How to improve the surface finish with NX CAM

NX CAM QuickTip | Get your surface finish as smooth as possible

Heinrich Flaum | 11/29/2022

In today's Quick Tip, we're going to look at the topic of surface finish. Usually, we want our finished workpiece to be as smooth as possible. However, it happens that the surface on the finished workpiece is much rougher and more faceted than it first appeared in Siemens NX. Therefore, today we will show you how to get from a multi-faceted or rough surface to a smooth surface.

In our example workpiece, the necessary settings have already been made and the toolpaths are defined. So, where does the faceting come from, which in the end is the basis for the surface quality of our workpiece?

The faceting on our workpiece depends on the length of each individual linear toolpath, which we can display with the so-called end points. An end point indicates the end of each tool motion. The more end points on the tool paths, the better the surface finish.

Displaying the end points

In the first step, we display the end points of our tool paths. To do this, we go to "More" and then to "End Point". However, the end points that are now displayed are still too far apart for us to get a satisfying result of the surface finish. How can we change this distance from end point to end point?

NX CAM Tutorial: Smooth vs. Rough Surface

Change the inner tolerance?

We go into the settings of our operation.

Many NX users think that they can influence the point distribution by setting the inner tolerance (in the tab: Method & Tolerance). But this is only partly true. As in our example, we don't get any fundamental better results, even if we reduce the value significantly.

Change maximum step value

Instead, we go to the "Strategy" tab and change the value at "Max. step value". This value specifies the maximum of each individual tool path length. Or in practical terms: this value reduces the distance from one end point to the next end point.

We'll try this out right away by changing the value from 30% to 5% tool diameter. We regenerate the operation.

There we go: our endpoints are now much closer to each other. We now have to zoom in really far to be able to recognize the individual end points or the lines between those points.

Endpoints are much closer to each other now

Since the end points are now much closer together and the individual paths of the tool to the next end point are much shorter, we thus get a much smoother surface on our finished workpiece.

Take another look at this QuickTip in practice.

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