Laser Scanner Optics Layout to Prevent 3D Workpiece Self-Shadowing
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Solution Overview
Problem
Current laser beam guidance systems face challenges in processing three-dimensionally shaped objects due to self-shadowing, which can lead to reduced processing quality or damage, and require complex and costly opto-mechanical systems for precise adjustment.
Innovation Solution
The device positions scanner mirrors farther from the focusing optics than in prior art, tilting the light path towards the optical axis to prevent self-shadowing, allowing for efficient processing of three-dimensionally shaped objects using simpler lenses and achieving high processing speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the scanner mirrors are positioned close to the focusing lens to maximize the processing area, then the processing area is increased, but self-shadowing occurs on three-dimensional workpieces leading to reduced processing quality
Solution Approach 1:
The patent positions the scanner mirrors at a distance greater than the focal length of the focusing lens along the optical axis, creating a spatial separation that changes the beam convergence angle. This dimensional adjustment in the optical path allows the laser beam to strike the workpiece at a more favorable angle, preventing self-shadowing while maintaining a large processing area through the galvo mirror deflection capability.
2Manufacturing precision
If laterally mounted additional mirrors are used to direct laser radiation onto three-dimensional objects, then self-shadowing is prevented, but the device complexity and alignment precision requirements increase
Solution Approach 1:
The patent makes the existing scanner mirrors serve a dual function: they both deflect the laser beam to achieve lateral scanning coverage and simultaneously control the beam's angular orientation to prevent self-shadowing. By positioning these mirrors beyond the focal point, the same components that provide scanning functionality also inherently control the beam convergence angle, eliminating the need for separate alignment mirrors and reducing overall system complexity.
3Area of stationary object
If the laser beam is focused with a flat-field lens at an angle away from the optical axis, then the processing area is maximized, but shadowing by workpiece protrusions occurs
Solution Approach 1:
The patent changes the key parameter of beam convergence angle by adjusting the scanner mirror position to be greater than the focal length of the focusing lens. This parameter change transforms the beam trajectory from one that creates shadowing (angled away from optical axis) to one that prevents shadowing (angled towards optical axis), while the galvo mirror deflection maintains the large processing area coverage.
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
This configuration enables improved processing quality and throughput by preventing self-shadowing and allowing for efficient machining of elevated areas on workpieces, such as welding plastic components, without the need for complex and costly systems.
Implementation Method 1
the laser beam is directed via a mirror arrangement
Implementation Method 2
a focusing optical arrangement with a focal point F, in which the laser radiation is focused
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a device for guiding a laser beam in order to machine a workpiece, wherein the laser beam is deflected by means of a mirror system and a focusing optical system onto machining points on the workpiece that can be preselected by suitably orienting the mirrors. According to the invention, the mirror system is arranged further than the single focal distance from the optical principal plane of the optical system. The device makes it possible to machine workpieces having elevations by means of a laser scanning device without self-shading occurring.