Finishing Stepdowns Fusion 360
Finishing Stepdowns, another parameter of the Passes tab in the 2D Contour. Using this parameter, we can add a specific number of finishing passes with a specified depth.
By entering 2 in the Finishing Stepdowns parameter and entering 1 in the Finishing Stepdown parameter, we will get:
In the NC code it will look like:
Both the NC code and the toolpaths clearly show the action of this parameter. We have several roughing passes, and then two finishing to a depth of 1 mm each.
How can we use this option?
For example, cutting parts from the stock, when we want to machine the entire part from one clamping. It is a situation when sometimes an extra allowances (eg 0.2 mm) are left on the bottom for manual breaking or cutting of parts.
We prepare the machining with a rough stepdown of 5 mm, where there is enough material to be removed in one pass and the cutting forces are quite large. And if the last pass was also 5 mm deep, it could tear the material that we left as an allowance at the bottom. Therefore, in this situation, we leave 1 mm for the finishing pass and the last pass is already 1 mm deep, where the material to be removed is much less than in previous passes, and the risk of breaking the allowance is much smaller.
Of course, we could do the whole procedure without these options in several operations, but as we’ve already mentioned, the less editing operations the better.
And this is one of the examples of using these options. A similar application may have this when machining internal contours, where the appearance of the bottom is important. In the same way, by removing a large amount of material, we risk that the bottom will be bruised. Then it is also worth applying a gentler finishing pass.