In this lesson, we'll find strengths and weaknesses in circular finishing toolpaths. After completing this lesson, you'll be able to create finishing toolpaths for circular geometry and analyze the strength and weakness of different toolpaths. To get started with this lesson, we wannaopen the supply dataset circular 3D milling. The first thing that we want to do is take a look at the adaptive operation that's in the file. It's using a large end mill and it's removing the majority of the material and this is getting us close to the point where we can actually finish the part. This is a circular or revolved part, so it's a good idea for us to explore some of the circular 3D options that we have to see what can be done on this part. And what are some of the things that we need to look out for when we're trying to plan these different tool paths. So we're going to be looking at a spiral, a radial and a morphed spiral. And to get started, we're going to go to our 3D drop down and we want to select 3D spiral. Remember that if you have tool tips turned on in your user preferences, you'll get a good idea of what these are going to do. So when we come into our user preferences on that first general page we have show tool tips turned on, we're going to say, OK. And this way if we hover over one of these options, such as spiral, you can get a preview and better understanding of what that toolpath is doing. Because these can be kind of distracting in videos, I often turn them off, but if you want to have that turned on, make sure that you go into your user preferences and make sure that show tool tips is turned on. For us, the first thing that we want to do is select the proper tool. So inside of our machining three access tools, we're going to select the 8th inch ball end mill. Once we have this selected, we can go to our geometry. The circular toolpaths are going to require a center point. This will allow us to select a circular edge, for example, this edge on the part, and it will automatically select the center point. From there, we can use the machining boundaries such as the Bounding Box, the Silhouette or the selection. We're going to be using the Silhouette in this case with the tools centered on the boundary. Also note that we do have the Avoid Touch Surfaces option that we saw with our 3D contour. We could use this to focus our attention just on certain areas as well. In the heights, instead of using the model bottom I want to make sure that it doesn't go below this face here. I don't want it to try to cut the outside, especially not with a 3D type of operation. We're going to leave all the rest of the settings as default as I want to compare these three operations with all the default settings to start. So to get started, we'll say OK, and allow the spiral to be created and then we'll preview this on the screen. So we can pretty quickly see that it does a decent job for things that have either flat or low curvature. But once we get closer to the vertical walls of this part, it's really not doing a great job keeping up with the curvature. If we turn on our cutting mills and go to a side, you can see exactly where the tool is moving. It does a great job up here and down in the bottom, getting us pretty close to a final shape. But again, in those more vertical regions it's just not able to hold that. So for right now, I'm going to right click and suppress it. And then I'm going to create my next operation which is a 3D Radio. So we want to navigate to 3D Radio, we're going to be using the same tool and again we need to select the center point. We're going to be using that Silhouette tool centered on boundary and again all the rest of the default settings, with the exception of the bottom, we want to make sure it doesn't drop below that face. When we have a 3D Radio, by default, you can see it has a lot finer resolution. If we take a look at this, it's kind of hard to see and understand what's going on. So for this tool, I'm going to go to simulate to allow us to see it removing stock. As we play through, you can see that the part is starting at the top and moving its way down. There are some settings that determine how far it's going to move in terms of an angular amount and how far around the part it's going to go. If we speed this up, you can see that as we go around this actually leaves a really good result. One of the downsides to this operation is just how long it takes. If we go into our machining time, you can see that right now it's about 15 minutes, which isn't really long. But some of the other operations can do this type of geometry a lot quicker, simply based on how it's moving around the part. Let's take a quick look at some of the options we have for Radio. Inside here, you see that we have an angular step of 1° by default and going from 0 to 360°. We can also set an inner and outer limit in terms of a diameter and we can also set the minimum step over. We're allowing it to cut in both directions, which means that it's going to go down the part and back up. We also can do some other options, such as turning on up milling or down milling, in this case, it's doing both. So once again, there are plenty of options that we could explore here. But let's take a look at our third operation. So let's suppress this for the time being. And now we want to go to our 3D and Morphed Spiral. Once again, we're going to use our ball end mill. Notice at this time our machining boundary doesn't have a center point selection. We're going to be using the Silhouette and I'm going to be changing, once again, the bottom height to a selection, but not adjusting anything else. Let's take a look at how this operation handles the same kind of geometry. So very quickly we can see that this is a much different approach to machining this geometry. The Morphed Spiral is taking the circular profile at the top and the square profile at the bottom and slowly blending between those two. So as it goes around, the spiral is actually moving its way out as it traverses around the part. So this is going to leave areas that are not getting machine. Are there ways in which we can improve this? Of course there are. So let's right click first and take a look at our machining time and this does this in about two minutes. So that's really quick for us to get close to that shape, but, obviously, we are not getting the resolution that we really want to see. What we could do is we could reduce the step over, in this case it's .0625, we can add an extra zero in there, making it much smaller. It's going to take a lot longer for it to calculate, but this will get us a little bit closer to that final shape. Before we do that, let's see how this affected our machining time. We went from about 2 minutes to 22 minutes. So that is a drastic change in how long it's going to take to cut the geometry. But if we play through, you can see that the result is going to be quite a bit closer to that final shape. Now, remember when we were looking at the Radio operation, the Radio gave us a really close shape in terms of the final that we were looking for in about 15 minutes. And this one gives us, again, a very similar result. It does a great job of cutting that geometry, but it takes a little bit longer at 22 minutes. So while we're looking at all of these round or circular types of operations, we have to remember that the 3D operations are model aware. So they are looking at the geometry in order to plan out where the tool is going to go. We also have to remember that every part is going to be different. The parts that we're looking at are designed to be tricky for these operations because this has large circular or curvature based areas and it also goes close to vertical. This means that certain operations are not going to do well. When we have these sort of circular operations, the Spiral and the Radio, they work really well on these types of round parts, assuming that they don't go close to vertical and then back to horizontal. That's where they really start to basically show their weakness. The Radio toolpath, in this case, is probably our best option. So if I were to machine this part, I would likely regenerate this operation and I would probably take this Morph Spiral out. And in this case, I'm just going to simply suppress it because we're getting a really good resolution based on this round part. The Morph Spiral will do better if it's not a truly round or revolved part, in this case, the part is more tailored to a Radio operation rather than that Morph Spiral. So it's always a good idea to try out these separate operations, especially with the default settings, just to see how it's going to approach your geometry. You don't have to spend hours and hours tweaking the settings to get a good idea of what it's going to do before you put in that time trying to figure out if it's a good fit. There are other ways in which we could approach a part like this. For example, we might use a circular toolpath just on the top and then we might approach this bottom section differently. But again, every geometry is a little bit different, and for us, let's go ahead and make sure that we save this, and then we can move on to the next step.