Multispindle CNC Synchronization for Collision-Safe Toolpaths

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Multi-spindle machine tools face challenges in maintaining synchronization and minimizing the risk of collision between tool spindles due to mechanical offsets, zero point shifts, and differences in dynamic restrictions, which can lead to asynchrony and potential collisions, especially when tool spindles are controlled independently to compensate for varying tool dimensions.

Innovation Solution

A method for computer-aided numerical control (CNC) that processes the same part program in two synchronized machining channels, allowing the first and second tool spindles to move differently while being forcibly synchronized, with the control device adjusting the speed difference between the tool paths based on the tool dimensions to ensure the movement of both spindles ends within a predetermined tolerance, thereby minimizing positional deviations and reducing the risk of collisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If tool spindles are controlled independently to compensate for different tool dimensions, then manufacturing precision is improved, but the risk of collision increases due to asynchrony

Engineering Contradiction:
Improveworkpiece dimensional accuracyVSAvoidcollision risk
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The control device measures actual tool dimensions (length, radius) and uses this feedback information to calculate and adjust synchronized movement parameters. The system continuously monitors tool spindle positions and adjusts movement commands to maintain synchronization despite dimensional variations, thereby preventing collisions while preserving manufacturing precision.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes movement parameters (speed, position, timing) dynamically based on measured tool dimensions. By adjusting these parameters in real-time according to actual tool characteristics, the system maintains synchronized operation and prevents collisions while accommodating dimensional variations for precise workpiece production.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If mechanical offset between tool spindles is reduced for compact design, then productivity is improved through better workspace utilization, but the risk of collision increases due to closer proximity

Engineering Contradiction:
Improveworkspace utilization efficiencyVSAvoidcollision risk
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The control device continuously monitors the actual positions and dimensions of tools in both spindles and uses this feedback to adjust movement commands. This real-time information allows the system to safely operate with reduced mechanical offset by dynamically compensating for positional variations, thereby maintaining compact design while preventing collisions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system transitions from static mechanical spacing to dynamic positional control. By using active control algorithms that adjust tool spindle positions and speeds in real-time based on measured parameters, the system can maintain safe operational distances even when mechanical offsets are minimized for compact machine design.

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If tool spindles are moved at different speeds to compensate for dimensional variations, then manufacturing precision is maintained, but synchronization becomes more difficult

Engineering Contradiction:
Improveworkpiece dimensional accuracyVSAvoidcontrol synchronization complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The control device uses feedback from tool dimension measurements to automatically calculate appropriate speed adjustments. This closed-loop control simplifies the synchronization task by using measured data to determine optimal movement parameters, reducing the complexity of manual synchronization while maintaining manufacturing precision.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system automatically adjusts synchronization parameters based on self-measured tool dimensions without requiring external intervention. The system serves itself by using its own measurement capabilities to determine and implement the necessary speed and position adjustments, thereby maintaining precision while managing control complexity internally.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4455809A1Control of a multispindle machine tool
Publication Date: 2024.10.30 SIEMENS AG
  • EP4455809A1 patent drawingFigure 1
  • EP4455809A1 patent drawingFigure 2~3
  • EP4455809A1 patent drawingFigure 4~5

AI summary

To control a multi-spindle machine tool (1), which has a first tool spindle (2a, 2b) and an independently controllable second tool spindle (2a, 2b), a first workpiece (5a, 5b) and a second workpiece (5a, 5b) are machined by synchronously executing a part program in two machining channels. The execution of the part program includes controlling the first machine axes to guide the first tool spindle (2a, 2b) according to a first toolpath, and the execution of the part program includes controlling the second machine axes to guide the second tool spindle (2a, 2b) according to a second toolpath. A machining result of the first workpiece (5a, 5b) at one end of the first toolpath is equivalent to a machining result of the second workpiece (5a, 5b) at one end of the second toolpath.The first machine axes and the second machine axes are controlled in such a way that the time difference between reaching the end of the first toolpath and reaching the end of the second toolpath is less than or equal to a predetermined limit value.