Machining Force Profiling for Turbomachine Defect Detection

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Solution Overview

Problem

Current methods for detecting material defects in turbomachine components, such as ultrasonic testing, often fail to detect internal defects like segregations, which can lead to component failure under low cycle fatigue loads, necessitating complex and time-consuming testing processes.

Innovation Solution

A method and device that utilize force profiling during machining to detect material defects by comparing the force curve with a predetermined setpoint curve, allowing for online diagnosis and simultaneous production and testing, thereby identifying defects like segregations without destroying the component.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If ultrasonic testing is used to detect material defects, then the testing process is simple and quick, but material defects like segregations may remain undetected

Engineering Contradiction:
Improvetesting speedVSAvoiddefect detection accuracy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent replaces traditional mechanical/physical testing methods (ultrasonic testing, etching tests) with a machining-based detection system. By monitoring forces, vibrations, and acoustic emissions during actual machining operations, the system detects material defects through their mechanical interaction with cutting tools, achieving both high detection accuracy and operational efficiency

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

Solution Approach 2:

The machining process itself serves dual purposes: producing the component and detecting material defects. The normal machining operations generate signals (force variations, vibrations, acoustic emissions) that reveal the presence of segregations and other defects, eliminating the need for separate dedicated testing procedures

Inventive Principle:
Principle #25Self-service

2Reliability

If complex procedures like etching tests are employed to detect segregations, then defect detection accuracy improves, but the testing process becomes more complex and time-consuming

Engineering Contradiction:
Improvedefect detection accuracyVSAvoidtesting procedure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex chemical etching procedures with mechanical machining-based detection. By monitoring force profiles, vibration patterns, and acoustic emissions during machining, the system achieves reliable detection of segregations without requiring chemical treatments or complex multi-step testing protocols

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

Solution Approach 2:

The patent combines the manufacturing process with the inspection process into a single integrated operation. The machining operations that shape the component simultaneously generate detection signals, merging production and quality control into one efficient workflow rather than requiring separate testing stages

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If destructive testing methods are used to detect internal defects, then defect detection reliability improves, but the component is destroyed and cannot be used

Engineering Contradiction:
Improvedefect detection reliabilityVSAvoidcomponent usability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The machining process detects defects in the component that will ultimately be used. By monitoring forces and vibrations during the creation of the functional part, the system identifies segregations and other defects without requiring separate destructive sampling, allowing the same component to be both tested and retained for service

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces destructive mechanical testing methods with non-destructive monitoring of machining parameters. The detection system uses force sensors, vibration sensors, and acoustic emission sensors to identify defects during normal machining operations, preserving the component for its intended application

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

4Reliability

If separate testing procedures are conducted after machining, then defect detection thoroughness improves, but production time increases

Engineering Contradiction:
Improvequality assessment thoroughnessVSAvoidproduction cycle time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent merges the manufacturing and inspection operations into a single concurrent process. Quality data is collected during machining through force and vibration monitoring, eliminating the need for separate post-processing inspection stages and reducing total production time while maintaining thorough defect detection

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The detection process continues uninterrupted during normal machining operations. Rather than pausing production for separate testing, the system continuously monitors machining parameters to detect defects, maintaining continuous productive action while simultaneously performing quality assessment

Inventive Principle:
Principle #20Continuity of useful action

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

Enables efficient detection of material defects during machining, reducing the need for destructive testing and saving time by allowing for real-time evaluation of component quality and defect assessment, thereby preventing potential failures.

Implementation Method 1

recording at least one force profile of at least one force acting on the at least one tool during machining using at least one force sensor

Methodology Applied
Scientific EffectForce sensing: Force

Data Source

PatentEP3814742B1Method for checking at least one subregion of a component and checking device for checking at least one subregion of a component
Publication Date: 2023.07.26 MTU AERO ENGINES GMBH
  • EP3814742B1 patent drawingFigure 1
  • EP3814742B1 patent drawingFigure 2
  • EP3814742B1 patent drawingFigure 3

AI summary

The invention relates to a method for checking at least one subregion (12) of a component, in particular a component of a turbomachine, comprising at least the steps: a) providing an unfinished component (10); b) producing at least the subregion (12) from the unfinished component (10) by machining the unfinished component (10) by means of at least one tool (16) and sensing at least one force curve (18) of at least one force acting on the at least one tool (16) during the machining by means of at least one force sensor (20); c) checking whether there is at least one deviation (22, 24) of the at least one force curve (18) from at least one predefined target curve (26) of the at least one force curve (18), the at least one deviation (22, 24) characterizing at least one material flaw (28, 36) contained in an unmachined segment (14) of the subregion (12). The invention further relates to a checking device (32) for checking at least one subregion (12) of a component.