When Laser Cutting Stainless Steel, How To Choose The Right Gas Assist To Improve The Cut Quality?

As an advanced metal processing technology, laser cutting technology has been widely used in industrial manufacturing in recent years. Its main advantages are fast cutting speed, high precision and small heat-affected zone, which can achieve complex shapes and high-precision cutting needs. Laser cutting can not only process various metal materials, but also shows great application potential in many fields such as automobiles, aerospace, construction and precision manufacturing.

However, when cutting difficult-to-process materials such as stainless steel, there are a series of challenges. First, the high thermal conductivity and toughness of stainless steel make it difficult to quickly dissipate the heat generated during the cutting process, which may cause the cutting edge to melt, deform or oxidize. Secondly, the balance between cutting speed and quality also brings challenges to the operation. Too fast cutting may cause rough edges or uneven cuts.

In the laser cutting process, the selection and application of auxiliary gas becomes an important factor in improving the cutting quality. Different gases have a significant impact on the cutting effect. For example, oxygen can increase the cutting speed, but may cause the formation of an oxide layer; while nitrogen can reduce oxidation and improve the quality of the cutting edge. Therefore, the rational selection and use of suitable cutting gas is crucial to overcome the challenges of stainless steel cutting and improve the cutting effect. Through precise gas-assisted cutting, not only can high-quality cutting results be achieved, but also production efficiency can be effectively improved and costs can be reduced.

Laser cutting is a processing technology that uses a high-energy laser beam to precisely cut materials. Its basic principles involve the generation, focusing, and interaction of lasers with materials.

● How laser cutting works

1. Laser generation: Laser cutting machines use lasers to generate high-intensity laser beams. Common types of lasers include fiber lasers, CO2 lasers, and solid-state lasers. These lasers emit monochromatic, highly coherent laser beams by exciting specific media (such as gas or solid materials).

2. Laser focusing: The generated laser beam is focused to a small focal area through a lens system. The energy density of this focal area is extremely high and can reach a temperature sufficient to melt or vaporize the material. The movement of the cutting head and the focusing of the laser jointly determine the shape and size of the cutting path.

3. Cutting process: When the focused laser beam irradiates the surface of the material, the instantaneous high temperature causes the material to melt (or vaporize) rapidly at the cutting point to form an incision. At the same time, auxiliary gases (such as oxygen, nitrogen, etc.) are ejected through the nozzle to help blow away the molten metal, ensure a clean incision, and improve cutting speed and quality.

● Interaction between laser and material

1. Absorption and reflection: The interaction between laser and material depends first on the optical properties of the material. Most metal materials have good absorption of laser and can effectively absorb laser energy. However, some materials (such as mirror metal) may reflect laser, resulting in reduced cutting efficiency.

2. Heating and melting: When the laser energy is absorbed by the material, the local temperature rises rapidly, causing the material to melt or evaporate. In the process of cutting stainless steel, the heat generated by the laser energy causes the material to melt rapidly under the action of the laser beam to form a molten pool.

3. Vaporization and injection: At higher energy density, the material will directly vaporize rather than melt, forming an incision and releasing steam. The role of auxiliary gas is particularly important at this stage. It can not only take away the molten metal and improve cutting efficiency, but also prevent the formation of oxides on the cutting surface, thereby ensuring the smoothness and neatness of the incision.

4. Heat-affected zone: Laser cutting usually has a smaller heat-affected zone because its heating is only concentrated near the cutting point, and the surrounding material is less heated, which reduces deformation and stress concentration problems, thereby improving cutting accuracy and component quality.

Through the above process, laser cutting technology can achieve efficient and precise metal processing, especially when processing high-strength materials such as stainless steel, showing unique advantages. Click here for more information

In laser cutting, choosing the right cutting gas is crucial to improving cutting quality, efficiency and reducing costs. Different gases have different characteristics and uses. The following is a detailed analysis of four commonly used cutting gases:

1. Oxygen

● Advantages: Oxygen is an extremely effective auxiliary gas that can significantly improve cutting speed and efficiency. It reacts with metal at high temperatures to generate oxides, thereby accelerating the melting of metal.

● Applicable situations: Very suitable for thicker stainless steel cutting, especially when there are high requirements for cutting speed and production efficiency, oxygen can achieve fast and efficient cutting.

● Note: When cutting with oxygen, an oxide layer may be produced on the surface of the cut, which will affect subsequent coating or welding. Therefore, the surface after cutting usually needs to be treated to remove oxides.

2. Nitrogen

● Advantages: Nitrogen can effectively reduce metal oxidation during the cutting process, improve cutting quality, and ensure smooth and neat cutting edges, especially for stainless steel materials.

● Applicable situations: Nitrogen is suitable for thin plates and fine cutting tasks with high surface quality requirements. This makes the cut edge cleaner and can directly meet the requirements of subsequent processing.

● Note: Compared with oxygen, nitrogen has a slower cutting speed, so it may affect production efficiency, especially when processing thicker materials.

3. Air

● Advantages: Air is a low-cost and easy-to-use cutting gas, suitable for processing tasks with limited budgets. It can be used as an alternative gas in many cases.

● Applicable situations: Suitable for cutting tasks with lower requirements, such as thin plate cutting or experimental purposes, and suitable for some non-precision cutting work.

● Note: The use of ordinary air may cause the cutting surface to be rough and form a thicker oxide layer, which affects the cutting quality and the feasibility of subsequent processing. Therefore, it is not recommended for use in strict occasions.

4. Helium

● Advantages: Helium has good thermal conductivity, which can improve the cooling effect and improve the quality of the cutting edge. This gives it unique advantages in specific industry applications.

● Applicable situations: Suitable for occasions requiring high precision and special applications, such as aerospace and medical equipment manufacturing, to ensure meticulous and high standards of cutting.

● Note: The cost of helium is relatively high, so its economic efficiency and cutting needs must be weighed when using it. Usually only used in specific situations where high-performance cutting is required.

Selecting the right cutting gas is an important part of the laser cutting process. Different gases have significant differences in cutting effect, speed and cost. According to the specific cutting material, thickness and quality requirements, the rational use of these gases can greatly improve the cutting efficiency and quality, ensuring the smooth progress of the production process. Click here for more information

During laser cutting, the type of cutting gas has a significant impact on the smoothness of the cutting edge and the width of the kerf. Choosing the right cutting gas can optimize the cutting effect and improve product quality. The following is a detailed analysis of these two aspects.

● Relationship between the smoothness of the cutting edge and the type of gas

1. Oxygen:

When used to cut steel and certain metal materials, oxygen can effectively increase the cutting speed and produce good cutting edge smoothness. The oxidation reaction of oxygen can provide additional heat, making the metal cut more clearly. However, for some materials (such as aluminum or stainless steel), oxygen may generate oxides, which will affect the smoothness of the cutting edge.

2. Nitrogen:

Nitrogen performs particularly well when cutting stainless steel and aluminum, and can effectively reduce oxidation, thereby improving the smoothness of the cutting edge. When cutting with nitrogen, due to its inertness, it will not react with the material, so a very smooth cutting edge can be obtained, reducing the need for subsequent processing.

3. Helium:

When cutting certain highly reflective materials (such as copper and gold), helium can effectively improve the cutting quality, reduce the heat-affected zone, and make the cutting edge smoother due to its low density and high thermal conductivity.

4. Air:

Although the cost of using air as a cutting gas is low, the effect is not ideal. The air contains impurities and moisture, which can easily lead to roughness and oxidation of the cutting edge, causing difficulties in later processing.

● Correlation between kerf width and cutting gas

1. Gas type:

Different cutting gases directly affect the kerf width. Taking oxygen cutting as an example, due to its strong reactivity, it often leads to a larger kerf width because heat and slag are generated during the cutting process, increasing the heat-affected zone of the incision. In contrast, nitrogen and helium can achieve narrower kerfs because they do not participate in the reaction.

2. Gas flow rate:

The flow setting of the cutting gas also has an important impact on the kerf width. The appropriate flow rate can ensure that the slag is effectively removed, thereby reducing the kerf width. If the flow rate is too low, slag may accumulate near the cut, increasing the kerf width and causing uneven cutting.

3. Cutting speed:

The cutting speed is also closely related to the selected gas type and flow rate. Faster cutting speeds usually achieve narrower kerfs when using nitrogen because the molten metal is quickly carried away by the gas flow, reducing the kerf width. However, if the cutting speed is too fast, it may result in incomplete cutting, so a balance must be found between cutting quality and kerf width.

4. Material properties:

The properties of the material itself (such as thickness, thermal conductivity, etc.) are also related to gas selection and kerf width. For example, when cutting thicker materials, the heat transfer and slag removal capabilities of the required gas will affect the kerf width.

Gas selection is crucial in laser cutting, and different gas types have a direct impact on the smoothness of the cut edge and the kerf width. Cutting gases such as oxygen, nitrogen, and helium must be reasonably selected based on the characteristics of the specific material, cutting requirements, and expected cutting quality. The gas flow setting will also have an important influence on the width of the cut, so in specific applications, the operator should make precise adjustments to achieve the ideal cutting effect. Click here for more information