Cutting Path Compensation for Offset Blade Curved Machining

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Solution Overview

Problem

Existing methods for machining thin sheets of soft materials using numerically controlled machine tools result in undesirable drifts of the cutting tool edge, leading to discrepancies between the predetermined cutting path and the actual cut, particularly for cutting tools where the cutting edge is spaced apart from the tool holder's operational axis.

Innovation Solution

A method for determining a cutting path that maintains correspondence between the cutting path performed by the cutting edge and the tool centre, involving the use of a processing unit to calculate and adjust the cutting path based on the curvature of the curvilinear segment and the spacing value between the cutting end and the operational axis, ensuring the cutting end follows the predefined path.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the tool centre follows the predetermined cutting path, then the tool positioning is simplified, but the cutting edge drifts from the intended path causing tears and cuts

Engineering Contradiction:
Improvetool positioningVSAvoidcutting path accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The system pre-calculates and stores a correspondence table between tool centre positions and cutting edge positions before machining begins. This preliminary action allows the control system to automatically compensate for the offset during machining, ensuring the cutting edge follows the predetermined path while the tool centre moves along a calculated compensatory path.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary computational layer (the control unit with correspondence table) that mediates between the simple tool centre positioning and the precise cutting edge trajectory. This intermediary calculates and stores the relationship between tool centre and cutting edge positions, enabling automatic compensation without complex real-time calculations during machining.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the cutting edge is spaced apart from the tool holder's operational axis, then cutting performance is improved, but path accuracy deteriorates due to drift

Engineering Contradiction:
Improvecutting performanceVSAvoidpath accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system changes the positional parameters by pre-calculating and storing the correspondence between tool centre positions and cutting edge positions in a lookup table. This parameter transformation allows the system to maintain a fixed offset (improving cutting performance) while compensating for the resulting drift through pre-computed position adjustments (maintaining path accuracy).

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4462206B1Method for determining a cutting path and associated processing unit
Publication Date: 2026.01.28 SCM GRP
  • EP4462206B1 patent drawingFigure 1
  • EP4462206B1 patent drawingFigure 2
  • EP4462206B1 patent drawingFigure 3~4b

AI summary

The present invention relates to a method (100) for determining a cutting path for a processing unit of a machine tool (M) comprising an operator group (G) which includes a tool holder (11) that mounts a cutting tool (12), wherein said cutting tool (12) comprises an edge (122) whose cutting end (121) is spaced from an operational axis (A) of said tool holder (11), and wherein said method comprises: obtaining (101) at least a portion of a predefined cutting path (40) comprising a curvilinear segment; obtaining (102) a spacing value (L) between said cutting end (121) of the edge (122) and said operational axis (A) of the tool holder (11); and determining a cutting path (Γ) based on said spacing value (L) and the curvature of said curvilinear segment.