Variable-Flute End Mill for Chip Room and Rigidity Balance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Tapered end mills face challenges in deep cutting and rough cutting due to insufficient chip room, leading to increased cutting resistance and potential tool breakage, especially when dealing with large chips.
Innovation Solution
The end mill features cutting edges along multiple spiral flutes with a unique flute bottom design, including a linear portion, a gradient portion, and an R-shaped portion, which secures chip storage capacity, improves rigidity, and maintains a constant rake angle for enhanced cutting performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the chip room is enlarged to store and discharge large chips, then the chip discharge performance is improved, but the tool cross-sectional area decreases leading to reduced rigidity and increased breakage risk
Solution Approach 1:
The flute bottom radius is designed to vary along the axial direction: smaller at the distal end to maximize chip room for large chip discharge, and larger at the shank side to maintain tool rigidity. This local variation in geometric properties allows simultaneous optimization of chip discharge capability and structural strength.
Solution Approach 2:
The solution moves from a uniform flute bottom radius design to a three-dimensional variable radius design that changes along the axial dimension. This dimensional approach allows the tool to have different functional characteristics at different locations along its length.
2Volume of stationary object
If the gradient angle of the flute bottom is increased to improve chip room, then the chip storage capacity is improved, but the core thickness decreases reducing tool strength
Solution Approach 1:
The gradient angle of the flute bottom is locally optimized: a larger gradient angle is applied at the distal end side where chip generation occurs to maximize chip room volume, while a smaller gradient angle is applied at the shank side to maintain adequate core thickness and structural strength.
Solution Approach 2:
The flute bottom is segmented into different zones with different gradient angles along the axial direction. The distal end zone has a larger gradient for chip storage, while the shank zone has a smaller gradient for strength, creating functionally differentiated segments.
3Volume of stationary object
If the rake angle is reduced to follow the flute bottom gradient, then the chip room is maximized, but the cutting quality deteriorates and cutting resistance increases
Solution Approach 1:
The rake angle is designed to be constant along the peripheral direction of the cutting edge, independent of the flute bottom gradient. This local quality optimization ensures consistent cutting performance and low cutting resistance at the cutting zone, while the flute bottom gradient separately optimizes chip room in the discharge zone.
Solution Approach 2:
The tool geometry is segmented into independent functional zones: the flute bottom gradient controls chip room in the discharge zone, while the constant rake angle controls cutting performance at the cutting edge zone. This segmentation allows independent optimization of each function without compromise.
Data Source
AI summary
End mill is provided with outer periphery cutting edges and end cutting edges along spiral flutes. Spiral flutes include first and second flutes. Flute bottom of first flute is with linear portion, R-shaped portion, and gradient portion. The linear portion extends in parallel to axis line O and in straight-line shape, from tool distal end toward rear end side to position separated from the tool distal end by length corresponding to tool outer diameter. The gradient portion is provided to the rear end side, and is inclined straightly toward outer side in radial direction toward the rear end side. The R-shaped portion connects rear end of the linear portion and front end of the gradient portion, and is curved in circular arc shape toward the outer side in the radial direction. Rake angles of the outer periphery and end cutting edges are constant over entire periphery.