Compensation Radius Allowance reference

Compensation Radius Allowance can serve 2 functions. If you use Compensation Type - In Control, this allowance can give you a variance to make small adjustments to the tool size, at the control. Compensation Allowance can also be used to create a small arc in the corner, when your tool radius matches the corner radius. This will eliminate burying the tool in the corner and creating chatter. So the corner will have additional stock left after the cut. This may not be acceptable or may require an additional cut with a smaller tool.

This feature provides more flexibility in production since the CNC operator is free to choose between different sizes of tools. However, since most CNC controls have limited NC block look-ahead capabilities and usually fail if the contour curvature exceeds the curvature of the used tool; the CAM software is required to make sure that these problems cannot occur for arbitrarily selected geometry.

Due to the limited NC block look-ahead, the CNC control has no way to ensure that the compensated cutter locations will not gouge another section of the original contour.

Fusion solves these problems by introducing the Compensation Radius Allowance setting on the Passes tab.

This parameter specifies a range of tool diameters that can be safely used instead of only the tool selected for the operation. The allowed range of tool radii start from the selected tool radius and goes up to the selected tool radius plus the given allowance.

Observe that sharp corners in the selected geometry are rounded by this allowance. Therefore, the parameter should not be set higher than necessary. However, the rounding is not always undesired since the machine can maintain a higher feed at these corners.

This parameter will give slightly different results compared to other CAM systems for simple examples, but it also guarantees that the CNC control can run the generated toolpath for arbitrarily complex geometry.

2D Contour from sketch with control compensation. The Red path is with no compensation radius allowance. The Green path is with a small compensation radius allowance. The Blue path is with a large compensation radius allowance.