Could Smid Have Made a Mistake? (TNR/Facing Example) - Page 2

1. Good thing we figured out that problem....the one that shouldn't ever exist.

2. Originally Posted by Mtndew
You only need it when you're doing a contour.
If programming by hand, it's not necessary. If programming at the control it will most likely spit out all moves with cutter comp.
I started programming cnc lathes back in 1989, used cutter comp in just about every situation.
There are exceptions of course. But more often than not the people who say to not use it either don't understand it or don't want to take the time to explain it.
Or they don't use it because it is not necessary if using cam. I've never used it, but also never had to hold a true radius, or some weird angle they wanted +/-.1 deg or something.

I've shared before, but had a guy that insisted he could do faster programming at the machine with canned cycles, sure maybe simple shoulders and bores ya. But get into profiling funky angles and blends it's a little different.

Now a question I have for you guys that do alot of lather programming at the control, don't you need all the tangent points when a radius blends into an angle? I ask because I did a little bit with an Integrex, and the guy programming always handed the prints off to me to dimension all the end points and stuff.

3. Originally Posted by Mike1974

Now a question I have for you guys that do alot of lather programming at the control, don't you need all the tangent points when a radius blends into an angle? I ask because I did a little bit with an Integrex, and the guy programming always handed the prints off to me to dimension all the end points and stuff.
"Need" is a strong word. As in do I "need" it to get the job done?=No. Is it about 10x faster to map it on software?=Yes.

Obviously there are formulas to find the points Cartesian, otherwise there wouldn't be software that could do it in the second place. Right?

R

4. Diamond
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Originally Posted by Mike1974
.....Now a question I have for you guys that do alot of lather programming at the control, don't you need all the tangent points when a radius blends into an angle? ......
Depends on how the drawing is dimensioned and how the control is spec'd. If the drawing has vertex dimensions and the control is optioned with corner rounding, then you do not need the tangent points.

The Geometry and Trigonometry to calculate most tangencies for lathe programming is pretty much what is taught in 7th-9th grade math(or it was in the dark ages when I went to school). Pretty simple really. Every once in a while there will be a drawing that needs higher level math to solve.

5. Stainless
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While machining an internal corner (included angle <180 degree), in the radius compensation mode,
1. if the corner radius is smaller than the nose radius, the control would alarm out.
2. if the corner radius is greater than or equal to the nose radius, the corner would be correctly made.
3. if the corner is sharp, it would be rounded by the nose radius. No alarm.
In no case, tangent points need to be calculated.

External corners (included angle > 180 degree), i.e., convex corners, are always correctly made.

6. Sinha is correct, but there are Radii into Angles and such that start to get fairly tricky. Angles that are Tangent to other Angles. Partial Radii that are Tangent to Angles other than 90°. That are tricky.

R

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Originally Posted by litlerob1
...... Angles that are Tangent to other Angles. .....
This expression is new to me. Can you explain "Angles that are Tangent to other Angles"?

8. Lets call it "transition" then. Tangent still works though, but I'm not a smart man.

9. Diamond
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Just jabbin at your ribs man.