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How to cut stainless steel depends on balancing precision, thickness, heat sensitivity, and cost. The wrong method can lead to tolerance drift, thermal distortion, and rising costs.
This guide helps you avoid those problems by matching the process to your project—whether you need precision, speed, or low cost.
Below is a quick overview of how the four main methods compare:
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Laser cutting: best for thin sheets that require high precision and fast cycle times.
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Waterjet cutting: suited for heat-sensitive components.
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Plasma cutting: best for thick, low-precision parts.
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CNC milling: preferred for complex geometries and low-volume precision parts.
Industrial Methods for Cutting Stainless Steel
Below are the primary industrial cutting methods for CNC machining stainless steel parts.
Laser Cutting
CNC laser cutters (typically fiber lasers) use high-powered laser beams to melt or vaporize stainless steel along a programmed path. Laser cutting uses assist gases (like nitrogen and oxygen) to control oxidation and remove molten material.
Laser cutting is best for CNC machining thin to medium stainless steel sheets, where precision and fast processing are priorities. Limitations include potential edge oxidation and lower efficiency on highly reflective custom stainless steel parts.
Waterjet Cutting
Waterjet cutting is a cold-cutting technique that uses ultra-high-pressure water and abrasive particles to slice through stainless steel. The effectiveness of the process depends on the abrasive selection, nozzle design, and slurry mechanics.
Waterjet is the perfect option for heat-sensitive parts. However, the tradeoff for no thermal deformation is slower cutting speeds, higher operating costs, and the need for additional finishing when machining tight-tolerance parts.
Plasma Cutting
Plasma cutting uses a high-temperature plasma arc to cut through stainless steel. The gas used is typically air or oxygen, electrically ionized into plasma at temperatures around 22,000 degrees. Plasma is often the go-to when cutting thick, structural stainless steel parts that do not necessarily need an excellent edge finish or tight tolerance.
CNC Milling
CNC milling is a subtractive machining technique that involves rotating cutting tools (such as end mills) to remove material from the stationary stainless steel workpiece. This method is best for precision parts that require tight tolerances, complex geometries, and top-notch as-machined surface finish.
However, CNC milling is slower than thermal cutting methods and requires higher setup and tooling costs. This makes it best suited for precision parts where tolerances and complex geometries are critical, rather than for large-volume or rough cutting applications. 
How to Choose the Right Method for Cutting Stainless Steel
Knowing how to cut stainless steel effectively requires evaluating multiple factors rather than relying on a single method. These factors are considered below.
Precision Requirements
CNC milling offers the tightest tolerance limits at ±0.01 mm, closely followed by laser cutting at approximately ±0.05 to 0.1 mm. Waterjet cutting offers tolerance limits between ±0.1 and 0.3 mm, while plasma cutting is approximately ±0.3 to 0.5 mm.
Therefore, CNC milling is the most suitable option for high-precision custom stainless steel parts. For more on achieving tight tolerances and surface finish, explore our precision machining guide. Laser cutting can also help with moderate- to high-precision parts. Waterjet is suitable for low- to moderate-precision components, while plasma cutting should only be considered if precision is not a requirement.
Geometry Complexity
For stainless steel parts with complex geometries, CNC milling and laser cutting are again the most suitable options. However, we frequently find that CNC milling is better for parts with complex 3D geometries, while laser cutting is more limited to 2D geometries.
Although waterjet cutting can also help with complex 2D geometries, it does so at a lower level than laser cutting and CNC milling. Plasma cutting is generally reserved for large structural cuts rather than intricate designs.
Therefore, use CNC milling for complex geometries, followed by laser cutting, and then waterjet. Plasma cutting is not a good option for complex designs.
Material Thickness
Waterjet cutting and plasma cutting are the best options for cutting thick stainless steel parts (>20 mm). Since waterjet and plasma can both be used for thick parts, edge quality and cost are often the differentiators. Waterjet cutting is preferred when edge quality is more important, while plasma cutting is chosen when cost is of higher priority.
In our experience, laser cutting is ideal for thin parts (<6 mm). For moderate thickness parts (>6 mm but <20 mm), laser or waterjet cutting can be reliably used.
Heat Sensitivity
Waterjet cutting is a cold-cutting technique, eliminating Heat-Affected Zones (HAZ) and making it the best choice when no thermal distortion is required in the custom stainless steel parts. At the other extreme, plasma cutting generates significant HAZ, significantly limiting its use when no thermal distortion is critical.
While laser cutting is less heat-intensive than plasma, both ASM International and AWS standards recognize that thermal processes alter microstructure at the cut edge, confirming that laser cutting does produce a heat-affected zone (HAZ). CNC milling is not a thermal process, but the friction involved in the operation generates heat, which may cause slight thermal distortion.
Therefore, when heat sensitivity is an important factor, use the waterjet method. For moderate HAZ, use laser cutting or CNC milling. Only use plasma cutting when heat distortion is not a concern.
Production Volume and Cost
Plasma is ideal for large structural stainless steel pieces because of its lower focus on intricate surface finishing and low cost. However, if a high-quality surface finish is required for large-volume projects, laser cutting is the next best option, as it has excellent automation capabilities.
On the other hand, low-volume, high-complexity projects will benefit more from CNC milling. Although CNC milling, along with waterjet cutting, has high cost implications, making it key to consider the cost-benefit ratio before choosing it.
How to Cut Stainless Steel: Process Selection Overview
Here is a quick overview of how the different cutting methods fare with different requirements.
| Requirement | Laser Cutting | Waterjet Cutting | Plasma Cutting | CNC Milling |
| Tolerance | 0.05–0.1 mm | ±0.1–0.3 mm | ±0.3–0.5 mm | ±0.01 mm |
| Geometry | 2D profiles, moderate complexity | 2D profiles, complex shapes | Simple cuts, structural parts | Complex 3D geometries |
| Thickness range | Thin to medium (<20 mm) | Thin to very thick (>50 mm) | Thick (>20 mm) | Low to medium (limited by tooling) |
| Heat impact | Moderate | None | High | Minimal |
| Edge Quality | Good | Moderate | Rough | Excellent |
| Production volume | High-volume | Low to medium volume | High-volume | Low to medium volume |
| Cost | Moderate | Highest | Lowest | High |
| Typical use case | Sheet metal parts, enclosures | Heat-sensitive parts | Structural components | Precision components, tight tolerances |
304 vs 316 Stainless Steel: How Material Affects Cutting
Most CNC projects that involve 304 and 316 stainless steel use laser cutting because of its advantages in thin sheet machining and fast automation. However, even when using the same cutting technique, the different material properties of the steel grades mean there are variations in cutting strategies.
316 stainless steel contains molybdenum, which increases the metal’s toughness but results in higher cutting forces, increased tool wear, and more heat generation. Therefore, 304 stainless steel is easier to machine and cut, translating to faster and easier machining.
Frequently Asked Questions
What Is the Best Way to Cut Stainless Steel?
There is no single best way to cut stainless steel, as different projects have different needs. CNC milling is preferred for complex designs, laser cutting for thin sheets and fast processing, waterjet for heat-sensitive parts, and plasma for thick, low-precision components.
Why Is Stainless Steel Harder to Cut Than Other Materials?
Stainless steel is harder to cut than other materials because of its high toughness and poor thermal conductivity, causing work hardening, heat retention, and faster tool wear.
What Tolerances Can Be Achieved When Cutting Stainless Steel?
Tolerances as tight as ±0.01 mm can be achieved when cutting stainless steel with CNC milling. Laser cutting can deliver as low as 0.05 mm, waterjet as low as 0.1 mm, and plasma as low as 0.3 mm.
Is 316 Stainless Steel More Difficult to Cut Than 304?
Yes, 316 stainless steel is more difficult to cut than 304 because it has higher toughness, leading to accelerated tool wear and work hardening during cutting.
Conclusion
There are four main cutting options when CNC machining stainless steel: laser cutting, waterjet, plasma, and CNC milling. Choosing a suitable cutting process early in the design phase is critical to reduce dimensional inaccuracies, lead times, rework, and costs.
Ultimately, the right choice depends on a thorough evaluation of tolerance, geometry, volume, cost, thickness, and heat sensitivity. Working with an experienced partner such as FastPreci for your stainless steel machining services helps with optimal process selection from the outset.
