EDM Electrode Replacement Determination via Dynamic Depth Tracking

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Solution Overview

Problem

Existing electrodischarge machining systems struggle to precisely judge the need for electrode replacement when machining workpieces with varying plate thickness, leading to potential waste due to conservative consumption ratios and inefficient electrode usage.

Innovation Solution

A replacement judgment apparatus and method that detects the residual length of the electrode by tracking the difference in positions between the start of each through hole, using a preset electrode consumption ratio and the difference between electrodischarge start and penetration positions to set the required electrode length for the next hole, and compares this to the detected residual length to determine if replacement is necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a preset electrode consumption ratio is used to calculate required electrode length, then the judgment is simple and quick, but the judgment precision deteriorates when workpiece plate thickness varies

Engineering Contradiction:
Improvejudgment speedVSAvoidelectrode replacement judgment precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system performs preliminary detection of the actual through-hole depth during the machining process. This detected depth information is then used to dynamically adjust the electrode consumption ratio calculation, ensuring that the replacement judgment is based on actual workpiece dimensions rather than preset values, thereby resolving the contradiction between simple calculation and precise judgment

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by using the detected through-hole depth from previous machining cycles to adjust the electrode consumption ratio for subsequent replacements. This closed-loop approach ensures that variations in workpiece plate thickness are automatically compensated, maintaining high judgment precision while preserving operational simplicity

Inventive Principle:
Principle #23Feedback

2Reliability

If a larger electrode consumption ratio is set for safety, then the risk of machining interruption is reduced, but electrode waste increases

Engineering Contradiction:
Improvemachining continuityVSAvoidelectrode waste
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The electrode consumption ratio is transformed from a static preset value to a dynamic parameter that is automatically adjusted based on detected through-hole depths. This dynamic adjustment allows the system to optimize the consumption ratio for each specific workpiece, ensuring machining continuity when needed while minimizing electrode waste through precise, data-driven calculations

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the consumption ratio parameter based on actual machining data. By detecting the real through-hole depth and recalculating the required electrode length accordingly, the system adapts the consumption ratio to match actual conditions, preventing both premature replacement (waste) and insufficient length (interruption)

Inventive Principle:
Principle #35Parameter changes

3Productivity

If electrode replacement is judged based on preset consumption ratio and average depth, then the process is efficient, but accuracy deteriorates for workpieces with non-constant thickness

Engineering Contradiction:
Improvemachining efficiencyVSAvoidelectrode length calculation accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system performs preliminary detection of the actual through-hole depth during machining. This实测 depth information is then used to calculate the precise electrode consumption, replacing the inaccurate average depth assumption. This preliminary measurement action enables both high efficiency and high precision in electrode replacement judgment

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system replaces the mechanical assumption of constant thickness with an electronic detection and calculation system. By using sensors and control algorithms to detect actual through-hole depths and calculate consumption ratios, the system achieves precise electrode length calculation while maintaining efficient automated operation

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

Data Source

PatentEP2881204B1Replacement determination device for electrical discharge machining electrode and replacement determination method
Publication Date: 2018.09.26 MAKINO MILLING MASCH CO LTD
  • EP2881204B1 patent drawingFigure 1
  • EP2881204B1 patent drawingFigure 2~3
  • EP2881204B1 patent drawingFigure 4

AI summary

In order to solve the problem of being unable to precisely determine whether or not electrode replacement is required and the problem of the wear ratio of the electrode being set high for safety reasons and the electrode being replaced while still being usable, this replacement determination method determines whether or not replacement of an electrode (10) that sequentially electrical-discharge machines a plurality of throughholes (22) in a workpiece (20) is required. The replacement determination method: detects the remaining length (La) of the electrode (10); detects the electrical discharge commencement position, being the position of the electrode (10) when electrical discharge starts; detects the throughole position, being the position of the electrode (10) when the workpiece is pierced; sets the required length (Lb) for the electrode (10) as required for machining the next throughhole (22), on the basis of the difference (E) between the detected electrical discharge commencement position and the detected throughole position; compares the detected remaining length (La) and the set required length (Lb); and determines whether or not electrode replacement is required.