Oxygen is an essential gas for laser cutting. It is used to react with the metal being cut, creating a high-temperature plasma that melts and vaporizes the material. The resulting cut is clean and precise.
There are several different types of oxygen generators that can be used for laser cutting. The most common type is a pressure swing adsorption (PSA) generator. PSA generators use a zeolite adsorbent to separate oxygen from air. The zeolite adsorbs nitrogen, leaving behind a stream of high-purity oxygen.
Types of Oxygen Generators Used for Laser Cutting
| Type of Generator | Description |
|---|---|
| PSA (Pressure Swing Adsorption) | Commonly used for nitrogen generation but can be adapted for oxygen; however, achieving the required purity (99.95%) is challenging due to argon contamination. |
| Membrane Technology | Offers a more straightforward solution for generating high-purity oxygen but may have limitations in flow rates compared to PSA systems. |
| Cryogenic Systems | These systems are capable of producing very high purity levels but are typically more expensive and complex to operate. |
Oxygen generators are a cost-effective and reliable way to provide oxygen for laser cutting. They can be used to supply a single laser cutter or an entire laser cutting shop.
Why Oxygen Generator for Laser Cutting?
Oxygen generators are essential for laser cutting because they provide a high-purity oxygen supply, which significantly enhances the cutting process.
Oxygen for Laser Cutting Benefits：
Improved Cutting Quality
Faster cutting speeds: Oxygen gas reacts with the molten metal, accelerating the cutting process.
Cleaner cuts: The high-purity oxygen minimizes the formation of slag and dross, resulting in cleaner and more precise cuts.
Thicker material cutting: Oxygen allows for the cutting of thicker materials, expanding the range of applications.
Cost-Effective Solution
Eliminates the need for oxygen cylinders: On-site oxygen generation reduces the cost of purchasing and storing oxygen cylinders.
Consistent supply: Ensures a continuous supply of high-purity oxygen, avoiding interruptions in production.
Reduced operational costs: Lower maintenance costs and energy consumption compared to traditional oxygen supply methods.
Environmental Benefits
Reduced carbon footprint: On-site oxygen generation reduces the need for transportation of oxygen cylinders, minimizing carbon emissions.
Sustainable solution: A more environmentally friendly approach to laser cutting operations.
Choosing the Right Oxygen Generator for Laser Cutting
- Material Compatibility
Oxygen is ideal for cutting carbon steel and mild steel, especially for thicknesses between 2mm and 20mm. It enhances cutting speed due to its exothermic reaction with metals, which generates additional heat during the cutting process.
Nitrogen is preferred for cutting materials like stainless steel, aluminum, and brass. It does not react with the material, resulting in higher edge quality and less oxidation, which is crucial for post-processing tasks like welding.
- Purity Requirements
For effective laser cutting, oxygen purity must be at least 99.95%. Higher purity levels enhance combustion efficiency, aiding in cleaner cuts; however, this often comes at a higher cost34. It’s advisable to invest in high-purity oxygen only when dealing with very thin metals that are prone to damage.
- Pressure Settings
For thin sheets (2-3mm), pressures can go up to 20-bar.
For thicker materials (over 20mm), pressures typically do not exceed 1-bar.
- Cutting Speed and Quality
While oxygen can increase cutting speed due to its reactive nature, it may lead to oxidized edges that can complicate subsequent processes like welding. In contrast, nitrogen provides a cleaner cut without oxidation but may require slower speeds depending on the thickness of the material.
4 Reasons Why Metals Can Be Cut by Oxygen:
1.Whether the ignition point of metal in oxygen is lower than the melting point
The essence of gas cutting is that the metal burns into slag in oxygen, and the slag is blown away to form incisions. Therefore, to enable the metal to be cut, the ignition point of the metal in oxygen must be lower than the melting point, otherwise, the metal will melt before it burns, which is not the so-called gas cutting. Moreover, the material melts before burning, and the quality of the cut obtained will be poor.
2.Is the melting point of the slag (oxide) of the metal combustion sound field lower than the melting point of the metal?
And whether the slag has good fluidity in the liquid state. Generally speaking, the melting point of the slag produced by metal combustion should be lower than the melting point of the metal. If the melting point of the slag is higher than the melting point of the metal, the slag will solidify before the liquid metal solidifies, thereby forming a solid film on the surface of the liquid metal, or the formed slag has a higher viscosity and is not easily removed by cutting oxygen. Blow away from the incision.
Metal is difficult to gas cut. However, if the generated slag has good fluidity and low viscosity, and the slag can be blown away from the incision by cutting oxygen, then the metal can be gas-cut.
3.When metal burns in oxygen, can it release more heat?
An important condition for smooth cutting is to ensure that the metal at the leading edge of the incision can be quickly and continuously heated to the ignition point. Therefore, sufficient heat generated by the gas flame and metal combustion is required to ensure that the above conditions are met.
If the metal burns in oxygen, the amount of heat released is too small too quickly and continuously heat the metal at the front edge of the incision to the ignition point, and the heavy metal is difficult to be gas-cut.
4.Whether the thermal conductivity of the metal is too good.
The heat generated by the gas flame and the heat generated by the burning of the metal are not all used to heat the metal at the front edge of the incision, but only a part of it, and the other part is lost through radiation, heat conduction, etc.
If the thermal conductivity of the metal is too good, and the heat used to heat the metal at the leading edge of the incision is not enough to ensure that the metal at the leading edge of the incision can be quickly and continuously heated to the ignition point, the cutting will be difficult to proceed smoothly.
Conclusion
Oxygen generators offer a reliable, cost-effective, and environmentally friendly solution for laser cutting operations. By providing a continuous supply of high-purity oxygen, they contribute to improved cutting quality, increased productivity, and reduced operational costs.
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