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# Thread: i j k errors

1. ## i j k errors

hello all been a while
did a search but found nothing helpful.
had a couple quite knowledgeable people (i thought) try to help
but still get same error ... invalid i or j @ line n5030
tia
stace

2. ## Re: i j k errors

N5020 G91 .....
N5030 G3 X-0.36 I-.36 J0.

With G91 active (N5020) the end point and the center point of your circle are identical (X == I). That will not work.

3. ## Re: i j k errors

If your using G91, then prior to line N5030 the tool needs to be positioned on the arc. Line N5030 would be G3 X0 Y0 I-.36 J0. Realize that I is saying the arc center is -.36 from the X cutting position.

Example:
G90 G1 X.36 Y0
G91 G3 X0 Y0 I-.36 J0

or

If center is not X0 Y0
G90 X-- Y--
G91 X.36
G3 X0 Y0 I-.36
G1 X-.36

If this helps, super. If not, just give a holler back.

I, J, & K are always incremental values. When used in arcs or circles, they represent the incremental value of the arc start to the arc center. Most arc errors are because these values are not correct in relation to the arc start.

4. ## Re: i j k errors

Originally Posted by BobHarper
If your using G91, then prior to line N5030 the tool needs to be positioned on the arc. Line N5030 would be G3 X0 Y0 I-.36 J0. Realize that I is saying the arc center is -.36 from the X cutting position.

Example:
G90 G1 X.36 Y0
G91 G3 X0 Y0 I-.36 J0

or

If center is not X0 Y0
G90 X-- Y--
G91 X.36
G3 X0 Y0 I-.36
G1 X-.36

If this helps, super. If not, just give a holler back.

I, J, & K are always incremental values. When used in arcs or circles, they represent the incremental value of the arc start to the arc center. Most arc errors are because these values are not correct in relation to the arc start.
thank for the quick reply i found an end mill close enough to get me out of a jam for this set... another set coming right up

5. ## Re: i j k errors

If you have Preditor Editor piece of cake.
Run your machine until it errors out (note line number)
Run Preditor and stop at line number that machine error out
Note,as best as can,where it all took place,geometrically
go back to CAD and you can try a variety of fixes at that particular point.
Ex.,,erase doubles.re-organize,and a good one that happens a lot on sharp corners that are less than 90 is do a fillet.Fillet not need to be big,,but something,,say .003,,,
good luck

6. ## Re: i j k errors

Originally Posted by jrmach
If you have Preditor Editor piece of cake.
Run your machine until it errors out (note line number)
Run Preditor and stop at line number that machine error out
Note,as best as can,where it all took place,geometrically
go back to CAD and you can try a variety of fixes at that particular point.
Ex.,,erase doubles.re-organize,and a good one that happens a lot on sharp corners that are less than 90 is do a fillet.Fillet not need to be big,,but something,,say .003,,,
good luck
Hard to remember.

I think "Make Arcs Tangential" was the geometry fix for these. But I like the duplicates thought too. I think 2 arcs in the same place causes some issues.

But it could be a post processor setup issue too. look for 221 to 228 in the post processor.

7. ## Re: i j k errors

I THINK I tried what u said see attachment

8. ## Re: i j k errors

Originally Posted by CNCFr
N5020 G91 .....
N5030 G3 X-0.36 I-.36 J0.

With G91 active (N5020) the end point and the center point of your circle are identical (X == I). That will not work.
can u tell me what will?

9. ## Re: i j k errors

Originally Posted by BobHarper
If your using G91, then prior to line N5030 the tool needs to be positioned on the arc. Line N5030 would be G3 X0 Y0 I-.36 J0. Realize that I is saying the arc center is -.36 from the X cutting position.

Example:
G90 G1 X.36 Y0
G91 G3 X0 Y0 I-.36 J0

or

If center is not X0 Y0
G90 X-- Y--
G91 X.36
G3 X0 Y0 I-.36
G1 X-.36

If this helps, super. If not, just give a holler back.

I, J, & K are always incremental values. When used in arcs or circles, they represent the incremental value of the arc start to the arc center. Most arc errors are because these values are not correct in relation to the arc start.

think i did what u suggested .. see attachment