Technological progress of Thermal cutting: from Oxycut to Fiber Laser

Advanced Manufacturing

Historically, different material cutting technologies have been developed for different sectors of the market, each with its advantages but also disadvantages and limitations. Usually they have been developed around a single type of cutting, but for some time now combined methodologies are being used, such as water and plasma, punching and laser or punching and shearing.

Cutting technologies are usually divided into two groups: thermal and mechanical. The first group, where heat is applied to the cut to separate the material, includes oxycut, plasma and laser cutting; the second group, where an abrasive action is used, includes water jet, punching, milling, electrical discharge machining, blade cutting, etc.

There has always been a great deal of competition between them, but recent technological progress is raising this competition to an extraordinary level, especially between high definition plasma, CO2 laser and most recently fiber laser technology. Of these last technologies, laser cutting has proved to be the most precise. Especially when working with thin materials and machining small holes. High definition plasma produces a similar quality to laser systems for greater thickness requirements. It is a good option for beveling.

The emergence in the laser world of fiber cutting technology is proving to be a revolutionary advance in terms of speed and costs, since it is a technology that offers the speed and quality of traditional CO2 laser cutting but lower maintenance and operational costs.

In which cases should each technology be applied?

For reduced thicknesses of up to 5mm, the properties of fiber laser may be better than the CO2 laser. It also gives performs better on reflective materials, such as copper or brass. As the thickness increases, the performance of fiber laser worsens, and it is better to use a CO2 laser which can generate greater power when cutting up to thicknesses of 30mm.

Machines that use plasma cutting technology are probably the most suitable for thicknesses of 5 mm upwards and certainly the best for thicknesses of 30 mm upwards, which laser cutting cannot handle, and can work on thicknesses of up to 90 mm in carbon steels and 160 mm in stainless steels. In addition, they are cheaper to buy than laser cutting machines which makes them a more interesting option for higher thicknesses in which the quality of the cut is important. However, prices of fiber laser cutting machines are slowly going down which is significantly reducing the gap between them.

However, for higher thicknesses, the most appropriate technology is oxycut, an old technique used a century ago that is ideal for preparing the edges of parts for welding.

What is the best option when using ranges for which all the technologies can be used?

Several machining options should be available depending on the technology. The same part, depending on where it is going to be processed will require a specific machining technique that makes the most efficient use of resources to achieve the desired cut quality. There will be times when a part can only be processed using one technique. Therefore, a system is needed that incorporates advanced solutions to assign the precise manufacturing route, depending on the material, the thickness, the desired quality or the diameters of the inner holes.

For overload situations that prevent manufacturing from moving forward, a software solution is needed that manages loads and assignment to work queues so that the user can choose a second machining option or an alternative compatible technology to process the part in another machine that is in a better situation and that enables the part to be manufactured on time. A software solution that even allows the task to be subcontracted if there is no excess capacity.

In all cases, the appropriate program to manage the use and combination of these machines with a single system is CAD/CAM. In order to achieve quality manufacturing, on time and at a lower cost, the software should also be able to assign and manage the ideal machine, combining technology and workload situation.