Now, let's put all that together, into a mill/turn center. We have a lathe, we have a mill, all on one machine. To program these new machines, we have to have the flexibility to toggle between turning and milling seamlessly and efficiently. We have to be table to turn with non-axisymmetric parts, so it's not enough to just have a 2-D profile of the part anymore. Just as in the multi-axis milling, you have to have complete tool axis control, simulation, and gouge checking. So it's really putting all of the previous technology and control into one machine.

So let's take a look at some of those mill/turn techniques. We will go back to our top level assembly, maybe drill down and look at the drivetrain, as there are several parts in here that might fit. One would be this gray part here, a bearing housing. Let's open that model up. As you can see, it is made out of a casting, and you could make this on a mill, but with all of those bearing seats and ID work required, a lathe would be a better way to make this part. Unfortunately, we have these drilled holes on the outside, so that means you are going to have to have 2 setups and go over to a mill. Instead, let's use a mill/turn center.

First I need to face off this front area, and I really have an option. I can do this as a face turning operation, but if my machine can handle it I could also hit it with a face mill cutter. You can see I have a lot more options now with a mill/turn center. In this case I turn down the outside, then choose a couple of ID tools to turn down the inside areas. If I can get at all of them from one side, that's the best of all worlds with only one setup.

I have finished my ID turning, but since I am on a mill/turn center, now I can choose to do some drilling. I'll simply choose my Œ" drill and perform a pecking operation, and now, all in one operation, I have turned the part and milled it completely. That is the sort of flexibility that a mill/turn center gives you, so your manufacturing system needs to be able to support that. You shouldn't have to make up 2 tapes, and you certainly shouldn't have to go to 2 systems to program the different aspects of your machine. You should be able to look at the operation inside of the programming system and in a full simulation as well, maybe with a couple of views such as an ISO view and a turned view. We can see the OD cut, the ID cut, and finally we drill the holes.

Let's move up in complexity a bit. Here is another part we put on to a mill/turn center. We start out with OD work, so let me zoom in here for a better view. As we look at it in a traditional view in the ZX plane, look what it does here as it gets down to the bottom. You will see that it looks like it is leaving an area. Why is it doing that? The answer is, if I roll this part around, sure enough we have a cam lobe over here. That is exactly the way I want my system to work - I want it to look at this part in 360, not just take a cross-section. It needs to be able to see that geometry and automatically adjust the turning operations to cut appropriately. Now I can cut here on the back side with more of a groove tool to clean out that area, and that just leaves the mill features I have to machine. Since I am on a mill/turn, I simply select a flat end mill and walk around that cam lobe. Maybe I'll choose a couple of passes in the profile direction with a radial lead in and lead out, and now I have milled out that part. Again, that is the sort of flexibility and control that I need.

Now we will put all of that together, as this is the type of part made for a mill/turn center. Considering the number of setups you have to make using traditional machines, some of these parts you just might not even bid on. But now you can, if you have a manufacturing system that can handle this sort of mill/turn operation. Here we will again start with some OD work and then face it down, traditional turning but again looking at the true turn profile of the part. Following the groove operation, I have the part turned down, so now I will move to a ball end mill and in this case perform a 5-axis swarf cut. We will rough out each of those cavities, and that is exactly the work you want to see. You need the flexibility while still maintaining that level of tool control that you have to have for any sort of multi-axis machining.