The Use of Laser Cutting in Sheet Metal Machining
Laser cutting has revolutionized the sheet metal industry in recent years. The precision, speed, and flexibility of laser cutting systems have made them an indispensable tool for sheet metal fabrication. In this blog post, we will examine the principles behind laser cutting, its advantages over traditional sheet metal machining processes, the different types of lasers used, and the applications where laser cutting excels.
How Laser Cutting Works
Laser cutting utilizes a high-power, focused laser beam to melt, burn, or vaporize material. The laser beam is focused through optics onto the workpiece. The focused laser beam provides a very high power density onto the small area of the workpiece, enabling it to melt, burn, or vaporize the material.
When cutting, the laser beam melts the material and a high-pressure assist gas, typically oxygen, blows the molten material out of the cut. This forms a cut in the workpiece along the path of the laser beam. The assist gas plays a crucial role, expelling the molten material to create a clean, high-quality cut.
Laser cutting can cut complex shapes and patterns with extreme precision. The laser beam can be precisely programmed and positioned using CNC (computer numerical control) to cut intricate shapes, angles, and holes. This allows parts to be produced from sheet metal efficiently, substituting multiple machining processes with a single laser cutting operation.
Advantages of Laser Cutting
There are several important advantages that laser cutting provides over conventional sheet metal machining processes:
- High precision: Laser cutting has a tolerance of +/- 0.001 inch and can achieve exceptionally smooth edges. This reduces secondary processing.
- High cutting speeds: Laser cutting is faster than processes like punching, stamping, and milling. Lasers can cut thinner metals at speeds over 100 inches per minute.
- Low force and distortion: The laser slices through sheet metal using a thin kerf. This results in low mechanical force and minimal component distortion.
- Flexible capabilities: Laser cutting machines can be rapidly reprogrammed for different parts. No tooling setup is required. This enables fast changeovers between jobs.
- Complex capabilities: Intricate shapes not feasible with mechanical cutting are possible. Parts can be nested closely to maximize material utilization.
- Automated operation: Laser cutting is highly automated for high productivity. Multiple sheet metal parts can be cut unattended.
- No tool wear: The laser beam remains consistent, unlike mechanical cutting tools that wear over time. This reduces machine downtime for tool changes.
Laser Types Used in Metal Cutting
The most common lasers used in sheet metal cutting are CO2 lasers and fiber lasers. CO2 lasers use a mix of gases – carbon dioxide, nitrogen, and helium – as the laser medium. This gas mixture is electrically excited to produce a beam with a wavelength of 10.6 microns. CO2 lasers can cut all commercial metals and are very cost-effective.
Fiber lasers use a solid-state diode-pumped fiber optic cable as the laser medium. They produce a beam with a near-infrared wavelength of 1.06-1.08 microns. Fiber lasers generate higher powers and cut speeds than CO2 for thinner gauge metals. They require less maintenance than CO2 lasers.
Fiber and CO2 lasers are capable of cutting all common sheet metals. This includes steel, stainless steel, aluminum, brass, copper and more. The different laser types and powers determine the thickness that can be cut. Lasers up to 10 kilowatts can cut steel up to 1 inch thick and aluminum up to 3 inches thick.
Laser Cutting Machine Configurations
Laser-cutting machines are available in several configurations:
- Flat sheet: Used for cutting flat sheet metals and plates. Single sheets are loaded manually or automatically from the stack.
- Roll feed: Sheet metal is loaded in coil form and fed into the laser system. Better for high-volume production.
- Tube/pipe: The laser cuts tubing and piping as it rotates and travels through the machine. For 3D tube cutting.
- Plate: Large stationary plates hold metal plate stock for laser-cutting structural shapes. Capable of cutting thick plates over 2 inches.
Precision cutting heads precisely locate and manipulate the laser beam over the workpiece. CNC positioning tables move the workpiece according to programmed paths. Fume extraction systems remove cutting smoke and fumes. Automated load/unload systems enable multiple sheets to be processed unattended.
Laser Cutting Applications and Examples
Laser cutting provides numerous benefits across many sheet metal fabrication operations:
- Prototyping – Quickly cut low-volume prototype parts with no tooling required. Rapid iterations support product development.
- Production cutting – Lasers excel at high precision, high-speed production cutting. Automated machines provide 24/7 operation.
- Hole cutting – Small and large holes with excellent edge quality and tolerance. Hole shapes beyond round like squares and slots.
- Fine feature and detail cutting – Intricate patterns, small features down to 0.001 inch, and delicate meshes benefit from laser precision.
- Cutting thick materials – Lasers can cut steel plates up to 1 inch wide in a single pass. Excellent for structural steel parts.
- Cutting reflective materials – Laser beams reflect well from all metals, unlike other machining processes. Good for aluminum, copper, brass, etc.
- No tool wear or changeovers – Eliminates production downtime for tool changes. Provides stable, consistent cutting.
- Limited fixturing – Low cutting forces reduce workpiece fixturing requirements. Single clamping is often feasible.
- Design flexibility – Unlimited part geometries. No need to design around tool access as with milling or punching.
Laser cutting provides transformative capabilities across many sheet metal fabrication applications from signage, metal furniture, enclosures and cabinets, HVAC ductwork, architectural metal, and many more. The technology continues advancing with higher precision, faster cutting speeds, and the ability to process a wider range of materials. Laser-cutting systems give sheet metal manufacturers a competitive edge through their efficiency, consistency, automation, and innovative capabilities. With laser cutting, no job is impossible.
Conclusion
This post reviewed how lasers cut sheet metal using a focused, high-energy beam of light. Laser cutting provides unparalleled precision, speed, efficiency, and capabilities versus traditional machining methods. The two main laser types used are CO2 and fiber lasers. Laser cutting machines are highly automated and flexible, enabling unattended processing with quick changeovers.
Laser cutting is advantageous for all types of sheet metal fabrication from rapid prototyping to high-volume production. It enables intricate part designs with fine details, small features, and holes that are difficult or impossible to produce mechanically. With capabilities that keep expanding, laser cutting systems are an essential asset for staying at the forefront of sheet metal manufacturing.