Dual-Assist Laser Piercing Nozzle for Thick Plate Dross Control
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Solution Overview
Problem
The existing methods for laser cutting thick metal sections face extended cycle times and incomplete cuts due to the buildup of oxidized metal debris, which leads to increased laser power requirements, enlarged piercing holes, and irregular cut surfaces, making it difficult to achieve high-quality cuts in thick plates.
Innovation Solution
A cutting nozzle system that uses a centrally located laser with coaxial pure oxygen gas and an adjacent direction-controlled nozzle to discharge high-pressure compressed air non-axially, effectively clearing molten metal and debris, allowing for rapid piercing and smooth transition to cutting with reduced cycle time and improved cut quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high pressure oxygen gas is applied coaxially to enhance piercing efficiency through oxidation, then piercing speed and energy efficiency are improved, but oxidized metal debris accumulates and deposits on the bottom face forming hardened dross, extending cycle time and potentially clogging the kerf
Solution Approach 1:
The gas delivery system is segmented into two separate nozzles: a central nozzle delivering oxygen coaxially with the laser beam for oxidation-enhanced piercing, and a peripheral nozzle delivering compressed air tangentially to blow debris away. This segmentation allows each gas to perform its specific function without interfering with the other, resolving the contradiction between oxidation efficiency and dross accumulation.
Solution Approach 2:
Compressed air acts as an intermediary substance that mediates between the oxidation process and the debris removal. The compressed air from the peripheral nozzle serves as a carrier fluid that transports oxidized metal debris away from the cutting zone and prevents it from depositing on the bottom face, thus eliminating the harmful dross deposit while maintaining the benefits of oxygen-assisted piercing.
2Manufacturing precision
If laser power is increased to address dross buildup, then cutting capability is improved, but piercing hole diameter increases and molten metal is blown from the cut, potentially clogging the kerf and damaging the focusing lens
Solution Approach 1:
The harmful effect of molten metal accumulation is extracted and removed by the peripheral compressed air nozzle. The tangential flow of compressed air actively extracts and evacuates molten metal and debris from the cutting zone, preventing it from clogging the kerf or reaching the focusing lens, thus allowing high power laser operation without the associated harmful effects.
Solution Approach 2:
A pneumatic system using compressed air is introduced to control and remove molten metal. The peripheral nozzle delivers high velocity compressed air that creates a pneumatic flow field capable of transporting molten metal particles away from the cutting zone, providing a non-contact method to prevent clogging and lens damage while maintaining high cutting power.
3Length of stationary object
If piercing operation time is extended to ensure complete material penetration, then piercing depth is improved, but heat input into the work increases causing excessive melting and irregular cut surfaces
Solution Approach 1:
The peripheral compressed air nozzle provides continuous debris removal throughout the entire piercing process. This continuous action ensures that molten metal is constantly evacuated from the piercing zone, preventing re-solidification and irregularities on the bottom face, thereby enabling complete penetration through thick material without excessive heat accumulation or temperature rise.
Solution Approach 2:
The system changes the parameters of the assist gas from a single coaxial oxygen stream to a dual-stream configuration with oxygen at the center and compressed air in a peripheral annular region. This parameter change creates a composite gas flow pattern that simultaneously provides oxidation for efficient heating and pneumatic removal of molten metal, enabling deep piercing with controlled temperature and smooth bottom surface.
4Device complexity
If single coaxial gas system is used to simplify the setup, then device complexity is reduced, but cycle time increases due to dross accumulation requiring higher power and longer operation
Solution Approach 1:
The gas delivery system is divided into two independent but coordinated subsystems: a central oxygen delivery system and a peripheral compressed air delivery system. Each subsystem is relatively simple in structure, but their combination creates a powerful integrated system that simultaneously achieves efficient piercing and debris removal, reducing cycle time without excessive complexity.
Solution Approach 2:
The dual-nozzle system performs multiple functions simultaneously: the central oxygen nozzle provides oxidation-enhanced heating for efficient material removal, while the peripheral compressed air nozzle provides debris evacuation and bottom surface cleaning. This multi-functionality allows the system to achieve both deep penetration and clean cuts in a single operation, reducing overall cycle time despite the added structural element.
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 formation of a piercing hole of intended shape and size in thick plates, reducing cycle time and preventing excess melting, thereby ensuring high-quality cuts with reduced dross and kerf instability, even in plates thicker than 12 mm.
Implementation Method 1
The piercing operation involves the application of a high energy laser beam from a cutting nozzle to plunge an initial hole into the metal plate, heating the plate
Implementation Method 2
The application of oxygen gas during the piercing operation enhances the piercing operation by increasing the efficiency of the cutting operation. This results because increased energy is obtained as a result of the oxidation of the molten material by the flow of the oxygen gas
Implementation Method 3
supplying an assist gas which is coaxial to the laser beam, in order to form the piercing hole by removing the molten metal from the heated part of the plate by the kinetic energy of the assist gas
Data Source
AI summary
A method and system is provided for laser piercing of thick plate material that allows for rapid transition to a cutting operation that can reliably produce a piercing hole and complete a cutting operation of the intended shape in a short time, while improving the cutting quality of the cutting after switching from the piercing operation. The cutting nozzle has a centrally located laser. The piercing operation applies a laser beam to the cut work while axially supplied pure oxygen gas is applied towards the cutting work. Additionally, a direction controlled nozzle adjacent the main cutting port provides a discharge of high pressure compressed air non-axially relative to the cutting operation to clear excess molten metal and debris from the kerf thereby increasing the efficiency of the piercing and shortening the cycle time.