Questions about tool# and H#

Hi Guys, I have a couple of questions. I am working on a couple of functions that require me to know the current  H#.

I do not see any reference to extract the Current H#. I can get the Z offset that is applied but not the current H#. And yes I do know that the H# is not really a number but a process. But having the actual current H# would be handy.

Any Ideas ???

( TP

snowgoer540 wrote:

I am not sure I know the use case for having a tool number and an offset number be different. That seems like a terrible idea, but I'm open to someone's explaination.


 
 

This doesn't apply to LCNC (yet), but other controls permit calling different offsets for a given tool number.  Different controls handle this in various ways, but my Fanuc 21T has 12 tool slots, but 16 offsets available in the table.  And the 'extra' offsets aren't just X or Z, there are also tool tip orientation and a matching wear offset.

The most frequent example of this is on lathes.

Case 1:
You can install a gang-style tool block on a turret position, such as a spot/drill/tap combo.  In my case the gcode would call T1212 for the spot, T1213 for the drill, and T1214 for the tap.

Case 2:
You want different offsets for a multi-function tool.  Generally, a drill/tap/reamer is set (on my lathe) to X0 offset.  Boring bars are not - they're set by the cutting tip.  In the case of multifunction tools (insert drills with boring capabilities), CAM programs aren't always able to handle them gracefully and you have to fudge it by defining two separate tools with the same tool number - but different offsets.

I'm sure there are other examples - perhaps with subspindle lathes where a rear turret position has the same tool (indexing) number, but a different offset.  I know Siemens 840 has 9 "tool correction" slots available.

Why bother with H# if it is always tied to the same T#?

A case comes to mind where the OP is doing prototype work and using a lot of tools NOT in the tool changer. Instead of unloading the ATC and reloading with the correct tools the OP simply manually changes tools and assigns the tool length offsets by changing the H#. The tool number stays the same and just the H# changes. This can save a ton of time when working on an unknwn prototype.

SO IF you knew the last H# and stored it away in a #param when it comes time to restart with the tool changer simply put back in the last Tool the ATC ran and input the saved H# and you are back in business. I know simply write it down ?? Yes but that is me working for the machine I prefere it the other way around (

( TP

Sounds like a recipe for a crash. What is wrong with Pathpilot's handling of tools not in the ATC as is?

snowgoer540 wrote:

I think I’m picking up what you’re putting down.

I don’t follow the use case for case 1 since they are 3 different tools. But I do follow having the same tool with different features at different Z offsets.

Linuxcnc can do that.

T1 M6 G43 H1
T1 M6 G43 H2
T1 M6 G43 H3

Would be tool 1 at three different offsets. But if I understand it correctly, it’s still not exactly what you’d be after since H2 and H3 correspond to T2 and T3’s offsets.

Unless I’m completely misinterpreting it. Admittedly I didn’t spend a ton of time on researching it …
 

[apologies to the OP if this side conversation is going off-track]

On a turret lathe the tool number is the pocket or index number.  Yes, there are three different tools - but you still have to command the lathe to rotate the turret to the correct position.

And once there you need different X/Z offsets for each tool in the gang block.

I'm not super familiar with LCNC's G43, but a quick read of the manual indicates you're absolutely correct on the "H" word after a G43.  It's not clear to me if that's just the Z offset, or all the offsets in the table for that tool number.  But I think you're right.

Having an H2, H3, Hn loaded in the tool table is exactly the right way to handle gang tools on a single turret position.  "Tool 1" corresponds with "turret position 1", and I suspect one would set up their table with tools #1 to #n corresponding with turret positions.  Tools after the highest turret position could be numbered #101-#199, #201-299, ect. for a somewhat logical brain-prompt. i.e.

T1 M6 G43 H101 calls turret position #1, with tool #101's offset.
T1 M6 G43 H102 switches to another tool in the same gang block.

Or some other scheme using variables/parameters might be set up in a remap.  A post processor might need some fairly significant tweaking so the CAM program makes sense to the user... but F360 (sort-of) permits calling tools using offsets which are not the tool number.