Ultrashort Laser Pulse Sequence for Precision Material Removal
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Solution Overview
Problem
Laser machining with ultrashort pulses causes undesired modifications and damage to surrounding material due to high laser pulse energy and intensity, leading to mechanical and thermal damage, particularly in materials with high thermal conductivity or low laser light absorption.
Innovation Solution
A method involving a sequence of laser pulses with reduced pulse energy and intensity, achieved through spatial overlap of consecutive pulses and adjustable pulse repetition rates, to minimize thermal and mechanical influence on adjacent areas, allowing for precise material removal with lower energy input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high laser pulse energy and intensity are used for material removal, then material removal efficiency is improved, but mechanical and thermal damage to surrounding material increases
Solution Approach 1:
The patent divides the material removal process into multiple sequential ultrashort laser pulses instead of using a single high-energy pulse. Each pulse delivers a controlled amount of energy below the damage threshold, and cumulative material removal is achieved through repeated application. This segmentation allows efficient material ablation while preventing thermal and mechanical damage to surrounding areas.
Solution Approach 2:
The patent employs periodic ultrashort laser pulses with specific repetition rates to achieve material removal. The periodic application of low-energy pulses allows heat dissipation between pulses, preventing thermal accumulation and damage. The pulse frequency is optimized to balance removal efficiency with damage prevention, creating a rhythmic processing pattern that maintains material integrity.
2Object-affected harmful factors
If a sequence of laser pulses with reduced energy is used, then damage to surrounding material is minimized, but the number of pulses required increases
Solution Approach 1:
The patent maintains continuous material removal action by using ultrashort pulse durations (10^-15 to 5×10^-10 seconds) that are short enough to prevent heat diffusion but long enough to deliver effective energy. The pulses are applied in rapid succession with optimized repetition rates, ensuring that material removal continues without interruption while each individual pulse remains below damage thresholds. This continuous action achieves both damage minimization and time efficiency.
Solution Approach 2:
The patent optimizes multiple parameters including pulse duration, repetition rate, and pulse energy to achieve the desired balance. By adjusting these parameters, the system maximizes material removal efficiency while keeping each pulse below damage thresholds. The parameter optimization ensures that the total processing time remains acceptable despite using multiple lower-energy pulses.
3Manufacturing precision
If ultrashort laser pulses are used for high-precision machining, then manufacturing precision is improved, but the complexity of controlling pulse parameters increases
Solution Approach 1:
The patent utilizes the intrinsic properties of ultrashort laser pulses to achieve self-regulated material removal. The ultrashort duration automatically limits heat diffusion, and the cumulative effect of multiple pulses naturally controls the removal rate. This self-service mechanism reduces the need for complex external control systems, as the physics of ultrashort pulses inherently provides the precision and damage prevention benefits.
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 reduces mechanical and thermal damage by distributing the required energy over multiple pulses, achieving precise material removal with lower laser pulse energy, minimizing damage to the surrounding material and maintaining control over the machining process.
Implementation Method 1
The use of laser pulses, in particular ultrashort laser pulses with a pulse duration in the range of between approximately 10−15 s and 5×10−10 s, for high-precision laser microstructuring is known
Data Source
AI summary
The invention relates to a method for removing material by means of a laser, wherein a sequence of laser pulses is generated and an area of material to be machined is irradiated with the sequence of laser pulses. Methods of this kind are used to cut a number of different materials. One problem with this method is that thermal or mechanical damage occurs in the surroundings of the area being machined and causes impairment of areas of material that are not being machined. The invention solves this problem by the pulse energy of a single pulse in the sequence of laser pulses being lower than the laser pulse energy required to produce material removal using an isolated laser pulse in the region irradiated with the single laser pulse of the sequence of laser pulses.