Bent-Curve Indexable Cutting Insert for Twist-Free Turning
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Solution Overview
Problem
The challenge in the technical field of turning is to manufacture indexable cutting inserts that can efficiently produce twist-free rotationally symmetrical surfaces using a cost-effective method, as existing methods with helical blades face difficulties in integrating indexable cutting inserts due to their helical shape.
Innovation Solution
An indexable cutting insert with a generally parallelogram-shaped flank face and two-fold rotational symmetry, featuring first and second cutting edges shaped as portions of bent curves, allowing for efficient manufacturing and use in a turning device with a cutting insert holder that ensures a twist-free surface by tilting the cutting insert relative to the workpiece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a helical blade is used to manufacture twist-free rotationally symmetrical surfaces, then the surface quality is improved, but the ability to use indexable cutting inserts is compromised
Solution Approach 1:
The helical blade is segmented into discrete indexable cutting inserts with bent curve cutting edges. Each insert represents a segment of the helical path, allowing the blade to be divided into replaceable units while maintaining the helical cutting action required for twist-free surfaces.
Solution Approach 2:
The cutting edge geometry is changed from a traditional straight or simple curved form to a specific bent curve shape. This parameter change in the cutting edge geometry allows the indexable insert to replicate the helical blade's surface generation capability while maintaining the benefits of indexability.
2Manufacturing precision
If a complex helical blade geometry is used to produce twist-free surfaces, then the surface quality is improved, but the manufacturing cost and complexity increase
Solution Approach 1:
By segmenting the helical blade into standard indexable inserts, the manufacturing of complex helical geometries is transferred to the insert fabrication process, which can be done using conventional grinding and forming techniques rather than expensive custom blade manufacturing.
Solution Approach 2:
The bent curve cutting edge geometry is designed to copy or replicate the effective cutting path of a helical blade. This allows the insert to produce the same twist-free surface quality without requiring the full complexity of a complete helical blade structure.
3Manufacturing precision
If the cutting insert has asymmetric geometry to match helical blade requirements, then the surface quality is improved, but the number of usable orientations is reduced
Solution Approach 1:
The cutting insert employs asymmetric bent curve cutting edges that are specifically shaped to generate twist-free surfaces. The asymmetric geometry is optimized for the cutting action while the insert body design ensures proper orientation during installation.
Solution Approach 2:
The indexable cutting insert is designed to perform multiple functions: it can be indexed to different positions (typically 4 positions) to provide multiple usable orientations, and each position maintains the twist-free surface generation capability through the bent curve geometry.
Data Source
Figure 1A
Figure 1B~1C
Figure 1D
AI summary
An indexable cutting insert comprises a flank face having a generally parallelogram shape and a plurality of side faces. The flank face is bounded by a plurality of edges. Each edge joins the flank face with one of the side faces. The plurality of edges comprises a first cutting edge and a second cutting edge. The first cutting edge has a shape corresponding to a portion of a first bent curve and the second cutting edge has a shape corresponding to a portion of a second bent curve. The second bent curve is obtainable by a translation of the first bent curve along a width direction of the cutting insert. The cutting insert has a two-fold rotational symmetry with respect to an axis of symmetry that is perpendicular to the width direction, a longitudinal direction of the cutting insert being perpendicular to the width direction and the axis of symmetry.