Figure 8 Oil Groove

[penjas14]

Does anyone have any experience with an OD figure 8 oil groove? It is a .750 pitch over 15 inches and at the beginning and end it has a .6565 turnaround. It is more of a fishing reel that a roller follows to wind up wire. Okuma has a G34 threading function which seems like any change in the thread it possible. Such as changing leads at any point and staying in the thread to go back and forth. I'm assuming I can't use a G1 cause once were out of the groove its position is lost. I have Mastercam x3 Lathe, but I'm probably gonna have to attack this one by hand. I have a good idea what my plan is, but am not sure if I'm gonna get the result that I want.
G34 x.990 z-17. f.750
z-20. f.6565
z-17. f.6565
z-5. f.75
z-3. f.6565
z-5. f.6565
x.980 z-17. f.75
......
This is kinda what I'm looking at, not sure if it will work as i plan.
Does anyone have any experience with this type of operation?

[JWK42]

This looks like a job for a VMC with 4th axis rotary table mounted along the X axis or a lathe with a C axis. I don't know if Okuma can run the code you show. You will probably get an Axis Reversal alarm.
We used to do this along time ago on an AB 7365 control on a J&L 312-A. ( 1980 vintage )
We have not been able to do it on any of our newer controls .

[jimiscnc]

I've been told a figure 8 internal oil hole groove can be made by staying in G32/33/34 and programming Z plus and minus over and over again.

I'd love to see the code for doing this!

-jim

[JWK42]

I just ran this on our Haas simulator and it shows the slide movements on the screen, however I have not made chips yet.
The issues that I can think of are maximum slide velocity and low RPM torque if you need a longer pitch such as the 4 inch pitch below. This set up requires a 200 IPM slide velocity.
I don't know about Okuma or Fanuc controls.
We have several Okuma lathes so maybe I can try this on one of them sometime.

%
O5555 (FIGURE 8 TEST)
N30 (WRITTEN 03-06-2009 09:48:28)
N40 (RETURNED 03-06-2009 10:30:48)
N50 G50 S150 M41
N60 G54 G90
N70 G53 G00 X0.
N80 G53 G00 Z0.
N90 T1
N100 S50 M03
N110 G00 X5. Z6.
N130 (START OF CYCLE)
N140 G01 X4. Z4. F0.5
N150 G32 U-0.003 W-4. F4.
N160 U-0.003 W4.
N170 U-0.003 W-4.
N180 U-0.003 W4.
N190 U-0.003 W-4.
N200 U-0.003 W4.
N210 U-0.003 W-4.
N220 U-0.003 W4.
N230 U-0.003 W-4.
N240 U-0.003 W4.
N250 U-0.003 W-4.
N260 U-0.003 W4.
N270 U-0.003 W-4.
N275 U.06 W4. ( LIFT OUT )
N280 G01 X4.5 F0.5
N290 G53 G00 X0.
N300 G53 G00 Z0.
N310 M30
%

[JWK42]

I just attempted to cut grooves using U and W words as shown above.
I had to go to 40 RPM with the F4. or else it errored out as "Feed rate to fast".
At 40 RPM and F4. and W4. it would not track.
At 40 RPM and F2. and W4. it seemed to track OK but I was cutting graphite so there was no load. I really do not think this method will work.
If you use it you will have to use a low feed rate such as F2. which sets the slide velocity to 80 IPM at 40 RPM and very little chip load or else it will lose it's path.
I havn't tried our Okuma's lately but when we first got one it would not work.
We now have special 4 axis CNC machines to do our oil grooves using a timing belt driven end mill.

[ED209]

Hi JWK42 could you describe the belt driven endmill in more detail. I find this rather interesting.

[JWK42]

We actually copied the idea from a grooving arm attachment for a Bridgeport mill many years ago. I'll attach a pic of one of our machines with the arm.
The end mill shank serves as the axel and is driven by a timing belt pulley bored to fit and held by one set screw.
This is a Comet MV-5 with a Troyke 4th axis. The groove arm is ran by a .75 HP 1750 RPM motor turned on and off with auxillary M codes.
I hope this Pic is large enough. I deduced quite a bit to attach here.