Types of sheet metal laser cutting
The market for sheet metal laser cutting machines has developed rapidly in recent years, with new types of machines being marketed by sheet metal laser cutting manufacturers, that are revolutionising the laser cutting process and the choices that users can make.
When specifying machines, users have three choices, dependent upon their own specific requirements, namely the traditional CO2 sheet metal laser cutting machines; the next generation fibre laser cutters, and the revolutionary direct diode laser or DDL.
The traditional CO2 laser has long been the preferred method, particularly in the +4mm sheet metal market. This type of machine uses CO2 laser gas and electricity to create a laser beam that is then applied to the sheet metal. Due to the high temperature operation, the CO2 laser is also equipped with a higher capacity chiller unit.
However, in recent years the market for sheet metal laser cutting equipment has begun to move towards new technologies, specifically fibre. Fibre lasers use optical fibres ‘pumped’ with diodes to create solid state laser cutting machines with far fewer components and no gas consumables.
The key issue that determines the choice of laser cutting machine is efficiency. The reason behind the rapid uptake in fibre is the superior production speeds, accuracy and significant cost-saving benefits.
Crucially, fibre lasers are equipped with a much better focusing capability, due to their ability to evaporate material at pinpoint and make a much smaller spot diameter, in comparison to CO2. This makes for a significantly more accurate and stable cut when cutting, particularly when working with thinner materials.
For example, Mazak’s OPTIPLEX 3015 FIBER laser cutting machine, uses fibre laser technology to channel increased beam density and laser energy into the cut, with a significantly shorter beam wavelength - approximately 90 per cent shorter than a CO2 laser beam. The result is significantly faster penetration of the material and the potential to increase productivity by more than 30 per cent. In addition, a fibre machine can also cut highly reflective materials, such as brass, copper or aluminum, which could potentially damage the optics in a CO2 machine. In addition to highly reflective material fiber lasers are also well suited to other exotic materials, such as hastelloy, Inconel and titanium.
For laser users, the addition of a fibre laser to their sheet metal laser cutting capabilities, also has additional benefits. In terms of running costs, Mazak has calculated that fibre users can benefit from an 80 per cent reduction in oscillator electrical power consumption; a 100 per cent reduction in laser gas consumption and a wall plug efficiency of 30-40 per cent. Fibre laser users will also benefit from an 80 per cent reduction in chiller unit electrical consumption.
In addition, maintenance costs can be significantly reduced with no moving parts in the laser, lower heat and longer diode life. The fact that fibre lasers are not equipped with bellows, and there is no requirement for mirror alignment or replacement, also reduces sheet metal laser cutting machine maintenance.
The final option for sheet metal laser cutting equipment users is direct diode laser technology, more commonly known by the acronym DDL. This technology uses diodes directly, thereby eliminating the ‘pumped’ fibre system used in fibre laser technology. This makes the DDL more efficient due to the elimination of the middle process.
DDL is a reliable laser source with no compromise on beam quality. Machines from sheet metal laser cutting manufacturers, such as the Mazak OPTIPLEX 3015 DDL, offer premium cutting performance which make them ideal for laser users requiring ultra-fast cutting and a high-quality cutting edge.
In terms of productivity, the OPTIPLEX DDL series can cut thin material 20 per cent faster than fibre lasers and thick materials with unsurpassed surface quality. The OPTIPLEX DDL is capable of a wall plug efficiency of 40-50 per cent compared to 10 per cent for a CO2 resonator; 15-20 per cent for a disc resonator and 30-40 per cent with a fibre resonator.
One final point. The choice of CNC is vital for laser cutting machines and sheet metal laser cutting users should seek out manufacturers that have equipped their machines with specialist sheet metal laser cutting software. Mazak, for example, is now equipping its DDL machines with a specialist laser CNC called PreviewG, which ensures that the CNC and laser cutting equipment work in complete harmony.