Cutting Insert Contact Circuit for Precise Edge Position Detection

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Solution Overview

Problem

Current methods for determining the contact between a cutting tool and an electrically conductive workpiece are inaccurate, leading to high risks of incorrect determinations and reduced quality of machined workpieces, especially in complex cutting processes where frequent tool changes are necessary.

Innovation Solution

A system comprising a cutting tool with electrically conductive inserts insulated from the toolholder, connected through an electrical circuit with resistors and a power source, allowing for precise measurement of electrical voltage to determine contact with the workpiece, enabling accurate identification of individual cutting edges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If electrical contact detection is used to determine cutting edge position, then measurement speed is improved, but measurement precision deteriorates due to high risk of incorrect determinations

Engineering Contradiction:
Improvetime for determining cutting edge positionVSAvoidaccuracy of cutting edge position determination
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The system divides the cutting tool into multiple independently detectable cutting inserts (n ≥ 2), each equipped with its own electrical connection unit and resistor. By insulating each cutting insert from the toolholder and providing individual electrical connections, the system can identify which specific insert contacts the workpiece, thereby improving measurement precision while maintaining fast detection speed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each cutting insert is given unique local electrical properties through individual resistors (R1, R2, ..., Rn) with different resistance values or individual connection paths. This allows the system to locally identify which specific insert is in contact with the workpiece by measuring voltage across each individual resistor, resolving the ambiguity of traditional contact detection and improving measurement accuracy.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If individual electrical connection units with resistors are used for each cutting insert, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveaccuracy of contact detectionVSAvoidcomplexity of electrical circuit
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system merges all individual electrical connection units and resistors into a single parallel electrical circuit connected to one power source. This allows individual detection of each cutting insert's contact status while sharing common components (power source, measurement system), thereby improving precision without proportionally increasing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The parallel electrical circuit configuration serves multiple functions simultaneously: it provides individual electrical connection for each cutting insert, enables independent voltage measurement across each resistor, and allows identification of which specific insert contacts the workpiece. This multi-functionality reduces the need for separate detection systems for each insert, managing device complexity.

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

3Measurement precision

If cutting inserts are electrically insulated from the toolholder, then measurement precision is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improveaccuracy of electrical contact measurementVSAvoidease of assembling cutting inserts
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The system introduces electrical insulating material layers as intermediaries between the cutting inserts and the conductive toolholder. These insulating layers (e.g., plastic or ceramic coatings) prevent unwanted electrical contact while allowing mechanical mounting, thereby maintaining measurement precision without significantly complicating the assembly process since the insulating material can be applied as a coating or integrated into the insert structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system provides highly accurate determination of cutting edge positions, reducing the risk of incorrect calibrations and improving the quality of machined workpieces by ensuring precise contact detection and wear monitoring of cutting inserts.

Implementation Method 1

the measuring unit is configured to measure an electrical voltage over each of the first connection units

Methodology Applied
Scientific EffectElectrical voltage measurement: Ohm's Law

Implementation Method 2

When a cutting insert mounted in the toolholder comes in contact with an electrically conductive workpiece, the electric power source, the first connection unit, the cutting insert, the electrically conductive workpiece and the second connection unit forms a closed electrical circuit, which results in an electrical current flowing through the circuit

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4159368B1A system and a method for determining contact between a cutting tool and an electrically conductive workpiece
Publication Date: 2024.05.29 SECO TOOLS AB
  • EP4159368B1 patent drawingFigure 1~2
  • EP4159368B1 patent drawingFigure 3

AI summary

The invention relates to a system for determining contact between a cutting tool (10) and an electrically conductive workpiece (20). The cutting tool (10) comprises a toolholder (11) and n cutting inserts (12,13,14,15) mounted in the toolholder (11), wherein n is an integer ≥ 2, wherein each of the n cutting inserts (12,13,14,15) comprises an electrically conductive surface layer. Each of the n cutting inserts (12,13,14,15) are electrically insulated from the toolholder (11). The system further comprises an electric power source (31) and each of the n cutting inserts (12,13,14,15) are connected in parallel to a first pole (48) of the electric power source (31) via a respective first connection unit (32,33,34,35) comprising a resistor (44,45,46,47). The system further comprises a second connection unit (49) connected to a second pole of the electric power source (31). The second connection unit (49) being configured to be electrically connected to an electrically conductive workpiece (20). The system further comprises a measuring unit (60) being operatively connected to an analysis unit (70). The measuring unit (60) is configured to measure an electrical voltage (UR44,UR45,UR46,UR47) over each of the first connection units (32,33,34,35), and the analysis unit (70) is configured to determine a contact between the cutting tool (10) and an electrically conductive workpiece (20) based on the measured electrical voltages (UR44,UR45,UR46,UR47). The invention also relates to a method for determining contact between a cutting tool (10) and an electrically conductive workpiece (20).