Laser Drilling Optical Assembly for Steep Wall Angles
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Solution Overview
Problem
Existing laser drilling techniques are limited in creating steep wall angles and aspect ratios due to reduced pulse intensity on inclined ablation flanks, resulting in vertical cuts or conical boreholes, which are not desirable for many applications.
Innovation Solution
A dynamic deflection device deflects the laser beam perpendicularly into two directions, combined with an optical assembly featuring two optical systems that focus the beam onto the processing plane, allowing for large and deep boreholes or cuts with a stable and inexpensive construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If perpendicular irradiation is used for laser drilling, then the construction is simple and stable, but the wall angle is limited to up to 85° and vertical cuts are not achievable
Solution Approach 1:
The patent introduces a new spatial dimension by positioning the focal point above the workpiece surface rather than directly on it. This elevated focal position allows the laser beam to approach the workpiece at oblique angles while maintaining perpendicular irradiation geometry, enabling wall angles greater than 85° and vertical cut flanks without complicating the optical system configuration
2Manufacturing precision
If rotating optical elements are used to guide the laser beam, then various wall angles can be achieved, but the deflection speed is reduced non-linearly for larger drilling diameters
Solution Approach 1:
The patent replaces the mechanical rotating optical elements with a static optical system that achieves angle control through geometric configuration. By positioning the focal point in space above the workpiece and using fixed optical elements, the system eliminates mechanical rotation while maintaining the ability to produce various wall angles, thereby preserving high deflection speed without non-linear reduction
3Measurement precision
If the focal point is positioned on the workpiece surface, then the laser beam can be focused precisely, but large angle of attacks can only be realised for large contours
Solution Approach 1:
The patent moves the focal point from the workpiece surface into the space above it, creating a three-dimensional focal position. This spatial relocation allows the laser beam to intersect the workpiece at various angles while maintaining precise focus, enabling large angles of attack for both small and large contours without sacrificing focus precision
4Volume of moving object
If the size of rotatable optical elements is increased for larger drilling diameters, then larger boreholes can be drilled, but the deflection speed is reduced
Solution Approach 1:
The patent eliminates mechanical rotation entirely by using a static optical system with a spatially positioned focal point. This substitution allows larger borehole diameters to be drilled without increasing optical element size or sacrificing deflection speed, as the angle control is achieved through geometric configuration rather than mechanical rotation
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
Enables the creation of positively and negatively conical boreholes, cylindrical shapes, and three-dimensional forms with vertical ablation flanks, overcoming the limitations of conventional systems by achieving larger angles of attack and aspect ratios.
Implementation Method 1
material processing techniques using short and ultra-short laser pulses for laser beam cutting or laser drilling
Implementation Method 2
an optical assembly, with which a laser beam exiting the deflection device can be focused onto a processing plane
Data Source
AI summary
The present invention relates to an assembly for material processing using a laser beam, in particular for laser drilling, comprising a dynamic deflection device (AE) for the laser beam (LS), and an optical assembly, with which a laser beam (LS) exiting the deflection device (AE) is focused onto a processing plane (W). Along an optical axis, the optical assembly has a first optical system (OS1) and a second optical system (OS2), which are designed and arranged such that the laser beam (LS) forms an intermediate focus (ZF) between the first and the second optical system (OS1, OS2), and intersects the optical axis when entering the first optical system (OS1) at an angle to the optical axis and at a distance therefrom between the second optical system (OS2) and the processing plane (W). The suggested assembly has a simple, stable structure, with which efficient ablation of large and deep boreholes or cuts in a workpiece is enabled.