Laser Cutting Microjoints With Asymmetric Power Ramping
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Solution Overview
Problem
Current laser cutting methods for producing microjoints in plate-shaped workpieces are complex, time-consuming, and reduce productivity, especially when dealing with workpieces thicker than 5 mm, as they require extensive rework and additional grooving, and often result in tilting issues due to uneven support systems.
Innovation Solution
A method that adjusts a single cutting parameter, such as laser power or cutting speed, with specific gradients to create microjoints of reduced thickness, allowing for simpler and more reliable production by ensuring the cutting process does not complete through the workpiece, thereby maintaining the microjoint in the lower area of the cutting gap, without altering other parameters like cutting gas pressure or focus position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple cutting parameters are changed during microjoint creation, then microjoint formation is achieved, but process complexity and time consumption increase
Solution Approach 1:
The patent applies parameter changes by adjusting only the laser power during microjoint creation while keeping other cutting parameters constant. This selective parameter modification achieves reliable microjoint formation without the complexity of coordinating multiple changing parameters, directly resolving the contradiction between reliability and process complexity
Solution Approach 2:
The cutting process is segmented into distinct phases: normal cutting phase and microjoint creation phase. During the microjoint phase, only laser power is modified while other parameters remain unchanged, simplifying the control process while ensuring reliable microjoint formation
2Strength
If microjoints extend across entire workpiece thickness, then workpiece parts are securely fixed, but removal becomes difficult and post-processing time increases
Solution Approach 1:
The microjoint is designed with local quality by limiting its presence only to the lower region of the workpiece thickness rather than extending through the entire thickness. This creates sufficient fixation strength at the critical lower area while leaving the upper region free for easy manual removal, eliminating time-consuming post-processing
Solution Approach 2:
Instead of creating a complete through-cut microjoint, the patent applies partial action by forming the microjoint only in the lower region of the workpiece. This partial microjoint provides adequate fixation during cutting while allowing easy removal afterward, resolving the contradiction between fixation strength and removal ease
3Reliability
If additional piercing and approaching steps are added for multiple microjoints, then microjoint formation is achieved, but productivity decreases
Solution Approach 1:
The patent maintains continuity of useful action by forming multiple microjoints in a single continuous cutting pass without additional piercing or approaching steps. The laser simply continues cutting along the contour, automatically creating microjoints at designated locations, which preserves productivity while ensuring reliable multiple microjoint formation
4Adaptability or versatility
If workpiece sections are randomly positioned on support strips, then support flexibility is maintained, but automated removal becomes difficult
Solution Approach 1:
The patent extracts the workpiece parts from the remaining workpiece by creating removable microjoints in the lower region. This allows workpiece parts to be easily removed by hand or automated systems regardless of their random positioning on support strips, resolving the contradiction between positioning flexibility and removal ease
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 approach enables the reliable and efficient production of microjoints with reduced thickness, facilitating easier separation of workpiece parts and maintaining productivity by minimizing the need for additional processing steps and reducing residues on the cutting edge.
Implementation Method 1
laser cutting a workpiece, in particular a plate-shaped one, along a path curve using a laser beam
Implementation Method 2
the laser power of the laser beam on a section of the path curve corresponding to the length of the microjoint is reduced from a higher laser power sufficient to cut through the workpiece
Implementation Method 3
the cutting gas pressure during the cutting process can cause the section to tilt
Data Source
Figure 1~2b
Figure 3~4
Figure 5a~5f
AI summary
The invention relates to a method for laser cutting an in particular flat workpiece (6) along a curve (K) by means of a laser beam (5). In order to produce a microjoint (14) which has a lower height (d) than the workpiece thickness (d) and does not lie at the end of the curve (K), during laser cutting the workpiece (6), the laser power of the laser beam (5) on a segment of the curve (K) which corresponds to the length (L) of the microjoint (14) is reduced from a higher laser power (PA) sufficient to cut through the workpiece (6) to a lower laser power (PS) insufficient to completely cut through the workpiece (6) and is then increased back to the higher laser power, the time for the power drop (-∆P) from the higher to the lower laser power being different from that for the power increase (+∆P) from the lower to the higher laser power.