EDM Measurement Piping Purge for Accurate Fluid Level Sensing

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Solution Overview

Problem

In electric discharge machines, sludge accumulation in measurement piping can lead to inaccurate pressure detection, affecting the measurement of the working fluid level, as described in Japanese Laid-Open Patent Publication No. 2017-064804.

Innovation Solution

The electric discharge machine incorporates a working fluid supply system that forces sludge back into the work-pan by supplying fluid into the measurement piping, reducing sludge accumulation and ensuring accurate pressure sensing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a pressure sensor is used to detect air pressure in measurement piping for working fluid level measurement, then the level measurement function is achieved, but sludge accumulation in the measurement piping causes deteriorated sensing accuracy

Engineering Contradiction:
Improveworking fluid level measurement accuracyVSAvoidpressure sensor detection reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent extracts the harmful element (sludge) from the measurement system by introducing a purging mechanism. A purging conduit is provided that allows working fluid to flow through the measurement piping to remove accumulated sludge, thereby separating the measurement function from the contamination risk and maintaining long-term reliability of the pressure sensor.

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If measurement piping is routed from the bottom portion of the work-pan to the outside, then the working fluid level can be measured, but sludge enters and accumulates in the measurement piping

Engineering Contradiction:
Improveworking fluid level measurement capabilityVSAvoidsludge accumulation in measurement piping
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by providing a purging mechanism that proactively removes sludge before it can accumulate to problematic levels. The purging conduit is designed to periodically or continuously flush the measurement piping with working fluid, preventing sludge buildup before it interferes with pressure sensor operation.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If the measurement piping is positioned at the bottom of the work-pan for level detection, then accurate level measurement is possible, but sludge naturally accumulates at the lowest point

Engineering Contradiction:
Improvelevel detection accuracyVSAvoidsludge accumulation at bottom position
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent uses hydraulic principles to solve the sludge accumulation problem. By introducing working fluid through the purging conduit and utilizing fluid flow dynamics, the system creates a hydraulic flush that removes sludge from the measurement piping. The flowing working fluid carries sludge particles out of the measurement system, preventing accumulation at the bottom position while maintaining accurate level detection.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 effectively prevents sludge accumulation in the measurement piping, maintaining the accuracy of fluid level measurements and ensuring reliable operation of the electric discharge machine.

Implementation Method 1

it is possible to force the sludge that has entered the measurement pipe from the work-pan to flow to the work-pan by the working fluid supplied to the measurement pipe

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 2

the air pressure inside a measurement piping routed from a bottom portion of a work-pan to the outside of the work-pan is detected by a pressure sensor and the level of the working fluid stored in the work-pan is measured in accordance with the air pressure

Methodology Applied
Scientific EffectPressure detection:

Data Source

PatentEP3527315B1Electric discharge machine
Publication Date: 2022.01.19 FANUC LTD
  • EP3527315B1 patent drawingFigure 1
  • EP3527315B1 patent drawingFigure 2
  • EP3527315B1 patent drawingFigure 3

AI summary

An electric discharge machine (10) is configured to perform electric discharge machining on a workpiece in a working fluid stored in a work-pan (42). The electric discharge machine (10) includes: a measurement piping (70) coupled to the work-pan (42) and having an air space (SP) inside; a pressure sensor (76) configured to detect a pressure of the air space (SP); and a working fluid supply portion (72) configured to supply the working fluid to the measurement piping (70).