Vertical Profile mark left after doing a lead out. is there a way to prevent it?

[nodott]

I am trying to see if there is a way to prevent from having this vertical mark from occurring after doing a profile cut. I am doing both a circular lead in and circular lead out with a 1 inch overcut but unfortunately that is still not preventing from the mark occurring when the end mill exits the cut.



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[TurboStep]

I am trying to see if there is a way to prevent from having this vertical mark from occurring after doing a profile cut. I am doing both a circular lead in and circular lead out with a 1 inch overcut but unfortunately that is still not preventing from the mark occurring when the end mill exits the cut.

Try moving the lead in/out to the corner of the part.
Step

[Steve Seebold]

Try circle in followed by your finish cut followed by 2 spring passes then circle out.

That’s what I do and I never get that line.

[al010964]

Try circle in followed by your finish cut followed by 2 spring passes then circle out.

That’s what I do and I never get that line.

+1 on the above.

It looks like you are leading out either vertically or at 90 degrees to the part. Depending on your CAM you might not be able to arc out, as Steve suggests ; if this is the case try changing to say a 30 degree lead out angle.... this will get rid of the dwell that causes the line.



Cheers,
Adrian

[joshetect]

Is that were the lead in happens? I try and enter/exit from the corner to stop that, I believe on lead in the cutter gets pulled into the work piece a little more on deeper profiles.

[C*H*U*D]

...I am doing both a circular lead in and circular lead out with a 1 inch overcut

How big of a radius is your lead in and out? A larger radius will create a smoother transition onto, and off of the part which could help with the line.

Try moving the lead in/out to the corner of the part.
Step

And ideally this is what I would also do. Whenever I can, my lead-in and out is on a corner so the line isn't noticeable at all.

[79rallysport]

This is in addition to the other good suggestions above...

Is your Lead-in and Lead-out feed-rate the same as your cutting feed-rate? I make mine the same, so the machine doesn't change velocity when entering or exiting a cut. A change in velocity right as it exits the cut will leave a vertical witness mark like that.

[draper-ballou]

Some of this could also be backlash. Starting and ending at a corner is usually the best option to avoid the issue.

[nodott]

I have the circular lead in and circular lead out with a radius of 2 inches. Lead length is set a 1 inch and a 1 inch overcut distance.

I am doing a small radius on the corners so I worry that the line will show up if I do the lead in/out on a corner edge. Still willing to try it as it might not be as noticeable on the corner radius as it does on the side of the workpiece.

[nodott]

This is in addition to the other good suggestions above...

Is your Lead-in and Lead-out feed-rate the same as your cutting feed-rate? I make mine the same, so the machine doesn't change velocity when entering or exiting a cut. A change in velocity right as it exits the cut will leave a vertical witness mark like that.

I checked the G-code and the feed speed is the same for the entire profile operation.

[AUSTINMACHINING]

Some of this could also be backlash. Starting and ending at a corner is usually the best option to avoid the issue.

This ^^
Do you get quadrant marks when milling a circle ?. I've got a couple thou backlash and not having witness marks is impossible, so I always "hide it" by entering on a corner (if there is one)

[al010964]

I have the circular lead in and circular lead out with a radius of 2 inches. Lead length is set a 1 inch and a 1 inch overcut distance.

I am doing a small radius on the corners so I worry that the line will show up if I do the lead in/out on a corner edge. Still willing to try it as it might not be as noticeable on the corner radius as it does on the side of the workpiece.

Sounds like you are going about it the right way... which means looking for other avenues, which others will be able to comment on better than me. The only thing I would suggest is just double check the simulations and make sure it is arcing as you intend it!

Sorry I can’t be of more help.

Cheers,
Adrian

[TurboStep]

I have the circular lead in and circular lead out with a radius of 2 inches. Lead length is set a 1 inch and a 1 inch overcut distance.

I am doing a small radius on the corners so I worry that the line will show up if I do the lead in/out on a corner edge. Still willing to try it as it might not be as noticeable on the corner radius as it does on the side of the workpiece.

As has already been mentioned this is due, to the most part, to backlash. For curved contours like a round boss or corner radii I always lead in and out at a tangent to the curved surface in straight line at roughly 45°.

This cancels out the effects of backlash. Under some conditions this can work against you, but if your photos show the results of a climb milling cut it should will work out for you.
Step

[nodott]

How big of a radius is your lead in and out? A larger radius will create a smoother transition onto, and off of the part which could help with the line.



And ideally this is what I would also do. Whenever I can, my lead-in and out is on a corner so the line isn't noticeable at all.

I tested out the larger radius today and that solved the problem. thanks for the idea C*H*U*D.