Thread-Milling Insert Radial Axial Positioning Rigidity

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Solution Overview

Problem

Thread-milling cutters with small diameters face challenges in achieving high rigidity due to the need for precise positioning of inserts, which often results in weakened tool holders and reduced accuracy.

Innovation Solution

A thread-milling insert with a longitudinal cutting edge and a tool holder featuring a pocket with two positioning planes and a protrusion on the abutment surface, allowing for stable radial and axial positioning, enhanced by clamping elements and a design that minimizes holder weakening, thereby increasing rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional positioning methods with multiple recesses and screws are used to achieve high positioning accuracy, then manufacturing precision is improved, but device complexity increases and holder rigidity decreases

Engineering Contradiction:
Improveinsert positioning accuracyVSAvoidpocket structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The positioning function is segmented into two independent components: radial positioning handled by positioning planes on the abutment surface, and axial positioning handled by the protrusion geometry. This segmentation allows each component to be optimized independently, reducing overall complexity while maintaining high positioning accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extracts the positioning function from the traditional screw-and-recess system and implements it through geometric features (positioning planes and protrusion) that are integral to the insert and pocket structure. This eliminates the need for separate positioning screws and complex recess geometries, reducing device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

2Manufacturing precision

If deep pockets are provided in the tool holder for insert reception, then insert positioning accuracy is improved, but holder rigidity deteriorates

Engineering Contradiction:
Improveinsert positioning accuracyVSAvoidholder rigidity
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The invention transitions from deep axial pockets to shallow pockets by utilizing the lateral dimension of the abutment surface for positioning. The positioning planes and protrusion create precise positioning in a lateral configuration rather than requiring deep axial engagement, thereby maintaining holder rigidity while achieving accurate positioning.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The positioning planes and protrusion are pre-configured on the insert and pocket during manufacturing to establish precise positioning geometry. This preliminary geometric configuration eliminates the need for deep pockets during operation, as the positioning is already established through the pre-formed abutment surface features.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If multiple clamping elements are used to secure the insert, then reliability of insert fixation is improved, but device complexity increases

Engineering Contradiction:
Improveinsert fixation stabilityVSAvoidclamping mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the positioning and clamping functions into a unified geometric system. The positioning planes provide radial positioning while the protrusion provides axial positioning, and the same geometric features also serve as reference surfaces for clamping elements. This merging reduces the number of separate components and simplifies the overall clamping mechanism while maintaining fixation reliability.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2420340B1Thread-milling insert and thread-milling cutter
Publication Date: 2014.04.16 VARGUS LTD
  • EP2420340B1 patent drawingFigure 1~2
  • EP2420340B1 patent drawingFigure 3~5
  • EP2420340B1 patent drawingFigure 6~7

AI summary

The invention relates to a thread-milling cutter comprising a tool holder (2) and at least one cutting insert (3) with a longitudinal cutting edge (30) mounted thereon, the tool holder (2) comprising at least one pocket (20) extending essentially in an axial direction (A) and adapted for receiving the at least one insert (3), and the cutting insert (3) having at least one positioning plane (31) on a first abutment surface of the insert (3) opposite the cutting edge (30) for a radial positioning of the insert (3) in the respective pocket (20), wherein at least one protrusion (32) is provided on the abutment surface, a side surface (320) of the protrusion (32) being oriented at an angle (α) to the axial direction (A) of the cutter (1) and adapted for contacting a surface (22) of the pocket (20) for an axial positioning of the insert (3). The invention further relates to an insert for a thread-milling cutter.