Three-Edge Cutting Head for Flat Shoulders and Chip Evacuation
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Solution Overview
Problem
Existing rotatable cutting heads with radially extending cutting edges often fail to achieve a truly rectilinear rotational profile and adequate chip evacuation, limiting their ability to efficiently drill and create flat shoulder surfaces between coaxial holes of different diameters.
Innovation Solution
A rotatable cutting head with three radially extending cutting edges, featuring a tip portion with axially forward-facing chisel edges, secondary and primary cutting-edge portions, and intermediate chip evacuation passages, configured to form a rectilinear profile and maximize chip evacuation volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional rotatable cutting heads with radially extending cutting edges are used, then drilling operations can be performed, but they fail to achieve a truly rectilinear rotational profile and adequate chip evacuation
Solution Approach 1:
The cutting head is segmented into three distinct cutting edges (first, second, and third cutting edges) spaced circumferentially around the central axis. Each cutting edge has its own cutting-edge portion that contributes to forming the rectilinear rotational profile. This segmentation allows the cutting head to achieve a true rectilinear profile while providing multiple pathways for chip evacuation, thereby resolving both the precision and productivity requirements.
2Productivity
If higher feed rates are enabled through improved cutting edge configuration, then drilling efficiency increases, but chip evacuation becomes more difficult
Solution Approach 1:
The invention introduces chip evacuation passages that extend in the axial direction through the cutting head, creating a three-dimensional chip evacuation pathway. The head flutes are configured to maximize the volume of these passages, allowing chips to be efficiently removed along the axial dimension rather than relying solely on radial evacuation. This dimensional approach enables higher feed rates while maintaining effective chip removal.
3Adaptability or versatility
If the cutting head is designed to machine flat shoulder surfaces between coaxial holes of different diameters, then versatility improves, but device complexity increases
Solution Approach 1:
The cutting head is designed with three circumferentially spaced cutting edges and head flutes that can perform multiple functions: standard drilling, shoulder surface machining between coaxial holes of different diameters, and chip evacuation. The rectilinear rotational profile created by the cutting-edge portions enables the cutting head to machine flat shoulder surfaces, while the integrated head flutes provide universal chip evacuation capability. This multi-functional design achieves versatility without proportionally increasing complexity.
Data Source
AI summary
A cutting head rotatable about a central axis, comprising a tip portion and an intermediate portion. The tip portion has an axially forwardmost tip point contained in the central axis and three axially forward facing front surfaces forming three chisel edges extending axially rearwardly away from the tip point, each front surface having a radially extending cutting edge comprising a secondary cutting-edge portion extending radially outwardly from one of the chisel edges, and a primary cutting-edge portion extending radially outwardly therefrom. Each primary cutting-edge portion is contained in an imaginary annular ring surface having an annular ring width spanning at least radially inner and outer end points thereof. In a front-end view of the cutting head, each primary cutting-edge portion is concave, and radial planes intersect the imaginary annular surface to form imaginary rectilinear lines, each having a length equal to the annular ring width.