Milling Insert Geometry for Stable Axial Edge Positioning

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Solution Overview

Problem

Existing cutting inserts for square shoulder milling tools face challenges in achieving precise positioning within the insert seat, leading to variations in axial runout and main cutting edge position, which affect the quality of the machined workpiece.

Innovation Solution

A cutting insert design featuring specific geometric configurations, including parallel extension planes, circumferential surfaces, and strategically positioned axial relief and abutment faces, ensures exact positioning by minimizing the impact of thickness deviations on axial runout and main cutting edge position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the cutting insert uses conventional support surfaces in the insert seat, then the insert can be supported in three directions (tangential, axial, radial), but manufacturing tolerances and thickness variations cause axial position deviations and affect the quality of the machined workpiece

Engineering Contradiction:

Improveaxial position of main cutting edgeVSAvoidconsistency of positioning

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The support function is segmented into two independent systems: (1) support surfaces in the insert seat providing tangential and radial support, and (2) the flat back surface of the insert providing exclusive axial support. This segmentation isolates axial positioning from thickness variations, as the axial support no longer depends on the insert's thickness dimension.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The flat back surface acts as an intermediary element between the insert and the axial support surface in the insert seat. This intermediary surface provides a stable, thickness-independent reference for axial positioning, mediating the interaction between the insert and the tool holder to eliminate the direct dependency on thickness tolerances.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If the cutting insert thickness varies due to manufacturing tolerances, then the insert can still be mounted in the insert seat, but axial runout and main cutting edge position are affected, deteriorating the quality of the 90° wall in the workpiece

Engineering Contradiction:

Improvethickness tolerance of cutting insertVSAvoidaxial runout of cutting insert

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The axial support function is extracted from the multi-directional support surface system and assigned to a dedicated flat back surface of the insert. This extraction isolates the axial positioning function from thickness variations, allowing thickness tolerances to be relaxed without affecting axial runout, since the axial support no longer relies on the thickness dimension.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The support surface geometry is changed from an angled configuration (dependent on thickness) to a flat back surface configuration (independent of thickness). This parameter change in the support surface orientation eliminates the coupling between thickness variations and axial positioning, allowing manufacturing tolerances to be improved while maintaining precision.

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If the support surfaces in the insert seat are angled to provide multi-directional support, then the insert is stabilized in multiple directions, but the axial position becomes sensitive to thickness variations and support surface angles

Engineering Contradiction:

Improvestability of cutting insert in insert seatVSAvoidaxial position of cutting edge

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The stability function is segmented into directional components: tangential and radial stability are provided by the support surfaces in the insert seat, while axial stability is provided by the flat back surface. This segmentation allows each direction to be optimized independently, with axial stability becoming independent of thickness variations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of using a single multi-functional support surface, the solution employs a dedicated flat back surface that provides excessive axial support functionality. This partial specialization ensures that axial positioning is over-determined and insensitive to thickness variations, while other directions maintain their original support mechanisms.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS11453074B2Cutting insert and milling tool

Publication Date: 2022.09.27 SECO TOOLS AB

AI summary

A cutting insert for a milling tool is provided. A median plane extends through the cutting insert. A longitudinal plane extends perpendicularly to the median plane. In a view towards a first side surface, a first axial relief face and a first axial abutment face form part of a first surface grouping on a first side of the longitudinal plane. In a view towards a second side surface, a second axial relief face and a second axial abutment face form part of a second surface grouping on the first side of the longitudinal plane. The first axial abutment face forms a substantially flat surface. The first axial abutment face extends perpendicularly to the median plane. The second axial abutment face forms a substantially flat surface. The second axial abutment face extends perpendicularly to the median plane.