Lathe Functions to Set Your Process Apart

Wade Anderson:

Hey, manufacturing world. Welcome to another episode of Shop Matters, sponsored by Okuma America. I'm your host, Wade Anderson. Joining me in the studio today is David Fisher. Welcome, David.

David Fischer:

Thanks for having me.

Wade Anderson:

All right. So, David, introduce yourself. Tell us a little bit about you.

David Fischer:

Yeah. David Fisher, lathe product specialist. I handle the turning centers. Been at Okuma for quite a while now. Will be 30 years come September. So, bit of a high watermark there for me. It's been great. I started off in the applications engineering department. Was in there for almost 20 years. And then moved over to technical support for sales in this position. So yeah, everything from working on the machines, to product management in applications, and now technical support for sales.

Wade Anderson:

Okay. So, I started with the company in 2005. So, you've been there a lot longer than I have, about twice as long, I think. So, I started years ago, and I've said this on a couple of podcasts, I think, but the very first chip I ever cut was on a LB15. I used to work for Holset-

David Fischer:

Great machine.

Wade Anderson:

Yeah. I worked for Holset Turbo down in Charleston at the time. And they had cells. They had two LB15s, and then they had a horizontal machining center. So, that was my first experience. I came from the fab world. I programmed Amada and Salvagnini shears and press and brake systems.

Wade Anderson:

So, the first chip I ever cut was a LB15 Okuma. And now, fast forward all these years later, I work for the company. But I remember when I first started, I knew what the LB15 was, and that was it. I really didn't know much of the product breadth. And you get involved with it, and you got LUs and LTs and GENOS lathes. And back then, there was ESLs. And MULTUS. And there's all these different models.

Wade Anderson:

Kind of talk us through what the different models are. So, if people out there are listening and they're familiar with an LU and not an LB, or vice versa, they know an LB, and they've never heard of an LT. What are these models? And what differentiates them?

David Fischer:

Okay. So, basically, we break it down to vertical and horizontals. And then we've got our turning centers and our multitasking centers. So, for the horizontal market, we'll break that down further into the number of saddles. So, when you talk about your LB15, that's our premium, which is now an LB3000, by the way. But that's our premium single-saddle machine. And you can get that turning-only, milling, Y-axis, sub-spindle. You can basically take it up to what would be right on the threshold of becoming a multitasking machine. So, you can do a part complete start to finish.

David Fischer:

When you move to the LUs, now we're getting to two saddles. So, with the LU, we have an upper and lower saddle. They can work independently, or they can work in a synchronized fashion. So, if you want to do pinch turning, which would allow you to add a measure of chatter suppression because your two tools are supporting each other and supporting the part. So, that takes you to a higher level of production, particularly for shaft work and that type of thing.

David Fischer:

And then we move up to the LT, which we can have two or three saddles, matching spindles. And they're all milling capable. You can put Y-axis on all three. A very high production type machine for very complex parts. Then we'd step up to multitasking, which would be our MULTUS product line.

David Fischer:

And we kind of do the same things on verticals. We go to a vertical, we have the LB EX is kind of our bread-and-butter horizontal turning machine. Whereas our 1SP-V EX is our bread-and-butter vertical turning machine. Box way construction, super rigid. Great for production. And we go all the way up to multitasking machines with our VTM-YB, which is almost like a vertical MULTUS platform, so to speak.

Wade Anderson:

Okay. It's like a MULTUS multifunction machine, standing it up basically.

David Fischer:

Yeah. Can't get a sub-spindle, but...

Wade Anderson:

Yep. Yeah. And you can't bar feed it.

David Fischer:

Right.

Wade Anderson:

So, out of the product line, do you have a favorite? Do you have one that you tend to gravitate to that you like running better than others?

David Fischer:

Yeah. I mean, the MULTUS is just one of those types of machines that you're only limited by your creativity. It's just a lot of fun to take that in different and unexpected directions. It can do a lot of things. It kind of got started in the market for high-end shops that have high capability. But then it's like, "Okay, well, let's turn this around. This is a great quick change machine." Right? So, for job shops, you don't want to invest a lot in fixturing, rotary tables, and all that kind of thing. With the MULTUS, that's all built into the platform. So, all that setup, all those extra machines, your investment setup time is minimal. And I can go from part to part to part very quickly.

David Fischer:

And having been in production... I worked in a production shop for 18 years before I came to Okuma. And it was just setup time was a major headache. Because we spent hours. We didn't have many CNC machines. When that setup time goes to single minutes, five minutes, ten minute setup time, all of a sudden, that stress of, "Oh, we got a hot job. You got to tear this down and set up another job." You may have to tear down three machines. That problem goes away because you're just talking minutes. So, who cares? Let's set up the next job. We can send the finished parts on the previous job to the stock room. And we'll get back on it when we finish up here. Yeah. The MULTUS is really great.

David Fischer:

But at the same time, I want to throw out here about the LB EX. That's just such a heritage machine. Which I call it heritage machine; it's been around for so long. It's evolved to such a high pinnacle of accuracy, thermal stability. It's truly an amazing machine. So, that's got a special place in my heart as well.

Wade Anderson:

Okay. So, lead me through, and I don't know, was there a predecessor to the LB15? Was there a model prior to that that we would've seen in the States?

David Fischer:

Well, the LB15 was sort of the... Okuma's been around for over 100 years.

Wade Anderson:

Well, yeah. Aside from the manual things.

David Fischer:

The newer machines, right. But the LB15 was sort of a watershed moment for Okuma. So, that kind of set Okuma on the map as a premium machine tool builder.

Wade Anderson:

So, you just mentioned something that might be interesting. I think a lot of people will know this, but some won't. But how Okuma actually got started in manufacturing. Eiichi Okuma decided that he wasn't happy with the thickness and consistency of the noodles and started making noodle-making machines. And went from designing the dies to roll the noodles, to realizing the equipment that he was using to roll the dies wasn't of good enough quality. So, he got involved in actually manufacturing everything to make the entire noodle-making machine, which led him to need metal cutting equipment to be able to cut the gears and turn shafts and things of that nature. And we got our first patent in 1914 for a manual lathe that hit production in 1918.

Wade Anderson:

And then you kind of fast forward to the United States. And my first introduction with Okuma was the LB15, the CNC lathe. And my father, and I had an uncle, that worked at Eaton's in Shenandoah, Iowa. And they kind of revolutionized their manufacturing process back in the day from going from vintage World War II-type manual lathes to a CNC lathe. And it was the Okuma LBs that they loaded the shop full of back when they first kind of turned on the CNC world. So, just a little quick injection of some history on Okuma.

David Fischer:

Okuma's been around for a long time. And you wouldn't think accuracy was all that important with making noodles, I guess is kind of what I'm thinking. How accurate does a noodle have to be? But evidently, it has to be pretty accurate.

Wade Anderson:

Right. So, the LB15, what has changed as you go through the different generations from like a 15 to an LB300 to an LB3000? What were some of the technological advances as we went through those machine model changes?

David Fischer:

Yeah. Real quick, more power, more torque are two things just right off the top. But probably the biggest thing, and I think something that's really appreciated by our customers, is the design of the machine that has made it more thermally stable, more thermally predictable, and then you add our technology on top of that. With the LB EX series, we added TAS-S, which is our thermal active stabilizer system. And that's software that controls the size of the machine as the machine heats up or cools down.

David Fischer:

So, now your operator doesn't have to be involved with constantly adjusting offsets. And even more important, when you put it in a automated cell. So, you just want that to run. And you've got minimal thermal growth. When you come in on Monday morning, everything's cooled down. And you start to run that cell, and it warms up and warms up, but that size really stays stable. So, that's been a big change.

David Fischer:

Okuma also introduced our PREX motors, which are on our milling motors, and most of our spindle motors, which is a magnetic segment-switching motor instead of a coil-switching motor. Very, very efficient. So, the motor can produce the same output but be smaller. So therefore, you've got less issues with balance. You can accel and decel faster because your moment of inertia is less because the rotor is smaller. So really, when you have motors in a confined space, that really makes a difference. It also generates less heat.

David Fischer:

So again, going back to that whole thermal stability question, now we're putting less heat into the system through our motors.

Wade Anderson:

I think that's a big talking point, I know I've touched on mills a lot. That's an easy thing for me to talk through, like a GENOS M560, for an example. But on the lathes as well, we spend a lot of time engineering out all the heat sources that we can. So, talk a little bit about the plane, if you will. So, if I remember right, the LB15s, the headstocks, basically were mounted flat. But then I think your headstock and your tailstock were both flat, but then your turret was mounted at an angle. So, as things heated up, things were growing apart from each other. How does that change from then to now?

David Fischer:

Yeah. And you can see this evolution as we went. So, we had the LB15, just as you said, coolant in the casting, different planes for the different machine components. With the LB15 II coolant, we moved that out of the casting and we put everything on the same plane, so a 30-degree slant bed. And of course, the turret's mounted that way. But then we set the tailstock and the headstock mounting to be 30-degrees as well.

David Fischer:

So now, when everything grows, it's growing in the same direction. And there's nothing you can do to not have growth. I mean, heat, it's physics. Right? So, that was the LB15 II. Then we went to the LB300. Well, that's when we went to our box slant bed design. So basically, it's a two-piece design. The guide way system, along with the mounting of the tailstock and the headstock, is one casting. And it goes on Okuma's philosophy of simple shape. So, in order to make this growth that's going to happen predictable, we need the shapes to be as simple as possible, so it makes it easy to predict.

David Fischer:

So, there's no shape that you're going to use in a machine tool simpler than a cube. So, we create that guideway system, the mounting, headstock mounting, tailstock mounting. That is a cube. And then we put that on a 30-degree base to give us the chip evacuation ergonomics advantages of a slant bed lathe. So, we get the best of both worlds through that.

Wade Anderson:

So, you're basically building it like a flat bed lathe.

David Fischer:

Correct.

Wade Anderson:

And you're using the base like a sine plate to stand it up and get that 30-degree benefit that you're looking for.

David Fischer:

Yeah. And again, if you back to the old flat bed lathes, they're very thermally stable. So, we kind of reach back to the past and are using that with our current machine because that is the best solution.

Wade Anderson:

Coming from a grinding background, if you ever look at the sub-micron grinders, super precision grinders, SAACKE grinders, they make one. Strausak used to make one. But if you look at those, all the motion system of those grinders is exactly what you're talking about. It's on a rectangle separate base part, and there's isolation pads from the bed, I should say, to the base. And they do that, again, to control thermal stability and growth. And then having that closed box, you've got a very rigid system, and then everything's mounted on the same plane.

Wade Anderson:

So, I looked at that, when I first started working at Okuma, coming from a grinder background. As soon as I saw that LB, the first thing that popped in my head is, "Wow, they're building this just like these sub-micron grinders," separating motion system from a platform that the largest piece of cast iron has a lot of angles and cutouts and areas for chip conveyors and things like that. It's more prone to the environment than the actual motion system. So yeah, very interesting.

Wade Anderson:

So, let's spend a little bit of time. I'd really like to know more about technologies that Okuma's got on their turning centers that maybe people don't hear enough about or know enough about. So, whether it's standard stuff on the control or just optional content that exists that people should be aware of. So, I'm going to kind of lob some out there and have you kind of step me through some of it.

Wade Anderson:

So, let's start a big one, and I might've touched on this on a previous podcast a year or so ago, but I led a tour at Japan many years ago. We went to the headquarters in Oguchi. In an auditorium, I asked how many people in the audience have Okuma lathes. Like 80% of everybody in the audience raised their hand. And I said, "Okay. Out of everybody that has Okuma lathes, how many know about harmonic spindle speed control?" And like all but two hands went down. And I thought, "Wow."

Wade Anderson:

That was a little bit of an eye-opener for me that, out of an audience this big, only two people in the crowd even knew what harmonic spindle speed control was. So, step me through a little bit on what harmonic spindle speed control is, if it's standard, and things like that.

David Fischer:

Yeah. And that really is surprising because it is a standard feature. So obviously, we need to get the word out there better. So, what harmonic spindle speed control is, it's a function that will help you manage chatter, vibration in the machine. So, a lot of your chatter is created by harmonic build up in the part. So, you first start cutting, and you're fine. But then those harmonics build. And they amplify each other. Right? And then you get chatter. You get vibration, you get chatter.

David Fischer:

So, what harmonic spindle speed control does is let us pick a variation in RPM by a percentage. I mean, typically, when I use it, I start off at 30%. That just seems to be a good base number to start with for me. And then you have the period of variation. So, how quickly do you want that RPM to change? And then there is a third option to let you plateau at the top and bottom of that RPM.

David Fischer:

So, what happens, and we do that basically to minimize striping because you are changing the RPM. So, you are changing the cutting conditions. And when you do that, it can create a change in your surface finish.

David Fischer:

So, what we do is, rather than come up to that peak RPM and then down instantly, we plateau there and then come down off of that. That helps minimize any kind of striping that you might get because of that.

David Fischer:

But it's entirely programmable. Once you come up with the numbers that work well for a given part, you can put those parameters in the program. The next time you run that part, you're all set to go. No need to adjust it. You're off and running. So, we can go to a longer length to diameter ratio when we're turning parts than we could without that feature.

Wade Anderson:

Okay. And that's one of the things that I saw it used most on is for that case exactly is length to diameter ratio. In a perfect world, you want the perfect setup, and you want everything correct where you wouldn't have the ability to induce chatter. Reality, though, is there's times where there’s geometries, you just, you have to do it. You have to get a length to diameter ratio beyond what you would want or is recommended. And this is a tool that can help assist you through some of those kinds of challenges.

David Fischer:

Without having to go to the added expense of a steady rest. And that introduces issues as well.

Wade Anderson:

Yep. Okay. How 'bout torque skip?

David Fischer:

Yeah. Torque skip, again, it's another feature that's standard on linear axes on Okuma machines. We can measure the load on our axes. So, with torque skip, it's typically thought of as when we're passing off a part from main to sub-spindle. We bring the sub-spindle up. We want to put some pressure on this part, make sure it's seated. We monitor that. We have the pressure we want to go to. It comes up, touches the part, goes to that load, and then it knows to go to the next step, which is typically clamp with the sub-spindle and clamp with the main spindle, go back, and you're off and running.

David Fischer:

But we can use it in far more creative ways than that. For example, we had a part where we were introducing sawed-off billets to the machine. And I would just say that they were less than precise. So, we had some variation in length. We were doing a center drill in the end, and we had to make sure that we had a proper center drill. So, we wanted enough taper for the center. We didn't want to get up on the barrel of the center drill, or we would lose contact with that taper. So, we had to find that end.

David Fischer:

So basically, we came in with the turret. We had a dummy tool just to push on that part. And we used torque skip. So, we came up, moved in, touched that part, went to our pre-set load. We knew we had the end of the part, captured that value. So now we knew the C position. And then, we could set our center drill to drill the proper depth.

David Fischer:

We could also use it to make sure they didn't load the improper part, too long, too short. Or if the person doing the cutting, if they mis-cut a part and got it too long or too short, it would alarm out. No sense going into production on a part that's going to be scrap or needed to be modified. So, a lot of different ways to use it.

David Fischer:

We also have an option available for C-axis torque. And C-axis is our spindle. So, we've actually used that to find a feature on a part. So, if you have a machine that has milling, we can go in there, find where a boss is, without having to use a gauging system, so casting.

Wade Anderson:

Right. Kind of clock the part...

David Fischer:

Right. Right. Yeah. It's not like we have to be within a thou, but we need to know where that boss is. We can check both sides, do a stock divide, come in there, and hit that boss right in the middle.

Wade Anderson:

Okay. And you touched on it, but some of the operations that you would do with a gauging cycle using a part probe, things like that, if you've got a machine that doesn't have gauging or a part probe, you can actually use torque skip to kind of get creative and find some of those features that way.

David Fischer:

Right. Right. And like I said, C-axis is an option, but everything else is standard. So, it's on the machine; make use of it.

Wade Anderson:

Yeah. So, tell me a little bit about peck turning. I know this is something you did some testing on recently on one of our LUs in the Partners building. Talk me through kind of what that process is. And where would it be beneficial for customers?

David Fischer:

Yeah. So, peck turning is a fairly new function. And it's primarily for dealing with stringy materials. We have customers that really struggle to get some of their difficult to machine materials under control for automation. And then, of course, any customer that works with plastic, that's build-in stringers, right?

Wade Anderson:

Right.

David Fischer:

Yeah. So, what this does is this lets me set a given amount of feed and then a given amount of dwell. So, I could set the feed in 50 thou and then dwell for... Typically, if I'm cutting steel or anything like a metal, I don't want to dwell on that surface for too long. So, I want to actually get back into the cut before I've done a full revolution. So, I can set that time delay, the dwell, to allow me to do that. So, I'm going to move in 50 thou, I'm going to dwell three-quarters of a revolution, and then I'm going to move 50 thou.

David Fischer:

Typically, from what I've seen, that's enough to break the chip of anything short of plastic. Plastic, you don't really care if it's sitting on the part so much, so you can let that dwell go a little longer. Make sure you break that chip, but...

David Fischer:

Yeah. For example, I had a part I was cutting. When I didn't use step feed function, that chip did not break from the start of that cut to the end. I was cutting about 175 millimeters, I think. My chip was 60 meters long.

Wade Anderson:

Wow.

David Fischer:

Right? So, we just ended up with this wad of chips around the part, around the chuck. And you had to dig your way out. So, we added this function, and we set it to a two-millimeter step. We kind of played around with two, 1.5. So, we ended up with a chip that was basically half a meter long, which still is pretty long chip. But it's a spiral. So, it kind of surprised me it was a half a meter long when I stretched it out. But it created an environment where the chips did not wrap around the part. The main thing. Right?

David Fischer:

We used two millimeters. We occasionally would get one that would hang up, a single chip. And I'm like, "Okay, if we're doing a manual load operation, the operator can just knock that chip off. No big deal." If we're doing auto load, we'd probably go more like 1.5 millimeters, which we didn't have any chip wrap at that point.

David Fischer:

So, you can play around with the parameters. Again, you can put it in the program. So, once you've come up with what works, save it in the program, you're done. That's good for the future.

Wade Anderson:

So, you just recall it through a G-code?

David Fischer:

Oh, no, no, no. It's basically, the program, it's a line in the code. When you hit cycle start, it'll load those parameters for that function, and it'll cut that way. That's one of the powers of our OSP that's really amazing. All these parameters, these functions, you just load them in the program once you have everything figured out. And then from then on out, it's just plug in the program, and off you go.

Wade Anderson:

Yeah. All right. What about, help me on the term, Z-W Overlap Function?

David Fischer:

Yeah. Yeah.

Wade Anderson:

Okay.

David Fischer:

So, this is a function... I mean, it's used on a sub-spindle machine.

Wade Anderson:

Right. Which, for us, is our W-axis.

David Fischer:

Correct. Correct. So obviously, you've got one turret. You've got two spindles. So, you're cutting on one side. You finish there, then you typically would go over and cut on the other side or transfer the part to the other side. With Z-W Overlap Function, it allows us to have a tool in both directions and program both spindles, and the turret will adjust for that.

David Fischer:

For instance, if we're drilling main and sub-spindle, and maybe I'm feeding it 12 thou on the main spindle, and I'm feeding it ten thou on the sub-spindle. Well, the turret's going to move in at 12 thou on the main spindle. The sub-spindle is going to move in at 22 thou because it's got to comp for the 12 thou that the turret's moving for the main spindle and then do the ten thou feed. So quite often, or most often, that's going to be used for ID work, drills, that type of thing, because we've only got one X-axis.

David Fischer:

But I have seen it used in high production situations. Sub-spindle machine was actually on our GENOS product. They used a double turning tool. And they used the offset to control one, and then they had an adjustment on the sub-spindle side. So, they had symmetrical parts. Both ends had the same features: drill, tap, turn, and chamfer. And they had this special adjustable turning tool. They turned and chamfered the OD at the same time. They drilled at the same time. They tapped at the same time. They're done.

Wade Anderson:

Wow.

David Fischer:

So yeah, very high production, very efficient use of their machine.

Wade Anderson:

That's a great way to reduce a lot of cycle time on your part.

David Fischer:

Yeah. Yeah. Definitely.

Wade Anderson:

Okay. So, on twin turret machines, so like an LU or an LT, talk through some of the functions on how you can basically mirror between two turrets.

David Fischer:

Yeah. So, something that's unique to Okuma for multi-spindle, multi-turret machines is we program everything as if it's upper turret, left spindle. And then we use G13, G14, to flip it upper to lower, and G140, G141, to go main to sub-spindle. So, it's really nice in that, if you decide to reprocess the part, you programmed it for the upper turret, now you want to do that machining from the lower turret, you don't have to reprogram it at all, change your radiuses or anything like that. You just put a G14 in front of it, and now it's running on the lower turret. So, it makes it very easy to handle.

David Fischer:

Also, my years of experience, I've always thought of Z negative, into the part; Z positive, moving clear of the part. In our process, that's true no matter what spindle you're on. So, any time I see a Z negative, I'm thinking into the part. So, very nice feature that way.

David Fischer:

And then with multiple turrets, we can run independent, or we can run synchronized. So, for our LT, we have two turrets, two spindles. I may have one turret on each spindle for most of the time, but the side that takes the longest time to produce, I may want to jump over there with both turrets for a period of time to balance my cycle time.

David Fischer:

So, we have synchronization codes. We call them P-codes. We can synchronize the program when we need to and then run independent when we don't need to. So, for things like pinch turning like we were talking about before or balance cutting, cutting with the two tools, we can sync that up perfectly, eliminate chatter, again, go to a longer length to diameter ratio.

Wade Anderson:

Okay. So, one last one, AB synchronization. Tell us what that is.

David Fischer:

That's basically a mirroring function. So, you can program the upper turret and then tell the lower turret to do what the upper turret's doing. My favorite example for this is grooving. If I have four grooves to cut a part, I'm going to program two of them for the upper turret. I'm going to shift the lower turret off to cut between the grooves that the upper turret's doing and just tell it to mirror what the upper turret's doing.

David Fischer:

And again, the more grooves, the better. Because I'm going to program half the grooves, and the other one's just going to follow what I tell the upper turret to do. So, any changes, I make it to the upper turret and they're automatically incorporated in the lower turret. So again, it's a mirroring function. It's one of those things where you can get as creative as you want to get with it. But you'll want symmetrical features on a part, basically. When I see that, I'm thinking, "Okay, I can use this function."

Wade Anderson:

Okay. Excellent. Well, David, thank you for joining us today. I really appreciate it.

David Fischer:

Oh, my pleasure. My pleasure.

Wade Anderson:

And thank you for joining us. If you have any thoughts, ideas, questions about this podcast, or ideas for future podcasts, please feel free to reach out to me. You can find me on LinkedIn. And be sure to check out all of Okuma's social media sites for additional videos and other machine content. Until next time, we'll see you then.