Both laser and waterjet metal cutting methods use machines that have a good life expectancy as they don't make direct contact with the work piece during the cutting process also do not use dynamic machining forces. So, when both technologies can do the job, how do fabricators determine which process to use? Understanding a few key factors can help them make the choice.
While choosing between laser and waterjet steel cutting technology, two important factors need to be considered - edge quality and speed.
Thickness and speed: A 0.75 thick section of stainless steel when cut using both the methods reveals the difference in quality (laser at top, waterjet at bottom). The major tradeoff is speed; for a metal sheet as thick as this, a waterjet machine requires nearly 80 percent more time to accomplish the same cut.
Laser technology is well-suited to cut metal parts up to 1⁄2 inches. But they can also cut metals up to 11⁄2 inches thick. On the other hand, waterjets can cut material up to 6 inches thick. Metal cutting with laser machines often have a speed advantage over waterjet machines, however, waterjets can cut through significantly thicker metals, and alternative materials, with ease.
Material and material surfaces: Other than cutting metal sheets and creating steel profiles , lasers can process other materials too, but this doesn't mean they should because on other surfaces than metals laser cutting can result in hazardous chemical releases. For example, on plastics and rubbers laser cutting releases byproducts which are chemically hazardous for the environment. In such cases, waterjet machines steel cutters can easily cut these other materials without hazardous chemical releases.
Material surfaces like that of copper and aluminum are difficult for the lasers to cut because of highly reflective properties of these metals. In such cases the edge quality attained by using waterjet technique is significantly better. Laser cutting technology can be best used on the smooth surfaces rather than textured surfaces as textured surfaces can alter disrupt the beams focus thus altering the flow of assist gas. Waterjet cutting method on the other hand produces smooth cutting irrespective of the metals texture and reflectivity.
A laser performs best on smooth surfaces; textured surfaces can alter the flow of the assist gas and disrupt the beam's focus. A waterjet, on the other hand, doesn't discriminate when it comes to reflectivity or texture.
End product finish: Since waterjet cutting method does not create any heat affected zone, thus it delivers smooth edge finishes eliminating the need for a secondary finish completely. Whereas the heat from laser metal cutting method produces a small heat-affected zone near the cut, which could require secondary finishing depending on the finish requirements.
