Multi-Axis Machining Path Planning to Reduce Jerky Axis Motion

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Solution Overview

Problem

Multi-axis machining systems face inefficiencies and high stress due to complex movements required for connecting path segments, leading to jerky axis movements and increased load on the machine, which reduces machining efficiency and increases wear on machine components.

Innovation Solution

A method that accounts for the movement profile of machine axes when determining machining paths, by defining an interpolation group of machine axes, determining interpolation start and end points, and calculating connection functions to generate a connecting path segment that minimizes unnecessary axis movements and collisions, thereby reducing reverse movements and protecting machine components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional connecting path segments are used in CAM systems, then the machining path can be generated from CAD data, but the machine axes perform jerky forward and backward movements leading to significant efficiency losses and high machine stress

Engineering Contradiction:
Improvemachining efficiencyVSAvoidcomplex superposition of movements
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-defining monotonic connection functions for each machine axis that specify the desired movement behavior before actual machining. These functions are calculated in advance to ensure monotonic (non-reversing) motion patterns, and the machine control system executes them during machining, preventing jerky movements and efficiency losses before they occur.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the movement parameters of machine axes by imposing monotonicity constraints on connection functions. Instead of allowing arbitrary complex motion paths, the system transforms the movement parameters to ensure each axis moves monotonically between positions, eliminating reverse movements and reducing machine stress while maintaining machining accuracy.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If complex superposition of movements is used to achieve simple connecting path segments in workpiece reference frame, then the tool position can be smoothly transitioned, but the machine axes experience significant stress and efficiency losses

Engineering Contradiction:
Improvesmooth tool path transitionVSAvoidmachine stress
Core Design Contradiction:
Stability of the object's compositionVSStress or pressure

Solution Approach 1:

The patent inverts the conventional approach by not calculating smooth connecting paths in the workpiece reference frame and then transforming to machine axes. Instead, it directly defines monotonic connection functions in each machine axis reference frame, ensuring smooth transitions and low stress simultaneously by working in the machine's native coordinate system rather than transforming from the workpiece frame.

Inventive Principle:
Principle #13The other way round (Inversion)

3Ease of operation

If conventional path calculation strategies are used, then engagement and connecting segments can be generated, but unnecessary reverse movements occur leading to time losses and increased wear

Engineering Contradiction:
Improvepath generation capabilityVSAvoidtime losses from reverse movements
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent ensures continuity of useful action by making connection functions monotonic for each machine axis, which eliminates reverse movements and ensures continuous forward progression. This allows the machining process to proceed without interruptions or time-wasting reverse motions, maintaining continuous productive action throughout the toolpath execution.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP4137899A1Method for determining a machining path and method for machining a workpiece by means of a multi-axis machining device
Publication Date: 2023.02.22 OPEN MIND TECH
  • EP4137899A1 patent drawingFigure 1~2
  • EP4137899A1 patent drawingFigure 3~4e
  • EP4137899A1 patent drawingFigure 5

AI summary

The invention relates to a method for determining a machining path (24) for material removal machining of a workpiece (14) using a multi-axis machining machine (10) (milling machine), wherein the path (28) to be determined connects a first (25) and a second (26) engagement path segment, wherein a travel path (connection function) is determined for at most N-1 of the N machine axes and a further machine axis is determined as a retraction machine axis that avoids a collision, and wherein the path (28) to be determined is determined by combining all determined travel paths.