Ball Endmill With Variable Gash Width For Chip Discharge
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Solution Overview
Problem
The existing ball end mills with alternating long and short radial cutting edges face a challenge in maintaining chip discharge performance without compromising the strength of cutting edges, particularly at intersections with the axis, where the thickness of the end mill body is reduced, leading to potential damage.
Innovation Solution
A ball end mill design with long and short cutting edges alternately formed, where the gash of the long cutting edge is wider than that of the short cutting edge in the circumferential direction, ensuring a sufficient chip discharge volume without notching the front end flank, thus maintaining the strength of the cutting edges by maintaining the thickness of the end mill body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the notch surface is spread to ensure a larger volume of pocket for chip discharge, then chip discharge performance is improved, but the thickness of the back metal is reduced, leading to reduced strength of cutting edges
Solution Approach 1:
The patent applies local quality by making the gash width vary along the cutting edge. Specifically, the gash width is larger at the front end side and smaller at the rear end side, creating different local characteristics: the wider front portion ensures adequate chip discharge volume, while the narrower rear portion maintains sufficient back metal thickness and cutting edge strength. This gradient design allows each local region to optimize for its specific function.
Solution Approach 2:
The patent changes the geometric parameter of the gash width along the length of the cutting edge. By gradually reducing the gash width from the front end toward the rear end, the design transitions from a uniform width configuration to a variable width configuration. This parameter change enables the front portion to provide adequate chip discharge volume while the rear portion maintains structural integrity and cutting edge strength.
2Productivity
If the gash of long cutting edge is made wider to ensure chip discharge volume, then chip discharge performance is improved, but the thickness of end mill body is reduced, leading to potential damage to cutting edges
Solution Approach 1:
The patent applies local quality by creating different gash width characteristics at different locations along the cutting edge. The front end side has a wider gash to ensure adequate chip discharge volume, while the rear end side has a narrower gash to maintain sufficient back metal thickness. This local differentiation allows the front portion to optimize for chip discharge while the rear portion optimizes for structural strength and damage resistance.
Solution Approach 2:
The patent changes the gash width parameter along the length of the cutting edge, creating a gradient from wider at the front to narrower at the rear. This parameter change enables the front portion to provide adequate chip discharge volume while the rear portion maintains sufficient material thickness for structural integrity and resistance to damage during high-feed machining operations.
Data Source
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AI summary
A ball end mill, which includes long and short cutting edges alternately formed, obtains excellent chip discharge performance without sacrificing the strength of cutting edges, particularly, at front end portions of the long cutting edges of an end mill body that intersects with the axis. An even number of cutting edges 7 are formed at intervals in a circumferential direction on a front end portion of an end mill body 1 rotated about an axis O and of which rotation trajectories formed around the axis O form the shape of a hemisphere. The cutting edges 7, which are adjacent to each other in the circumferential direction with one cutting edge interposed therebetween, are long cutting edges 7A that intersect with each other on the axis 0 on the front end portion of the end mill body 1, and the other cutting edges 7, which are adjacent to each other in the circumferential direction with one cutting edge interposed therebetween, are short cutting edges 7B that include inner peripheral ends at positions distant from the axis O. A gash 6A of the long cutting edge 7A and a gash 6B of the short cutting edge 7B, which is adjacent to the long cutting edge in an end mill rotation direction T, connect with each other on a front end side of the end mill body 1. The gash 6A of the long cutting edge 7A is wider than the gash 6B of the short cutting edge 7B in the circumferential direction on at least the front end side of the end mill body 1.