[Geo Girl]

my part looks exactly like dcoupar's dwg. I will try a few things this morning and maybe try to explain things a bit more. There are no other lines in my program besides the spindle speed and tool call up (with the correct offset)

[Geo Girl]

"Change to
G03 X1.968 Z-.984 R0.984 F.02
and see what happens. "

here is what happens, tool reaches X0 Z0 but then moves in a clockwise motion away from the part to aprox Z.500 and then comes around to touch the final diameter at the correct Z-.984. if it was possible to machine what its doing it would look sort of like a donut.

i have some G-codes on on my modal screen that i am not sure what they are for. here is what they are and maybe you guys can tell me what they are for and maybe they are causing problems.
G25
G69
G22
G64
G18 ZpXp plane should be correct right?
G13.1
G50.2

I set my Z0 by touching the face of the part and the X is correct. verified this.

[cogsman1]

R=.020 P=3 (Tool comp. settings on offset page) this.

You said the R=.02 in one post, but where did you get a tool with .020 radius? Not a normal size. Are you sure that is what is on there. That will make a big error on a ball.

Otherwise try;

T0202
G00 X0 z.1
Z0
G1G42Z0F.003
G03 X1.968 Z-.984 R.984
G1Z-1.0

[Geo Girl]

I tried your program (removed my tool comp offset just to start at 0)
your program does what my others have done. Moves to X0 Z0 but then arcs away from Z0 in the positive direction and makes a huge arc around back to X1.968 z-.984.

urgghhh

R=.020 P=3 (Tool comp. settings on offset page) this.

You said the R=.02 in one post, but where did you get a tool with .020 radius? Not a normal size. Are you sure that is what is on there. That will make a big error on a ball.

Otherwise try;

T0202
G00 X0 z.1
Z0
G1G42Z0F.003
G03 X1.968 Z-.984 R.984
G1Z-1.0

[dek]

i might be being dull but should clockwise rotation be g02

[Geo Girl]

i`ve tried that too. i`m about to break something!!

i might be being dull but should clockwise rotation be g02

[dek]

are you calling the front face zero,because on one machine i use it must be a +
i.e.start point xo z2
g03 or g02 x1.968 z1.016 r0.984

[Geo Girl]

Yes the front face is zero, but if on your machine it must be a + how do you put a radius in a program if your radius is into the part somewhere?

I can try that.

are you calling the front face zero,because on one machine i use it must be a +
i.e.start point xo z2
g03 or g02 x1.968 z1.016 r0.984

[dek]

because where it finnishes is z1.016 and rad
if not try
g00 xo z.1
g01x0 z0
g02 x1.968 z-.984 I0 k-0.984
this gives the centre of the rad I is where the tool is to the centre of the rad in x and k is in z

[dcoupar]

G25 - Spindle speed fluctuation detection OFF.
G69 - Coordinate rotation cancel (M series - not applicable to T series)
G22 - Stored stroke check function ON.
G64 - Cutting mode (M series - not applicable to T series)
G18 ZpXp plane should be correct right? - Yes, that is correct.
G13.1 - Polar coordinate interpolation mode cancel.
G50.2 - Polygonal turning cancel.

I don't see any active G-codes that should cause a problem.

You originally said it's a 1/2" ball, which I would guess means a 0.250 radius insert? When you touch off the tool, you touch the face to the end of the part and the bottom of the tool to the OD and set your offset, correct? Therefore you can't start at X0 Z0 because the tangent point of the radius would be 1/4" (1/2" dia) above center. So you need to start the arc at X-0.5 Z0.

If you have a front turret lathe, I would guess that a clockwise arc is G02... but I could be wrong.

As NeilW said, maybe the R is giving you problems although I've never had a problem with it.

Try the following:

G00 X-0.5 Z0.1
G01 Z0 F0.01
G02 X1.968 Z-1.234 K-1.234
G00 X2. Z0.1

[Geo Girl]

OK, so here is what happened when I ran your program,

it made a concave arc into an imaginary part (air cutting) to an x-1.7 but actually made a complete 360 arc. If I changed it to G03 the part made a convex arc (which is good) but only arc'd to X.72 dia then linear moved out to X1.968 before rapiding out.

Do you guys think something is wrong at this point?

G25 - Spindle speed fluctuation detection OFF.
G69 - Coordinate rotation cancel (M series - not applicable to T series)
G22 - Stored stroke check function ON.
G64 - Cutting mode (M series - not applicable to T series)
G18 ZpXp plane should be correct right? - Yes, that is correct.
G13.1 - Polar coordinate interpolation mode cancel.
G50.2 - Polygonal turning cancel.

I don't see any active G-codes that should cause a problem.

You originally said it's a 1/2" ball, which I would guess means a 0.250 radius insert? When you touch off the tool, you touch the face to the end of the part and the bottom of the tool to the OD and set your offset, correct? Therefore you can't start at X0 Z0 because the tangent point of the radius would be 1/4" (1/2" dia) above center. So you need to start the arc at X-0.5 Z0.

If you have a front turret lathe, I would guess that a clockwise arc is G02... but I could be wrong.

As NeilW said, maybe the R is giving you problems although I've never had a problem with it.

Try the following:

G00 X-0.5 Z0.1
G01 Z0 F0.01
G02 X1.968 Z-1.234 K-1.234
G00 X2. Z0.1

[dek]

is you machine set for x radius or x dia

[HuFlungDung]

To clarify, Geo Girl said the part was like one half a ball, not that the tool was a 1/2" ball

G90
G00 X0 Z.1
G01 X0 Z0 F.01
G03 X1.968 Z-.984 I0 K-0.984
This code should work if the machine has diameter programming, and incremental arc centers. Actually, absolute arc centers will also have the same code in this particular situation, so the controller should accept it either way.

Run a simple program machining a square cornered shoulder on the part. Get sorted what your X values actually are representing: diameter or radius.

What does your tool callout look like? Are you using a 4 digit format?

[dcoupar]

"To clarify, Geo Girl said the part was like one half a ball, not that the tool was a 1/2" ball"

Well now don't I feel like an idiot? Thanks HuFlung for pointing that out.

Geo Girl, in case i missed it what is the radius of your turning tool?

[Geo Girl]

Looks like .031" rad

"To clarify, Geo Girl said the part was like one half a ball, not that the tool was a 1/2" ball"

Well now don't I feel like an idiot? Thanks HuFlung for pointing that out.

Geo Girl, in case i missed it what is the radius of your turning tool?

[Geo Girl]

Hi,

My tool callout T0202
yes 4 decimal places,

I ran your program (i ran this myself awhile back too)
it is egg shape that turned to an OD of .984 at the end point.
My machine is definately set at dia turning tho.

To clarify, Geo Girl said the part was like one half a ball, not that the tool was a 1/2" ball

G90
G00 X0 Z.1
G01 X0 Z0 F.01
G03 X1.968 Z-.984 I0 K-0.984
This code should work if the machine has diameter programming, and incremental arc centers. Actually, absolute arc centers will also have the same code in this particular situation, so the controller should accept it either way.

Run a simple program machining a square cornered shoulder on the part. Get sorted what your X values actually are representing: diameter or radius.

What does your tool callout look like? Are you using a 4 digit format?

[HuFlungDung]

G90
G00 X1.968 Z.1
G01 Z-.984 F.01

If you run this code, what diameter do you get as a result?

[sinha_nsit]

G90 not needed here in G-code system A

[sinha_nsit]

"Change to
G03 X1.968 Z-.984 R0.984 F.02
and see what happens. "

here is what happens, tool reaches X0 Z0 but then moves in a clockwise motion away from the part to aprox Z.500 and then comes around to touch the final diameter at the correct Z-.984. if it was possible to machine what its doing it would look sort of like a donut.

i have some G-codes on on my modal screen that i am not sure what they are for. here is what they are and maybe you guys can tell me what they are for and maybe they are causing problems.
G25
G69
G22
G64
G18 ZpXp plane should be correct right?
G13.1
G50.2

I set my Z0 by touching the face of the part and the X is correct. verified this.

G64 is not for Fanuc T-series. How can this be displayed?
Which control are you using?

[Geo Girl]

X1.968

G90
G00 X1.968 Z.1
G01 Z-.984 F.01

If you run this code, what diameter do you get as a result?