Comparing Metals

Laser cutting is more sensitive to material quality than waterjet, plasma and other cutting processes. This sensitivity, however, was more apparent in the past. Roughly ten years ago, procuring quality plate thicker than 0.5 in was quite difficult. Because surface finish can dramatically impact the quality of laser cutting and negatively affect cutting speeds, waterjet and plasma cutting technologies were heavily relied on. But, times have changed.

Today, most steel suppliers offer laser-quality plate up to 1 inch thick. Laser-quality thick plate has a very tight, smooth mill scale; tighter chemical consistency; and typically has lower silicon and manganese content. While it’s true that these premium products come with a slightly higher price, the added expense is more than made up for with increased feed rates, higher quality parts, less scrapped parts and less head crashes due to part tip-ups and blow-outs.

Because of the shift to laser-quality thick plate, waterjet and plasma technology is losing market share to laser cutters. But, of course, there’s more to the equation than just the availability of quality materials. The base characteristics of the material are also important to consider when cutting with lasers, be it CO2 or fiber.

As an example, when comparing steel to aluminum, fabricators must keep in mind that aluminum exhibits about a third of the density of steel. While waterjet may have a much slower feed rate on mild steel and stainless steel, the lower density aluminum can be processed much fast with waterjet, especially in thicknesses greater than 0.25 in. Feed rates that closely compete with laser are actually quite commonplace.

 

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