A Guide to Eliminating Laser Cut Burr and Slag

Laser cutting technology has become a key role in current industry, especially in automotive manufacturing, aerospace, electronic equipment manufacturing, and medical devices. However, the inevitable slag burr problem generated during laser processing has been plaguing manufacturers.
When laser oxidizes material, heating leaves a rough slag residue, which is similar to a broken burr. It mainly appears at the bottom edge. The burr affects the quality of products a lot, not only the appearance but also increases the workload and cost of subsequent processing. And the worst thing is it may pose a safety risk to operators. In precision machining or high-performance applications, burrs usually firstly become terrible by acid, corrosion, or particulate matter capture and accumulate.
However, the formation of laser slag burrs is closely related to the parameters in the laser processing process. Appropriate parameter settings can ensure the effective interaction of the laser beam with the material and effectively reduce burrs. Therefore, ACLPRESS will introduce here how to adjust the laser parameters, including laser power, pulse frequency, speed, focal length, cutting gas, and gas flow and pressure to reduce laser slag burrs and improve product quality.
1. Increasing the pulse frequency and reducing the power can generally reduce slag generation.
2. Properly increasing scanning speed can promote better slag removal. Of course, steel plates of different thicknesses, material properties, and cutting requirements determine the optimal scanning speed and width.
And our suggestion is: 
Thinner steel plates: use faster scanning speeds and smaller scanning widths to improve cutting speed and quality;
Thicker steel plates: require slower scanning speeds and larger scanning widths to ensure cutting quality
3. Laser focus position:
The focus position determines the beam diameter and power density on the product surface and the shape of the incision.
The larger the focal length, the coarser the spot, and the wider the slit, which in turn affects the heating area, slit size, and slag removal capacity.
Usually:
Zero focus: The smallest spot and the narrowest slit are suitable for high-precision thin plate cutting with fast speed
Positive focus: The cutting section is smooth, and the cutting speed could be slow. That is better for cutting medium and thick plates with requirements for cutting sections. The denser the plate, the higher the focus.
Negative focus: The cutting speed is faster, but the cutting section surface is rougher. It is better for cutting medium and thick plates with low requirements for cross-section quality. The denser the plate, the lower the focus.
If the burr goes inward during cutting, probably because the focus is too low, and it needs to be raised; if the burr goes outward, the main reason probably is the too high focus.
At the same time, using an appropriate cutting speed, and air pressure, is also beneficial to burrs removal.
4. Optimize material surface treatment:
Proper treatment of the material surface before laser processing can help minimize slag generation. For example, using chemical methods to clean the surface, eliminate oil and impurities, and conduct sandblasting or laser grinding can keep a good material flatness and surface roughness, and reduce slag adhesion.
5. Use assisted gas for blowing:
During laser processing, using auxiliary gas for blowing is a common method to remove slag burrs. By spraying high-pressure gas into the laser processing area, the molten material can be quickly discharged and the burrs can be blown away. Commonly used auxiliary gases include air, nitrogen, oxygen, and other inert gases, and the specific selection depends on the properties of the material and process requirements. Pure gas can effectively blow away the slag generated during cutting and reduce the formation of burrs. Nitrogen is a commonly used assist gas because it prevents oxidation and helps get a cleaner cutting section.
6. Maintaining cleanliness and alignment of the laser cutting head is crucial to ensure the quality of the cuts. 
Any dirt or damage can result in a shift in laser focus, leading to increased burrs. Regular cleaning and calibration of the laser cutting head can prevent these issues.
7. Control cutting speed: 
Incorrect cutting speeds, whether too or too slow, can result in the formation of burrs. Excessive speed may prevent the laser beam from fully cutting through the product, while excessively slow speeds can cause the laser to linger, leading to the melting of the bottom surface and the accumulation of slag. The key to minimizing burrs lies in determining an appropriate cutting speed based on the material's thickness and type.
8. Optimize cutting path: 
Optimizing the laser cutting path can reduce the number of starts and stops during the cutting process, thus the formation of burrs. A well-designed cutting path can enhance cutting efficiency and minimize the heat-affected zone, resulting in smoother cutting edges.
9. Use post-processing methods: 
Laser-processed products may require post-processing to eliminate any remaining slag burrs. Common methods for post-processing include mechanical polishing, electrolytic polishing, and chemical dissolution.  Mechanical polishing involves grinding, sanding, and polishing to burrs, while electrolytic polishing and chemical dissolution use electrolysis or chemical reactions to dissolve and eliminate burrs. In this situation, either mechanical or chemical deburring methods can be employed to eliminate the burrs, such as grinding, polishing, or the use of deb agents.
Conclusion: The removal of laser slag burrs is crucial for enhancing product quality. By taking into account machine equipment and material characteristics, making appropriate laser parameter selections, and implementing post-processing techniques, the formation of burrs can be greatly minimized. In turn, leads to improved cutting quality, enhanced production efficiency, and the attainment of higher precision and superior surface quality.