Disc Cutter Undercut Insert Retention

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Solution Overview

Problem

Disk tools experience reduced service life due to asymmetrical wear and material breakouts, leading to increased transverse forces and potential complete breakage of cutting inserts during high-speed machining operations.

Innovation Solution

The design incorporates an undercut on the cutting insert's frontal contour parallel to the axis of the threaded hole, allowing for additional movement in the transverse direction, combined with a V- or U-shaped lower contour for enhanced force absorption, and the elimination of chip splitter grooves for improved chip distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional flat seating surfaces are used for cutting inserts, then the structure is simple and easy to manufacture, but asymmetrical wear and material breakouts cause increased transverse forces leading to cutting insert breakage

Engineering Contradiction:
Improvecutting insert stabilityVSAvoidseat structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by designing the seating surface with an undercut geometry that creates an asymmetric profile relative to the cutting insert base. This undercut structure, formed by the intersection of the first and second seat supports, provides asymmetric mechanical interlocking that prevents transverse movement and leveraging forces while maintaining manufacturing feasibility through standard machining operations.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent introduces a new dimensional feature by creating an undercut in the seating surface that extends below the original flat seating plane. This additional dimensional element, formed by the overlapping seat supports, provides extra mechanical constraint in the transverse direction without significantly complicating the overall seat structure, as it can be achieved through conventional machining of the seat supports.

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

2Reliability

If cutting inserts are secured with only axial fastening, then the structure is simple, but lateral forces from asymmetrical wear cause complete breakage of cutting inserts

Engineering Contradiction:
Improveresistance to lateral forcesVSAvoidfastening mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies beforehand cushioning by designing the undercut seating surface to preemptively counteract transverse forces before they can cause damage. The undercut geometry creates mechanical interference that cushions against lateral movement and leveraging forces, preventing the progression from asymmetrical wear to complete insert breakage, while requiring no additional fastening components beyond the standard axial screw.

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

3Productivity

If higher cutting speeds and feed rates are used to improve productivity, then machining efficiency increases, but asymmetrical wear and material breakouts increase transverse forces reducing tool life

Engineering Contradiction:
Improvecutting speed and feed rateVSAvoidtool service life
Core Design Contradiction:
ProductivityVSDuration of action of moving object

Solution Approach 1:

The patent applies preliminary anti-action by designing the undercut seating surface to preemptively counteract the harmful transverse forces that arise during high-speed machining. The asymmetric undercut geometry creates mechanical interference that opposes lateral movement and leveraging forces before they can accumulate and cause insert failure, thereby enabling sustained high productivity while extending tool service life.

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP3175944B1Disk tool and cutting insert therefor
Publication Date: 2020.03.18 GEBR LENNARTZ
  • EP3175944B1 patent drawingFigure 1~2
  • EP3175944B1 patent drawingFigure 3~4
  • EP3175944B1 patent drawingFigure 5~6

AI summary

The invention relates to a disc tool (1) such as a disc cutter or disc saw with a disc-shaped base body, which has a plurality of circumferentially spaced, approximately L-shaped recessed seats (10) in the region of its lateral surface (5), each with a seat support (20) arranged on one leg of the L-shaped seat (10) and a seat assembly (30) arranged on the other leg of the L-shaped seat for the positive locking reception of a respective cutting insert (50) with a cuboid or prismatic basic shape, comprising at least one cutting edge (53a, 53b) and a lower contour that interacts with at least one seat support surface (31) of the seat (10) and an end face contour that interacts with at least one seat contact surface (31) of the seat (10) for positive locking retention of the cutting insert (50) in the respective seat (10), so that cutting forces acting transversely on the cutting insert (50) are to be received from the respective seat (10),wherein the respective cutting insert (50) has a through bore (51) extending between the lower contour and an upper surface opposite it for receiving a fastening bolt (70) which is detachably screwed into an associated threaded bore (22) in the disc-shaped base body, and wherein the cutting insert (50) forms an undercut with the seat (10) in the area of ​​the seat contact surface (31) in the direction of the axis of the threaded bore (G) of the base body and parallel to the disc plane in the area of ​​the end face contour.