[jaru-eri]

I need a g-code program for making spheres on a rope with 4 axis milling or semi-spheres with 3 axis.
Can anybody help me?

[Kiwi]

jaru-eri
Is this the path with a 'A' rotation you require?

[jaru-eri]

something like this with one or two spheres.

[Kiwi]

I've never used or programed for a rotating axis.
Would the code be something like this?????

G01 X-100 Y0 Z5 A0
G01 X-99 Y0 Z7 A360
G01 X-98 Y0 Z9 A360

The X and Z following the arc while the A axis rotates 360 deg. on each block??????
Is 'A' the correct letter to use??
If I can get the basics right, I will look into writing a generator.

[Geof]

something like this with one or two spheres.

If you can tolerate a small fillet where the sphere blends into the shaft between the spheres you can do this by helical interpolation in X and Y while the A axis rotates continuously; the Z axis would move from the OD of the original stock down to the OD of the shaft between the spheres

The axis of the spindle has to be aligned with the A axis and (of course) with the center position of the sphere.

[jaru-eri]

I've never used or programed for a rotating axis.
Would the code be something like this?????

G01 X-100 Y0 Z5 A0
G01 X-99 Y0 Z7 A360
G01 X-98 Y0 Z9 A360

The X and Z following the arc while the A axis rotates 360 deg. on each block??????
Is 'A' the correct letter to use??
If I can get the basics right, I will look into writing a generator.

I´m just a beginner in this game, so I don´t know what the best choice will be. Maybe it wil be better to let the x axis go the full length and rotate the a-axis step by step between each x movements? It depends on which axis which is best to maintain against wear and of course to keep the operation as silent as possible.

[Geof]

I´m just a beginner in this game, so I don´t know what the best choice will be.....

Read what I suggested, and wave your arms around or do some sketches until you understand what I am getting at. It will work and you do not need anything other than plain G-code. You may have to do a little experimenting to get sizes correct but that is all.

[Kiwi]

Geof's idea sounds good but the cutter will need to have a larger overhang, so will need to be a larger diameter which will leave a bigger fillet.
This could be re-machined with a smaller cutter.

Maybe it will be better to let the x axis go the full length and rotate the a-axis step by step between each x movements?

This will leave larger cusps at the longer radius with excessive cutting on the shorter radius relative to the rotating axis.

[Geof]

Geof's idea sounds good but the cutter will need to have a larger overhang, so will need to be a larger diameter which will leave a bigger fillet.....

The length of the can be less than the radius of the sphere, maybe considerably less because the curvature of the sphere provides clearance for the nose of the holder. This is why I say you interpolate X and Y and come down in Z with A rotating constantly.

I have done thousands of partial spheres on manual machines using an inward facing fly-cutter rotating around the center of the sphere while the sphere was rotated under the cutter. The interpolation method I describe here is completely equivalent.

Have a look at the pictures in Post #10 in this thread:
http://www.cnczone.com/forums/showthread.php?t=35881

[Kiwi]

jaru-eri
What are the sphere and rope diameters.
Also what material are you using, plastic, wood or metal?

[jaru-eri]

jaru-eri
What are the sphere and rope diameters.
Also what material are you using, plastic, wood or metal?

Spheres 1" rope 3/8" I use wood.

[Kiwi]

jaru-eri
Not sure if this is what you are wanting.
Program attached which creates a stepped arc on the XZ plane with 'A' rotation.

[jaru-eri]

jaru-eri
Not sure if this is what you are wanting.
Program attached which creates a stepped arc on the XZ plane with 'A' rotation.

Thankyou very much Kiwi. I will try out your programs. You have been to great help.

[jaru-eri]

jaru-eri
Not sure if this is what you are wanting.
Program attached which creates a stepped arc on the XZ plane with 'A' rotation.

KIWI
I´ve now tried this program. The problem is that it doesn´t generates any feedrates (there should be two feed options because the rotary axis moves slow).

The other problem is that the A - destiny repeats itself to 360 and because of that it stops up. It should instead advance with 360 between each zx movement. Like 360 - 720 - 1080....

[Kiwi]

jaru-eri
Modified version attached. To alter Feed Rate use Find and Replace in NotePad.
I will add the feed rates as Inputs if required.

[Andre' B]

Looks like a lathe part to me.

[jaru-eri]

jaru-eri
Modified version attached. To alter Feed Rate use Find and Replace in NotePad.
I will add the feed rates as Inputs if required.

This file got a vbp extension. My computer ask me for a program to open it within. What shall I do?

[Kiwi]

jaru-eri
Sorry sent the wrong file. I will replace the one posted on #15