Curved End Mill Gash Geometry for Chip Discharge
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Solution Overview
Problem
End mills with linear cutting edges face issues with chip retention and twining, as chips are prone to be retained in the gash and are difficult to discharge, leading to increased cutting resistance and potential tool breakage.
Innovation Solution
The end mill features a tool body with a helical flute and a concavely curved cutting edge, where the cutting face is formed as a recessed curved surface, guiding chips spirally towards the center and facilitating easy discharge, while the gash angle and helix angle are optimized to reduce chip twining and enhance rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a linear end cutting edge is used, then the structure is simple and easy to manufacture, but chips are retained in the gash and difficult to discharge, leading to chip twining
Solution Approach 1:
The end cutting edge is formed with a concave curvature instead of a linear shape. The gash is recessed from the outer circumferential side toward the axis line, creating a curved cutting face that guides chips away from the gash and prevents retention and twining
Solution Approach 2:
The gash is recessed in the axial direction from the outer circumferential side toward the axis line, adding a dimensional component to the chip discharge path. This axial recess creates a curved surface that directs chips toward the helical flute for efficient discharge
2Object-generated harmful factors
If a concavely curved end cutting edge is used, then chip discharge is facilitated and twining is suppressed, but the rigidity of the end mill may be reduced
Solution Approach 1:
The recessed amount m is controlled within specific limits (m ≤ 0.05D where D is the tool body diameter) to balance chip discharge performance with structural rigidity. The gash angle β is also optimized (20° ≤ β ≤ 65°) to achieve both effective chip guidance and sufficient structural strength
3Object-generated harmful factors
If the gash is recessed deeply toward the axis line, then chip discharge is improved, but the cutting edge length is reduced and rigidity decreases
Solution Approach 1:
The recessed amount m is limited to m ≤ 0.05D to ensure that the gash provides effective chip discharge guidance without excessively reducing the cutting edge length or compromising the rigidity of the tool body
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design allows for efficient chip discharge, reduces twining, and enhances the durability and rigidity of the end mill, ensuring effective cutting and minimizing the risk of tool breakage.
Implementation Method 1
chips can be spirally produced so as to guide the chips toward the center side of the curved surface
Implementation Method 2
a helical flute recessed in a rim of the tool body in such a manner that the helical flute is twisted around the axis line
Data Source
AI summary
An end mill that facilitates discharge of chips and enables twining of chips to be suppressed is provided. An end mill (10) includes a tool body, a helical flute, an end cutting edge, a flank, and a gash. The gash forms a cutting face of the end cutting edge. The cutting face is formed as a recessed curved surface and the end cutting edge comprised of a ridge between the cutting face and the flank is concavely curved.