Multi-Spindle Channel Synchronization for Collision-Free CNC Machining

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Solution Overview

Problem

Multi-spindle machine tools face a high risk of collisions due to asynchronous movements of tool spindles caused by discrepancies in tool dimensions, tool wear, and other mechanical and dynamic factors, leading to unsynchronized machining operations.

Innovation Solution

A method for computer-aided numerical control (CNC) synchronizes the machining of two workpieces using independent tool spindles by controlling machine axes to minimize differences in scalar quantities like arc length during machining, using a PI controller to adjust feed rates and ensure synchronized tool movements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If independent tool spindles with different tool dimensions are used to machine workpieces, then manufacturing flexibility and adaptability are improved, but synchronization between spindles deteriorates leading to collision risks

Engineering Contradiction:
Improvetool dimension compensationVSAvoidspindle synchronization
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The control system continuously monitors the actual positions and machining progress of multiple tool spindles, compares them against synchronized reference values, and automatically adjusts feed rates and motion parameters to maintain synchronization. This closed-loop feedback mechanism enables independent spindles with different tool dimensions to operate synchronously without collisions

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically changes motion parameters including feed rate, speed, and acceleration profiles for each spindle based on real-time synchronization requirements. By adapting these parameters individually for each spindle while maintaining coordinated control, the system accommodates different tool dimensions while preserving synchronization

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If machine axes are controlled to minimize differences in scalar quantities like arc length, then machining precision is improved, but control complexity increases

Engineering Contradiction:
Improvemachining result consistencyVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The control system introduces intermediary synchronization parameters such as arc length, machining progress, or time stamps that mediate between the independent motion control of multiple spindles and the requirement for synchronized machining results. These intermediary parameters serve as common reference frames that simplify the coordination of complex multi-spindle operations while ensuring precision

Inventive Principle:
Principle #24Intermediary (Mediator)

3Volume of moving object

If tool spindles are positioned closely to minimize mechanical offset, then machine tool compactness is improved, but collision risk increases

Engineering Contradiction:
Improvemachine footprintVSAvoidcollision hazard
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The control system continuously monitors the actual positions and machining progress of multiple tool spindles, compares them against synchronized reference values, and automatically adjusts feed rates and motion parameters to maintain synchronization. This closed-loop feedback mechanism enables independent spindles with different tool dimensions to operate synchronously without collisions

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts motion parameters including feed rate, speed, and acceleration profiles for each spindle based on real-time synchronization requirements and spatial constraints. By making the control system adaptive and dynamic rather than static, closely positioned spindles can operate safely without collisions while maintaining compact machine dimensions

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4700508A1Channel synchronization in multi-spindle machine tools
Publication Date: 2026.02.25 SIEMENS AG
  • EP4700508A1 patent drawingFigure 1
  • EP4700508A1 patent drawingFigure 2
  • EP4700508A1 patent drawingFigure 3

AI summary

The invention relates to a method for the computer-aided numerical control of a multi-spindle machine tool (1) which has a first tool spindle (2A) equipped with a first tool (3A) and a second tool spindle (2B) that can be controlled independently of the first tool spindle (2A) and is equipped with a second tool (3B), wherein: - a first workpiece (5A) is machined using the first tool (3A) by executing a predetermined part program in a first machining channel, and a second workpiece (5B) is machined using the second tool (3B) by executing the part program in a second machining channel synchronously with the first machining channel; - the execution of the part program in the first machining channel involves the control of first machine axes (X1, Y1,The invention includes Z1) for guiding the first tool spindle (2A) according to a first toolpath (TA), and the execution of the part program in the second machining channel includes controlling two machine axes (X2, Y2, Z2) for guiding the second tool spindle (2B) according to a second toolpath (TB), wherein a machining result of the first workpiece (5A) at one end of the first toolpath (TA) is equal to a machining result of the second workpiece (5B) at one end of the second toolpath (TB). To synchronize the movements performed by the first tool spindle (2A) and the second tool spindle (2B), the invention provides that at least one first scalar quantity (BA, BB) dependent on a machining progress is detected in each machining channel, and the first machine axes (X1, Y1, Z1) and the second machine axes (X2, Y2, Z2) are controlled accordingly.that a difference (ΔB) between the scalar quantity (BA) recorded in the first processing channel and the scalar quantity (BB) recorded in the second processing channel is reduced.