Alternating Helix End Mill for CFRP Burr Suppression
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Solution Overview
Problem
Existing end mills used for cutting fiber-reinforced composite materials, such as carbon fiber-reinforced plastics, suffer from short tool life due to burr formation and work chatter, especially when machining large workpieces, leading to increased processing costs and reduced quality.
Innovation Solution
An end mill design featuring first cutting edges with a positive helix angle and second cutting edges with a negative helix angle, arranged alternately in the circumferential direction, with distinct phase angles and helix angles, ensures continuous engagement and counteracting cutting forces to prevent burr formation and reduce chattering, thereby enhancing tool life and machining quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If an end mill with high-hardness coating (e.g., diamond coating) is used to increase tool life, then the abrasion resistance is improved, but burrs still occur in CFRP machining and the tool life remains short
Solution Approach 1:
The cutting edges are segmented into right-handed helical cutting edges and left-handed helical cutting edges that are disposed alternately in the circumferential direction. This segmentation allows different cutting edges to handle different portions of the workpiece thickness, with each type directing cutting forces toward the center to suppress burr formation while maintaining continuous cutting action for extended tool life.
Solution Approach 2:
The invention employs asymmetric helical cutting edges with opposite handedness (right-handed and left-handed) arranged alternately. This asymmetry creates complementary cutting actions where the different helical directions produce cutting forces that both engage the material effectively and direct forces toward the workpiece center, preventing burr formation while maintaining cutting edge integrity and extending tool life.
2Volume of moving object
If large workpieces are machined with limited fixing points, then the workpiece size capability is improved, but work chatter occurs and damages tool edges, shortening tool life
Solution Approach 1:
The cutting edges are divided into multiple segments with alternating helical directions, allowing the cutting forces to be distributed and directed toward the workpiece center. This segmentation stabilizes the cutting process on large workpieces with limited fixing points, reducing work chatter and preventing tool edge damage, thereby extending tool life.
3Manufacturing precision
If the upper portion and lower portion of the region to be machined are cut separately with right-handed and left-handed helical cutting edges in a stepped arrangement, then burr suppression is attempted, but the burr suppression is insufficient
Solution Approach 1:
The invention merges the functions of right-handed and left-handed helical cutting edges into a single circumferential arrangement where both types are disposed alternately along the same cylindrical surface. This merging allows simultaneous engagement of both cutting edge types with the workpiece, creating complementary cutting actions that effectively suppress burrs while maintaining a relatively simple tool structure compared to stepped arrangements.
Data Source
AI summary
An end mill includes first cutting edges which spiral in a direction defining a positive helix angle and second cutting edges which spiral in a direction defining a negative helix angle, the first cutting edges and the second cutting edges being disposed at positions shifted in a circumferential direction. The first cutting edges and the second cutting edges are each configured to be continuous over an effective cutting edge length. At an axially forward end of the end mill, a first phase angle between one of the first cutting edges and its adjacent second cutting edge located adjacent to the first cutting edges in an opposite direction to a tool rotation direction is set to be different from a second phase angle between the second cutting edge and its adjacent first cutting edge located adjacent to the second cutting edges in the opposite direction to the tool rotation direction.