In this lesson, we'll be creating multiple step roughing passes. After completing this lesson, you'll be able to use 2D contour for roughing and finishing toolpaths, analyze a ramp cut versus a lead in cut, and demonstrate how to create finishing toolpaths. Let's carry on with the file from our previous example, and let's begin programming this part. The file already does contain a setup with a coordinate system. The first thing you'll notice is that the coordinate system is down here in this corner and X is pointing up and to the left. So in reality, the part needs to be in a different orientation. So I'm going to use my ViewCube to place it in this orientation. If we want to reset our home view, we can use this drop-down arrow, and we can set current view as Home, either a Fixed Distance away, or a Fit to View. This means that anytime I move it and rotate it, the Home button will now reorient my view as such. This is helpful especially in a situation where the part is maybe designed in a different orientation that we're going to program and you want to retain that home view to make it easy to snap back to a certain position. Now that we've reset our home view, let's plan out the first operation. As I mentioned in the previous lesson, we're going to start by machining the outside of the shape first. In this case, we're going to make an assumption. The assumption is that the part has already been drilled and tapped and is held from the bottom. The four holes in the large pocket are holding the part down to a fixture, which means that we can machine the entire outside contour all the way down. So what we're going to do is we're going to start with a 2D contour operation. We're going to select our tool. Again, we want to go into our supplied tool library and grab tool number 10, the half-inch flat end mill. From here, we're going to go into geometry. For contour selection, we're going to grab the bottom outside contour. Notice that the arrow is on the outside of that contour. Also notice that we have several options in here such as Rest Machining and Stock Contours. For this operation, let's go ahead and leave Stock Contours and all the other options off, and we'll come back and make adjustments if we need to. For our heights, the bottom height is the selected contour, and we're going to go ahead and use that option, but we're going to offset it just slightly minus 0.05. So that way, the tool goes down below the bottom edge. For our passes, there are several things in here we need to be aware of, the first of which is we have a Multiple Finishing Pass option, and we have a Repeat Finish Pass, which will enable a spring pass. Because we're starting with a solid block, we don't have to be too worried about spring passes because this is a relatively thick or solid piece, but we do need to be aware of maybe doing a multiple finished pass. This will allow us to come down and rough the outside, do a single finished pass and step in a small amount to ensure that we're getting a really nice finish cut. Notice that we also have some options in here for deviations. Now, these minimum cutting radius value will allow us to push the tool into certain areas a little bit deeper. Then the finishing smoothing deviation is amount of smoothing that's applied to finish passes. Right now, we're not going to be using any smoothing. The Compensation is going to be set to In Computer. The Sideways Compensation is set to Climb Cutting. So as we're taking a look at the rest of our options, we have leads on all finish passes, which means that it will do a lead in and a lead out for each of the finish passes. Notice that the number of step overs is set to two by default. We also have a Finishing Overlap. So the Finishing Overlap amount will allow us to dictate the start and stop difference. If we have this set to zero, it's going to lead in and lead out the exact same point. If there's any vibration or chatter that happens, you'll likely get a small davit into that area. So what we want to do is we want to increase this a small amount by 0.125. We also have a Lead End Distance. This will specify the distance the feed rate begins before ending the geometry. So if we look at the graphic here, you can see that the green lines starts before the end of our contour. So we're going to leave this option set to zero, but in some cases, this actually might help because it will change the feed rate before the end of the contour. It'll do this based on some other parameters that are set for the lead in and lead out feed rates. The rest of the options, we're going to go ahead and leave on. We don't want to cut both ways. We don't really have to worry about preserving the order because we're only cutting a single contour, but we do want to make sure that we turn on roughing passes. The maximum step over of 0.475 should be okay, and we want to turn on Multiple Depths. This is not an adaptive toolpath. We can't simply go all the way down and start cutting because the shape of our final part is not the same as the shape of our stock. This means that we're going to engage more material in certain areas than others. So we want to make sure that we have Multiple Depths and Multiple Roughing Passes. So we're going to start with one roughing pass, and we'll analyze whether or not that's enough. For the Multiple Depths, we have many options in here. The Maximum Roughing Stepdown by default right now is 0.039, and this is carried over from a metric conversion. For us, we're using a half-inch tool. So I'm going to allow it to stepdown a quarter inch in max. For my Finishing Stepdowns, I'm going to say one. Notice that the Finishing Stepdown amount is currently 0.007. This is a very small amount. If you'll remember, minus 0.05 is how much we're going past that bottom contour. So I'm going to set my Finish Stepdown to 0.06. This is going to allow me to stepdown past everything, all the way at the bottom of the geometry, and allow me to cut everything that's needed. In terms of some of the other options, we're only going to finish at the final depth. This will allow us to ensure that we don't have a bunch of step lines in the part, but we're going to do that final small cut at the very bottom. So this way, we're using the entire fluid of that half inch gin mill. Notice that we can rough at the final depth. We can use even stepdowns if applicable. We can order by depth, by island, by step. We can use all of these other options. These aren't going to apply because we're dealing with a single contour, but do note that we actually do have a Thin Wall option. So the Thin Wall option allows us to do several things. This allows us to think about the forces that are applied to the wall as we are machining it. This option will help by reducing the amount of vibration and chatter we see. At this point in time, because we're dealing with one solid piece of stock, we don't have to use it yet. But when we get back to finishing the upper edge, we will turn on that Thin Wall option. Lastly, we want to come into our linking parameters. We're going to leave most of these as default. However, I do want to make an adjustment to the Leads and Transitions. I'm going to increase this to 0.125. For the Linear Lead Distance, I'm going to increase this to 0.125 as well. Then the Vertical Lead-In Radius, I'm going to reduce this. I don't think this needs to be as big. I'm going to set this to 0.05. We also have a Ramp option for the contour. Right now, what we're going to be doing is leading in and leading out from the horizontal direction in X and Y. But we do have the option to ramp down along this contour. By turning this on, it will ramp down at two degrees around the part until it reaches each of those stepdowns, and then it'll continue around the part. So this is another great option to help us remove material quickly in a different way that we can engage the part. So now you can see on the screen, we have some red lines. The red lines indicate a ramp section. The blue lines indicate a feed rate section. To get an idea what this looks like, we're going to simulate it and take a look. Make sure that we turn on Stock, and I'm going to turn off the Toolpaths. I'm going to use the timeline at the bottom and simply drag my cursor. So you can see as it's going around, it's ramping down, and then it's going to come back in, and it's going to do the same thing at a finish pass. Here's my final finished pass, and we'll go ahead and play through this. So now you can see it's able to cut all the way down to the outside shape of our part. It's done this in a few different steps, but you'll notice that there are some pieces that are left behind. In order to handle this, we can make some adjustments, and we do see that there is a small warning. It says that lifting feed plane to topmost ramp and lifting retract plane to feed plane. So these are some warnings that were getting with the toolpath. So let's quickly go in and make some adjustments. We're going to take a look at the heights, and we'll do this from the back or left side. So you'll notice right now that my clearance height is pretty high. I'm going to drag this down a little bit. My retract height is pretty high. So we can set the retract height, which is currently from stock top. We can set that down a bit farther by selecting it and moving it down or entering a manual value. Then we have the blue plane, which is our feed plane, which is currently against it to top height. That's 0.1 above right now. Then we have the top of stock, which is set based on our stock setting. Then the bottom height is our selected contour. One of the things we are getting is this vertical lift issue right here. But if we turn off Leads and Transitions, then we'll be using only our ramp setting. We can adjust these if we need to. For example, we can increase the Vertical Lead-In if we need to, or we could make sure that the Lead-In is perpendicular, and adjust some of these settings to see if we can actually get a result that doesn't produce an issue. So what I want to do is I'm going to take the Horizontal Lead-In values back down. Now that I've seen the toolpath, I think that we can adjust these values back to the smaller amount, and I can set the Vertical Lead-In Radius back to 05 as well and give that a try. So now the toolpath has been recalculated. There are still some issues. So navigate back to home view. It is still giving me some warnings about the lifting feed plane. But one thing you'll notice is that these feature flags are telling us that there was a warning, there was a problem with lifting to the feed plane or the retract plane, and what it did was it made an adjustment to go to the safest distance that it could. So it's telling me that in certain cases where it's in this case going up over the part, that it had to lift to a different plane. Otherwise, it was going to intersect with my stock. That warning isn't going to keep me from using this toolpath or posting this code to a machine, but it does give you an idea as to some of the issues that we are seeing. Another way potentially around this is to again make another edit, going into linking perimeters, and turning the ramp off, which means that the tool is going to come down external to the part. Then it'll use that Lead-In and Lead-Out. By using just this option, we are now getting away from the issue that we're having from lifting up and going back to the start of that ramp position. There's a lot more to do on this part, but this is a great time for us to go ahead and save the file before moving on to the next step.
