G99 and G98 planes

[kccadcam]

I've uploaded a file to the FTP under MC9 called: Clearance height.zip

Look at the parameters.

 

The post should have put G98 for different R heights, but put G99 because the first hole clearance was .1

 

Anybody else run into this??

At least it was just a CDrill!!!

[perfecseal mankato]

I have never ran into this before,

but I looked at the file. The only thing I could come up with was the incremental top of stock,

had a bearing on this. When I drill holes I always leave top of stock set at absolute, since this has no bearing on the drill cycle except for the G98 G99 plane. Leaving top of stock at absolute will always give you a G98 unless retract = clearance.

[kccadcam]

quote:

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When I drill holes I always leave top of stock set at absolute, since this has no bearing on the drill cycle except for the G98 G99 plane. Leaving top of stock at absolute will always give you a G98 unless retract = clearance.

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If top of stock is absolute then it would drill "air" all the way down to the other steps.

Just change the absolute clearance plane to .101 (.001 higher than retract) and it works just fine.

Strange bug......

[perfecseal mankato]

Kevin,

I just played with the file some more.

The incremntal retract is .100 and the depth was

-.05 incremental, which adds up to .100.

(-.05 inc. + .100 retract inc.)this is causing the post to output a G99. I changed the retract to .101 incremental and it now will output a G98.

I looked at my default ops and noticed I have all my drill cycles output a .125 clearance plane.

That may be one reason I have never ran into this before.

[Jim Evans from CNC Software]

Kevin,

 

The logic in the post checks to see if the reference height and the intial height are equal. If so then a G99 is output. If they are not equal then a G98 is output. On your first operation your intial height and refernce height will be the same hence the G99.

 

The G99/G98 (sgdrlref) is only output on the first hole. You can modify these sections to what ever you want, but by default this is what happens.

[kccadcam]

Thanks Jim,

Another way of doing it is to reverse the drill points, starting at the lower ones first, then it will spit out G98.