PUMA600/700 Live tooling accuracy

[fitzpatrick2362]

Looking to purchase Puma 600/700 with live tooling.

Does anyone have experience of the live tooling on these machines or any other lathes with relation to accuracy.

We would be creating PCDs of holes up to 800mm diameter with 0.002 true position.

My concern is that when we are carrying out heavy turning work and come up against the occasional machine crash the turret will lose its accuracy.

Also, does anyone use the live tooling for anything more complex than holes.

Creating slots, flats etc.

Just interested to here your opinions.

[MadMax]

I'm not sure what a PCD is, but it seems to me that the live tool positioning is about as accurate as the cutter positioning given that the tools are held in the same tool turret as the cutting tools. I'm easily holding sub 0.001" tolerances on the static tools so I'm guessing that the live tool positioning in the Z-Y directions has to be that good plus whatever radial play you've got in the live tool bearings. My live tools are pretty worn now (they were bought used) and have developed about 0.001" radial TIR just off the collet face when I hold a ground shaft and push on them. That being said, I think they'll end up drilling centred when they spin.

C-axis interpolation seems to be very good on my lathe. I'm doing some circular interpolation to finish out a hole that's not on the spindle axis. My gauge pins only go to 0.0005" increments, but I haven't been able to measure any variations in my hole diameter so I don't think the interpolated holes are out of round by more than 0.0005" or out of diameter. I've looked at the holes under a microscope and I can't see any interpolation ribs or other funny obround features around the pin. Surface quality of slots or polygons seems to be quite nice if the part doesn't flex too much.

0.002" is a pretty big distance for a machine that is in good adjustment, but I note that my turning diameter can vary by nearly 0.001" from cold start to warmup so if you want 0.002" positioning repeatability, you'll probably need to do a warmup cycle to get 0.002" positioning over a big 800mm part. My machine travel is much shorter at sub 300mm. I would expect more cool-warm variations for a much bigger machine. Still, thermal expansion issues seem to be be fairly repeatable if you have a steady part to part production cycle. If I was really picky, I'd run a different program at the beginning of each day with a compensated program after the first couple hours.

Everything kind of goes out of whack after a turret bump. I find that the entire turret may either shift in a single axis or it can twist out of axis after a crash (depends on the geometry and energy of the hit). I pretty much touch every tool in and check turret parallelism after a hit. I don't think there's any sense of accuracy after a crash if you don't reset all the offsets and check the turret parallelism. I've got a lot of operations with long boring bars. Everything goes to chattering sh*t after a crash if I don't confirm that they're cutting across spindle centre height.

My Daewoo is significantly smaller than the one you're considering. I've got a Puma 200, but I've found it to be a pretty decent design from a crash recovery perspective. The toolchanger is fairly easy to realign and so is the spindle. Plenty of space to access the adjustment and fixturing screws in this design and my machine is a pretty old '97 build.

[grweldon]

I have the short version of the 300MC. I have used live tooling to cut irregular profile pockets in chuck jaws for holding odd shaped parts. Works well.

I also find that after a turret bump, the headstock may have to be adjusted or the turret adjusted. I've had factory service techs in once to do mine. A knowledgeable, competent maintainence tech could easily do this. We don't have one!

[Dr Dug]

I have aligned turrets many times.
On the Doosan machines there are dowel pins.
There are 4 tapered holes and only 2 pins used. The two unused holes are "Master Pin" holes. So, in theory, you can re-align the turret by inserting two new pins in the Master Pin holes.

If you know you will crash the turret, I'd suggest that you remove the two pins that are in the machine. This will allow the turret to move when crashed. If they are not removed then something else "Will" move. Allowing the turret to move during a crash makes the crash less severe. Now you can take the two pins you removed, loosen the turret bolts for the curvic coupling and align the turret with any of the 4 tapered holes. This works; I've done it many times.

On turrets that the pins were left in and the machine is crashed; the pins bend and often the saddle moves; making the alignment much more difficult.

Also, buy a co-ax indicator. It is the only way to be sure you get back to X0, Y0.

[bdyenter]

I have PUMA 700 with Live tooling> Very happy with it !

Comes in handy when drilling radial holes on castings, bolt circles. Not always
the best for time, but it depends on how you set up your shop and run your jobs.

One thing that impresses me is that there is some balls in that gear-box for the live tooling. Largest tap I have done thus far is 1"-8 un and had no
problem. Accuracy is there.... but as the guys mentioned above... if someone else has there paws on the machine other than you... then with me it's trust nothing. I always indicate center on live tools. Having the tool out as much as .010 from a crash will put a bolt circle off I believe .020 in location.

So u gotta be carefull with these guys if you want to use the live tooling with accruacy. That goes with any machine, not just Doosan.

Another benefit is adding a 24" chuck in this frame. This provides a 6 1/2" throat diameter in the drawtube. I do shaftwork that are sometimes 120"-150" long. Nice to be able to choke anything up to 6 1/2" at anytime.

Plus a tailstock is a bonus as well.

I have a 60hp with high/med/low gearbox. Another bonus for heavy hogging for roughing material. I use a CNMG-543 and turn .300/side feeding .022 ipr. @ 500-600 sfm. Chips come off like nickels hitting the glass. Thats in low gear M41 with left hand tooling as well and still have room to step to a CNMG643 and get to .350-.400/side. Cool stuff man! Reason I specify left hand tooling is that it is a must when you do roughing like this. Otherwise you will creat lift off your riser gibs. Not good (: so use left hand tooling for heavy roughing like this