Wire EDM Machining Time Estimation Using Blended Speed Feedback

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Solution Overview

Problem

Existing methods for estimating machining time in wire electrical discharge machining face inaccuracies due to differences in material, shape, and machining conditions, leading to insufficient precision in predicting the end of machining time.

Innovation Solution

A method that calculates remaining machining time by combining predicted and actual machining speeds in a predetermined ratio, with dynamic adjustment of reference rates based on machining stability and stages, allowing for continuous updates and cumulative calculations across multiple machining stages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If predicted machining speed is used to estimate machining time, then calculation is simple, but precision of estimated machining time is insufficient

Engineering Contradiction:
Improvecalculation complexityVSAvoidprecision of estimated machining time
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent combines predicted machining speed and actual machining speed in a predetermined ratio to calculate the estimated machining speed. This merging of two speed sources resolves the contradiction by maintaining calculation simplicity while improving estimation precision through the complementary strengths of both prediction and measurement.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent dynamically changes the reference rates of predicted and actual machining speeds based on machining stability and machining stage. By adjusting these parameters adaptively, the system maintains high estimation precision while keeping the calculation method relatively simple and manageable.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If actual machining speed detected during machining is used for prediction, then precision of estimation is improved, but precision of calculated remaining machining time becomes insufficient due to large fluctuation at initial stage

Engineering Contradiction:
Improveprecision of estimated machining timeVSAvoidstability of machining process
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent dynamically adjusts the reference rate of actual machining speed based on machining stability and the current stage of machining. During the initial unstable period, the reference rate is lowered to reduce the impact of fluctuations. As machining progresses and stabilizes, the reference rate is increased to improve precision, thus resolving the contradiction between using actual speed for precision and accounting for initial instability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent divides the machining process into multiple stages and applies different reference rates for predicted and actual machining speeds in each stage. This segmentation allows the system to handle the initial unstable period differently from the stable machining period, improving overall estimation accuracy while accounting for process stability variations.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If reference rate of actual machining speed is increased, then precision of estimated machining time is improved, but error is large at initial period where machining is not stable

Engineering Contradiction:
Improveprecision of estimated machining timeVSAvoidreliability of estimation at initial stage
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent dynamically adjusts the reference rate of actual machining speed based on machining stability and the current stage of machining. During the initial unstable period, the reference rate is lowered to reduce the impact of fluctuations. As machining progresses and stabilizes, the reference rate is increased to improve precision, thus resolving the contradiction between using actual speed for precision and accounting for initial instability.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3305451B1Machining time-estimating method for wire electrical discharge machine and control device for wire electrical discharge machine
Publication Date: 2022.08.03 MAKINO MILLING MASCH CO LTD
  • EP3305451B1 patent drawingFigure 1
  • EP3305451B1 patent drawingFigure 2
  • EP3305451B1 patent drawingFigure 3

AI summary

A machining time-estimating method for a wire electrical discharge machine for estimating the remaining machining time (Tr) during the machining of a workpiece comprises: a step for setting a predicted machining velocity; a step for determining the actual machining velocity; a step for determining an estimated machining velocity so as to incorporate the predicted machining velocity and the actual machining velocity at a specified ratio, that is, a reference ratio; and a step for calculating remaining machining time from the estimated machining velocity. By executing the actual machining velocity-determining step to the remaining machining time-calculating step repeatedly to estimate remaining machining time moment by moment, remaining wire electrical discharge machining time is estimated with reduced error.