Electrode Wear Compensation for Complex Blade Machining

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Solution Overview

Problem

Existing methods for manufacturing centrifugal compressor blades, such as EDM and ECM, face challenges due to electrode wear, which requires time-consuming adjustments and is inadequate for complex 3D geometries, leading to inefficiencies in material removal and production costs.

Innovation Solution

A method and system that dynamically compensate for electrode wear by updating the wear compensation for each pocket based on the previous pocket's wear, using a spindle with five-axis movement and a processor to select and update the compensation, allowing for precise machining of complex blade geometries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional EDM or ECM methods are used to manufacture compressor blades, then material removal is achieved, but electrode wear occurs requiring time-consuming adjustments and reducing manufacturing precision

Engineering Contradiction:
Improveblade geometry precisionVSAvoidelectrode adjustment time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The system pre-calculates and stores compensation values for electrode wear in a lookup table before machining begins. During machining, the processor simply retrieves the pre-calculated compensation value based on the current pocket and electrode wear state, eliminating the need for time-consuming real-time measurements and adjustments.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback mechanism where the processor monitors the current pocket being machined and automatically retrieves the appropriate compensation value from the stored data, applying it to maintain manufacturing precision without manual intervention.

Inventive Principle:
Principle #23Feedback

2Ease of manufacture

If traditional EDM or ECM methods are used to manufacture complex 3D blade geometries, then material removal is achieved, but the process is inadequate for complex geometries and requires frequent electrode adjustments

Engineering Contradiction:
Improvecomplex geometry machining capabilityVSAvoidproduction rate
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The system pre-calculates compensation values for all possible pockets and electrode wear states before machining begins. This preliminary preparation enables the system to handle complex 3D geometries efficiently by having all necessary compensation data ready in advance, eliminating production delays.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adapts to changing machining conditions by automatically selecting and applying the appropriate compensation value from stored data based on the current pocket and electrode wear state, enabling efficient processing of complex geometries without manual intervention.

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If electrode wear compensation is applied manually, then some precision is maintained, but the process is time-consuming and reduces productivity

Engineering Contradiction:
Improvetool path accuracyVSAvoidmachining speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The processor continuously monitors the machining state and automatically retrieves and applies the appropriate compensation value from pre-stored data based on the current pocket and electrode wear, maintaining manufacturing precision without manual intervention and thus preserving productivity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-compensation by automatically selecting and applying the correct compensation value from its stored database based on the current machining conditions, eliminating the need for operator intervention and maintaining both precision and productivity.

Inventive Principle:
Principle #25Self-service

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 approach reduces the gap between the real and ideal tool paths, improves machining accuracy, and adapts to changing conditions, enabling efficient production of complex blade geometries without the need for frequent electrode adjustments.

Implementation Method 1

EDM is a manufacturing process whereby a wanted shape of an object, called workpiece, is obtained using electrical discharges (sparks). The material removal from the workpiece occurs by a series of rapidly recurring current discharges between two electrodes, separated by a dielectric liquid and subject to an electric voltage.

Methodology Applied
Scientific EffectElectrical discharge: Electric Spark

Implementation Method 2

When the distance between the two electrodes is reduced, the intensity of the electric field in the volume between the electrodes is expected to become larger than the strength of the dielectric (at least in some point(s)) and therefore the dielectric breaks allowing some current to flow between the two electrodes.

Methodology Applied
Scientific EffectDielectric breakdown: Dielectric

Data Source

PatentEP2490851B1Tool compensation method and device
Publication Date: 2018.12.19 GE OIL & GAS US HLDG I INC
  • EP2490851B1 patent drawingFigure 1~4
  • EP2490851B1 patent drawingFigure 5
  • EP2490851B1 patent drawingFigure 6

AI summary

A Method and machine tool for compensating a wear of an electrode that machines a workpiece. The method includes selecting a current pocket from plural pockets of the workpiece; updating a wear compensation to be applied to the electrode for the current pocket based on wear compensation of a previous pocket, where the previous pocket is adjacent to the current pocket; and applying the updated wear compensation to the electrode for machining the current pocket.