In this lesson, we'll talk about rest machining. After completing this lesson, you'll be able to analyze different approaches to machining a pocket, modify tool path parameters, and identify the most efficient tool path option. At this point in our course, we've already created several rest machining operations, but we haven't really taken the time to understand rest machining and really why we'd want to apply it. In general, we really are looking for a handful of things when we talk about machining parts. Depending on your industry of course these will change, but in general, we want to figure out how to machine parts as quickly as possible. We don't want to sacrifice things like surface quality or tolerances, and we want to minimize the amount of wear on our tools. Because of these reasons, it makes the most sense to use our adaptive tool paths whenever possible into use rest machining operations. So that way we can utilize larger tools to remove the most amount of material quickly, and use this smaller tools to come back and take smaller chunks. So let's take a look at this file, open and closed 2D rest machining and understand the three different strategies that we could use when we're machining this part. Now, this example has a pocket in the center that has some smaller regions in the corners which means that we can't come in with a large tool and get into those corners, and we really need to use a smaller tool to finish it off. We also have a couple open pockets on the outside. So in this file, we have three setups. Setup 1 contains a 2D adaptive roughing operation with a half-inch end mill. Then we come back and do some rest machining with a smaller end mill, and finally a 2D contour to finish off all of the pockets opened and closed. In Setup 2, we have a very similar strategy. However, instead of using a larger end mill and then coming back and doing rest machining, we simply use that adaptive tool path with a single smaller tool that's small enough to get into all the corners. Then we come back of course with a 2D contour to simply clean up all the outside perimeters of all of our pockets. Then the last option, Setup 3. We're using a traditional 2D pocket. When you have a traditional 2D pocket operation, this means that were not traditionally looking at keeping a consistent chip load on the part, but were really following the outside shape or the profile of our pocket. This means that we often have areas where we're engaging a large amount of material or a large section of our tool specifically when we go into and out of corners. This means that we have sections where we have a spike in the load on the tool, and then we have a smaller section where we're not engaging in those corners. Because of this, we have to be careful with how much we cut with our tool. So traditionally, you'll see these pocket operations take smaller depth cuts or multiple depths rather than going to a full depth for a pocket and having full engagement among tool. So in this style, we have a 2D pocket then we still have rest machining, but the rest machining again as following the multiple depth strategy as well as the multiple step ends based on the shape of our pocket then finally a 2D contour. So all three of these strategies are fairly similar in nature but taking a look at the adaptive tool paths as well as using adaptive rest machining, we're really going to start to understand the benefits. So the first thing I want to do to get started and I'm going to select "Setup 3". I'll activate it. But then I'm going to simulate this. So I simply want to start playing it, and you can speed it up if you want to. But I want to take a look at this strategy that's used here. So the tool has a small helical entry, then it starts to move around and again matching the shape of our pockets whether it's open or closed. It is able to enter the open pockets from the outside so it does have a good strategy there. However, again, as we get into and out of these corners, were engaging large amount of material which means that we're going to see the loads on the tool spike as well as the wear. Then it's going to ultimately come back and it'll do that contour toolpath to do the finishing cuts on everything. Now, the last operation in all three of these the 2D contour is going to be the same across the board. We're doing a single finishing cut on all of our pockets, so there's really no difference in that operations specifically. So what we're really going to focus on here is going to be the difference between our 2D pocket and rest pocket operations, and then our adaptive in our adaptive rest. So with this setup, Setup 3, if we go to statistics, we can see that the total machining time is about 26 minutes. It's machining distance is approximately 500 inches. There are three operations into tool changes. If we activate Setup 2, this has got the least number of operations. This has two operations. We're looking at an adaptive with a smaller end mill, and then we're taking a look at the contour again using that same smaller end mill. So if we take a look at the way that this is going to approach it. Again, it's using that adaptive motion which is keeping that consistent load on the tool. The load is something that we program into the tool path so we can dictate how much material is getting taken out of each cut. But you can see the strategy here is taking a full depth cut and it's moving in keeping that load or the amount of engagement on that tool consistent. Then it comes back and it does our 2D contour to finish. If we take a look at the statistics here, you can see that this is machining time about 10 minutes, and the machining distance is 230 inches. Now, if you remember the pocket operation, the traditional 2D pocket was about 500 inches of machining distance. This is because it had to handle multiple depths. So we're going to close this, and we're going to take a look at Setup 1 now, and again we want to select "Setup 1" then go into "Simulate", and we're going to play through this. So by far, this one is starting with the largest end mill. It has a half-inch end mill, and you can see the helical entry is actually able to take out quite a bit of material just by entering the part. Then again, using this adaptive tool path, it's taking inconsistent chip load on the tool. As much as it can clear out what the end mill, it's going to work back into each corner as far as it can go. It'll wrap it over, and then it'll go to the outside of the open pockets. It will clear them out relatively quickly, and then it'll make it tool change. You can see there are some issues in the tool path. We have some red sections where we're engaging material, and what's happening is there's a small amount of material that's left by in these original operations which simply means that we need to do a little bit more work in terms of setting up these operations, and we'll talk more about that when we actually get into the setup. But what we want to take a look at is the approach to this tool path. It's taking the large end mill and It's coming back with the smaller end mill to get the areas where it couldn't reach. Then ultimately, it's ending up with that contour operation that all of them were ending with. If we take a look at the statistics, you can see that the machining time is just over seven minutes, and the machining distance is a 190 inches. So we were able to reduce the amount of machining distance because we started out with that larger end mill. We're also able to reduce the machining time by three minutes. Three minutes might not seem like a lot but when we're talking about the difference between seven minutes and 10 minutes, that's a 30 percent difference. Also, considering that traditional 2D pocket was around 26 minutes, we've dropped almost 20 minutes off the machining time. So this is a drastic change when we're machining these parts. Again, there are more things that we can do here. We can edit the tool paths to increase the efficiency, may be increased the chip load based on the actual tool that we have, and again there are multiple things that we can do, increase the RPM and the feed rate et cetera. But the main thing that we want to understand we want to focus on is really just the main difference in the programming, the machining time, the amount of feed distance that we're seeing between very similar operations. The adaptive rough and the adaptive rest versus the single adaptive tool path with the smaller end mill. That alone even though we're increasing the number of tools we're using or introducing a tool change in there, we're actually reducing the overall time by quite a bit. Then if we take a look at this versus a traditional 2D pockets style operation, well, we're really dropping a whole lot of time here for relatively simple part. So just keep this in mind as we start to program, and we start to utilize these rest machining operations even on these fairly simple parts where we're talking about 2D or 2.5D stout machining, it can make a drastic difference in how many parts you can cut it an hour, and how quickly you can remove that material. So from here, I urge you to go into each of these tool paths and just simply edit some of the parameters. For example, if we come into the adaptive roughing toolpath and we edit this, we can come into the passes and the stock to leave and we can reduce this to 0.01. This will allow that half-inch end mill to cut a little bit more material out, and maybe reduce the amount of time that we have when we come back with that adaptive rest tool path. When we take a look at the adaptive rest, we can come in and modify the parameters for rest machining. For example, we could increase or decrease the diameter of the tool that was used to create. In this case, if we increase that to 0.55 and 0.30, this is telling it that it's leaving a little bit more materials. So this smaller end mill that comes back is actually going to remove just a bit more material. So maybe we won't have this small areas that are left behind by that first operation. So a lot of different things that we can do here, and again I really urge you to just play around with these because there's no penalty to playing around and validating this digitally. Once you're done with that, make sure that you go ahead and save your file, and then move on to the next step.
