3D CNC Radius Correction for Mixed Face and Circumferential Milling
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Solution Overview
Problem
Current CNC milling methods cannot accurately produce desired workpieces when there are dimensional differences between the tool defined in the CAD-CAM process and the actual tool available, especially when simultaneous face and circumferential milling is required, as existing 3D radius correction techniques can only correct one machining path at a time.
Innovation Solution
A method for 3D radius correction in CNC milling that calculates a mill path with positions of the mill cutter tip, specifies surface normals for both end face and circumferential milling surfaces, and uses correction vectors to adjust the milling tool orientation, allowing simultaneous face and circumferential milling with dimensional differences between the original and available tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If 3D radius correction is applied for face milling or circumferential milling separately, then the desired surface can be generated with accurate dimensions, but simultaneous face and circumferential milling cannot be performed accurately with one programmed mill path
Solution Approach 1:
The patent merges separate 3D radius correction methods for face milling (CUT3DF) and circumferential milling (CUT3DC) into a unified correction approach. The machine tool controller now applies both face milling correction vectors and circumferential milling correction vectors simultaneously to a single mill path, enabling accurate simultaneous face and circumferential milling without requiring separate programming or machining steps.
2Manufacturing precision
If a milling tool with specific dimensions is defined in CAD-CAM but a different tool is available on the machine, then the workpiece cannot be manufactured true to size or requires compromising accuracy, but replacing the tool is not always possible
Solution Approach 1:
The system dynamically adjusts milling path parameters based on the actual tool dimensions. When a tool with different dimensions than specified in CAD-CAM is available, the controller calculates correction vectors that compensate for the dimensional differences. This allows the workpiece to be manufactured true to size using the available tool without compromising accuracy, effectively decoupling tool selection from dimensional accuracy.
3Manufacturing precision
If individual 3D radius correction is performed for each machining path, then accurate surfaces can be produced, but the machining process becomes more complex and time-consuming
Solution Approach 1:
The patent combines multiple correction calculations into a single unified correction process. Instead of performing separate 3D radius corrections for face milling and circumferential milling on separate mill paths, the system calculates and applies both correction vectors simultaneously to one mill path, reducing the number of machining passes and overall processing time while maintaining surface quality.
Solution Approach 2:
The unified correction approach allows continuous machining of both face and circumferential surfaces in a single uninterrupted mill path execution. The controller continuously applies both face milling and circumferential milling correction vectors throughout the entire machining operation, eliminating the need to stop, reprogram, or switch between separate machining operations.
Data Source
AI summary
In a method for 3D radius correction in CNC milling, a mill path of an original milling tool producing a surface contour on a workpiece is calculated for an original milling tool based on dimensions of the mill cutter tip, with the positions of the mill cutter tip specified by an NC program. A surface normal of an end face milling surface and a surface normal of a circumferential milling surface are then specified, for each position of the mill cutter tip taking into account dimensional differences between an actually available milling tool and the original milling tool. By specifying along the mill path a spatial orientation of the milling tool axis, a correction vector is specified from the milling tool orientation, dimensional differences and the surface normals, and the workpiece is machined by traversing the mill path with the actual milling tool under consideration of the correction vector.