Beam-Forming Unit Cooling for High-Power Laser Focus Stability
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Solution Overview
Problem
Existing beam-forming units for laser machining face challenges in cooling high-power laser beams, leading to focus shifts and increased friction due to excessive heating, which affects the machining head's functionality, especially at powers above 8 kW.
Innovation Solution
A sealed cooling system within the beam-forming unit's outer housing, utilizing a cooling water circuit for immovable components and active forced movement of a cooling medium, combined with a reflective coating and air/gas cooling, effectively reduces heating and thermal lens effects in movable components, ensuring stable operation at high laser powers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If gas or water cooling systems are used to cool the laser machining head, then the optical components can be cooled, but the laser machining head must be enlarged
Solution Approach 1:
The cooling channels are integrated directly into the optical components themselves, with channels formed within the lens structures. This nesting approach allows the cooling system to be contained within the existing component volumes rather than requiring separate external cooling apparatus, thereby improving cooling effectiveness without significantly increasing the overall head size
Solution Approach 2:
The cooling function is merged with the optical components by forming cooling channels directly within the lens structures. This combination eliminates the need for separate cooling assemblies and reduces the overall volume required for the laser machining head while maintaining effective cooling capability
2Productivity
If high laser power is used for machining, then productivity increases, but heating of optical elements causes focus shift and thermal lens effects
Solution Approach 1:
Cooling channels are pre-formed within the optical components before assembly, allowing cooling medium to be introduced immediately upon operation. This preliminary preparation of the cooling pathway enables immediate heat removal when high power laser operation begins, preventing thermal accumulation that would cause focus shift and thermal lens effects
Solution Approach 2:
A cooling medium (gas or liquid) is introduced as an intermediary substance that absorbs heat from the optical components. The cooling medium flows through channels within the optical elements, acting as a thermal intermediary that transfers heat away from the high-power laser interaction zones, thereby maintaining optical element temperatures and preventing focus shift while allowing high productivity operation
3Temperature
If movable components are cooled actively with cooling medium, then thermal effects are reduced, but hoses may be damaged by repeated traversing movements
Solution Approach 1:
The mechanical connection method is replaced by forming cooling channels directly within the movable optical components themselves. This eliminates the need for external hoses that would be damaged by repeated movements, while maintaining effective cooling of the movable components through the integrated internal channels
Solution Approach 2:
The cooling channels are nested within the movable optical components, creating a self-contained cooling system. This nesting eliminates the need for external flexible hoses that connect to movable parts, thereby preventing hose damage from repeated traversing movements while maintaining active cooling capability for the movable components
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The described cooling system provides effective convective cooling without damaging hoses and enhances heat dissipation, maintaining the beam-forming unit's performance and stability even at high laser powers by actively cooling movable components and using reflective coatings to manage scattered radiation.
Implementation Method 1
a cooling water circuit arranged or formed on an immovable component of the beam-forming unit for water cooling of the immovable component and the cooling medium
Implementation Method 2
the beam-forming unit can be at least partially provided with a coating that is highly reflective for the laser wavelength, to reduce heating of the coated part of the beam-forming unit
Implementation Method 3
a cooling system for forced movement of a cooling medium to actively cool a movable component of the beam-forming unit
Implementation Method 4
The active cooling of the movable component by the moving cooling medium reduces the heating of the movable component and the lenses and associated length changes and thermal lens effects
Data Source
AI summary
The disclosure relates to a beam-forming unit for forming a laser beam and focusing the laser beam onto a workpiece. The unit includes a movable component, an immovable component, and a cooling system configured for movement of a cooling medium to actively cool the movable component. The cooling system has-a cooling water circuit on the immovable component configured for water cooling of both the immovable component and the cooling medium.