2D Adaptive Clearing – Adaptive machining
2D Adaptive Clearing, this strategy can be found under the name adaptive machining or adaptive milling. What do we mean by that? In short and in simplification, it is a machining strategy that prepares the tool path more optimized, avoiding sudden changes in the cutting direction and, above all, adapting to the shape of the machined geometry. This strategy allows you to obtain a smooth and smooth tool path and makes sure that the tool is not too heavily loaded.
To select this strategy from the 2D menu, choose 2D Adaptive Clearing.
The first tab – Tab, looks standard. Let’s choose a 12 mm cutter here.
In the Geometry tab, select the contour of the pocket.
If you check the bottom contour of the pocket, make sure that the Selected contour (s) option is selected in the Heights tab in the Bottom Height section of the From parameter.
Let’s go to the Passes tab.
As you can see, there are not many new parameters here compared to the standard pocket processing. In fact, we only have two new parameters – Optimal Load and Use Slot Clearing.
The Optimal Load parameter determines the degree of tool engagement in machining. Compared to the usual pocket processing, the tool is loaded unevenly. All the time he is working with a certain step to the side. If, for example, a longer straight section is machined, the situation is not bad, but as soon as the cutting direction changes, the tool can be heavily loaded.
The following example has a standard pocket processing. Even with added roundings in the corners.
The situation when changing the cutting direction from the X axis to the Y axis is not ideal. Despite the small cutting step (1/3 of the diameter) the tool in these places will be more loaded than in places where machining is carried out along one axis.
In the figure below, we have shown a fragment of the simulation of machining a standard 2D pocket pocket operation. The tool moves along the X axis. As for the load, it is OK.
But what happens when you change the cutting direction, for cutting along the Y axis?
It is clearly visible that at this point the tool is more involved in machining and we have a sudden, temporary stroke of the tool load. This is not beneficial. In such places the tool uses up more quickly. Often when machining on a machine tool, we can clearly hear the moments in which the cutting direction changes. It should give us food for thought.
The situation is different when using the Adaptive Clearing 2d strategy. Here, the tool will be loaded the same throughout the entire machining. According to the value entered in the Optimal Load parameter. We determine what part of the diameter will be involved in the machining. If the cutting direction changes, the tool path will be properly prepared to maintain the load and not exceed it. This method of machining allows you to increase the feed rate and increase the depth of one pass. Increasing the depth will contribute to better use of the tool. With proper implementation of such a strategy, we can use the full working length of the blade.
Looking at the tool path itself, we see a huge difference compared to standard pocket machining. In places where there is a lot of space, the tool works with a fixed step of transition. In the corners, where it is tight, the transition step is smaller so as to maintain a constant load on the tool. In addition, we do not have abrupt changes in the cutting direction here. The tool path is smooth and all transitions are smooth. After the simulation, you can clearly see how the material is removed.
By carrying out the machining with the same parameters that we used to process the pockets using the 2D Pocket operation, the 2D Adaptive Clearing will be longer. But the 2D Adaptive Clearing strategy will allow you to use higher feed rates and a greater depth of one pass. It is worth to check it experimentally. The starting point can be the parameters that we use in standard pocket processing, and then we can slowly raise them.
I would start by increasing the machining depth to the full working length of the tool, and I would reduce the step to the side, e.g. up to 0.2 mm, and increase the feed and speed slowly. Then I would slowly step up to the side.
Another parameter, distinguishing 2D Adaptive Clearing from the 2D Pocket machining, is the Use Slot Clearing parameter. This parameter can be used when processing long and narrow pockets or simply grooves (which we can deduce from the parameter name). Using this parameter, the material from the center of the pocket will be removed first, and then the path will be generated along the outer contour.
This is how the pocket processing works using 2D Pocket strategy.
This is the tool path in the Adaptive Clearing 2D strategy.
It’s better and after a few attempts we could get a really good result when it comes to machining time and tool wear.
A below the 2D Adaptive Clearing strategy using the Use Slot Clearing option.
As before, after several attempts we can achieve really good results.
When the Use Slot Clearing option is selected, the Slot Clearing Width parameter will appear, which is responsible for the width of the groove, which will be machined in the first place, before the tool will process the remaining areas.
2D Adaptive Clearing (and its counterparts in other CAM systems) were created on the basis of trochoidal milling. This method was created already in the 80’s, but only the possibilities of computers and CAM systems allow to draw the most benefits from this method of milling. In short, this can be summarized as follows: we reduce the cutting width (step to side – ae) while simultaneously (often significantly) increasing the depth of cut (ap) and feed.