How Thick of Metal Can a Laser Cut?

Laser cutting is an incredibly useful development to arise in the past half-century. Projecting extreme heat in an incredibly narrow stream, laser cutting allows manufacturers and welders to cut custom pieces and parts out of metal with the utmost precision. Like so many other technologies, it's a contributor to the increased sleekness and reliability of many modern machine parts.

Of course, as with all technologies, laser cutting is an ever-developing field, which means it's never perfect. There are always obstacles to push beyond, and limits to overcome. When it comes to laser cutting thick steel, those limits manifest primarily in factors like the materials able to be cut, the power of the lasers, and - as a result of those things - the maximum thickness of metal that the lasers can handle.

What Metals Can a Laser Cut?

Lasers can cut through many materials and are typically used on a select few types of metal - in particular, carbon steel, mild steel, stainless steel, steel alloys, and aluminum.

ㆍCarbon steel: Steel is a mixture of iron and carbon. Carbon steel is steel with an especially high amount of carbon.

ㆍMild steel: Mild steel has a low concentration of carbon compared to carbon steel.

ㆍStainless steel: Stainless steel adds small amounts of chromium to create resistance to corrosion.

ㆍOther steel alloys: Alloyed steel is bonded with one or more other elements to strengthen it.

ㆍAluminum: Aluminum materials are useful due to being lighter than steel ones.

In addition to these metals, lasers can be used to cut through many non-metallic materials, from wood to plastic to ceramics. However, it most often gets used to cut metal, specifically those listed above.

What Is the Maximum Thickness a Laser Can Cut?

It seems simple enough to ask for a single maximum limit on thickness for all laser cutters, but it's more complicated than that. Many variables are at play in how a laser cuts through a piece of metal, so the maximum laser cutting thickness depends on the specific laser and material being used, among other things.

For the sake of naming a specific number, we can pair a high wattage laser - 6,000 watts - with a metal like stainless steel. In this case, the laser cutting maximum thickness would typically be about 2.75 inches.

But that thickness is contingent on those particular variables. The same laser paired with carbon steel could probably only handle up to 1 5/8 inches, while a 4,000-watt laser could only penetrate 1 inch of stainless steel.

The maximum thickness would go up immensely for non-metallic materials like wood and plastic, as they're much less dense and strong than steel or aluminum.

Laser Cutting Power vs. Material

When looking at what the maximum cutting thickness of a laser, you should analyze two factors in particular - laser power and material. A laser at one wattage won't be able to cut through as thick a material as a laser at another. Likewise, the same laser won't be able to cut through the same thickness of carbon steel as it will aluminum.

Some of the most common laser wattages to encounter are 3,500, 4,000 and 6,000. Lasers of 6,000 watts are excellent for cutting through especially thick or strong metals, though in many cases the lower wattages are more than enough to get the job done.

Material Strength

The strength of a given metal can vary depending on factors like the ratio of different elements in the alloy, but there are still tendencies for certain types of metal to be stronger or weaker than others. Here is a brief overview of how the previously mentioned materials stack up against each other, from hardest to easiest to cut.

ㆍCarbon steel: High amounts of carbon provide an added layer of strength to a metal.

ㆍMild steel: Being lower in carbon content than carbon steel, mild steel proves easier to cut. However, though more cuttable, finished products made of mild steel are stronger and more resilient than those with higher amounts of carbon.

ㆍStainless steel: The presence of chromium combats rust and often makes the material less ductile and harder to cut. It doesn't have the same effect as carbon, though.

ㆍAluminum: Aluminum is typically a very ductile material, as anyone experienced with aluminum foil knows. It rarely proves a significant problem for lasers.

ㆍNon-metallic materials: Unsurprisingly, at the bottom of the list are materials like wood, plastic and ceramic, which have much less strength than metal.

Other steel alloys can appear at various places on the list as well, depending on the specific alloy and the ratio of elements included. Again, none of these rankings are definitive, as they can vary from case to case depending on a particular metal's structure. One type of stainless steel can be much softer than another, for instance. But the above list can help give a sense of how things often are.

Cutting Speed

It's also worth considering speed. Lasers with higher cutting power can get through greater thicknesses, but they can also cut through smaller thicknesses in less time. Likewise, a laser can cut through weaker materials more quickly than stronger ones. This can sometimes contribute value to using a high-wattage laser even if you're not dealing with particularly thick or strong metal.

Speed is also affected by the use of gas in the process, however. Metal can't just be cut through carelessly, as this would leave burrs and other inconsistencies on the cut edges. As the cuts are being made, gas has to be applied at high pressure to smooth out those issues. Stainless steel, for instance, uses nitrogen, while carbon steel uses oxygen. The type of gas and time needed to properly apply it can have an impact on the speed of the process, which is another way the process depends on the material being cut.

When deciding on what power laser cutter you need, you have to weigh these factors against one another, as well as against what you need the laser for. You may not need the highest-power laser for a certain job.

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