Thread Cutting Insert with Multi-Level Protrusions for Chip Control
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Solution Overview
Problem
Existing thread cutting inserts struggle to reliably curl and control the discharge direction of cutting chips, especially in the posterior cycles of radial infeed, leading to chattering vibrations and accuracy issues due to excessive cutting resistance and thin chip handling challenges.
Innovation Solution
A thread cutting insert design featuring main cutting edges with wiper thread cutting edges and a specific arrangement of convex protrusions on the rake face, where the first and second convex protrusions are positioned closer to the main cutting edge than the third, allowing for controlled chip curling and discharge without increasing cutting resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If convex protrusions are provided on the rake face to curl thick cutting chips in anterior cycles, then chip handling is improved, but the extremely thin cutting chips in posterior cycles fly out without resistance and extend uncontrollably
Solution Approach 1:
The rake face is segmented into multiple zones with different convex protrusions (first, second, and third convex protrusions) arranged at different positions and heights. This segmentation allows each zone to handle chips of different thicknesses appropriately, with lower protrusions handling thicker chips and higher protrusions controlling thinner chips in posterior cycles.
Solution Approach 2:
Different regions of the rake face are given different local properties through the varied convex protrusions. The first convex protrusions are positioned closer to the cutting edge with lower height for initial chip engagement, while the third convex protrusions are positioned farther away with higher height for final chip curling and discharge control, creating locally optimized chip handling zones.
2Manufacturing precision
If the cutting amount increases gradually in radial infeed method, then thread formation accuracy is improved, but cutting chip thickness varies extremely from thick in anterior cycles to extremely thin in posterior cycles
Solution Approach 1:
The chip breaking mechanism is made dynamic through the multi-level convex protrusions that adapt to varying chip thicknesses during the cutting process. As cutting progresses and chip thickness decreases, the chip interacts with progressively higher convex protrusions, providing continuous adaptation to the changing chip conditions throughout the multiple cutting cycles.
Solution Approach 2:
The convex protrusions are pre-positioned on the rake face to provide preliminary chip engagement and curling action. The first and second convex protrusions prepare the chip by initial curling in anterior cycles, while the third convex protrusions are positioned to control the final chip discharge in posterior cycles, anticipating the varying chip thickness conditions before they fully develop.
3Reliability
If first and second convex protrusions are positioned closer to the main cutting edge, then chip curling control is improved, but the structure complexity increases
Solution Approach 1:
Multiple chip control functions are merged into a single integrated convex protrusion structure on the rake face. The first, second, and third convex protrusions work together as a unified chip breaking and discharge control system, combining chip curling, thickness control, and discharge direction management in one structural element rather than separate mechanisms.
Solution Approach 2:
The convex protrusions serve multiple functions simultaneously: they act as chip breakers for thick chips in anterior cycles, provide progressive chip curling control as cutting progresses, and manage chip discharge direction in posterior cycles. This multi-functionality reduces the need for separate chip handling mechanisms, offsetting the structural complexity with functional integration.
Data Source
AI summary
A thread cutting insert includes main cutting edges that have a pair of thread cutting edges and wiper thread cutting edges for full profile on side edges of a rake face formed on the insert body respectively. The pair of thread cutting edges is formed in a convex V shape as viewed in a plane facing the rake face, and the wiper thread cutting edges for full profile are connected to posterior ends of the thread cutting edges. An inner portion of a V-shaped projection of the rake face, which is formed on the front side of the wiper thread cutting edge for full profile by the pair of thread cutting edges, is formed not to protrude from the thread cutting edges as viewed in the plane. A first convex protrusion projecting from the rake face, a second convex protrusion higher than the first convex protrusion, and the third convex protrusion higher than the first and second convex protrusions project on the rear side of the wiper thread cutting edge for full profile of the rake face as viewed in the plane, and the first and second convex protrusions are positioned closer to the main cutting edge than the third convex protrusions.