Lathe Profiles

[dmbgo]

I haven't gotten my head around profiles, but I thought I'd have yet another try on my lathe. I thought I'd start easy and am trying to put a 45 degree chamfer for a distance of 1.5mm on the end of a 15mm diameter rod. Every time I enter, what I think are the correct dimensions into intercon, I get a backwards chamfer in the graph. What I want is a chamfer that has a 12mm diameter at Z0 and tapers at 45 degrees to Z-1.5mm, where it has the same diameter as the rest of the rod. Instead I get a taper that has a 15mm starting diameter at Z0 and finishes at X12mm, at Z-1.5mm. I have tried various combinations of settings without success.

[dmbgo]

I just received an email saying that tblough had replied and offered some help, but it's not here?

[dmbgo]

Actually, I can now see one mistake I've made, I should have the profile taking only 1.5mm off the X direction, not 3mm, so it would finish at 13.5mm in X, not 12mm. I'll try that tomorrow, but I suspect it wont solve the problem.

[tblough]

If you'd posted the Intercon .lth file we could see where you are going wrong and offer some guidance. Without that, here's the way I would approach the problem:

[suntravel]

Yeah with the .icn file it would be better to locate the problem.

Uwe

[dmbgo]

chamfer.lth

(793 Bytes) Downloaded 1 time

Sorry for not posting my efforts at creating a taper - I'm my own worst enemy. Here it is attached now, although a bit late .

[dmbgo]

I had a question, so I thought I would ask ChatGPT, to see what it said. Here is its reply:
Here is what I see in intercon, using the 15mm Chamfer.lth file that was provided on the forum. There were a lot of movements accross the face of the bar. I don't know why?
ChatGPT said:

Thanks for sharing the screenshots — they clearly show how the Intercon profile was built. You're right to question the multiple passes across the face of the part; here's what’s happening and why:
Why you're seeing multiple face passes:

The extra moves across the face (Z = 0 area) are due to the way the Profile and Finish Pass blocks are defined:

In your program, the taper section starts at Z = -1.5 mm and goes all the way back to Z = 0 mm, finishing at X = -0.2 mm.

But the Profile Start is set to Z = +0.5 mm, and the Profile End is also Z = +0.5 mm.

This causes Intercon to machine everything between Z = 0.5 and your contour — and that includes redundant cleanup facing passes across the flat face of the bar.

How to fix it:

To eliminate the unnecessary facing passes, you can:
Option A: Shift the Profile Start Z down

Change Profile Start Z from 0.5 to 0.0 — so the profile operation begins flush with the part face.

Likewise, adjust Profile End Z to 0.0.

This will:

Stop Intercon from clearing "extra stock" between 0.5 mm and 0.0 mm (which doesn’t exist).

Avoid generating toolpaths across the part face.

Suggested Parameters

Update the Profile Cycle (N0002 and N0008) like this:

Start Z: → 0.0

Start X: → 16.0

Leave Depth of Cut, feedrate, and spindle speed as-is unless you're optimizing.

Also double-check that:

You don’t have a Finish Pass or redundant Linear segment at Z=0 unless needed.

If you want to retain a chamfer, the taper segment should start at Z = 0 and end at Z = -1.5.

Optional Enhancements

If you're doing just a single chamfer and cleanup isn't needed elsewhere:

You could remove the Finish Pass block entirely (N0007).

Limit the profile to only cut the taper portion.

Let me know when you try it — and yes, if you document your final solution, it would be very valuable for others in the Acorn/Intercon community too.

[suntravel]

There was the line missing to tell the CNC where to start...

Uwe

[tblough]

FYI, the finish cut has nothing to do with it. The,face passes are included because I programmed a feedrate move from 12mm to -0.2mm diameter. Delete line,6 and they will go away. ChatGPT is worth exactly what you paid for it. If you remove the finish pass, the face cuts will remain since they are part of the roughing. You also don't want to start on your surface. Switching from Z0.5 to Z0 will result in chipped carbide, since the control RAPIDS from the return position, to the first point in your program.

I programed a face cut because that's how I would normally handle cleaning up and chamfering a bar end.

[dmbgo]

chamfer.lth

(1.33 KiB) Not downloaded yet

Tom, I have edited your 15mm Chamfer.lth file, to do exactly what I wanted, but I am wondering why your file was different? Here is my edited file.