Tool Path Generation for Substitute Tools Using Contact Point Trajectories

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Solution Overview

Problem

Existing machine tools face challenges in accurately machining workpieces using substitute tools, as the offset function may lower machining accuracy and increase time, and the tool type is often unchangeable, especially when dealing with three-dimensional tool paths and varying workpiece shapes.

Innovation Solution

A tool path generation method that calculates a tool path for a substitute tool by determining the portion that generates the machining surface in a machining area, setting a virtual advancing direction, and positioning the substitute tool within a specific range to match the specified tool's path, allowing for accurate machining with tools of the same type but smaller diameter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an offset function is used to generate a tool path for a substitute tool with smaller diameter, then machining can be performed with available tools, but machining accuracy decreases and machining time increases

Engineering Contradiction:
Improvetool substitutabilityVSAvoidmachining accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent changes the fundamental parameters of tool path generation by transitioning from offset-based methods to contact point trajectory methods. The contact point trajectory is calculated based on the actual geometry of the substitute tool and the workpiece, dynamically adjusting the tool path parameters to maintain machining accuracy despite tool diameter differences

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent moves from two-dimensional offset-based tool path generation to three-dimensional contact point trajectory calculation. By considering the spatial relationship between the substitute tool geometry and workpiece surface, the system calculates accurate tool paths in three-dimensional space, resolving the accuracy loss inherent in simple offset methods

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If an offset function is used to generate a tool path for a substitute tool, then machining can be performed with available tools, but machining time increases

Engineering Contradiction:
Improvetool substitutabilityVSAvoidmachining time
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent performs preliminary calculation of the contact point trajectory between the substitute tool and workpiece before actual machining. By pre-calculating the optimal tool path based on the specific substitute tool geometry, the system eliminates the need for time-consuming trial-and-error adjustments during machining, thereby reducing overall machining time

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a virtual model of the substitute tool and calculates its contact point trajectory with the workpiece. This virtual copying approach allows for precise tool path generation without physical trial machining, significantly reducing the time required to adapt to different substitute tools

Inventive Principle:
Principle #26Copying

3Reliability

If the tool type is fixed, then the machine tool can operate with standard tools, but it cannot adapt to different workpiece shapes requiring different tool types

Engineering Contradiction:
Improveoperation stabilityVSAvoidworkpiece shape adaptability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal tool path generation system that can handle different workpiece shapes and substitute tool configurations using the same contact point trajectory calculation methodology. The system adapts to various tool types and workpiece geometries by calculating the specific contact points between the substitute tool and workpiece surface, eliminating the need for specialized programming for each tool-workpiece combination

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2907621B1Tool path-generating method, machine tool control device and tool path-generating device
Publication Date: 2019.12.04 MAKINO MILLING MASCH CO LTD
  • EP2907621B1 patent drawingFigure 1
  • EP2907621B1 patent drawingFigure 2
  • EP2907621B1 patent drawingFigure 3

AI summary

A tool path-generating method for computing a tool path to process a workpiece, wherein the tool path for a designated tool when processing using the designated tool is previously established. The tool path-generating method comprises a path-computing process for computing, on the basis of the tool path for the designated tool, the tool path of a substitute tool differing from the designated tool when processing with the substitute tool. The path-computing process computes the portion that ultimately forms the machined surface when the workpiece is processed using the designated tool and sets the tool path for the substitute tool on the basis of the portion that ultimately forms the machined surface.