Over 50 Percent Wall-Plug Efficiency Fiber Laser

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1 Over 50 Percent Wall-Plug Efficiency Fiber Laser World record wall-plug efficiency for high power industrial lasers Fig. 2 Efficiency of pump diodes and fiber block Fig. 1 The development of the wall-plug efficiency (WPE) in the last years High power laser performance is determined by output power, beam quality and stability. Other key factors are total cost of ownership, size and weight. At the moment, IPG s fiber lasers achieve single mode beam quality up to an output power of 10 kw. The first 100 kw fiber laser for material processing was delivered by IPG in High performance fiber lasers from IPG have been established in industry for more than 15 years in 24/7 production. Significant improvements in wall-plug efficiency occurred in recent years from 25 % in 2008 up to 50 % in 2015 (Fig. 1). Reducing energy costs is a key theme in the manufacturing industry. Energy is a large factor of the total cost of the end product, driving demand for energy- efficient technology. Between December 2012 and December 2015, all non SMEs performed a so-called energy audit according to DIN EN Exceptions include companies that already work with an energy management system according to DIN EN ISO This new regulation helps show potential for improvement in energy-efficiency and environmental compliance. The new ECO laser family represents all advantages of IPG industrial lasers with 50 % wall-plug efficiency. This new development demonstrates the advantage of vertically integrated industrial laser production. All the key components are developed and manufactured in-house. Each component has the potential for higher efficiency but the balanced optimization of each component part leads to the maximum possible total wall-plug efficiency. Examples are the pumping diodes. The single emitter diodes are manufactured using telecom-proven technology and processes. Each pump diode is qualified to telecommunication industry standards, which sets IPG apart from all alternative industrial pump diodes manufacturers. The path to 50 % wall-plug efficiency The key reason for a higher efficiency is not a single component; instead the interaction of various components makes it possible to establish the highest efficiency in a fiber laser. The main components for optimization are categorized as follows: Diode modules design optimization Advanced design of fiber blocks Active and passive fibers; design optimization Small insertion losses of IPG components: a) feeding & process fibers, b) beam switches & fiber couplers Laser modules with digital electronics IPG s power supplies The challenge is to optimize all individual components to a higher efficiency and to keep the best functionality with all components. For example, the efficiency of the laser pump diode design and optimisation are important. The wavelength is optimized that it has a maximum absorption at a current of 6 A (Fig. 2, top). Here, the pump diodes reach an efficiency of 64 %. This part of the optimization describes the conversion of the electrical current into the optical pump wavelength of 975 nm. Consequently, the efficiency of the fiber block was improved to a higher value. A key part of a fiber block is the active fiber. It introduces amplification by mixing the propagating light with pump laser light, in the presence of rare earth metal ions embedded in the fiber core. The active fiber transforms optical power at 975 nm into 1070 nm, the laser operating wavelength. The optical fiber s unique properties make it an ideal active gain medium for amplification to higher powers. It is flexible and easy to handle. The huge surface to volume aspect ratio facilitates heat removal and helps to avoid thermal lensing. Points of improvements to higher efficiency are splice points of the pump fiber and general heat management of the whole fiber block. All in all, the fiber block efficiency achieved today is around 86 % (Fig. 2, bottom). The ECO lasers include new digital control electronics of laser modules, replacing the analog modules electronics. With additional optimization the conversion efficiency of input DC voltage into PLD s current goes up to 14 Laser Technik Journal 2/ WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

2 Communications Fig. 3 Example of wall-plug efficiency (WPE) by a YLS ECO 98 %. A laser module includes a fiber block, pump diodes and an electronic controller. The entire laser module with all components achieves an efficiency of 54 %. In addition to module electronics, the power supply of the laser is critical to overall efficiency of the laser. The peak conversion efficiencs of input voltage from mains into the DC voltage that is required for laser modules is 96 %. The optical efficency is influenced by losses in optical components. IPG manages the development and manufacturing of all optical components in our fiber laser system. Besides fibers, we make other critical optical components, including lenses for beam switches or couplers and optics for the fiber outlet. The coating plays a crucial role in optimizing these optical components. In contrast to conventional coatings, IPG uses multilayer coating. By optimizing the selection of raw materials, the composition of the coatings is controlled. Power losses from optical surface should be kept low as possible. For instance, insertion loss for fiber-to-fiber couplers and beam switches are under 1.5 %. The coatings of optical bulk elements contribute to high efficiency; we observe < 0.2 % losses of any optical bulk element. In summary, the efficiency of the whole high power fiber laser system achieves over 50 % (Fig. 3). This is only possible because IPG is able to design and manufacture the whole product line and component parts of a fiber laser system. Advantages of in-house chiller development An additional factor that significantly contributes to energy efficiency is the corresponding chiller for each laser system (Fig. 4). To reach optimization between chiller and laser, their interdependence must be managed. For this reason IPG has its own laser chiller product line. One key challenge is the communication between laser and chiller to facilitate switch-on and switch-off timing. IPG s communication protocol optimizes the system so that the chiller only operates when it is really necessary. The following features are uniquely combined in the new chiller systems: Energy-efficient with scroll compressor by standby Well-spaced water cooled condenser Additional sub-cooling for higher efficiency Regulation of cooling water rate via CAN bus connection laser / chiller Closed cooling circuit for optics Special compact design for integration In combination, the laser with optimized chiller wall-plug efficiency is up to 46 %. There are two kinds of laser chillers available. Water-to-air and water-to-water chillers for fiber lasers with output power up to 6 kw. By using only a heat exchanger the efficiency can reach even higher compare to a chiller. Fig. 4 IPG chiller layout Fig. 5 YLS CUT laser 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Laser Technik Journal 2/

3 Innovation in fiber technology Because of a higher efficiency, it is possible to generate more laser light in one laser module. This will allow manufacture much more compact laser products. One example is the new YLS CUT laser (Fig. 5). It is specifically designed for high performance in harsh cutting environments. Features are a compact design with a hermetically sealed cabinet. To optimize internal humidity a dehumidifier is installed as standard. The YLS CUT Series contains all the latest technical efficiency improvements for diode modules, fiber modules, digital electronics and power supplies. Another new market innovation based on a compact design is the multicore fiber laser. There are multiple applications in the high power range where the multicore fiber laser has advantages against standard laser systems. Basically, a defined number of fibers from the laser can be used. Each fiber has independent power control, opening up a wide range of application possibilities. One current application in field is brazing of hot dip zinc coated steel with a tri-focal fiber laser (Fig. 6). In commercial laser brazing achieving a high quality seam with hot dipped coated steel remains a challenge, in comparison to electrolytically galvanized zinc coated steel. In tri-focal laser brazing, the main laser spot is accompanied by two smaller spots, with a Fig. 6 Principle of a tri-focal fiber defined separation. The two small spots are located on the edge of the brazing seam and ablate a part of the coating, immediately prior to brazing. The small spots actually clean the brazing path so that the filler material flow significantly improves. The result is a reproducible brazed joint with increased strength and better appearance. Generally key effects are: Reliable brazing process Increased brazing speed High quality seam appearance Inline cleaning process Maximize joint strength The continuous improvement of processes requires laser beam sources with adaptable properties. For many years, IPG has offered its customers a test fiber laser system, in the Burbach application center. The multicore fiber laser offers new ways to optimize a wide variety of process developments in various markets. The tri-focal fiber laser is, for now, ideally adapted to the brazing processes. However, in other applications a multicore fiber laser will realize significant benefits using more fiber cores, different fiber diameters or independently powered multi-cores. Michael Stark IPG Laser GmbH, Tel.+49(0) , mstark@ipgphotonics.com, Laser Beam Shapes Under Control When the application dictates the laser beam shape Industry 4.0 beckons Since 2008, Limo has been supplying the Prague-based company Medicom with industrial laser systems that have proven effective in process-stable laser transmission welding for plastic fuel filter enclosures. Limo has been Medicom s key supplier of diode laser modules since the year 2000, says Michal Horáček, Project Manager Industrial Lasers Division at the Prague-based Medicom Inc., one of the world s leading manufacturers of laser systems for industrial production and medical technology. The use of these components in laser systems for the medical industry went so well that, after eight years, the two sides expanded their business relationship to include the industrial sector. Horáček notes: When we started a new product line of welding lasers in 2008, Limo products were our first choice because of their high performance and excellent reliability. Since then, Limo has supplied a large number of industrial laser systems (ILS) that Medicom integrates into its welding lasers. These systems comprise fibercoupled 200 W diode laser modules that feature an intelligent laser processing head and a sensor for non-contact temperature measurement (pyrometer) Fig. 1 The industrial laser systems from Limo are the heart of Medicoms welding lasers, which are used by well-known automotive suppliers for the reliable production of pressure- and liquid-tight plastic fuel filter enclosures. (Source: Medicom) 16 Laser Technik Journal 2/ WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

4 Communications Fig. 2 Custom beam shape: These fuel filter enclosures are assembled using Medicom welding lasers, in which industrial laser systems with an intelligent laser processing head can also be adapted to complex 3D contours. (Source: Medicom) and have become the heart of our laser welding system, as Horáček puts it. The systems are used by notable automotive suppliers to weld fuel filter enclosures, whose weld seams remain reliably sealed even where the plastic is exposed to extreme pressures (up to 30 bar). Peter Bruns, Director Applications & Technical Service at Limo in Dortmund says: With our solutions, it is even possible to weld automotive components made of glass fiber reinforced plastic, where weld seams need to withstand pulse pressures of up to 65 bar over a temperature range of 40 to +125 C. One special feature is the new intelligent laser processing head, which offers extremely versatile beam geometry and intensity distribution and, thanks to a controlled, locally limited energy impact, also ensures an ideal temperature distribution in the component. Just like the L³ Limo line laser system with its patented beam shaping capability, this new head can be used to produce diverse beam geometries and weld complex 3D contours. Because the beam shape is adapted to each individual application, both the quality and productivity of the assembly process can be increased. Another feature is the process control integrated in the head. This control is based on the synergy of precision pyrometric temperature measurement with laser output measurement and thus enables real-time control and diagnostics, says Bruns. Because we know what is being measured and how to measure it, this process control works across a very wide range of applications in the contour or simultaneous welding of non-homogeneous plastics, for example. For one large German automotive supplier in particular, a solution was designed that is fully in keeping with the industry 4.0 concept. Here, Limo developed a laser head program which controls the process and monitors the welding operation. This results in what is referred to as machine-to-machine communication via the fieldbus. As Bruns explains, For each component, the system signals whether the individual welding operation including all of the welding parameters was OK or not OK. Thanks to the closed-loop control system and fully in-line quality control, customers benefit from a stable and fast welding process. They can also satisfy mandatory documentation requirements for safety components. Because the standard laser processing head already includes the necessary software, laser transmission welding 4.0 is now also possible at other companies and in other industries, according to Bruns. These applications demonstrate how a company in the laser industry was able to transform itself from a pure component manufacturer into a reliable process supplier that fills the role previously performed by general contractors. Most jobs at Limo start with a feasibility study, says Bruns. In many cases, we then conduct testing under series production conditions in a pre-production run. This Dortmund-grown process expertise is now being utilized in many different industries, e.g. for the temperature-controlled welding of endless plastic profiles with application-specific laser line distributions, the non-porous and splashless joining of PC and PMMA plastic parts, or the assembly of lightweight components made of composites (e.g. glass and carbon fiber reinforced plastics) WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Laser Technik Journal 2/

5 Precise, Flexible and Easy to Integrate A new generation of ytterbium fiber lasers for marking plastics, metals and many other materials Laser marking has become one of the preferred methods for product identification, decoration and material processing. Due to ever increasing quality standards, new legal and industrial regulations, or the manufacturer s intent to add value and safety to their products, many applications have already been developed and still, new fields of use arise. Especially medical technology and automotive industries show a growing demand for reliable, accurate and at the same time efficient direct part marking and identification solutions, which enable safe traceability and provide counterfeit-protection. Nowadays, part marking systems not only have to mark reliably. They also have to demonstrate flexibility, as the applications, requirements and materials of our customers vary widely and become more and more complex. Only tailored solutions ensure optimal marking results, easy integration and at the same time cost-efficient processing. Our clients have different requirements in terms of marking speed, marking quality and marking precision. This requires flexibility, said Michael Strzyz, Director Product Management for Foba. The new series of fiber laser marking systems has been developed to create more clarity and take the complexity out of laser marking. With the Y-Series, Foba introduces a modular platform consisting of nine compact and flexible fiber marking lasers spanning power and pulse width ranges. The proprietary scan head technology offers tunings for optimal marking quality and high marking speeds. The easy, quick, reliable and cost-effective integration into various production environments and systems is one of the key customer requirements when it comes to installing a marking laser. The modular design of the Y-Series takes this major requirement into account as it includes nine different ytterbium fiber laser sources (λ = 1,064 nm) which are identical in construction, spanning power (2 50 Watt) and pulse width ( ns) ranges and two continuous-wave lasers (cw) on one modular platform. Additional features include various optics, a choice of marking fields, two beam turn versions for Fig. 1 Marking laser Foba Y.0200 (with integrated IMP vision system) integrated in a Foba M2000-P laser marking station straight-out or 90 beam exit, a patented camera system and major customer interfaces (TCP/IP, Profibus) for flexible integration. Across all industries, parts and products are becoming smaller, and more and more complex in shape. Across the entire product life-cycle, reliable readability of all marked contents is of utmost importance. Permanent and precisely positioned markings are among the most decisive quality criteria particularly in the automotive, automotive supplies and medical technology industries where safety comes first. What is more, many manufacturers have to mark a variety of different products which leads to varying requirements on the marking quality and therefore also on the marking speed. With the two scan head tunings High-S (for higher marking speeds) and High-Q (for higher marking quality), the Y-Series offers two parameter sets for each one of these use cases. The new High-R (resolution) marking field calibration offers an uncompromisingly accurate mark positioning and a substantial reduction of marking field distortions. Both is crucial when marking small parts and applying large marking contents, but also when high code integrity is required. All Y-Series fiber marking lasers are available with the optional vision system IMP (intelligent mark positioning) directly integrated in the marking head. IMP is the core of Foba s holistic vision-aided laser marking process HELP (holistic enhanced laser process), which offers verification prior to marking and Fig. 2 Stainless scalpel holder with black marking validation right after. The validation of marking contents right after the laser marking helps to avoid marking errors, reduces scrap and non-conforming products, and ensures process reliability. Particularly important for manufacturers with strict quality and code and data integrity: 1D and 2D contents are directly read back during post-mark validation and characters and images are immediately verified. The fiber laser marking systems in the new Y-Series are perfect for the reliable laser marking of various plastics (i.e. epoxy resins, foils), metals (aluminum, steel, titan, etc.) and many other materials with codes (QR, DMC, bar codes), alphanumeric signs, logos, graphics and images. Y-Series marking lasers are specifically engineered for the corrosion-resistant marking of medical stainless products. The powerful new fiber lasers are not least due to their flexibility best suited for the precise and efficient direct part marking (DPM) in almost all industrial areas ranging from the automotive and automotive supplies industries through medical and safety technology to electronics and others Laser Technik Journal 2/ WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

6 Communications Intelligent Beam Monitoring for a Perfect Cut The 2D laser cutting machine TruLaser 5030 fiber features two new functions and an additional choice of laser power Fig. 1 With numerous intelligent functions and as much as eight kilowatts of laser power, the TruLaser 5030 fiber achieves first-rate quality in both thin and thick sheet metal. (Source: Trumpf) The performance capacities of the 2D laser machines and the solid-state lasers made by Trumpf continue to advance. Worthy of special mention are the BrightLine fiber function, which turned the solid-state laser into an all-purpose tool, and the CoolLine feature. The latter stabilizes the cutting process for thick mild steel by way of closely defined cooling. This makes it possible, for instance, to cut extremely tight curves. Among these features is the intelligent beam monitoring system Smart Beam Control. It lends even greater reliability to the solid-state laser machines in the TruLaser Series Smart Beam Control automatically regulates the laser s focal position during the cutting process itself. This function makes for constant superior reliability and makes it possible, in addition, to carry out a diagnosis of the cutting system. This can also be done from a remote location, using Teleservice. The new Condition Guide function for the TruLaser Series 5000 enhances transparency. A single glance is enough to determine the machine s status. A traffic light system provides information on the condition of key elements that affect the machine s cutting capacity. The Condition Guide can, if desired, provide information on corrective actions to be taken by the operator. Line charts show the history of the particular condition and simplify forecasting the need for intervention. Consequently, maintenance work can be planned both efficiently and in harmony with actual needs. In addition to the 3, 5 and 8 kw power levels offered in the past, the TruLaser 5030 fiber is now also available with the 6 kw TruDisk 6001 laser. Especially at medium and heavy sheet metal gauges this makes for quick processing. Fig. 2 The Smart Beam Control function automatically regulates the focal position of the laser during cutting and, in this way, ensures consistently high process reliability. In addition, a diagnosis of the cutting system is possible also from a remote location, using Teleservice. (Source: Trumpf) Using the TruDisk 6001 and the functions cited here the TruLaser 5030 fiber cuts mild steel, stainless steel and aluminum up to 25 mm thick and copper and brass as much as 10 mm thick, both quickly and with enviable dependability WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Laser Technik Journal 2/