Wire EDM Corner Shape Control for Infinitesimal Path Blocks

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Solution Overview

Problem

Wire electrical discharge machines face low machining accuracy when dealing with curved path shapes defined by combining extremely short path blocks, as the machining shape cannot be determined from the movement commands of each block.

Innovation Solution

A control device and method for a wire electrical discharge machine that includes an infinitesimal-block determination unit, path shape determination unit, offset direction acquisition unit, and inner/outer corner determination unit to identify whether the path shape defined by consecutive blocks is a right-hand or left-hand corner, and whether it is an inner or outer corner, based on coordinates and machining program data, allowing for precise control of electrical discharge machining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If curved path shapes are defined by combining multiple extremely short path blocks, then the path can be constructed with basic movement commands, but the machining accuracy deteriorates because the machining shape cannot be determined from individual block commands

Engineering Contradiction:
Improvepath definition capabilityVSAvoidmachining accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The control device performs preliminary analysis of consecutive block commands before machining to determine the overall path shape (corner, curve, etc.). This preliminary determination of machining shape from multiple blocks enables the system to prepare appropriate machining parameters in advance, resolving the accuracy issue while maintaining the ability to define complex paths using basic movement commands

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control device introduces an intermediary analysis function that processes multiple block commands together to determine the machining shape. This intermediary layer translates individual movement commands into meaningful path shape information, enabling accurate machining control without requiring complex individual block commands

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the control device analyzes multiple consecutive blocks to determine path shape, then machining accuracy improves, but the control processing complexity increases

Engineering Contradiction:
Improvemachining accuracyVSAvoidcontrol processing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The control device segments the path analysis into discrete units by examining consecutive blocks of commands. This segmentation approach allows the system to analyze path shapes in manageable portions rather than processing the entire program at once, reducing control processing complexity while maintaining machining accuracy

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control device changes the parameter of analysis from individual block commands to aggregated path shape characteristics. By transforming multiple movement commands into simplified path shape parameters (corner, curve, straight), the system reduces control processing complexity while preserving the information needed for accurate machining

Inventive Principle:
Principle #35Parameter changes

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

Improves machining accuracy by accurately determining path shapes and adjusting machining conditions, enhancing the precision of machined surfaces in corners defined by infinitesimal blocks.

Implementation Method 1

performs electrical discharge machining on a workpiece by applying a voltage between a wire electrode and the workpiece

Methodology Applied
Scientific EffectElectrical discharge machining: Electrical Discharge Machining

Data Source

PatentEP4438213A1Control device for wire electric-discharge machining machine, and control method for wire electric-discharge machining machine
Publication Date: 2024.10.02 FANUC LTD
  • EP4438213A1 patent drawingFigure 1
  • EP4438213A1 patent drawingFigure 2
  • EP4438213A1 patent drawingFigure 3

AI summary

In a control device (18) for a wire electric-discharge machining machine (10), if it has been determined that the length of a route defined by two blocks is equal to or less than the diameter of a wire electrode (12), a route shape determination unit (32) determines whether the shape of the route defined by the two blocks is a right corner or a left corner on the basis of the coordinates of three points established from origin points and end points of the two blocks. If it has been determined that the shape of the route is a left corner or a right corner, an inner/outer corner determination unit (36) determines whether the shape of the route is an inner corner or an outer corner on the basis of an offset direction.