Cutting Insert Clamping Geometry for Precise Pre-Centering

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Solution Overview

Problem

Existing carrier tools fail to achieve a precise, form-fitting engagement between the clamping element nose and the clamping trough, leading to inaccuracies in clamping and increased risk of ceramic cutting plate damage during machining operations.

Innovation Solution

The carrier tool design features a clamping element nose with an annular contour that encloses an elevation in the clamped state, maintaining contact only with the annular surface, ensuring a pre-centered and precise fit, and utilizing a conical, catenary depression, or spherical cap-shaped ring surface to minimize contact with the cutting plate, allowing for reliable clamping of ceramic inserts without cracking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the clamping element nose contacts the elevation for clamping, then the clamping force is sufficient, but the positioning accuracy and form-fitting engagement deteriorate

Engineering Contradiction:

Improveclamping forceVSAvoidpositioning accuracy

Core Design Contradiction:

ForceVSManufacturing precision

Solution Approach 1:

The clamping element nose is segmented into two distinct functional zones: an annular contour for form-fitting engagement with the annular surface (positioning function) and an internal clamping surface for contacting the elevation (clamping function). This segmentation allows each zone to perform its specific function optimally without interfering with the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the clamping element nose have different geometric properties tailored to their specific functions. The annular contour has a specific profile matching the annular surface for precise positioning, while the internal clamping surface has a geometry optimized for applying clamping force to the elevation. This local differentiation of geometric quality enables simultaneous achievement of positioning accuracy and sufficient clamping force.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If the clamping element nose contacts the annular surface, then the positioning accuracy is sufficient, but the clamping force on the elevation is insufficient

Engineering Contradiction:

Improvepositioning accuracyVSAvoidclamping force

Core Design Contradiction:

Manufacturing precisionVSForce

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The clamping element nose merges two previously separate functions into a single integrated component: the annular contour provides positioning through engagement with the annular surface, while the internal clamping surface simultaneously provides clamping force through contact with the elevation. This merging eliminates the need for separate positioning and clamping elements.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If the clamping element nose encloses the elevation completely, then the clamping is secure, but the insert is at risk of cracking or breaking

Engineering Contradiction:

Improveclamping securityVSAvoidrisk of cracking or breaking

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The clamping element nose features a localized clamping surface that contacts only a specific region of the elevation, rather than enclosing the entire elevation. This localized contact distributes the clamping force more favorably and avoids concentrating stress at critical points that could initiate cracks in brittle ceramic materials.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The design intentionally avoids complete enclosure of the elevation, converting what might seem like a deficiency (incomplete clamping) into a benefit by preventing stress concentration and crack initiation. The partial contact approach reduces harmful stress concentrations while maintaining sufficient clamping security through optimized contact geometry.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentEP3242764B1Carrier tool

Publication Date: 2021.12.29 CERAMTEC GMBH

Figure 1~5
Figure 6~7
Figure 8~9

AI summary

The invention relates to a carrier tool (1) comprising a clamping element (2) with a clamping element projection (3) and comprising a cutting insert (4) with a clamping recess (5) on the cutting insert surface (13) for machining workpieces. The clamping recess (5) has an annular indentation (9) with a recess base (7), and the indentation (9) transitions from the recess base (7) into the cutting insert surface (13) via an annular surface (8). The indentation (9) surrounds an elevation (10), the tip (11) of which lies above the recess base (7) and below the cutting insert surface (13). The clamping element projection (3) engages into the clamping recess (5) and thus clamps same on the carrier tool (1). In order to allow a pre-centering of the contour of the clamping element projection (3) and the contour of the clamping recess (5) when closing the clamping element (2), the contours of the clamping element projection and the clamping recess thus engaging into each other in a form-fitting and precisely positioned manner, the clamping element projection (3) has an annular contour (12) which surrounds the elevation (10) in the clamped state but does not contact the elevation and rests solely on the annular surface (8).