Rotatable Lens Arrays for Thick Sheet Laser Cutting Absorption
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Solution Overview
Problem
Existing laser processing machines face difficulties in cutting thick sheet metal with an appropriate slit width while maintaining a high laser absorption rate, as increasing the condensing diameter of the laser beam reduces the incident angle, leading to lower energy density and absorption ratios.
Innovation Solution
The laser processing machine employs a collimating lens, a condensing lens, a first lens array, a second lens array, and a rotation mechanism to adjust the condensing diameter and incident angle, ensuring high absorption rates by rotating at least one of the lens arrays, thereby maintaining the incident angle close to the Brewster angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the condensing diameter of the laser beam is increased to widen the cut slit width for thick sheet metal, then the cut slit width is improved, but the incident angle of the laser beam is decreased leading to lower laser absorption rate
Solution Approach 1:
The patent employs a rotatable lens array that can dynamically adjust the incident angle of the laser beam while maintaining a fixed condensing diameter. This dynamic adjustment capability allows the system to optimize both the cut slit width and laser absorption rate simultaneously, resolving the contradiction between these two parameters.
Solution Approach 2:
The patent changes the incident angle parameter independently from the condensing diameter by rotating the lens array. This parameter separation allows the condensing diameter to remain constant (maintaining appropriate cut slit width) while the incident angle is adjusted to optimize laser absorption rate, thereby resolving the technical contradiction.
2Volume of moving object
If the incident angle of the laser beam is decreased to increase the condensing diameter, then the condensing diameter is improved, but the energy density on the sheet metal is lowered
Solution Approach 1:
The rotatable lens array provides dynamic control over the incident angle, allowing the system to maintain a fixed condensing diameter (appropriate for thick sheet metal) while adjusting the incident angle to preserve high energy density. This dynamic adjustment resolves the contradiction between condensing diameter and energy density.
Solution Approach 2:
By changing the incident angle parameter through lens array rotation while keeping the condensing diameter constant, the system can optimize energy density without compromising the condensing diameter needed for appropriate cut slit width in thick sheet metal processing.
3Volume of moving object
If the incident angle of the laser beam is decreased, then the condensing diameter is increased, but the emission angle becomes close to 90° reducing absorption ratio
Solution Approach 1:
The patent uses a dynamically rotatable lens array to independently control the incident angle from the emission angle. This dynamic adjustment allows the emission angle to be optimized for high absorption ratio (close to Brewster's angle) while the incident angle and condensing diameter are maintained at appropriate values for thick sheet metal cutting.
Solution Approach 2:
The patent separates the control of incident angle and emission angle parameters through the rotatable lens array mechanism. This allows independent optimization: the incident angle is set to produce the desired condensing diameter, while the emission angle is adjusted via rotation to maximize absorption ratio, resolving the contradiction between these parameters.
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 allows for efficient cutting with a desired slit width and high laser absorption rates, even with thick sheet metal, by adjusting the condensing diameter and maintaining the incident angle near the Brewster angle, ensuring effective molten metal discharge.
Implementation Method 1
a collimating lens configured to convert an incident laser beam into a collimated beam
Implementation Method 2
a condensing lens configured to focus the converted collimated beam so as to irradiate a sheet metal
Implementation Method 3
a first lens array structured by arranging a plurality of first microlenses in a planar shape so as to refract the incident laser beam by each of the first microlenses
Implementation Method 4
a second lens array structured by arranging a plurality of second microlenses in a planar shape so as to make the laser beam emitted from each of the microlenses of the first lens array incident and refracted by a corresponding one of the second microlenses
Data Source
AI summary
A laser processing machine includes a collimating lens configured to convert a laser beam into a collimated beam, a condensing lens configured to focus the collimated beam onto a sheet metal, a first lens arrays structured by arranging a plurality of first microlenses in a planar shape so as to refract the laser beam by each of the first microlenses, a second lens array structured by arranging a plurality of second microlenses in a planar shape so that a center thereof is set at a same position in an optical axis direction as a center of the first lens array so as to make the laser beam emitted from each of the first microlenses incident and refracted by a corresponding one of the second microlenses, and a rotation mechanism configured to rotate at least one of the first lens array and the second lens array along an outer periphery thereof.