Quadrant marks at 90 degrees

[Mic6]

I'm milling a half moon shaped ring about 3.6 outer radius. The finish is perfect except for a quadrant mark at 90 degrees. I circle on at 180 mill around and circle off at 0. ANy ideas what's causing this?

[Al_The_Man]

Backlash!
Al.

[pit202]

or and wrong backlash compensation

[Ginger_Ninja54]

most likely the compensation for backlash in parameters.

[Boots]

All the replies are correct. Your tool is dwelling momentarily while the backlash is being handled by your drives. You can correct this if it is a Fanuc control. I don't know about others but to make sure you are adjusting it correctly you must contact the manufacturer and get the parameter numbers. Another way is to do the Bore with a large Bore Bar or Boring Head. This works well. Just feed into position on the X and Y (for better accuracy on location) then feed in using a Boring Cycle where the Bore Bar stops turning, (at the bottom and positions it's self with spindle lock) then moves off .02 inch before retracting. So as not to drag the point of the tool on your finished surface. Then you won't have to put up with the dwell marks. Do that to rough it out to with in .015 to .020 inch of your finished size. Then Bore it.

[durgam605]

check your post processor. most will default to break arc at quadrant. if not try a G8 in the arc move and be sure to turn it off afterward with a G9.

[Matt@RFR]

Originally Posted by durgam605 check your post processor. most will default to break arc at quadrant. if not try a G8 in the arc move and be sure to turn it off afterward with a G9.

Are you running a Haas?? They don't even list a G8 and G9 is "Exact Stop".

[durgam605]

my mistake. im thinkin of a fadal.