Lathe Profiles

[dmbgo]

Thanks for your explanation Tom, it was only conjecture on my part. I would always ask on the forum, rather than trust an AI. Perhaps that will change someday, but not now

[dmbgo]

I put your reply to the Ai to see how it would respond Tom. Here's its answer, a bit too late for self recrimination on its part though!"Thanks for sharing that — and yes, his response is both technically correct and practically valid for real-world turning practice. Let’s break it down precisely, separating fact, convention, and where AI-style logic might mislead if it's not context-aware:
He's right on these key points:
1. Line 6 (X = -0.2) is causing the facing

"Delete line 6 and they will go away"

Absolutely correct — that line instructs the lathe to cut across the face of the part, from 12 mm down to -0.2 mm diameter (i.e., centreline and beyond). That’s a facing move, and it's part of the profile, not the finish pass.

So yes, removing it will stop the redundant face passes — that’s the root cause, not the finish pass.
2. Finish pass isn't responsible

"If you remove the finish pass, the face cuts will remain"

Correct again. The roughing logic generated by Intercon will cut the entire defined profile, including the face, if it’s part of your contour. The finish pass just follows the same geometry more cleanly — but isn't what adds those face moves.
3. Don’t start a profile at Z = 0

"Switching from Z0.5 to Z0 will result in chipped carbide"

This is a solid machining best practice. Starting Z slightly forward of the part (e.g. Z0.5) is normal to allow:

Safe entry and clearance

No risk of crashing a tool edge into spinning stock

Space for tool nose radius to blend in before engaging the cut

So while Intercon will let you start at Z=0, Z=0.5 or Z=1.0 is safer unless you’re doing something very controlled.
So, what did I get wrong?

I incorrectly said:

“Set profile start Z to 0 to avoid face passes”

That’s not accurate unless the profile itself doesn’t include any facing moves (like your N0006 line to X = -0.2). So the issue is not the Z Start of the profile, but the fact that you asked for a full face cut down to centre.

He’s right — Intercon is faithfully doing what you asked.
Final Summary — Best Practice

Want a clean chamfer on the OD only? End your profile at X = 12 or wherever your chamfer ends, don’t go to X = 0 or negative.

Keep Z start > 0 (e.g., Z = 0.5) for safety.

Delete face moves like N0006 if not needed.

AI is only useful when combined with domain knowledge. And I always welcome correction — like in this case.

[suntravel]

Work trough the tutorial examples in the manual step by step to understand Intercon.

It is worth the time.

Uwe

[cncian]

... and please stop posting results from ChatGPT. Post something original based on your experience.

[dmbgo]

... and please stop posting results from ChatGPT. Post something original based on your experience.

If you bothered to read the thread, rather than just posting "off the cuff", you would see that I was just presenting Ai's solution as an example.