Arc-Edge End Mill for High-Feed Double-Curved Surface Machining
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Solution Overview
Problem
Existing end mills struggle to efficiently process compound curved surfaces with good finished surface properties at high feed speeds, often resulting in burr formation and surface roughness issues.
Innovation Solution
The end mill features a bottom edge with a curved convex shape and a radial edge at the corner, both in arc shapes. A region on the axis of the end mill lacks a cutting edge, reducing burr formation, and a center edge with a smaller radius is added to further suppress surface roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a cutting edge is provided at the tool center of the lens tool, then the tool can process the center region of the workpiece, but burrs are generated due to zero cutting speed at the center
Solution Approach 1:
The patent removes the cutting edge from the tool center axis region, extracting the problematic zero-cutting-speed zone from the active cutting area. This eliminates burr generation at the center while maintaining cutting functionality in the surrounding regions through the arc-shaped bottom edge and center edge configuration.
Solution Approach 2:
Instead of providing a cutting edge at the tool center (conventional approach), the patent inverts the design by creating a region without cutting portions on the axis. The cutting function is achieved through the arc-shaped edges that approach but do not contact the center axis, reversing the traditional center-cutting paradigm.
2Productivity
If the bottom edge has a large curvature radius to enable high feed speed processing, then processing time is reduced, but the vicinity of the tool center is left uncut and transfers edge shape to the finished surface
Solution Approach 1:
The bottom edge is segmented into multiple functional zones: an arc-shaped cutting portion for high-speed processing, a non-cutting region on the axis to prevent burrs, and a center edge with smaller radius to finish the center area. This segmentation allows each zone to perform its specific function optimally.
Solution Approach 2:
Different regions of the bottom edge are assigned different qualities and functions: the arc-shaped portions have large curvature for high feed speed, the center region has no cutting portion to avoid burrs, and the center edge has smaller radius for precise center finishing. Each local region is optimized for its specific purpose.
3Adaptability or versatility
If tip point control is used to process compound curved surfaces, then machining can be performed with the lens tool, but the edge shape in the vicinity of the tool center is transferred to the finished surface
Solution Approach 1:
The problematic center cutting edge that causes edge shape transfer is extracted/removed from the tool design. The center region is left uncut by the main bottom edge, preventing the transfer of tool edge geometry to the workpiece surface during tip point control operations.
Data Source
AI summary
The purpose of the present invention is to perform machining on a double-curved surface to have good finished surface characteristics while achieving high speed feeding. An end mill (2) is provided with a bottom blade (2A) formed in a curved convex and circular arc shape, and a radius blade (2B) located at the edge and formed in a circular arc shape. The bottom blade (2A) has a region where a blade part is not formed on the axis of the end mill (2), and the end mill (2) is further provided with a center blade (2C) in the region of the bottom blade (2A). The center blade (2C) is formed in a circular arc shape with a radius smaller than that of the circular arc part of the bottom blade (2A).