Five-Axis Tool Path Smoothing for Stable Surface Machining

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Solution Overview

Problem

Existing methods for surface machining with five-axis machine tools fail to effectively correct tool posture changes across multiple tool paths, leading to surface quality issues due to tool deflection, center of rotation deviations, and acceleration/deceleration changes, resulting in slight variations and production errors.

Innovation Solution

A method and device that generate a tool path by averaging tool postures across multiple tool paths, correcting the tool posture and verifying interference to prevent surface irregularities, using a tool path generation device that incorporates tool posture smoothing and interference avoidance processing units to ensure smooth posture changes and accurate machining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the tool posture is changed to machine different surfaces of the workpiece, then the adaptability of the machining process is improved, but the machining precision deteriorates due to tool deflection, center of rotation deviation, and acceleration/deceleration changes

Engineering Contradiction:
Improvetool posture change capabilityVSAvoidmachined surface quality
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent performs preliminary calculation of the corrected tool posture at each machining point by averaging the tool posture from multiple adjacent tool paths before actual machining. This pre-correction of tool posture data eliminates the need for real-time adjustments during machining, thereby preventing surface quality deterioration while maintaining the ability to machine different surfaces.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a corrected tool posture model by copying and averaging posture data from multiple adjacent tool paths. Instead of directly using the original tool posture commands that cause surface irregularities, the system generates a new corrected posture command set based on averaged data from neighboring paths, effectively eliminating the harmful effects of posture changes.

Inventive Principle:
Principle #26Copying

2Manufacturing precision

If the tool direction commands are corrected along a single tool path, then the machining precision along that path is improved, but the adaptability to handle posture changes across multiple tool paths deteriorates

Engineering Contradiction:
Improvetool posture accuracyVSAvoidmulti-tool path handling capability
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent merges tool posture data from multiple adjacent tool paths by calculating the average posture at each machining point. This combination of data from different paths enables the system to handle multi-tool path machining while maintaining precision, as the averaged posture command smooths out the discontinuities that would otherwise occur at transition points between paths.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extends the correction approach from a single-tool-path dimension to a multi-tool-path dimension by incorporating data from adjacent paths. This dimensional expansion allows the system to address posture changes not just along one path but across the entire multi-path machining operation, thereby maintaining both precision and adaptability.

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

3Manufacturing precision

If the tool posture is corrected by averaging across multiple tool paths, then the machining precision and surface quality are improved, but the computational complexity increases

Engineering Contradiction:
Improvesurface qualityVSAvoidtool path generation complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent performs the computationally intensive averaging calculation of tool posture from multiple paths in advance, before actual machining begins. By completing this complex computation during the programming/setup phase rather than during machining, the system achieves high surface quality without adding complexity to the real-time machining control.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces complex real-time mechanical adjustments during machining with pre-calculated corrected posture commands. Instead of using complex feedback mechanisms or real-time sensors to adjust tool posture during machining, the system substitutes this with offline computational analysis that generates corrected G-code commands, thereby improving surface quality without increasing operational complexity.

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

Data Source

PatentEP3603883B1Tool path generation method and device
Publication Date: 2023.04.26 MAKINO MILLING MASCH CO LTD
  • EP3603883B1 patent drawingFigure 1
  • EP3603883B1 patent drawingFigure 2
  • EP3603883B1 patent drawingFigure 3

AI summary

The present invention sets, as a point (POM) to be machined, a single machining point on a plurality of tool path rows, selects, as a machining point (PI(i)) of interest, a machining point in a prescribed range with the point to be machined as the center, calculates the tool orientation at the point to be machined by way of averaging the tool orientation of the selected machining point of interest, corrects data pertaining to the tool orientation of the point to be machined by way of the calculated average tool orientation, acquires the shape data of a workpiece to be machined and the shape data of a ball end mill to be used, performs an interference check for the workpiece and the ball end mill on the basis of the corrected tool orientation data, and generates a new tool path on the basis of data pertaining to the corrected tool orientation when no interference between the workpiece and the ball end mill occurs.