Laser cutting

Laser cutting is a manufacturing process which uses a focused laser beam to precisely cut, machine, or engrave materials such as metal, plastic, or wood.

What is Laser Cutting?

Laser cutting or Laser Beam Machining (LBM) is a manufacturing process that involves cutting through the material by focusing a high-energy laser. In other words, laser cutting involves cutting a workpiece by melting and evaporating the corresponding portions of material with a focused light beam that moves along a path provided by a CNC code.

LASER is an acronym for Light Amplification by Stimulated Emission of Radiation.

Industries such as Automotive, Aerospace, Medical equipment manufacturing, Electronics and Consumer goods use Laser cutting extensively to make components like gearwheels, exhaust system protection, cooling holes in turbine blades and jet engine vanes, knives and blades for household appliances and Medical implants, pacemakers, stents, and other medical equipment.

How does laser cutting work?

The main components of a laser cutter include:

The process takes a series of steps that start with generating and programming the desired cutting pattern. From here, the machine is loaded with the program to begin cutting.

• Laser generation – The resonator receives energy from the power supply and generates the laser beam.
• Laser amplification – The two mirrors located at the ends of the head amplify the intensity of the laser beam by making it flow through the amplifying medium.
• Laser direction and focus – Depending on the type of laser cutting technology, a fibre optic cable or a group of mirrors in the focusing head give direction to the laser beam. Then, a lens achieves the energy focus required for the laser beam to be able to cut.
• Gas supply – The cutter blows gas through the nozzle to clear the molten from the kerf.
• Cutting – Once the head focuses the energy, the laser melts and evaporates the material. The movement of the cutting head occurs automatically along the pattern created in the CNC program, thus making the corresponding kerf. In some cases, the workpiece moves while the cutting head stays still.

Types of Laser beam machining

There are different laser cutting technologies; the main difference is the medium they use to remove the molten from the workpiece. However, there may be other relevant differences.

• Fusion Laser Beam Machining
• Flame Laser Beam Machining
• Remote Laser Beam Machining
• Thermal stress fracture
• Stealth dicing
• Vector Laser Beam Machining

Laser types in Laser beam machining

• CO₂ Lasers  – Manufacturers use Carbon Dioxide (CO₂) lasers for cutting non-metallic materials like wood, acrylic, plastic, fabric, leather, and paper. If coated with a layer, the CO₂ laser can cut metal to stop the reflection.
• Nd: YAG Lasers – These lasers can cut many materials, including metals and non-metals, but they are less common than CO₂ and fibre lasers.
• Fibre Laser Cutting – Fibre lasers are ideal for cutting metals, ferrous metals like steel and non-ferrous metals like aluminium, copper, and brass. They are highly efficient and have a high cutting speed.
• Direct Diode Laser Cutting – These types of lasers are known for their high energy efficiency and use diode lasers, which are becoming more popular for cutting thin sheet metals.
• Solid State Laser Cutting – Solid State Laser includes various lasers that use a solid medium, such as Yttrium Aluminium Garnet (YAG) or Ruby, to generate the laser beam. Manufacturers use Solid-state lasers to cut metals, ceramics, and some plastics.

Common Laser cutting materials

Laser-cutting materials

• Mild steels
• Stainless steels
• Aluminium alloys
• Copper
• Brass
• Foiled sheets
• Galvanized sheets
• Carbon
• Glass
• Wood
• Leather

What are the advantages of Laser cutting?

• Materials variety – Laser cutting can process various metallic and non-metallic materials. Therefore, manufacturers can use it for many applications and industries.
• High precision and accuracy – Laser cutting can achieve thin cuts with kerfs below 0.5mm. Moreover, manufacturers applying laser cutting can achieve tolerances of +/-0.1mm.
• High-quality finish – Laser cutting can achieve edges with low roughness and almost no burr formation. Manufacturers can benefit from lower costs and increased productivity as it reduces the need for post-processing.
• High speed and set-up efficiency – Laser cutting can cut at very high speeds depending on the power supply and the thickness of the workpiece. For example, a 2mm steel plate can be cut 30mm/s using a CO₂ laser cutter at 200W. Also, laser cutting only requires setting up the cutting program since there is neither tool changing nor clamps or other workpiece holders to be set. It only requires placing the material on the cutting area.
• Non-contact – It uses energy to cut through the workpiece. Therefore, no contact between the cutting tool and the material eliminates the tool wear problem.

What are the disadvantages of laser cutting?

• Sheet Thickness – Laser cutting can work only with 0.5-30mm material sheets. This range is low compared to alternatives such as plasma cutting.
• Power efficiency – It is a high power consuming manufacturing process. As a result, manufacturers see an increase in operational costs.
• Initial investment – The cutting process requires a high initial investment. Manufacturers may find cheaper alternatives for their applications.
• Material limitation – Laser beam machining cannot cut highly reflective material directly since the surface of the workpiece could reflect the laser beam into the machine, which could result in significant damage. However, this potential damage can be diminished by preparing the surface with a covering layer that absorbs the light from the laser. Also, modern laser cutters already integrate a self-protection system. An alternative would be using other machining technologies.
• Heat generation – might affect the material warping and deformation – thermally sensitive material.

What is the difference between laser and plasma cutting?