Oxygen plays a crucial role in laser metal cutting, especially when cutting materials such as carbon steel. When oxygen is used as an assist gas, it reacts with the molten metal, creating an exothermic reaction that generates additional heat. This heat helps to enhance the cutting process, resulting in faster cutting speeds and improved efficiency.
Furthermore, oxygen assists in burning away the molten material, resulting in a cleaner cut edge. The exothermic reaction between oxygen and the metal also helps to remove any oxides that may have formed during the cutting process, further improving the final cut quality.
However, it is important to note that the use of oxygen can lead to increased oxidation, which may not be desirable for certain applications. Therefore, it is essential to carefully consider the specific requirements of the application before choosing oxygen as an assist gas.
Nitrogen is known for its ability to improve the overall cutting quality and efficiency of the process. As a non-reactive gas, nitrogen does not cause oxidation, making it ideal for applications where minimal oxidation is desired. This is particularly important when working with metals such as stainless steel, nitinol, tungsten, and aluminum, where oxidation can negatively affect the quality of the cut.
In addition, nitrogen acts as a cooling agent to cool the material and reduce the heat-affected zone, resulting in a smoother surface finish. It also aids in reducing the risk of burring, ensuring cleaner edges.
Argon, also an inert gas, offers several advantages when used as an assist gas in laser metal cutting including titanium. Its primary role is to shield the molten material from the surrounding atmosphere, preventing oxidation. By creating a protective barrier, argon helps to maintain the integrity of the cut edge, resulting in cleaner edges and reduced burring.
Argon aids in reducing the heat-affected zone, ensuring minimal distortion and improved overall surface finish. Its inert nature ensures that the cut quality remains consistent, even when working with highly reactive metals.
Factors to Consider When Selecting and Using Assist Gasses in Laser Metal Cutting
When selecting assist gasses in laser metal cutting, careful consideration of the following factors can help to ensure optimal performance and cut quality:
- Metal Type: Different metals may require different assist gasses. Various metals and metal alloys have different densities, thermal properties, and surface reactions to assist gasses.
- Cut Quality: Determine the desired cut quality and select an assist gas that can help achieve those requirements. Factors such as edge smoothness, minimal burring, and absence of oxidation should be considered.
- Material Thickness: The thickness of the material being cut can affect the choice of assist gas. Thicker materials may require different assist gasses or a combination of gasses to achieve optimal results.
- Laser Wavelength & Power: Utilizing CO2 or Fiber based laser systems will impact how assist gasses are selected and implemented. Too much or too little power will negatively affect the cutting process and edge quality.
- Cutting Speed: The cutting speed can impact the choice of assist gas. Some gasses, such as oxygen, can enhance cutting speed, while others, like nitrogen, may slow it down. Consider the balance between speed and cut quality.
- Application Requirements: Consider the specific requirements of the application, such as regulatory standards, customer specifications, or industry norms. Ensure that the chosen assist gas meets these requirements.
- Gas Pressure and Flow Rate: Ensure that the gas pressure and flow rate are set correctly. Insufficient pressure or flow can have a negative quality result. The appropriate pressure and flow rate will vary depending on the specific metal and assist gas being used.
- Nozzle Design: Use a nozzle design that allows for efficient gas delivery (pressure & flow) and effective removal of molten material. The design should promote good gas coverage and minimize gas turbulence.
- Nozzle Height: Maintaining the proper distance between the nozzle and the metal being cut will ensure optimal gas delivery and debris removal while cutting..
- Gas Purity: Use high-purity assist gasses to minimize impurities that can affect the cut quality. Impurities in the gas can cause inconsistent cutting and compromise the overall quality of the cut.
With a quarter century of laser metal part fabrication, Micron Laser’s optimal assist gas selections will redefine the quality of your metal cuts. Micron Laser remains your trusted partner in laser cut metal parts with a visual quality your customers will notice.