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THE EXPERT'S VIEW

Laser technology, a key vector for advanced manufacturing

The expert´s view: David Gómez, director of the Laser for Manufacturing Lab at IK4-TEKNIKER

It is nowadays considered that laser is one of the industry's key enabling technologies that has made a significant contribution in terms of developing the so-called Industry 4.0 concept. As a result of an extensive amount of experience in the development of technology for laser applications, IK4-TEKNIKER has established the “Laser for Manufacturing Lab” to offer global laser technology solutions applied from an integral perspective to advanced manufacturing.

Since its inception in 1960 when it was classified as "a solution in search of a problem", the development of laser technology and how it is to be applied to different sectors, productions areas and fields of science has never stopped advancing.

In our lives, the use of laser can be seen in a number of everyday actions such as bar code reading, document printing or accessing the Internet, although this technology is also useful in different areas of health sciences such as operations performed to correct myopia or carry out dermatology treatments.

The world of manufacturing has never lost sight of how useful laser applications have become nor of how important tool they are for metrology, inspection, monitoring or material processing.

To date, and since their introduction in the 80s and 90s, the development of new sources of laser radiation, such as fibre technology featuring significant increases in power ratings and peak energy, have given rise to a new generation of high-performance laser devices. These systems are nowadays used extensively thanks to significant cost reductions. A case in point has to do with diode lasers and for which a "Moore's Law" is currently under discussion to increase power and reduce costs.

Due to the above mentioned factors, laser is nowadays considered to be a key enabling technology in the industry whose contribution is highly significant in terms of furthering the so-called fourth industrial revolution or Industry 4.0.

On the one hand, it is expected that certain conventional processes shall be replaced by others based on laser technology, whilst, on the other, the use of laser is giving rise to new production processes such as additive manufacturing of metals as one of the most outstanding examples.

Industrial processes that are more efficient, resilient and productive

Production processes based on laser technology clearly meet the requirements posed by the so-called Industry 4.0 in terms of customisation and resilience, reduction of life cycles, greater productivity or improved sustainability.

Basically, laser processes are easy to digitise because their fundamental parameters can be controlled (speed, beam size and shape, amount of energy per pulse and power).

What this actually means is that a single laser source can be used to develop completely different processes such as cutting, welding or cladding. In addition to this, the inherent features of this technology provide excellent adaptation capacities that do not only make it possible to modify designs quickly, but also allows different products to be customised in a single process.

It must also be stressed that the higher average power ratings achieved by these lasers together with the development of beam processing techniques (multiplication, conversion and shaping) are delivering increasingly higher productivity rates that are making it possible to manufacture complex structures that, until now, could not be approached in a profitable manner. A clear example of this can be found in the micro-drilling of large surfaces for aeronautical applications and in which high-speed drilling would make it feasible to develop hybrid laminar flow control structures (HLFC).

Finally, laser is also an excellent tool used to measure and calibrate machines or end parts and to monitor and inspect throughout a process as no contact is required for this technique. In this regard, for instance, modern interferometric multilateration techniques have made it possible to automatically check the geometry of a machine tool throughout its entire work volume in short periods of time and with hardly any human intervention.

Additive manufacturing and 3D printing of metallic materials

The development of additive manufacturing techniques is a fundamental pillar for the so-called Industry 4.0 approach because it helps to obtain components quicker and with greater resilience and accuracy in certain applications.

These technologies, however, have been fundamentally used to obtain plastic prototypes, which explains why additive manufacturing has been repeatedly associated with "rapid prototyping". In many instances, the scaling of these processes in accordance with real manufacturing situations requires that materials with good mechanical and thermal properties be used. Consequently, this means that metallic materials must also be used. Thus, the obtainment of metallic parts represents a significant landmark in terms of implementing additive manufacturing in production processes.

Nowadays, laser technology provides the two main additive manufacturing methods on metal: Selective Laser Melting (SLM) and Laser Metal Deposition (LMD).

In the first case, the part is generated layer by layer on a bed of metallic material in the form of powder. The final quality of the part is determined by the thickness of each layer manufactured (generally speaking, a few dozens of microns) and by the parameters and quality of the laser that has been used for the melting.

On the other hand, Laser Metal Deposition (LMD) is based on injecting metal powder (LMD using powder) or metal wire (LMD using wire) on the focalising plane of a high-power laser to produce direct melting of the material on the surface under consideration.

The main advantage of the LMD technology is that it allows additive manufacturing to be carried out on surfaces with complex geometries as well as on parts manufactured beforehand using other technologies.

Furthermore, the size of the parts manufactured is only limited by the machine's range of motion, meaning that large parts (>1m3) can be manufactured at high deposition speed settings (>2Kg/hour). Generally speaking, manufacturing practices of this kind require machining in the case of applications for which a good surface finish is a must.

In those instances in which a good finish is required, LMD manufacturing only requires a minimal superficial machining post-treatment that does not take up too much time.

LMD: injection using power and metal wire

Nowadays, LMD technologies using powder and wire injection coexist at an industrial level and both are applied in different cases. As regards powder, it is a much more widespread and technologically developed process, as easier to use and materials are more readily available. This explains why it is frequently used for tasks involving reinforcements and repairs.

However, recent progress reported in terms of header design and materials in the form of wire have given rise to advantages such as an insignificant loss of material deposits, higher deposition speeds, to greater process adaptability to machining-additive manufacturing hybrids and to a healthier work environment, among other benefits.

The importance of process control

It must also be stressed how important it is to control these manufacturing processes as they clearly determine the structural and mechanical features of the end parts. Likewise, an in-depth characterisation (structural, chemical, mechanical, etc.) is required throughout the entire process, from the base material used to the end part itself. It is unquestionable that these issues are very significant as regards certifying and accepting products manufactured by means of these technologies.

In addition to the aforementioned remarks with regard to laser-based manufacturing processes, there is nowadays a significant trend focused on designing and manufacturing sources, components and equipment to deliver processes that are quicker, more reliable and safer. In this regard, new designs are being looked into for the ultimate purpose of developing small components and manufacturing complex equipment.

Generally speaking, it can be concluded that, based on its current state of the art, laser technology can be rated as a key vector in terms of developing advanced manufacturing processes demanded by industry 4.0 and that it clearly complements traditional processes (cutting, welding, machining, heat treatments, etc.).

This technology has also given rise to the onset of new manufacturing processes in the field of additive manufacturing for metals.

The Laser for Manufacturing Lab

Without ever losing sight of this trend and after nearly 20 years of work connected to developing laser technology to meet these new requirements, IK4-TEKNIKER has set up the “Laser for Manufacturing Lab, that offers global solutions based on specialised and comprehensive knowledge related to laser technology applied from the integral perspective of advanced manufacturing: manufacturing processes -specialised in LMD using wire-; the design and manufacture of equipment and components; additive manufacturing, inspection and measurement.

The Laser for Manufacturing Lab offers a means to reach out to the industry more efficiently and to meet specific advanced manufacturing need thanks to the possibilities offered by laser technology and which provides a 360º vision on this technology and how it can be applied. With the support provided by in-house knowledge and equipment, it also guarantees integral process control that includes the structural and mechanical features of the end parts.

This initiative forms part of a joint and coordinated offer comprising all the solutions developed in this field at IK4-TEKNIKER that can be classified as follows: