the top of the metal is at 0 and the the tip of the torch is at 0. It raises the z axis to the pierce height. ( I use .13 in this case) and starts cutting.
Hope this helps.

That helped out bunches. Thanks for the explanation!

So I would set up the floating Z head switch in mach3 under - config / ports and pins / input signals / Z Home, correct?

Would I need to configure the (Safe Z) as well (config / safe_Z setup) and if so whats the common setup to go with as I see that it gives 3 options to choose from?

TIA

[MonoNeuron]

I think setting the safe Z height for rapids is a good idea to clear any tip ups that may occur and if your Z head is pretty quick then setting it to about 2" or higher wouldn't hurt and it would also clear any hold down you may be using for thin plate (like heavy pieces of steel bar to keep things flat.).

[tulsaturbo]

So I would set up the floating Z head switch in mach3 under - config / ports and pins / input signals / Z Home, correct?

Anyone???

[MonoNeuron]

Yes. It is the home switch
If it doesn't behave as it should then click the check box for high or low depending on which way it goes

[Larken]

This is the code it then produces for every pierce.
N0110 G28.1 Z0.12
N0120 G92 Z0.0

What is the 0.12 in the 1st line for ??

[creepy]

setting the offset in Mach3 config/Zhome will not help the THC post, only manual Z homes.

you have to add "switchoffset post variable" when doing your toolpaths. its the big "V" on the side menu of sheetcam. it will display just like a toolpath in the side menu, with the check mark, etc.

you have to have it there or the post processor will make your switch offset zero in the g-code. the way it should work is that the switchoffset gets put in the g-code automatically, from the switchoffset variable. you should not have to go into the g-code and edit in the value. Or, alternately, edit the post you are using to generate code to include the switchoffset variable.

I had exact same issues, was continually editting the switch offset into the new programs.

[Islam]

What is the 0.12 in the 1st line for ??

For the line : G28.1 Z0.12
The 0.12 value is the absolute Z value that torch moves till reaching it first, and then start Z homing.
I could be any value, but 0.12" or 3.0mm is suitable because it is the min. value that more than any switchoffset value.