Cutting of material is the first step of turning steel plates into fabricated parts. To ensure any subsequent processes are not affected it needs to be done accurately and quickly. But not all steel plate cutting services are the same, in this article we will take a look at the different types, and their strengths and weaknesses.

How is Steel Plate Cut?

There are a few main types of plate-cutting services available at Metals Supermarkets, each with its own benefits, listed below are the commonly used types.

Plate Sawing

Most commonly used on bar sections and narrow plates, sawing is done using a hardened steel or tungsten-tipped blade. This can be either in a band saw or circular saw configuration.

Band saws tend to be available in wider capacities, with some facilities being able to cut up to 1m wide sections. Circular or cold sawing is usually more limited on maximum section size but offers greater accuracy and squareness.

Oxy-Propane Cutting

Using the same principle as gas torches, or acetylene torches – albeit using a different fuel gas – oxygen-propane cutting machines are often used to divide up very large slabs of material into smaller plates for shipping.

Whilst they can be mounted to a CNC machine, many mills use them on a simple dolly system, where tracks can be placed on top of the metal plate, with a motorized carriage that holds the propane torch.

Accuracy is not this machine’s strong point, but it is extremely versatile, allowing cutting to happen wherever the plate is, with a very small amount of tools and cost.

Laser Cutting

Laser cutting technology has revolutionized the fabrication industry, with CNC machines being able to cut parts from carbon steel, stainless steel, aluminium and more with incredible speed and precision.

Laser cutting allows parts to be cut in any conceivable shape, with down to 0.1mm dimensional tolerances. One downside to laser cutting is cost, the machinery and consumables are very expensive. They are also limited by thickness, for many machines materials above 20mm tend to need Water Jet cutting for the best surface finish.

Water Jet Cutting

A slightly different process, water jet cutting uses high-speed, high-pressure water, with abrasive particles, to cut through the material. It is much more versatile than laser cutting, it can cut almost anything.

Thickness is also not a problem, with accuracy and cut quality remaining excellent far beyond laser cutting’s capacity. The downside is that water jet machines are even more expensive to run and maintain. For materials 25mm and above, water jet cutting provides the best results.

Plasma Cutting

Before laser cutting was affordable, plasma cutting was the best way to cut materials under 20mm thick. For a slight reduction in part accuracy parts can be cut at a fraction of the cost, for plasma equipment is much more affordable.

Working in a similar way to an arc welder, the plasma torch uses high-current electricity to create an arc between the torch and the workpiece. Once the arc is initiated, high-pressure gas is forced into the plate, ejecting the now molten metal through the bottom of the plate.

Plasma cutting performance is good on carbon steel, stainless steel and aluminium. Due to higher variability in the cutting process, part accuracy is closer to 0.7mm, and can sometimes leave harsher striations on the cut edge, when compared to laser.