In this lesson, we'll be finding 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, let's upload and open the supplied file Circular 3D Milling. This file already contains an adaptive toolpath, and if we go to simulate, navigate to the next operation, we can see what's been created. We have a roughing operation, and now we need to finish off this geometry. So to do this, we're going to explore three of the circular type toolpaths. In the 3D section, we have a spiral, radial, and morphed spiral. We want to take a look at these and see how they can apply to this circular geometry and when we might want to use them and when we might want to avoid them. So to get started, let's go to 3D, and select spiral. For our tool, we're going to navigate to our supplied library and we want to grab tool number six, the eighth-inch ball endmill. In the geometry section, we need to select center points. So we're going to grab one of these edges which will automatically grab our center point. We'll use the silhouette type and tool containment on boundary. There are several different things that we can do inside of here such as select specific model surfaces that we want to use as well as turn on or off avoid or touch surfaces. For example, if we want to avoid this face and we only want to contain the tool within the circular area, we can use that as an option. For right now, let's leave all of these options off and go to our Passes section. In here, you'll note that there are some options to cut inside the outside. We can also go clockwise or counterclockwise. We can change this spiral mode to use spiral with circles. We also have some options to determine the inner and outer limit in the stepovers. We're going to leave everything as default right now and say "Okay" just to get a look at what this toolpath will do. Once it's created and we see the basic foundation of what this toolpath does, let's navigate to select setup one and simulate. We're going to go to the next operation and then we'll play through the spiral. As we watch this, you can see that the tool starts at the center of our part and it spirals its way around the geometry. Now, we don't have a really fine resolution set for our stepdown. So you can see there are a lot of areas, especially the more vertical sections, that are really getting omitted. This is not something that we would use for our final toolpath with its current settings, but it does help us understand the tool motion itself. I'm going to close this, and I'm going to go back, and I'm going to edit some of my settings. First, I want to go to Geometry, avoid touch surfaces, and select this bottom face, then say "Okay." Now, when the toolpath recalculates, you can see that it no longer extends past that circular face where the fillet is and it doesn't ever go out to the rest of the geometry. So this is a way to help contain where this tool is actually cutting. Let's go back in and edit it one more time. We navigate to the Passes section. Note that inside of here, we can change this spiral mode to spiral with circles. What this will do is it'll create a circle toolpath at the beginning and the end. If we zoom in, it starts out with the spiral entity and it creates a circular option at the end. If we navigate back to Passes, we can use some of the options to go clockwise if we want to, we can change to axial offset passes, which will allow us to change the direction in which it's cutting, and we can also change this stepover. I'm going to make this stepover rather small, 0.0025, and say "Okay." Now, we're going to get a really fine resolution cut. If we select Setup1 and simulate, again, going past the operation, I'm going to speed this up and I'm going to play through our spiral. So now that we've reduced that step, you can see that we're getting a much finer resolution on the overall geometry. So this looks really close to what the final shape is. You can see, as we get into the vertical walls, we're starting to see the gray underneath. If we change the stock to transparent and go to a front or a right view, you can see that we're matching the geometry of the final part. I'm going to navigate back to a home view and turn transparency off. Again, it's only going to the area which we designated to avoid which means that we're going to have a nice smooth transition between here because we've already cut this geometry in the adaptive toolpath. Now that we've seen a little bit of what spiral can do, let's take a look at our next option, and this is going to be radial. We're going to use the same ball endmill. We're going to select the same center point. Again, we're going to leave all of these options turned off for now. Same thing in the Passes section, we're going to use all of the defaults and say "Okay" just to get an idea what the toolpath does. With the default settings, we can instantly see that this takes a different approach to cutting. Let's "Control" select adaptive, and then simulate. We'll go to next operation, and we'll play through what this radial cut does. The spiral starts at the center and works its way around the geometry going down. However, the radial starts at the center and works its way vertically up and down the walls moving in a one-degree increment by default all the way around the part. If we speed this up, you can see that with these default settings, we're getting a really nice cut on the part. You can see that we're matching the geometry. You can see the gray sort of bleeding through this color. If we go back into our radial toolpath and check out the options, inside of our Passes section, you can see the angular step by default is one degree going from zero to 360. We also have the option to set inner and outer limits. We can change the minimum stepover. We can also allow it to cut both ways. We can determine whether or not it's going to be cutting up or down or both. So there are a lot of different options that we have inside of here. But the default setting of moving over one degree for the size of tool and the size of geometry that we have, works pretty well. In our Geometry section, again, we have model, which we can focus on certain areas. We also have the avoid touch. We can select this area and avoid it to keep the tool from extending past there. Once we say "Okay" and it recalculates this, you can see that the tool goes down to this area, does that small linking perimeter, and then goes back up. Using the option in here for geometry, we can extend the offset on the boundary a small amount, let's say, 0.05. We can say "Okay" allow it to recalculate. But because we've restricted it using that avoid, we're not going to be extending past that edge. So there are many other options inside of here but the majority of them deal with the angular stepover and allowing us to start at the center and work our way up and down this geometry. Now, so far, we've taken a look at these two toolpaths that are really ideal for this type of thing. There's one more that I want to talk about in the 3D dropdown. We're going to take a look at morphed spiral. The morphed spiral toolpath is really good for dealing with complex geometry that has a lot of curvature. However, there are some instances where you're going to find one toolpath is going to be much better than another. In the case of a circular part like this, using a radial or a spiral cut is going to give us a better result than using the morphed spiral. You'll notice that we're not selecting a center point for this operation. We have the same options for slope, rest machining, tool orientation model, and avoiding touch surfaces. But we're not driving this based on a center point of a circular body. In the Passes section, again, we have very different options. You'll notice that we can dictate inside the outside just like we could with radial. We have a stepover value. We can determine whether it's going clockwise or counterclockwise. We can use up-down milling. But for the most part, we have a restricted set of options that we have when we're talking about calculating spiral, for example. We're going to say "Okay" and just take a look at what these default settings will give us. So we can instantly see a slightly different approach. It's matching the external geometry which is a square and it's morphing between the square going up to the circular profile at the top. Now, on the surface of things, that might seem like a great option. However, if we "Control" select adaptive and we simulate this, we can see exactly how this is approaching the cut. It starts out with a spiral and then slowly morphs between the circular geometry out to the square geometry. With the case of this specific part, it makes a lot more sense to try a spiral or a radial toolpath because they're not morphing between a square and a circle, they're simply taking the circular geometry and they're cutting it all the way out to the edge. Now, we could come back, and we could modify the parameters to make this toolpath work a little bit better. By going into Passes, we can reduce the stepover value down to 0.0025 which is an extremely fine stepover. Then, we can say, "Okay" and we can take a look at the result. Now, we're going to get a much finer resolution or stepover but at the cost of a lot more cutting time. So if we go back to adaptive and "Control" select morphed spiral, and once again, we go to the next operation. If we play through this with the much finer resolution on the step down, we're going to get a really good result. However, we are still morphing between two shapes, a square and a circle. So ultimately, we have to plan out these toolpaths that we use based on the geometry that we're cutting. In this case, my first choice would likely be a radial toolpath rather than trying to use spiral or morphed spiral. My second option would be a spiral. Lastly, I would go to this morphed spiral. The only instance I would choose the morphed spiral, in this case, is if we had complex geometry on this part and the radial or the spiral just wasn't able to cut it. But for right now, I highly suggest as I always do that you play around with each of these toolpaths, manipulate some of their options, and just see what you can get them to do based on changing those options. Always make sure after you change something you save a new version of your file. That way you can always go back to that version if you need to. Once you're done with that, go ahead and move on to the next step.
