Turning Insert Pocket Recesses for Accurate Multi-Direction Cutting

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Solution Overview

Problem

Conventional turning tools have limitations in cutting depth and accuracy, especially when turning in multiple feed directions, and are prone to insert wear and deformation, particularly when using CNC-lathes for machining complex shapes.

Innovation Solution

A turning tool design featuring a pocket with specific side support surfaces and recesses that form gaps with the circumferential side surface, allowing for greater positional accuracy and reduced deformation, enabling use in multiple feed directions with enhanced cutting depth and reduced wear, using a cemented carbide insert with convex side support surfaces and a conical coupling portion for improved stability and chip control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the turning insert is made by pressing and sintering without grinding the side contact surfaces, then manufacturing cost and time are reduced, but the insert deforms and becomes convex, reducing positioning accuracy

Engineering Contradiction:
Improvemanufacturing cost and timeVSAvoidinsert positioning accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The pocket side surfaces are designed with different geometries in different regions. The first and third pocket side surfaces have first and fourth support surfaces that contact the insert, while the second and fourth pocket side surfaces have second and third support surfaces. This local differentiation provides precise positioning contact points without requiring the entire insert side surface to be ground, thus maintaining accuracy while reducing manufacturing complexity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The support surfaces on the pocket side surfaces act as intermediaries between the rough pressed-and-sintered insert and the precise positioning requirement. These support surfaces provide the necessary contact geometry to position the insert accurately without requiring the insert itself to be precisely ground.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the distance from the cutting edge to the side support surface is increased, then chip control is improved, but the insert is prone to bending and cracking

Engineering Contradiction:
Improvechip controlVSAvoidinsert structural integrity
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The pocket side surfaces are designed with different geometries in different regions. The first and third pocket side surfaces have first and fourth support surfaces that contact the insert, while the second and fourth pocket side surfaces have second and third support surfaces. This local differentiation provides precise positioning contact points without requiring the entire insert side surface to be ground, thus maintaining accuracy while reducing manufacturing complexity.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If conventional turning tools are used for multiple feed directions, then tool versatility is limited, but using multiple tools increases complexity and reduces productivity

Engineering Contradiction:
Improvefeed direction capabilityVSAvoidmachining efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The turning insert and pocket are designed with symmetric features and specific geometries that enable the same insert to be used effectively in multiple feed directions. The support surfaces and gap configuration allow the insert to maintain proper positioning and cutting geometry whether turning in longitudinal directions or facing directions, eliminating the need for multiple specialized tools.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges the functionality of multiple specialized turning tools into a single universal turning insert. By combining the necessary support surfaces, gaps, and geometric features in one insert design, the tool can perform multiple turning operations that previously required separate tools, thus simplifying the toolset and improving productivity.

Inventive Principle:
Principle #5Merging (Combining)

4Manufacturing precision

If the pocket side surfaces contact the circumferential side surface tightly, then positioning accuracy is improved, but insert movement and deformation increase

Engineering Contradiction:
Improveinsert positional accuracyVSAvoidinsert stability
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The contact between the pocket side surfaces and the insert's circumferential side surface is segmented into discrete support surfaces and gaps rather than continuous contact. The first and third support surfaces provide positioning contact, while the gaps between them allow the insert to expand slightly without generating deforming forces, thus maintaining both accuracy and stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The gaps between the support surfaces on the pocket side surfaces and the insert's circumferential side surface act as beforehand cushioning. These gaps anticipate and accommodate thermal expansion or slight dimensional variations in the insert, preventing the development of deforming forces that would otherwise cause bending or cracking while maintaining precise positioning through the support surfaces.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP4091749A1A metal cutting turning tool
Publication Date: 2022.11.23 SANDVIK COROMANT
  • EP4091749A1 patent drawingFigure 1~2
  • EP4091749A1 patent drawingFigure 3~4
  • EP4091749A1 patent drawingFigure 5~6

AI summary

A turning tool (1) comprising a turning insert (2) and a tool body (3), the turning insert (2) comprises opposite facing top and bottom surfaces (4, 5) connected by a circumferential side surface (6), the turning tool (1) comprising a pocket (7) for the turning insert (2), the pocket (7) comprises a bottom support surface (8) and first and second pocket side surfaces (9, 10), the first and second pocket side surfaces (9, 10) forms an acute angle (Y), the first pocket side surface (9) comprises first and second side support surfaces (11, 12), in that the second pocket side surface (10) comprises third and fourth side support surfaces (13, 14), in that a first recess (15) is formed between the first and second side support surfaces (11, 12), in that a second recess (16) is formed between the third and fourth side support surfaces (13, 14), and in that each recess (15; 16) forms a gap (26, 27) between the circumferential side surface (6) and the respective pocket side surfaces (9, 10).