Laser Nozzle Insulation with Ferromagnetic Presence Detection

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Solution Overview

Problem

Existing insulating parts for laser processing heads do not allow for user-friendly monitoring of their presence, leading to potential collisions between the processing head and the workpiece due to incorrect capacitive distance measurements, and are often costly to produce.

Innovation Solution

An insulating part made of a ferromagnetic material, such as iron or a nickel/cobalt/iron alloy, embedded in a ceramic or plastic body, which can be detected by a sensor to ensure the presence of the insulating part is monitored, preventing collisions and overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional insulating parts (ceramic, aluminum with coating, plastic rings) are used, then electrical insulation is achieved, but monitoring of insulating part presence becomes impossible leading to potential collisions

Engineering Contradiction:
Improvecollision preventionVSAvoidmonitoring system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A ferromagnetic body is introduced as an intermediary element within the insulating part. This mediator enables the sensor to detect the presence of the insulating part indirectly through magnetic field interaction, solving the monitoring problem without requiring direct electrical contact or complex wiring modifications.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces electrical monitoring methods with a magnetic field-based detection system. Instead of using electrical contacts or complex circuitry to detect insulating part presence, a magnetic sensor detects the ferromagnetic body, substituting a simpler mechanical/magnetic field interaction for complex electrical monitoring.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If internal capacitance monitoring is used to detect missing insulation, then collision prevention is possible, but the method fails with actively shielded measuring lines where internal capacitance is eliminated

Engineering Contradiction:
Improveinsulation monitoringVSAvoidcompatibility with different measuring methods
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The ferromagnetic body serves as a universal intermediary that works with any sensor type (capacitive, inductive, or magnetic field-based). This mediator enables detection across different measuring methodologies, making the system adaptable to various distance control technologies including actively shielded measuring lines.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the detection parameter from electrical capacitance to magnetic field interaction. By using a ferromagnetic body instead of relying on electrical capacitance changes, the system becomes compatible with different sensor types and measuring methods, including those that eliminate internal capacitance through active shielding.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If a ferromagnetic body is embedded in the insulating part, then sensor-based monitoring becomes possible, but manufacturing complexity increases

Engineering Contradiction:
Improveinsulating part monitoringVSAvoidinsulating part production
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The insulating part is segmented into two functional components: the insulating material body and the embedded ferromagnetic element. This segmentation allows each component to be manufactured separately using optimal processes, then combined through simple embedding, reducing overall manufacturing complexity while enabling sensor monitoring.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The insulating part becomes a composite structure combining insulating material with a ferromagnetic body. This composite approach enables both electrical insulation and magnetic field interaction properties, allowing sensor-based monitoring while maintaining the insulating function. The ferromagnetic body can be embedded during molding or assembly, keeping the process relatively simple.

Inventive Principle:
Principle #40Composite materials

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

This solution allows for inexpensive production and user-friendly monitoring of the insulating part, preventing damage to the laser processing head and ensuring accurate distance control, while also providing thermal protection by emitting a warning signal when the Curie temperature is exceeded.

Implementation Method 1

An insulating part, which holds an electrically conductive nozzle on a housing of a laser processing head in an insulated manner, has been proposed, which has an electrically insulating body and a ferromagnetic body

Methodology Applied
Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 2

Laser processing heads, in particular laser cutting heads, are therefore equipped with a capacitive distance sensor system for capacitively measuring the distance between the workpiece and the cutting nozzle. The distance sensor system has a conductive cutting nozzle tip as the sensor electrode, which together with the workpiece forms the measuring capacitor

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 3

an alloy with a low Curie temperature, in particular an alloy based on nickel/cobalt/iron. At temperatures below the Curie temperature, the presence of the insulating part can be detected with such a ferromagnetic body. If the temperature of the laser processing head and thus the temperature of the ferromagnetic body rises above its Curie temperature, the body can no longer be detected by a sensor

Methodology Applied
Scientific EffectCurie temperature effect: Curie Point (ferromagnetic)

Data Source

PatentEP3500393B1Insulation part for the insulated mounting of an electrically conductive nozzle and laser processing head with a sensor assembly for detecting such an insulation part
Publication Date: 2021.04.07 PRECITEC GMBH
  • EP3500393B1 patent drawingFigure 1~2

AI summary

The invention relates to an insulation part for supporting an electrically conductive nozzle in an insulated manner and to a laser machining head comprising a housing (10) through which a working laser beam path (11) is guided that exits through an electrically conductive nozzle (17) on the machining side, said nozzle being supported on an insulation part (18) held on the housing (10) and being electrically connected to a resonant circuit (24) of a distance measuring circuit (22) in order to capacitively measure distances. The aim of the invention is to allow the presence of an inexpensive insulation part (18) to be monitored in a user-friendly manner. According to the invention, this is achieved in that the insulation part (18) comprises a ferromagnetic body (26), and a sensor (27) for detecting the ferromagnetic body (26) is provided on the housing (10), said sensor being connected to a monitoring circuit (29) which outputs a warning signal in the event of a missing insulation part (18).