Lathe Finish Pass

[M_CODE1]

I am programing a part that has a shoulder on it, that has a .025 radius in the corner. When my finish pass comes to the corner it does not follow the R.025 with the 1/64 radius tool I am using. Anyone have any ideas why the tool path is going up to the shoulder and forgeting about the radius.

 

Thanks

[Guest]

is the radius part of the actual chain or is just the straight line chained?

[M_CODE1]

yes the radius is part of the chain

[Guest]

OK, are you using the lead in/lead out to shorten the contour?

[M_CODE1]

No, I not using them to shorten the countour, just to extend them .05". I tuned the lead in/out off and it still did it

[Guest]

Can you share your file?

[M_CODE1]

John, you got mail

[Philcott]

Mike, Have you tried deleting the chain and rechaining it? My guess is there is something wrong there. I have not seen a radius ignored in a chain before.

 

I would be interested in the solution to this issue.

[Guest]

Mike,

 

Regenerate the 3 OP2 ops. It appears something got changed in your roughing path and the stock did not update properly. On the file you sent the rad was under cut after the rough, thus the finish tool saw no stock in the radius and just square cut. The regeneration fixed the stock update and allowed the finish tool to cut the radius.

[M_CODE1]

Thanks John, but i am still having the problem. This is strange, after I regenerate the file it forgets about the corner and does not put the radius in. Below I posted the program befroe and after I regenerated it. THe shoulder is at Z-1.2015, FYI.

 

ONE MORE IN TILL THE BIG 200..............

 

 

FROM THE FILE JOHN SENT ME, NO REGENERATION by me

 

( TOOL - 2 OFFSET - 2 )

( LFINISH LATHE FINISH 55 DEG INSERT - 1/64 )

N100 G50 S3200

N102 G0 G97 G95 X37. Z7. T020202 S2600 M03 M42

N104 G95 M8

N106 G0 X.2916 Z.0631

N108 G95 G1 Z.0131 F.004

N110 X.3669 Z-.0246

N112 G3 X.3761 Z-.0357 I-.011 K-.0111

N114 G1 Z-1.1921

N116 G2 X.3949 Z-1.2015 I.0094

N118 G1 X.4049

N120 G3 X.4362 Z-1.2172 K-.0156

N122 G1 Z-3.2454

N124 G3 X.9976 Z-3.7037 I-.2337 K-.4583

N126 G3 X.9552 Z-3.8497 I-.5145

N128 G1 X.9347 Z-3.898

N130 G1 X1.0054 Z-3.8627

N132 G0 X37. Z7. M9

N134 M02

 

 

FROM THE FILE JOHN SENT ME, AFTER I REGERERATED

 

( TOOL - 2 OFFSET - 2 )

( LFINISH LATHE FINISH 55 DEG INSERT - 1/64 )

N100 G50 S3200

N102 G0 G97 G95 X37. Z7. T020202 S2600 M03 M42

N104 G95 M8

N106 G0 X.2916 Z.0631

N108 G95 G1 Z.0131 F.004

N110 X.3761 Z-.0292

N112 Z-1.2015

N114 X.4049

N116 G3 X.4362 Z-1.2172 K-.0156

N118 G1 Z-3.2454

N120 G3 X.9976 Z-3.7037 I-.2337 K-.4583

N122 G3 X.9552 Z-3.8497 I-.5145

N124 G1 X.9347 Z-3.898

N126 G1 X1.0054 Z-3.8627

N128 G0 X37. Z7. M9

N130 M02

[Guest]

Mike that is strange, I just reopened the file I sent you and regenned the last 3 ops again a couple of times and it's fine.

 

So I am not sure at this point what you've got going on there.

 

 

You might try recreating the ops.

[M_CODE1]

Well I final found the probem, looks like my chaining tolerance and Minimum arc length tolerance were set to high. They were at .02" on each.

 

John, would this be why it came out all right on your seceen and not mine?

 

Second question, what would be the recomended values for the tolerances under the system config? I do mostly 2 axis lathe work and 3 axis mill programing.

 

I have now

 

.001 chaining

.014 planar

.005 arc length

.1194 min step size

500 max step size

.005 chordal diviation

.005 max surface devation

.005 toolpath tolerance

 

 

Thanks

 

I FINALLY MADE IT....200 POSTS

[Ron Branch @ Verisurf]

What tolerance do you make your parts to. If .02 is good enough for you guys then make it .02. I have all mine at .001 or better on just about everything.

[Bob Hedrick]

For Lathe, I would use the out-of-the-box defaults for tolerances; especially the system tolerance and chaining tolerance. The module that updates the stock model is not very tolerant of imperfect geometry. When you take a cut with a tool, the software is essentially doing a 2D boolean subtract with geometry that shares a lot of tangent edges. Anyone that has worked with solids knows how dicey that can be.