Z0 for Tool 0 changes when other tool offsets entererd.

[Zadig]

I’ve been scrapping parts lately thinking it was my error but I no longer believe this. I set my work up using T,0 as my reference and all the tool offsets work from that. I’ve been getting parts that are coming out small or big but thinking I’d incorrectly set T,0 Z,0 I’ve one job at the minute that involves 20 tool changes, not many but enough to gauge when something goes wrong mid workpiece. Today, One operation came out too big and as it was a tool that I had changed mid job, I thought I’d input the wrong tool offset in the table. However, the offset was correct but I changed the offset in the table by .002” to re machine the part. When I did machine the part it came out .025” too small. I checked the offset in the table and it was correct so I went back to T,0 and checked my reference 0 and this had changed. So my question is, are there any known issues with this. I’ve got a an order I need to get out desperately and I’ve been struggling with this for some time so any help would be gratefully received, Cheers Guys.

[Zadig]

Machining time on this part is 5hrs and unless I spot something untoward I only know when I take it off the mandrel. I really could do with some help on this.

[CL_MotoTech]

If you send t0 to Z0 is the tool tip where it should be?

[ger21]

Don't you have to zero the Z axis when you start the machine?

[Zadig]

Apologies for the late reply and thanks for the input. My machine is a Shizuoka knee mill so the machine is homed on all three axis before I start. If I alter the knee, I have to reset work zero each time. I use a Haimer taster for this and all my tools are set off the machine on a tool setter using the Haimer as a reference. The problem I’ve been having is that work, only on the Z plane has been coming out the wrong size. I thought this was my error for a long time but I noticed, after a tool change that the tool was removing more than it should have been doing. When I went back to M6 G43 T0 H0 and checked my Z work co-ords , Z had shifted. I had not changed the Z settings at any time, however, I had changed, due to a worn tool, a setting in the “tools” database. This offset was correct and it was what caused me to check my work co-ords again. This has happened on three occasions. I managed to get one part off the machine this weekend but to do so I touched off each tool with a gauge each time. I didn’t find any any errors but no changes to the tool database were made.

[dezsoe]

Could you try to run it with separating the M6 G43 T0 H0 into 2 lines: M6 T0 and then G43 H0? The execution order may mess it up.

[CL_MotoTech]

It has been quite some time, but one time I replaced a tool, updated the tool table, and the Z was wrong. After that I have taken updating the tool table then cycling the tool out, then back in. If the tool currently is in place, that cycle isn't required. My guess was that tool length on effectively changes when the tool gets loaded, so even if you save the tool table it doesn't change the current tools length. Maybe I am wrong about that, but that was impression I got back when I first started using my tool changer with UCCNC.

[CL_MotoTech]

I typo'd the crap out of that.

So to clear it up, i found if I had t1 shown being in the machine, and I changed t1's length in the table (saving and applying), the change wasn't effective until I cycled to another tool, then back to t1.

Maybe I am wrong about this, but ever since I had my issue with z height I have cycled the tool if it was in the spindle at the time of changing the tool length.

[Zadig]

Dezsoe. I’ll give this a try but I don’t see how it would change my initial work offsets I.E Z0.

Moto. Yeah, I’ve figured this out too. In order for the revised offset to be used it has to be called again. The problem wasn’t so much the offset as the fact that my work co-ords changed, notably Z0. I’m pulling parts off the machine now but checking tool length offsets at each tool change. No problems so far but no offset changes mid op. I’ll keep monitoring and report any findings.