When cutting single-sided features on a tube, a portion of the laser power may pass through the cut, impinging on the opposing wall’s interior surface. Depending on the tube’s internal diameter, this may affect the material, resulting in either a slight color change or material removal that can often be corrected with electro polishing or another, similar post-process.
At a certain internal tube diameter, however, thermal damage will be significant, and beyond recovery by post processing. This is when you should consider a wet laser tube cutting process, one in which a coolant – usually water – runs inside the tube during the process.
Wet cutting is beneficial in three key ways:
- The water’s refractive index and the change in the index caused by the flow diffuse the laser beam, reducing the power density.
- The water cools the tube’s internal surface.
- The water transports debris away from the cut and tends to reduce dross.
Should YOU use a wet or a dry laser tube cutting process? Follow these simple guidelines to determine the best method*:
- Internal diameter > 0.15-inch – Use dry laser tube cutting
- Internal diameter 0.08-0.15-inch – Use either wet or dry
- Internal diameter < 0.08-inch – Use wet laser tube cutting
*Of course, the recommendations are subject to cut features and tube wall thickness.