A Guide To Metal Cutting | Comparing Metal Cutting Methods

Metal cutting is a foundational manufacturing process where material is resized or shaped into final parts. The choice of cutting method—be it mechanical, thermal, or abrasive—is a critical business decision driven by the required tolerance, material thickness, and production volume.

In this blog, we’ve highlighted the most popular industrial methods below, detailing their mechanisms and trade-offs to help you select the ideal solution.

Categorizing Cutting Forces: HAZ and Kerf

Metal cutting can be fundamentally divided based on the force applied to the material:

• Mechanical Cutting (Saw, Shear): Uses physical force, abrasion, or shear stress. Benefits include minimal heat-affected zones (HAZ) and a lower risk of material hardening or warping. However, mechanical methods typically have a wider kerf (the material removed by the cut), which increases material waste.

• Thermal/Erosion Cutting (Laser, Plasma, Waterjet): Uses intense heat or highly accelerated abrasive particles. These methods offer a very narrow kerf and superior geometric complexity but can introduce heat (HAZ), which may require secondary finishing to remove hardened edges.

Mechanical Cutting Methods

These methods use contact and force to separate the material.

1. Saw Cutting

Sawing uses a blade with sharp metal teeth (circular or band saw) to slice the material through abrasion.

Mechanism: The teeth abrade and chip away the material along the cut line. Band saws use continuous saw blades for consistent action, while circular saws use a rotating blade for fast, straight cuts.

Benefits: Saw cutting offers a high cut quality with little need for additional finishing and is excellent for thick materials or large, varying cross-sections (tubes, bars). It achieves fast processing rates and is cost-effective for large block cuts.

Limitations: The kerf width is relatively wide, and the material must be held stationary to avoid vibration.

Best Suited For: Titanium, stainless steel, brass, bronze, large diameter pipes, and solid bars.

2. Shearing

Shearing is a non-chip-producing process that uses two slightly offset blades—a stationary lower blade and a moving upper blade—to slice the metal.

Mechanism: The force applied causes the material to deform until the shear strength is exceeded, leading to a clean fracture along the line.

Benefits: Shearing is highly adaptable and requires no chips, minimizing material waste. It is fast and extremely affordable for straight cuts in large quantities.

Limitations: It is strictly limited to straight lines and is not suitable for complex geometries or thick, hollow materials that may deform under pressure.

Best Suited For: Thin metal plates and sheets (under 1/4 inch) of aluminum, stainless steel, and brass.

Read More: Types of Metal Cutting Tools

Thermal and Erosion Cutting Methods

These methods use heat or high-velocity particles to melt or erode the material, allowing for fine detail.

3. Laser Cutting

Laser cutting uses a strong, concentrated beam of light to heat, melt, and evaporate material.

Mechanism: The laser beam is precisely guided by digital (CNC) controls. A clean, thin cut is usually accomplished by blowing the molten material using an auxiliary gas (such as oxygen or nitrogen).

Benefits: Laser systems offer extremely high positional accuracy and precision (tight tolerances). They feature a very narrow kerf (minimal waste) and allow for complex, intricate geometries. They are ideal for high-volume production.

Limitations: Limited to thinner gauge materials (generally under 3/4 inch). The process creates a HAZ (Heat-Affected Zone) and can leave dross (molten residue) on the underside, which requires deburring.

Best Suited For: Thin stainless steel, titanium, and copper plates and sheets.

4. Plasma Cutting

Electrically conductive materials are cut using a high-temperature plasma jet.

Mechanism: An electrical arc superheats a gas (air, oxygen, or nitrogen) until it reaches the plasma state, melting and vaporizing the metal.

Benefits: Plasma is significantly faster than laser cutting for thicker materials and can cut metal up to 1 inch or thicker. It is an economical choice for general fabrication.

Limitations: Lower precision and a larger HAZ compared to laser or waterjet, resulting in rougher edges and often requiring heavy secondary finishing.

Best Suited For: Thick carbon steel, stainless steel, and aluminum plate, where speed is prioritized over micro-tolerance.

5. Waterjet Cutting

Waterjet cutting is usually a highly pressurized stream of water, often mixed with particles (such as garnet) that cut and abrade the metal.

Mechanism: This is a "cold cutting" technique, as the material is separated by erosion, not heat. The high-pressure stream acts like a physical blade.

Benefits: Virtually no HAZ (Heat-Affected Zone), eliminating thermal distortion or hardening. It can cut extremely thick or dense materials (up to 6 inches thick) with good precision and can handle reflective materials that lasers cannot.

Limitations: Slower than plasma or laser for thin materials. The kerf is wider than a laser's, and the garnet abrasive is expensive, leading to higher operating costs.

Best Suited For: Titanium, thick aluminum, tool steel, and exotic alloys that are sensitive to heat.