CNC Tool Path Velocity Optimization Under Axis Dynamic Limits

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Solution Overview

Problem

Current CNC machining processes do not maximize productivity due to insufficient consideration of dynamic limits of drive axes, maximum cutting speed, and cutting volume, leading to conservative parameter settings and reduced efficiency.

Innovation Solution

The method involves iteratively increasing path velocity along the tool path within dynamic and processing limits, using a simulation-based quality analysis to adapt the NC program, and optimizing machining parameters to enhance productivity while maintaining workpiece quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conservative speed and acceleration values are used in NC-programming to ensure part quality, then manufacturing precision is improved, but productivity deteriorates

Engineering Contradiction:
Improvepart qualityVSAvoidproduction time per part
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies dynamics by making the speed and acceleration values adaptive rather than static. The control device continuously adjusts these parameters based on real-time monitoring of actual values versus limit values, allowing the system to operate at optimal speeds when conditions permit while maintaining quality when limits are approached. This dynamic adjustment resolves the contradiction by enabling high productivity when possible while ensuring quality when necessary.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameters of speed and acceleration from fixed conservative values to variable values that are continuously optimized. By monitoring actual speed and acceleration against dynamically determined limit values, the system adjusts parameters in real-time to maximize productivity while maintaining part quality. This parameter optimization resolves the contradiction between using conservative values for quality and higher values for productivity.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If maximum cutting speed and cutting volume are used to maximize productivity, then productivity is improved, but manufacturing precision deteriorates due to machine overload and poor surface quality

Engineering Contradiction:
Improvecutting speedVSAvoidpart surface quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements feedback by continuously monitoring actual speed and acceleration values and comparing them against limit values. The control device uses this feedback to adjust parameters in real-time, ensuring that maximum cutting speeds are used when the machine can handle the load while preventing overload conditions that would degrade surface quality. This closed-loop feedback system resolves the contradiction between maximizing productivity and maintaining manufacturing precision.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts cutting parameters based on real-time machine state and monitored performance. Rather than using fixed maximum values that could cause overload, the system adapts speed and acceleration limits based on actual machine response and performance metrics, enabling sustained high productivity without compromising surface quality.

Inventive Principle:
Principle #15Dynamics

3Reliability

If lower speed and acceleration values are programmed to avoid machine overload and ensure safety, then reliability is improved, but productivity deteriorates

Engineering Contradiction:
Improvemachine safetyVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent changes speed and acceleration from fixed conservative parameters to dynamically optimized parameters. By continuously adjusting these parameters based on real-time monitoring and calculated limit values, the system maintains reliability through safety monitoring while maximizing productivity by operating at the highest safe speeds. This resolves the contradiction between using lower values for safety and higher values for productivity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The control device performs self-optimization by automatically calculating and adjusting speed and acceleration limits based on monitored machine performance. The system serves itself by continuously adapting parameters to maintain both safety and productivity without external intervention, resolving the contradiction between conservative safety settings and aggressive productivity settings.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3213161B1Method for optimizing the productivity of a machining process of a CNC machine
Publication Date: 2022.12.07 BIG DATA IN MFG GMBH
  • EP3213161B1 patent drawingFigure 1

AI summary

The present invention relates to a method for optimizing the productivity of a machining process of at least one CNC (Computer Numerical Control) machine, the CNC machine comprising at least one machining tool movable by one or a plurality of drive axes, the machining process being controlled by a given NC (Numerical Control) program defining at least a tool path for the at least one machining tool and a path velocity profile along the tool path, wherein the method includes increasing the path velocity along the tool path as compared to the path velocity profile defined by the given NC program, wherein increasing the path velocity along the tool path is effected in due consideration of the respective dynamical limit of each of the one or the plurality of drive axes, in particular in due consideration of the maximum axis- velocity and the maximum axis-acceleration of each of the one or the plurality of drive axes, and in due consideration of processing limits affecting the path velocity due to the machining capacity of the CNC machine, in particular of the machining tool. The method further comprises adapting the given NC program by the increased path velocity along the tool path.