Laser Cutting Setpoint Planning for Real-Time Path and Process Control
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Solution Overview
Problem
Existing laser cutting technologies fail to effectively coordinate the control of process setpoints and path setpoints, leading to quality losses and instability in the cutting process, particularly when dealing with high inertial forces and complex geometries.
Innovation Solution
A method for calculating a spatially and time-resolved, combined setpoint data set that integrates both physical and kinematic processes, using a process model and a machine model coupled via feed rate and nozzle spacing, to ensure coordinated control of laser cutting and movement processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If rapid change in feed rate is executed for corners and small radii, then path traversal speed is improved, but contour errors and quality losses occur due to high inertial forces
Solution Approach 1:
The system performs preliminary calculation of inertial forces and required feed rate adjustments before executing path traversal. The control unit calculates the feed rate profile in advance, taking into account the mass of moving components and desired contour accuracy, then pre-adjusts feed rate commands to prevent excessive inertial effects during actual movement.
Solution Approach 2:
The system dynamically adjusts feed rate based on real-time calculation of inertial forces. The control unit continuously monitors path geometry, calculates required acceleration and deceleration, and adapts feed rate commands dynamically to maintain optimal balance between traversal speed and contour accuracy, particularly at corners and small radii.
2Manufacturing precision
If process feed rate is reduced to maintain cutting quality, then manufacturing precision is improved, but productivity decreases
Solution Approach 1:
The system changes process parameters (feed rate, laser power, gas pressure) in a coordinated manner based on path geometry and cutting conditions. Instead of uniformly reducing feed rate, the control unit calculates optimal parameter combinations that maintain cutting quality while minimizing productivity loss, adjusting parameters locally at critical sections rather than globally.
Solution Approach 2:
The system applies different feed rate and process parameter settings to different sections of the workpiece based on local requirements. Critical sections with tight tolerances receive adjusted parameters for high quality, while less critical sections maintain higher feed rates for productivity, optimizing the overall balance between quality and throughput.
3Reliability
If coordinated control of process setpoints and path setpoints is implemented, then cutting quality and process stability are improved, but system complexity increases
Solution Approach 1:
The system merges the control of process setpoints and path setpoints into a unified control framework. The control unit integrates calculations for both process parameters (laser power, gas pressure) and motion parameters (feed rate, acceleration) into a single coordinated control algorithm, reducing the need for separate control loops and simplifying the overall control architecture.
Solution Approach 2:
The system implements feedback mechanisms where sensor data from the cutting process is continuously monitored and used to adjust both process and path setpoints. This coordinated feedback control ensures that changes in one parameter automatically trigger appropriate adjustments in related parameters, maintaining process stability without requiring complex manual coordination.
Data Source
AI summary
A control unit for calculating a spatially and time-resolved, combined setpoint data set for control of a laser cutting process includes a measurement data interface for accessing sensor data during the cutting operation, a process interface to a first memory that stores a process model that estimates status data of the laser cutting process and a cutting result, a machine interface to a second memory in which a machine model is stored which represents a kinematic behaviour of the laser cutting head and estimates status data of a movement process and the cutting result thereof, and a processor that executes an algorithm that couples the process model and the machine model via a feed rate value and/or via a nozzle spacing value. The processor accesses the process model and the machine model in order to calculate the spatially and time-resolved, combined setpoint data set with coordinated setpoints.