VM1 Setting zero's manually (no probe)

[mafitch7479]

Forgive my ignorance, but I'm very new to using a CNC mill.

Can someone tell me the proper way to set up tool offsets manually on a VM1, without using the probe because the part is too tall. For example, we're using 3 tools on this process, and endmill, and two drills.

My thought is that to set the part zero, you use the first tool in the part setup and set the z offset in part setup to zero (by touching off on the part), and then in the tool setup page, change the offset for that tool to zero (which should match with the part zero). For the next tool, you shouldn't touch the part setup, only the tool setup, and set the offset to zero only in the tool setup page. Then do the same for the third tool.

Is that right, or am I way off?

EDIT: I guess we need to use the part probe to the right of the table, which makes sense. But the question is still valid should the situation arise that we wouldn't have the ability to use that probe. Again, I'm not talking about the plastic probe for setting part zero, I'm talking about the tool probe that's on the table.

[Shane123]

worse comes to worse, you could always take out the g43 H# out of the programs and just calibrate each tool to the top of the part, if the part was programmed from the top being zero on the z. you wont have a z offset to adjust, would have to do that in the program, but it works.

i am sure some of the old timers could chime in with the 1" block method of touching off everything to the table...

[stevieboy]

I don't have a setting probe so have to do all my jobs like this.

If the top of the part is going to be Z zero just set all the tools to the same common datum. For example a block and shim on top of the part. So, like shane says, if the block is 1" and the shim is 0.010" draw each tool down until it just grips the shim and set all the tool zero's there. Do all the tools in turn in the same way. Then go into part setup, scroll down to the Z offset and type in -1.010". If the previous job had a part setup Z offset then don't forget to "clear" it before you do this though.

What you've done is set all the tools to Z zero at 1.010" above the job and then told the control to drop the part zero by the same amount to bring the zero down onto the job.

A nifty trick here is if the job is a raw billet to start with then you could type a slightly bigger amount into the part setup Z offset, maybe -1.020" then use a face mill to just kiss the top of the block and take a lick off to clean it up.

Hope this helps. There are also other ways but this is about the quickest and easiest. Again, like shane says, you can't have any Z offsets in your program if your running it in NC mode.

[mafitch7479]

I don't have a setting probe so have to do all my jobs like this.

If the top of the part is going to be Z zero just set all the tools to the same common datum. For example a block and shim on top of the part. So, like shane says, if the block is 1" and the shim is 0.010" draw each tool down until it just grips the shim and set all the tool zero's there. Do all the tools in turn in the same way. Then go into part setup, scroll down to the Z offset and type in -1.010". If the previous job had a part setup Z offset then don't forget to "clear" it before you do this though.

What you've done is set all the tools to Z zero at 1.010" above the job and then told the control to drop the part zero by the same amount to bring the zero down onto the job.

A nifty trick here is if the job is a raw billet to start with then you could type a slightly bigger amount into the part setup Z offset, maybe -1.020" then use a face mill to just kiss the top of the block and take a lick off to clean it up.

Hope this helps. There are also other ways but this is about the quickest and easiest. Again, like shane says, you can't have any Z offsets in your program if your running it in NC mode.

That makes sense I suppose.

Although, the boss did just order some really short probes, so that should eliminate that issue.

What is the "official" difference between the offset z on the part setup page, and the offset in the tool setup page?

I'm learning on the go as we run the mill, and have a totally different way of thinking than the current machinist, so I'm trying to pay close attention to what he does, and put it into my own meaning that makes sense to me. There's just those few little things that don't make any sense at all some days though

[bloke]

The offset in the part setup page will add / subtract an offset to all the tool lengths equally. An example would be if you had ran a program on a billet that was 100mm high, and set the tools to the top surface, you could leave the offset as 0.000mm.
If the next billet was 2mm taller, adding an offset of +2mm in the part setup Z offset will raise all the tools by 2mm as opposed to changing the length offset for every tool in the program individually.

[mafitch7479]

The offset in the part setup page will add / subtract an offset to all the tool lengths equally. An example would be if you had ran a program on a billet that was 100mm high, and set the tools to the top surface, you could leave the offset as 0.000mm.
If the next billet was 2mm taller, adding an offset of +2mm in the part setup Z offset will raise all the tools by 2mm as opposed to changing the length offset for every tool in the program individually.

Awesome, that's exactly what I thought it meant.

[Cmailco]

I'm not a big proponent of applying tool offsets in part setup's 'Z' parameter but that's only because we use to do most of our work off of a tooling plate, leaving that surface as the common datum. That, and I remember a few crashes due to offsets that weren't cleared out before a program was saved... and/or were simply missed by the operator.

On parts that are somewhat flat, or perhaps where you're only drilling and interpolating thru holes/bores... you could always opt to set the tool off the top of the part with .0015-.002 with shim stock, set tool zero and be done with it. Eliminates the need to offset and reduces the chance for data entry error.