HuFlungDung
Diamond
- Joined
- Jan 19, 2005
- Location
- Canada
I know nothing about Omniturn, but have run older controllers with very few features, and made extensive use of G92.
On a lathe with a single toolpost, you should choose a reference tool. After the machine is homed, then you should set the machine coordinate system by accurately describing the reference tool position (on that toolpost) with a G92 command. The Z is not so important as the X value, which will then determine how far to X0. The Z value will need to be reset according to the job, anyway. But the reference tool should have a Z length offset of zero.
Preferably, this initial G92 global setting would be done in MDI, as this would be equivalent to a more modern machine going to a parameter and getting a G53 coordinate system value that way. You probably might not have a G53 coordinate system per se, but that is because the machine only has one coordinate system and no work offsets (wild guess). Only difference on the older controls is that you have to do this G92 setting correctly after every startup.
Now the only reason I can think of to invoke further G92 commands on a 'per tool basis' is because the machine physically executes a tool offset whenever the tool number is called (or you have front and rear toolposts). This machine motion while executing the tool offset can get you into collision trouble if large values are entered in the tool offset table. So G92 can be used under those circumstances to 'trim the fat' off of excessive offset values.
So for multi-tool machines (with two or more fixed toolpost positions), I would attempt to establish 'tape measure G92s' for each tool, with the cross slide at home. Chances are that for setting offsets at each toolpost, you will have to first set the appropriate G92 for that toolpost, and then take your trial cuts to establish a relatively small tool offset value.
It would then be necessary to establish a routine in programming to habitually call the predetermined G92 for a given toolpost position. This should only be necessary to establish which side of center the toolpost is actually on, as otherwise, tool offset directions (in X) become ambiguous.
Make it an ironclad habit to return to machine home after every program reset, and before every toolchange.
On a lathe with a single toolpost, you should choose a reference tool. After the machine is homed, then you should set the machine coordinate system by accurately describing the reference tool position (on that toolpost) with a G92 command. The Z is not so important as the X value, which will then determine how far to X0. The Z value will need to be reset according to the job, anyway. But the reference tool should have a Z length offset of zero.
Preferably, this initial G92 global setting would be done in MDI, as this would be equivalent to a more modern machine going to a parameter and getting a G53 coordinate system value that way. You probably might not have a G53 coordinate system per se, but that is because the machine only has one coordinate system and no work offsets (wild guess). Only difference on the older controls is that you have to do this G92 setting correctly after every startup.
Now the only reason I can think of to invoke further G92 commands on a 'per tool basis' is because the machine physically executes a tool offset whenever the tool number is called (or you have front and rear toolposts). This machine motion while executing the tool offset can get you into collision trouble if large values are entered in the tool offset table. So G92 can be used under those circumstances to 'trim the fat' off of excessive offset values.
So for multi-tool machines (with two or more fixed toolpost positions), I would attempt to establish 'tape measure G92s' for each tool, with the cross slide at home. Chances are that for setting offsets at each toolpost, you will have to first set the appropriate G92 for that toolpost, and then take your trial cuts to establish a relatively small tool offset value.
It would then be necessary to establish a routine in programming to habitually call the predetermined G92 for a given toolpost position. This should only be necessary to establish which side of center the toolpost is actually on, as otherwise, tool offset directions (in X) become ambiguous.
Make it an ironclad habit to return to machine home after every program reset, and before every toolchange.
