Straight Line Cutter Compensation on Haas Controller

I have a 2000ish Haas EC400 dedicated to a certain part. In part of the program we have a saw programmed to cut on the edge with a diameter offset to fine tune a measured dimension. The program below is an section of the saw cut.

G154 P1
G00 G90 X6. Y-0.8
Z8.
G01 Z7.03 F50.
G01 G41 D14 X4.297 Y-0.8
Y-2.12
Y-0.8 F200.
G40 X6. Y-0.8
G00 Z8.


As you can see, the saw cuts in the negative Y then reverses in the positive Y. My question is, when there is a cutting path that reverses in a single axis, how does the controller react to a non-zero cutter comp.

Thank you for any input you are willing to share.

It's going to offset to the other side of the X position by the amount in the offset register.

If you want to stay on the same X position, you need to change to G42 on the conventional cut.

You should incorporate a lead-in/lead-out move larger than the value in the offset register.

Will the path offset as a quick move or gradually through the full move of the positive Y movement? I really thought that the controller might just fault out. I suppose I'm curious on how and when the machine calculates and implements the cutter comp.

panchodan said:

Will the path offset as a quick move or gradually through the full move of the positive Y movement? I really thought that the controller might just fault out. I suppose I'm curious on how and when the machine calculates and implements the cutter comp.

Click to expand...

I can't answer specifically how that machine handles it. It's reading ahead- it could just bomb out, it could make the X shift on the feed move so it's on the other side by the end of the cut, it could make the cut and shift before reversing direction. But at the end of the Y positive feed move, it will be on the other side of the line.

The amount of the offset might make a difference. A couple thou it might be fine, where 2" would alarm out. I believe with the code you posted, it's going to cut an angled line on the Y positive feed move.

That's why you want a lead-in/lead-out move and switch from G41 to G42.

Run it in air and watch the numbers, you will be able to see when it is moving in X. It's the tangent point of the tool at the X/Y endpoint that is being compensated.

Thank you for your time and input. This is an older program that I inherited that will need some cleaning up. And you are correct that I won't completely know until I just run the program and see what the numbers present. Thank you again.

If I was programming that, I would eliminate the conventional spring cut, which is just going to dull the cutter as it rubs it's way back to the starting point.

If you can't extract the slit saw from the slot at Y-2.12 (because there is something in the way like the part or a clamp), I would move away a little bit in X before feeding back to Y-0.8.

If you need a spring cut, it's better to climb it. Or better yet, leave a little bit of material to clean up on the finish pass.

.02

I believe we will be going with your first suggestion. We will have enough clearance to move perpendicular to the cut to turn off cutter comp.

I did a dry run to just to check the Distance to Go numbers though a step through and the results were interesting. When the program got to the Y positive move the Distance to Go showed the Diameter offset value as the next move (we have the machine set to Diameter instead of Radius). Upon pressing start for that line of code, the machine quickly made the offset move, then went right into the Y move as programmed without a second Start press. Again it was all curiosity that drove this little exercise, but I'm glad I have a little more insight to how the control determines when and where to apply the cutter comp. Thank you again for your time and input.