Laser Cutting Limitations: Can it Cut Through Thick Steel?

Laser Cutting Limitations: Can it Cut Through Thick Steel?

Laser cutting has redefined what’s possible in modern fabrication. From razor-sharp designs in signage to the seamless edges on custom components, the precision and speed of laser metal cutting make it an essential tool in today’s manufacturing toolkit.

But despite its power, this technology has boundaries, especially when cutting thick stainless steel.

At KNS Metals, we regularly field the question: Can you use a laser to cut through thick stainless-steel sheet?

The answer is yes, but with a few caveats.

Let’s break down how cutting with a laser works, what factors affect its capabilities, and where those limits lie.

What Exactly Is Stainless-Steel Laser Cutting?

Put simply, laser cutting involves directing a highly focused beam of light (the laser) onto a material, heating it to the point of melting or vaporising, and then using a gas jet to blow away the excess. The result? Ultra-precise, clean cuts in metals, plastics, wood, and more.

With the right setup, laser cutting steel, aluminium, or even intricate laser-cut stainless-steel designs becomes fast, accurate, and efficient. And thanks to advanced metal laser cutting equipment, this method can work on materials from delicate foils to structural plates.

But the thicker the material, the more challenging the job becomes.

Can You Laser Cut Thick Stainless Steel?

The short answer: yes, but there’s a limit.

Stainless steel—due to its density, reflectivity, and thermal conductivity—is one of the more demanding metals to work with. Laser cutting stainless steel becomes more difficult as the material gets thicker. That’s because thicker steel absorbs and disperses more heat, requiring more energy to maintain a clean, accurate cut.

Most laser metal cutting systems today can handle stainless steel up to 10–20mm thick, depending on the laser’s wattage and steel grade. Beyond that, the cut quality drops, making the process slower, less efficient, and more prone to heat distortion.

Factors That Influence Cutting Thickness

The maximum thickness you can cut using a laser to cut stainless steel doesn’t rely on one factor alone.

Here’s what determines how deep a laser can go:

1. Laser Power (Wattage)

• 1000W machines typically cut up to 5mm stainless steel.
• 2000W lasers can handle 8–10mm with ease.
• 3000W+ systems can take 12–20mm, depending on quality settings and other variables.

The stronger the beam, the deeper the cut. But higher wattage doesn’t always mean better results; it also increases operating costs and heat risk.

2. Material Grade

Different grades of stainless steel behave differently under laser exposure. For example:

• 304 stainless (most common) cuts well up to moderate thicknesses.
• 316 stainless, with added corrosion resistance, is denser and harder to cut cleanly at high thicknesses.

3. Assist Gas

Gases like oxygen or nitrogen clear molten material during laser metal cutting and maintain edge quality. Nitrogen is preferred for stainless steel to prevent oxidation and ensure clean, burr-free cuts.

4. Cutting Speed

Speed must be reduced as the material thickens. Going too fast can result in incomplete cuts or poor edge quality. Going too slow? Excess heat buildup and potential warping.

5. Beam Focus and Quality

High-end machines (like our Bystronic and Yawei CO₂ and fibre lasers) use adaptive optics and autofocus cutting heads to maintain beam quality, even across thicker or uneven surfaces.

General Cutting Guidelines for Stainless Steel

These are not hard limits but practical guidelines. The quality of the laser cutting steel depends not just on depth, but on the right balance of machine settings, material prep, and environmental control.

Challenges When Laser Cutting Thick Stainless Steel

The thicker the sheet, the more attention you must give to the process.

Here are some of the common issues we troubleshoot in-house at KNS:

• Edge roughness on thicker plates
• Heat-affected zones (HAZ) leading to discolouration or distortion
• Slower production speeds, impacting timelines
• Increased gas usage, which adds to operating costs
• Reflectivity, which can damage equipment if not managed properly

That’s why not every workshop is equipped to handle laser-cut stainless steel in higher thicknesses. It takes experience, precision, and the right machine setup.

When Not to Use Laser Cutting for Thick Steel

Despite the impressive capabilities of laser metal cutting, sometimes it’s not the right choice.

If your project requires:

• Cutting steel thicker than 25mm
• Materials with multiple reflective layers
• Ultra-budget production at high volume

Then plasma cutting, water jet cutting, or mechanical saw cutting may offer a more cost-effective or suitable alternative.

That said, if you’re targeting speed, precision, and minimal finishing work, laser cutting steel sheet metal up to 20mm thick is still a top-tier option.

Alternatives & Workarounds for Laser Metal Cutting

For projects that push the boundaries of what a laser can do, we often explore hybrid options:

• Multi-pass cutting: Layered cutting to avoid heat warping
• Pre-heating thicker materials: Aids beam penetration
• Tag-team fabrication: Combining laser-cut panels with secondary cutting or welding techniques

Our team of metal fabricators works closely with clients to understand the full scope of your project and recommend the best path forward.

Get Precision Stainless Steel Laser Cutting in Melbourne

At KNS Metals, we’ve invested in some of Australia’s most advanced metal laser cutting equipment, capable of handling complex shapes, thick steel, and intricate detailing.

Whether you’re working with large architectural panels or compact, high-spec components, we’ll deliver results that meet your tolerances and timeline. From CAD design through to final fabrication, our stainless-steel laser cutting process is built for consistency, clarity, and confidence.

Contact our Melbourne-based team today to learn how we can support your project with expert laser cutting solutions, no matter the thickness.