Top mistakes in metal cutting

Contents:

Since 2003, we have been manufacturing CNC machines and have identified the most common mistakes made by both beginners and even experienced users when working with fiber laser metal cutting machines. Avoiding these mistakes can significantly improve cutting quality, machine longevity, and overall efficiency.

Failure to follow safety regulations

Adhering to safety precautions is essential when operating a laser machine. Always wear protective goggles, never leave the machine unattended, and avoid standing in the path of moving components. Under no circumstances should you touch the working head or material while the machine is in operation. Detailed safety guidelines and maintenance recommendations are available in the machine’s data sheet.

Incorrect machine settings

A metal cutting machine is capable of producing precise, clean cuts, but incorrect settings—especially regarding focus and pressure—can lead to poor results. All parameters must be configured based on material type, thickness, gas type, nozzle size, and laser power. To assist our customers, we provide a table of recommended parameters for metal laser cutting.

Selecting settings at random is a critical mistake. For example, excessive pressure can lead to valve or regulator failure, and mixing oxygen and nitrogen lines can cause malfunctions.

Failing to monitor gas levels

If you are using separate cylinders of auxiliary gas (such as nitrogen or oxygen), there is a risk of running out of gas mid-process, leading to rejected parts. The same applies to air supply—if your compressor does not have sufficient storage capacity, it may cause interruptions. While pressure gauges can indicate gas levels, relying on single cylinders is inefficient. Instead, using gas bundles is recommended for continuous operation.

Layout and design issues

Several common errors occur in part layout and design:

1. Dimensional inaccuracy: if there is a discrepancy between the design and the actual part, check the cut thickness compensation and gear ratios. Wattsan metal laser machines offer a positioning accuracy of 0.02 mm. If deviations exceed this tolerance, mechanical issues may be the cause—though this is rare. For instance, if a machine has suffered physical impact, such as a forklift collision, it may require recalibration.
2. Incorrect cutting prioritisation: always cut internal features before external ones. If the outer contour is cut first, the part may fall out, making it impossible to complete internal cuts properly. It may also drop between the slats, causing instability during cutting.
3. Underutilising machine software: many users fail to use the full functionality of their machine’s software. For example, the nesting function optimizes part placement on the sheet, reducing material waste and saving time. Automated nesting can be completed in just a few clicks, whereas manual arrangement may take 30–60 minutes.
4. Ignoring piercing zones and bridges: without properly set piercing zones, initial piercings may occur within the part’s contour, leading to defects and rejected parts. Setting piercing zones outside the main contour helps ensure cleaner cuts. Additionally, bridges should be used to keep parts connected until cutting is complete, preventing them from falling and causing damage to the laser head.

Laser head collisions

If the laser head contacts the metal, immediately stop the operation and inspect the machine’s mechanics. Pay special attention to the nozzle and ceramic ring. The laser beam alignment should also be checked—this can be done using adhesive tape. To prevent collisions, keep the worktable clear of foreign objects.

Material overheating

Overheating is a common issue, especially for inexperienced operators. To avoid this:

• Distribute the cutting sequence across different areas of the sheet.
• Utilize pre-pierce and path cooling functions for thick materials.

These techniques help maintain cut quality and prevent warping.

Cutting on rusted material

Cutting through rust is not recommended, as it can degrade cut quality. However, if unavoidable, use the D-film function to remove rust or oxidation from the cutting path before proceeding. While this requires extra processing time, it ensures a clean and precise cut.

Neglecting machine maintenance

Routine maintenance is crucial for maximizing machine lifespan. Regularly inspect and maintain:

• Lubrication systems
• Optical components
• Guide rails
• Cooling systems

A maintenance schedule should be displayed in the workshop to track service intervals. These details can also be found in the machine’s data sheet.

Conclusion

Avoiding these common mistakes can significantly improve the efficiency, precision, and durability of fiber laser metal cutting machines. By adhering to safety measures, using correct settings, optimising layouts, and maintaining equipment properly, users can achieve higher-quality results while extending the lifespan of their machines.

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