Why is my CNC plasma cutter not cutting through?
When a CNC plasma cutter fails to cut through the material, it interrupts production, wastes consumables, and can damage both parts and equipment. This problem usually points to an issue with setup, consumables, power, or torch height. Identifying the root cause quickly helps restore clean, consistent cutting performance.
A CNC plasma cutter relies on the correct combination of amperage, air or gas quality, torch height, speed, and consumable condition. When any of these factors is incorrect, the plasma arc may lose energy, become unstable, or fail to penetrate the metal fully. In many cases, the issue is simple and can be resolved by adjusting settings, replacing worn consumables, or checking airflow.
Incorrect amperage is one of the most common causes. If the amperage is set too low for the material thickness, the arc will not have enough energy to achieve full penetration. Likewise, excess cutting speed can cause the torch to move faster than the arc can maintain, leaving uncut sections or slag-heavy edges.
Another frequent issue is poor air quality or insufficient pressure. Moisture, oil, or inconsistent pressure can affect arc stability, reduce heat concentration, and lead to partial cuts. Regular maintenance of air filters, compressors, and dryers is essential for reliable results.
Torch height plays a critical role. Too high, and the arc widens and loses intensity; too low, and the arc becomes unstable or damages the nozzle. Modern CNC systems, such as CR PLASMA’s, incorporate automated height control to prevent this.
Finally, worn consumables, electrodes, nozzles, or shields can drastically reduce cut quality and penetration. Replacing them regularly restores proper arc shape and energy focus.
Low Amperage: Insufficient power for the material thickness prevents full penetration.
Too Fast Cutting Speed: Torch outruns the arc, leaving uncut or poorly cut areas.
Poor Air Quality: Moisture, oil, or low pressure destabilises the arc.
Incorrect Torch Height: Too high or too low disrupts arc focus and penetration.
Worn Consumables: Old nozzles or electrodes weaken the arc and reduce cut depth.
Material Properties: Coatings, rust, or excessive mill scale can affect arc performance.
Machine Setup: Incorrect grounding or loose connections reduce cutting efficiency.
A CNC plasma cutter usually fails to cut through when power, speed, air quality, or torch height is incorrect. Resolving these restores proper penetration.
