Laser Ablation of Safety Rupture Discs
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Solution Overview
Problem
Existing methods for producing safety/rupture discs with pre-calculated breaking thresholds are inefficient due to mechanical alterations and high production costs, as they often involve direct contact with tools that cause mechanical and crystalline structure changes, leading to inaccurate and costly production with significant tool degradation.
Innovation Solution
A method using a pulse laser to directly create non-through cuts on the disc surface by ablating material with carefully selected wavelength, pulse duration, and motion parameters, minimizing heat-affected zones and resolidified layers, allowing for precise control of score depth and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mechanical cutting methods (punches, micro-milling) are used to create non-through cuts, then cuts can be made with direct tool contact, but this causes mechanical alterations and crystalline structure changes in the disc material, leading to inaccurate breaking thresholds and tool degradation
Solution Approach 1:
The patent replaces mechanical cutting tools (punches, micro-milling tools) with a laser beam for creating non-through cuts. This substitution eliminates direct mechanical contact between tools and the disc material, preventing mechanical alterations and crystalline structure changes that would otherwise occur. The laser beam achieves precise material removal through ablation without the harmful side effects of mechanical machining, thereby maintaining both cut accuracy and the reliability of the breaking threshold.
Solution Approach 2:
The patent utilizes laser parameters (wavelength, pulse duration, power, scanning speed) to control the cutting process. By adjusting these parameters, the laser can precisely remove material to create non-through cuts with controlled depth and minimal heat-affected zones. This parameter control enables accurate cutting while preserving the metallurgical structure of the disc material, resolving the contradiction between manufacturing precision and breaking threshold accuracy.
2Productivity
If laser beam is used to directly machine non-through cuts on the disc, then production speed increases and costs decrease, but this causes significant heating and burning of the disc, oxidizing the material and changing the metallurgy of the metal
Solution Approach 1:
The patent employs pulsed laser operation instead of continuous laser beam. The laser delivers energy in short pulses with specific duration (e.g., nanoseconds to microseconds), allowing the material to cool between pulses. This periodic action enables material ablation through repeated heating cycles while limiting the total heat input, thereby preventing excessive heating, burning, and oxidation that would occur with continuous laser exposure. The pulse frequency and duty cycle are controlled to optimize material removal while minimizing thermal damage.
Solution Approach 2:
The patent uses ultra-short pulse durations (nanosecond to picosecond range) to deliver energy so rapidly that material ablation occurs before significant heat diffusion can take place. The laser pulse rushes through the material interaction process extremely quickly, removing material through direct ablation rather than gradual melting and oxidation. This 'rushing through' approach minimizes the time window for harmful thermal effects to develop, achieving high-speed cutting with minimal heat damage.
3Object-affected harmful factors
If protective material layer is applied and removed before laser cutting, then direct laser contact with disc is prevented, but this involves very long work times and high production costs
Solution Approach 1:
The patent extracts or removes the protective material layer step from the manufacturing process entirely. Instead of applying a protective layer before laser cutting and then removing it afterward, the invention uses laser parameters and processing techniques that allow direct laser interaction with the disc material without causing harmful effects. This eliminates the time-consuming steps of layer application and removal while maintaining the benefits of protected cutting through proper laser parameter selection and process control.
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 method enables the production of safety discs with precise control over breaking thresholds and minimal resolidified layers, achieving consistent performance and reducing production costs by minimizing heat damage and tool degradation.
Implementation Method 1
ablating at least one non-through cut in the foil element by directly applying said laser beam to the foil element to remove material from the foil element
Implementation Method 2
remove material by two physical effects: by melting the material or through direct vaporization or ablation
Data Source
Figure 1~2
AI summary
A method for production of safety/rupture discs (1) comprises the steps providing a foil element (la), selecting a wavelength for a laser beam of a pulse laser within a range of between 800 nanometers and 1800 nanometers, selecting a pulse repetition rate for the laser beam within a range of between 15 KHz and 800 KHz, selecting a pulse duration for the laser beam less than 10 nanosecond and ablating at least one non-through cut (2) in the foil element by directly applying said laser beam to the foil element to remove material from the foil element (1a) thereby obtaining a safety/rupture disc.