Variable-Helix End Mill Geometry for Deep Shouldering Milling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional end mills face challenges in achieving effective deep shouldering milling due to increased vibration and reduced tool life when milling high hardness materials, as they tend to bend and experience chip evacuation issues, limiting effective cutting depth to twice the diameter.
Innovation Solution
The end mill design incorporates varying radial rake angles and helix angles, with specific geometries in the front half of the cutting length to reduce vibration, compensate for structural weaknesses, and enhance chip evacuation, allowing for effective cutting depths greater than 2.5 times the diameter while maintaining good surface finish.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If end mill cutting length is increased beyond 2D, then deep shouldering milling capability is improved, but vibration increases and tool life decreases
Solution Approach 1:
The patent applies local quality by varying the radial rake angle along the cutting length - teeth in the front half have different radial rake angles than teeth in the rear half. This localized geometric variation optimizes cutting performance at different positions along the extended cutting length, enabling deep shouldering milling while controlling vibration and maintaining tool life
2Length of moving object
If end mill cutting length is increased beyond 2D, then deep shouldering milling capability is improved, but surface finish quality deteriorates
Solution Approach 1:
The patent implements local quality through position-dependent radial rake angle variation, where teeth at different axial locations have optimized geometries. This localized optimization ensures consistent surface finish quality across the entire cutting length, even when milling at depths exceeding 2D
Solution Approach 2:
The patent employs periodic action through alternating flute designs and varying radial rake angles at different tooth positions. This periodic variation in geometry helps dampen vibrations and maintains surface finish quality during deep shouldering operations
3Object-affected harmful factors
If radial rake angle is decreased in front half teeth, then vibration is reduced, but cutting edge strength may be compromised
Solution Approach 1:
The patent applies local quality by using different radial rake angles for teeth in the front half versus the rear half of the cutting length. Teeth in the front half have reduced radial rake angles to minimize vibration during initial material engagement, while maintaining sufficient cutting edge strength through optimized geometry in this specific location
4Volume of moving object
If flute depth is increased, then chip evacuation space is improved, but vibration and chip abutment increase
Solution Approach 1:
The patent implements local quality by varying flute geometry and radial rake angle at different axial positions. This localized optimization provides sufficient chip evacuation capacity in regions where chips are generated, while controlling vibration through optimized flute design and reduced radial rake angles in the front half
Data Source
AI summary
An end mill includes a plurality of teeth and flutes. The teeth and their associated flutes include one or more correlated physical parameters. One such correlated parameter is that, at an axial location in a front half of an effective cutting length, at least one tooth of the plurality of teeth has a rake angle smaller than an average rake angle value of the plurality of teeth, and, at the same axial location, a flute preceding each such tooth has a helix angle larger than an average helix angle value of the plurality of flutes.