[fishy steve]

hi, i have a problem, we are running a twin turret okuma lathe, and are haveing problems with the bottom turret cutting a inside threads, as it is cutting down. our "engineer" says we should use the second turret and cut up, instead of a simple fix of just switching some tools around to thread from the top turret. i tried to explain to him that flipping it around will be a night mare as it will reverse all the programing and offsets as the all the + would be negatives and so on... he thinks the machine will be smart enough to figure it out on his own, but i fail to see how a machine will be smart enough not to do what its programmed to do... i did some research and i found G68 and 69 which is mirror image on and off, think this would help in this situation? sorry if my explanation of all this is hard to undertsand...

[littlerob]

[quote=fishy steve;846985]

hi, i have a problem, we are running a twin turret okuma lathe, and are haveing problems with the bottom turret cutting a inside threads, as it is cutting down.

I don't understand what this means.

our "engineer" says we should use the second turret and cut up,

Does he mean use a left hand tool?

instead of a simple fix of just switching some tools around to thread from the top turret. i tried to explain to him that flipping it around will be a night mare as it will reverse all the programing and offsets as the all the + would be negatives and so on...

If you change any of it you are going to have to do all that anyway aren't you?

I don't know about G68-9. I DO know that there shouldn't be any problem using your lower turret to cut ID threads. Maybe if you let us know exactly what the problem is than we could go from there. IE. Problem with the program?

[zooloader]

So what is actually the problem with threading? Is it surface finish, tool life,...?
What form is it?
What Dia?
How long?
What material?
What condition is your lathe in?

[OkumaWiz]

The Okuma Twin Spindles use G13 and G14 for A and B turret and use G140 and G141 for Left and right spindles. That being said, the SAME code can run on left, Right, A and B spindles. I know that on some Fanuc machines everything has to change, but Okuma did a really nice job on their software. Even the chucking commands, coolant commands, nose comp, Lap cycles, Milling cycles, etc. will work properly. You can even CALL a subroutine and run it on either spindle.

So your "engineer" is mostly right. You will still need to touch off a new offset depending on what turret and what spindle mode you are in.

The threading should be primarily the same no matter which mode or turret you are using. Please be more specific on the problem you are experiencing and check the basics such as tool centerline, stickout, etc.

Best regards,

[mitchd]

We used a lot of 4 axis Okuma's for threading. Is the problem chips rolling to the bottom of the part and chipping out the tool? If this is the case your eng is right.Using the top turret will keep the insert away from any chips gravity is pulling to the bottom of the part.
Mitch.:cheers:

[sankar]

When using OKUMA DOUBLE TURRET Lower turret don't have High pressure coolant. Upper turret have high pressure coolant, Tht's why any operation use upper turret come out chips from the part.
While running any threading chips never broken because you can not change feed rate. Feed rate is depends on the thread pitch.
When doing threading operation more chips rolling on the part, you put Mid on Manual and single block and stop spindle. Then remove the chips from the part and cycle start release mid on manual, single block also. Then you make a good thread.

[underthetire]

You haven't really lived until you've done a 4 axis Acme thread! Helped set up a shop years ago, lots of pucker factor that first part !

[littlerob]

You haven't really lived until you've done a 4 axis Acme thread! Helped set up a shop years ago, lots of pucker factor that first part !

Ok I quit , what does this mean? It's still single point. Do you mean because of the huge chips, and doing OD and ID at the same time? :withstupi

[underthetire]

Ok I quit , what does this mean? It's still single point. Do you mean because of the huge chips, and doing OD and ID at the same time? :withstupi

Actually, It was upper and lower turret threading the inside of a ring. Since one turret was always threading 180deg before the other turret, we ran a smaller tool for roughing on the upper and the correct size on the lower. Still single pointing, just X2. That was about 1991, on a LR-15BB, with 250PSI coolant.

[littlerob]

Actually, It was upper and lower turret threading the inside of a ring. Since one turret was always threading 180deg before the other turret, we ran a smaller tool for roughing on the upper and the correct size on the lower. Still single pointing, just X2. That was about 1991, on a LR-15BB, with 250PSI coolant.

Makes sense now, you start the turret that is finishing 1/2 af one lead further out. Very close turrets especially when retracting. HMMM Sorry for the hijack Steve

[underthetire]

Very close turrets especially when retracting. HMMM Sorry for the hijack Steve

Thats why we came up with the Beaver Tail ( as a joke ). Was two pieces of thin copper with doubleside tape and wires comming off. You basicaly stuck one sheet per side on the inside of your ass cheek so when you really puckered it would E-stop the machine.

[littlerob]

@ UTT. Man I wish the "beavertail" were implemented with all new operators, pucker activated E-stop, where are the bio-mechanichal engineers when we need them?

[OkumaWiz]

Oh c'mon...everyone knows if you use a sphincter switch you'll gain .25 second reaction time over a "beaver tail"!

Steve - you still with us? Betcha wisha weren't. (flame2)

You gotta love the high tech discussions going on here and the technical knowledge you are gaining...

Best regards,