End Mill With Varying Flute Depth For Chip Discharge
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Solution Overview
Problem
End mills face challenges in balancing chip discharge efficiency with maintaining rigidity, often resulting in breakage at the proximal end due to reduced core thickness for larger chip discharging flutes, and require enhanced breaking resistance and chip discharge properties.
Innovation Solution
The end mill design features chip discharging flutes with equal core thickness and varying flute depths, along with gashes and planar rake surfaces, to guide chips effectively while maintaining structural integrity, and includes asymmetrical cutting edges to reduce resonance and improve chip discharge efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chip discharging flutes are made larger to improve chip discharge efficiency, then chip discharge property is enhanced, but core thickness of end mill body decreases leading to reduced rigidity and increased breakage risk
Solution Approach 1:
The patent applies local quality by varying the depth of chip discharging flutes along the axial direction. The flute depth is greater at the front end (cutting edge side) and gradually decreases toward the rear end (proximal end side). This localized variation allows larger flute openings at the front for effective chip discharge while maintaining sufficient core thickness at the rear for structural strength, thereby resolving the contradiction between chip discharge efficiency and breaking resistance.
2Productivity
If chip discharging flutes are made larger to enhance chip discharge property, then chip flow is improved, but rigidity of end mill body is lowered causing deflection and reduced cutting accuracy
Solution Approach 1:
The patent implements local quality through progressive flute depth reduction from front to rear. The deeper flutes at the front end facilitate smooth chip flow and discharge, while the shallower flutes toward the rear maintain body rigidity and minimize deflection during cutting operations, thus preserving cutting accuracy while ensuring effective chip discharge.
3Manufacturing precision
If core thickness is increased to improve rigidity and suppress deflection, then cutting accuracy is maintained, but chip discharge capability is reduced
Solution Approach 1:
The patent resolves this contradiction by applying local quality through spatially varying flute depths. The front portion of the end mill features deeper flutes that prioritize chip discharge capability, while the rear portion maintains larger core thickness for rigidity and cutting accuracy. This localized differentiation allows both chip discharge efficiency and cutting precision to be optimized simultaneously.
4Ease of manufacture
If uniform flute depth is used throughout the end mill body, then manufacturing is simplified, but breaking resistance at proximal end is reduced due to insufficient core thickness
Solution Approach 1:
The patent applies local quality by specifying different flute depths at different axial positions. The flute depth is gradually reduced from the front end toward the rear end, creating varying core thicknesses along the axis. This approach prioritizes breaking resistance at the proximal end where it is most critical, while still maintaining reasonable chip discharge capability at the cutting end, accepting increased manufacturing complexity as a necessary trade-off for improved reliability.
Data Source
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AI summary
There is provided an end mill which exhibits favorable chip discharging property and favorable chipping resistance of an end cutting edge even under a working condition where a lot of chips is discharged. An end mill 10 includes end cutting edges 2 located at a front end side of an end mill body 1 including rotation axis O, peripheral cutting edges 5 and helically extending chip discharging flutes 7. Each of a plurality of the peripheral cutting edges 5 and each of a plurality of the chip discharging flutes 7 are alternately located from the front end side to a side of the proximal end portion, and a distance (ta, tb) between a deepest position p of the chip discharging flute 7 and the rotation axis O is set equal among the respective chip discharging flutes in a cross section taken along the rotation axis O of the end mill body 1. The chip discharging flute 7 includes a first region 20 which is located at the side of the peripheral cutting edge 5 and includes the deepest position p, a second region 21 which is located at a side of a heel 3, and a boundary 22. A distance uc from the rotation axis O to the boundary 22c located at the side of the proximal end portion is set larger than a distance ua from the rotation axis O to the boundary 22a disposed on the front end side.