The increasing demands in industry, for example for products in the consumer electronics sector or for assistance systems in cars, and the continuous development in semiconductor are leading to significant miniaturization in electronic components. These requirements are inevitably also transferred to ultra-precise manufacturing and thus ask for monitored production steps. In the context of Industry 4.0 and other developments in the context of modern production sensors to supervise production steps are crucial. An essential component here is non-destructive testing (NDT) and specifically optical metrology and overall end of line qualification. The FlyingSpotScanner (FSS) provides OCT measurements for thickness and topography based on a breakthrough, unique technology that enables high-speed, non-contact inspection for quality assurance across a wide range of materials and surfaces. The FSS310 Version has changed the semiconductor market. Thanks to its huge scan area of 310mm, a 12 inches diameter wafer can be fully checked for TTV, bow and warp in just 10 seconds. Due to the movable mirror system, long paths of linear axes are replaced by short rotary movements, resulting in an extreme reduction of the measuring time. The FLYING SPOT SENSOR FSS310 was awarded with the SPIE Prism Award in 2023.
The increasing demands in industry, for example for products in the consumer electronics sector or for assistance systems in cars, and the continuous development in semiconductor are leading to significant miniaturization in electronic components. These requirements are inevitably also transferred to ultra-precise manufacturing and thus ask for monitored production steps. In the context of Industry 4.0 and other developments in the context of modern production sensors to supervise production steps are crucial. An essential component here is non-destructive testing (NDT) and specifically optical metrology. Complete 3D measurement of objects using white light interference in mass production is time consuming and therefore not well-suited for use as a means of inline inspection. In addition, the long measurement cycles with complex sequences generate large amounts of data and the effort for processing the data must also be included in overall considerations. The Flying Spot Scanner (FSS) intelligently avoids these disadvantages and is therefore ideal for inline inspections. To meet the need of additional, even complex and time sensitive measurement tasks, Precitec Optronik has developed the Flying Spot Sensor. The active measuring head was specially developed for in-line use and ideally complements the spectral interferometric sensor to form a smart inspection system. The light from the sensor is coupled into the measuring head via a light guide and deflected by a mirror system, a so-called galvanometer scanner. Finally, the light passes through a telecentric lens, which serves as a focusing module on the outward path and as a measuring aperture for the reflected light. Due to the movable mirror system, the measuring light beam can be deflected at different angles and thus the measuring spot can be freely positioned within the field of view of the lens. Long paths of linear axes are replaced by short rotary movements, resulting in an extreme reduction of the measuring, or scanning time. By using specialize focusing modules, the Flying Spot Scanner can be adapted to different application scenarios. These optics are characterized by a low curvature of the focal plane, very small telecentric errors and a very large depth of field. The measurement system can also be used in two operating modes, a thickness mode, or a distance mode. The two operating modes can be selected at will via the digital interface, which means that the switching process can be easily integrated into an automatic measuring sequence.
There are many distinct commercial sensor systems for monitoring or controlling laser processes. Most of them are based on camera or photodiode technology. Furthermore, the introduction of real in-process measuring systems in laser material processing like OCT has significantly increased the safety of both defect detection and process control [5][6][7][8][9]. The focus of this contribution, however, relates to the use of artificial intelligence algorithms to "See New Things". We will discuss how classified, physical properties can be derived from already reliable process information - "seeing the unseen", so to speak. Instead of defining complex rules for algorithms, the use of Data Science and Machine Learning methods reveals hidden structures in noisy unstructured data and make it possible to find the relationships of the data to the physical measurement. There are several systems available in the market which capture or measure and analyze physical effects of the process zone and their properties during the laser processing, but none of these effects and properties stand for “seam quality” for themselves, which is typically defined by mechanical, geometrical and metallurgical properties of the solidified seam. The process properties like emitted visible and thermal radiation or geometrical values of the melt pool or the penetration depth of the laser forming the keyhole (penetration depth) only provide indications of how the desired quality might be achieved. When welding thousands of seams per shift during serial production for Li-Ion batteries in e-mobiles, very often users would like to stop their fully automatic machines once the laser process is suddenly running out of previously set boundaries. Such an approach allows users to find systematic faults where and when they occur, rather than at the end of the line where quality inspection takes place and the line is still running, producing more and more parts with the same faults. When it comes to the use of artificial intelligence algorithms the following questions must be answered: ▪ Is it possible to map an input time series to a real value? ▪ Can we get out the strength of the weld from the process emissions? ▪ Is the information buried in the signal? The vision, which can be represented by Figure 1, is that by using the data from process emissions and specific data models, a relationship to physical quantities can be established. Thus, AI goes a significant step beyond the simple "good-bad" statement.
The increasing demands in industry, for example for products in the consumer electronics sector or for assistance systems in cars, and the continuous development in semiconductor are leading to significant miniaturization in electronic components. These requirements are inevitably also transferred to ultra-precise manufacturing and thus ask for monitored production steps. In the context of Industry 4.0 and other developments in the context of modern production sensors to supervise production steps are crucial. An essential component here is non-destructive testing (NDT) and specifically optical metrology. Precitec Optronik is developing since decades intelligent sensor systems based on chromatic confocal or interferometric measurement principle. To meet the need of additional, even complex and time sensitive measurement tasks, Precitec Optronik has developed the Flying Spot Sensor. The active measuring head was specially developed for in-line use and ideally complements the spectral interferometric sensor to form a smart inspection system. The light from the sensor is coupled into the measuring head via a light guide and deflected by a mirror system, a so-called galvanometer scanner. Finally, the light passes through a telecentric lens, which serves as a focusing module on the outward path and as a measuring aperture for the reflected light. Due to the movable mirror system, the measuring light beam can be deflected at different angles and thus the measuring spot can be freely positioned within the field of view of the lens. Long paths of linear axes are replaced by short rotary movements, resulting in an extreme reduction of the measuring, or scanning time. By using specialize focusing modules, the Flying Spot Scanner can be adapted to different application scenarios. These optics are characterized by a low curvature of the focal plane, very small telecentric errors and a very large depth of field. The measurement system can also be used in two operating modes, a thickness mode, or a distance mode. The two operating modes can be selected at will via the digital interface, which means that the switching process can be easily integrated into an automatic measuring sequence.
Laser cutting process is a very broad application requesting a high beam quality. Optimizing the beam shape is a promising solution to the challenge of cutting thicker parts while maintaining a sufficient cutting speed.
We describe here a beam shaper compatible with industry standard equipment handling up to 16kW average power delivering an optimized non-symmetric shape. The different shapes are examined by means of online high-speed X-ray images, enabling to reconstruct the cutting front and to calculate the absorbed irradiance on the processed sample. This allows to compare the results with conventionally processed samples.
It becomes clearer and clearer that there is more than a gradual transition in automotive industry, especially when it comes to the future propulsion systems. Whether we talk about e-mobility or hydrogen drive, laser and photonics industry take the chance to transform manufacturing processes, convince decision makes on the undoubted advantages of photonic tools in the relevant production chains. As most of the applications e.g., in e-mobility start from scratch one can directly use the most profitable manufacturing tools. There is no need to transform an already existing process from the “pre laser age” into modern times. This paper reviews some of the applications in battery production from the perspective of a supplier of sensor technology and processing tools, without claim of completeness. The focus will concentrate on laser welding as here process monitoring and control plays an important role, laser marking, drilling, surface processing will not be part of the deliberations. This contribution to the Photonics West '22 LASE conference describes the intersection between photonics and demands when it comes to efficient production tools for tomorrow’s mobility. Further intersections with respect to Industry 4.0 and artificial intelligence haven’t even been mentioned, but here we easily find more examples which underscore the uniqueness of the laser in the context of e-mobility.
Not only surface treatment has established itself as a field of application for the Direct Metal Depostion process, direct "printing" or the production of near net shape structures is an essential field of application for metal powder build-up welding. Although the nozzle technology has been continually improved, the powder efficiency is below 100%. It is far away from process boundary conditions to take the decision whether metal powder or wire is the best solution for a specific application. In the recent years the use of wire was not part of the discussion e.g. when talking about a multi-directional welding path or building 3D structures because of the missing tool.
The new processing head CoaxPrinter is a promising solution to increase the use of wire in LMD. The compact and easy to use device has shown excellent build up results with repeatable quality and homogenous inner structure of the melted wire, supported by OCT sensor technology.
Nowadays the laser is a conventional tool in industrial manufacturing, for a wide spam of applications, from subtractive to additive, from cutting to welding. The main topic in production today is headlined with the word digitalization and Industry 4.0. In this context the laser is playing a dominant role, because it is possible to produce a part directly from a digital model by contactless processing. This unique feature allows for monitoring processes with smart devices, which is a key issue of Industry 4.0. Especially sensor technology is a leading part related to Smart Factory and predictive maintenance and even process control. Transforming machine elements into intelligent cyber physical systems involves the integration of smart sensors for condition and process monitoring. This contribution of Precitec to the SPIE LASE Conference will present some of the highlights in the area of laser metal deposition and 3D printing using innovative laser processing heads in combination with sensor strategies to fully monitor and even control the manufacturing process with the OCT sensor principle. Sensors based on OCT (optical coherence tomography)/ low coherence interferometry are different to all the other technologies because the measurement is not affected by the process emissions and thus open new horizons in laser materials processing. The use of this method in laser applications has risen in the last years. Since its first appearance in 2008 [1], application examples were shown for laser cutting [2], selective laser melting [3], laser micro machining [4], laser drilling [5] and laser welding [6]. For the latter, a huge potential is foreseen [7] [8].
Talking about purified assembled printed circuit boards (PCBs), e.g. in automotive industry for control of airbag or antilock braking systems (ABS) one of the main issues is the protection against environmental impact. The error-free functionality has to be guaranteed even under extreme conditions and this warranty has to be provided for even a decade.
The process of conformal coating is not new but nowadays manufacturer of PCBs starts to use the conformal coating process not only at selected areas, the full board is going to be protected. To keep the costs under control it is inevitable to measure the thickness of the coatings. An intelligent design of the full process chain implementing the conformal coating process are perfect conditions to integrate sensor technology for process control.
This feature will describe the implementation of an optical sensor technology for the inspection of the conformal coating process to illustrate the benefit of optical sensors in today's industry.
Laser materials processing, e.g. welding/ additive manufacturing with cw sources or surface modification with short and ultra-short pulsed lasers is a highly dynamic process, requiring a sensor with high temporal and spatial resolution for evaluating the result of the treatment. Especially in the context of Industry 4.0, digitalization and predictive maintenance reliable sensors get much more into focus. A major drawback of this photon-material interaction with respect to the acquisition of trustworthy measurement data from the interaction zone is the presence of intense process emissions and steep temperature gradients. Common devices used as sensors for process monitoring, like CMOS/IR cameras or photo diodes, help to get an idea of the resulting quality but the acquired data is always perturbed by hot vapor emerging from the workpiece surface. Sensors based on OCT/ low coherence interferometry are different to all the other technologies because the measurement is not affected by the process emissions and thus open new horizons in laser materials processing. The use of this method in laser applications has risen in the last years. Since its first appearance in 2008 [1], application examples were shown for laser cutting [2], selective laser melting [3], laser micro machining [4], laser drilling [5] and laser welding [6]. For the latter, a huge potential is foreseen [8].
Since the moment when it was possible to achieve the necessary power density to start the process of deep penetration welding, accompanied by a keyhole, there is hope - and need - to measure the depth of this vapor channel. In the decades in which the technology of deep penetration welding has been used, various approaches have been developed that allow a message about the depth of the keyhole. All these approaches have one thing in common, the basics of determining the depth are based on secondary information, such as the dimension of the melt pool, or the strength of the emissions from the plasma or the metal vapor. Except by means of X-ray or destructive testing no method has been developed so far to determine the real keyhole depth. With the IDM system (In-Process Depth Meter) it is now possible to bring a system to market, which can measure the depth of the keyhole in industrial laser welding applications. It is important to bring up, that not only laser welding as a highly dynamic process, requiring a sensor with high temporal and spatial resolution can profit from this sensor technology. The use of this method in laser applications has risen in the last years. Since its first appearance in 2008 [1], application examples were shown for laser cutting [2], selective laser melting [3], laser micro machining [4], laser drilling [5] and laser welding [6]. For the latter, a huge potential is foreseen [8].
Even after the 50th anniversary of the laser invention and about the same time this unique tool is used in industry the improvement of the beam material interaction is still ongoing, at universities, research institutes and inside the R and D facilities of companies. Sometimes the focus of this work is different. Whereas one side is trying to understand the science and physical coherences, the other hand side’s goal is to succeed with a unique selling point with a user benefit of this technology. But despite these differences, the ultimate goal is to approve, lasers to be conventional tools and remain competitive to other technologies or even extend or exceed the technological borders. This contribution of Precitec to the LASE 2018 will try to demonstrate the recent technical innovations developed inhouse. These new features, one in the area of laser cutting will be briefly described technically but the main part of the paper will show the benefits of these devices.
The essential basis for a reliable and target-aimed process control is the understanding of the interaction between the laser beam and the treated material and this was gained by thorough research on the influence of the process input parameters on the interaction sub processes and on the treatment result. The main players con-ducting this research over the decades have been research facilities and institutes and this research is still in progress. Since the moment when it was possible to achieve the necessary power density to start the process of deep penetration welding, accompanied by a keyhole, there is hope - and need - to measure e.g. the depth of this vapor channel. In the decades in which the technology of deep penetration welding has been used, various approaches have been developed that allow a measurement of the depth of the keyhole. The aim of this contribution is to show a compact overview on the different approaches to monitor and/or control micro and macro laser welding processes and especially bring out those which successfully have been transferred from laboratory to serial production in the recent past and will be in the near future.
Laser materials processing in general offers several possibilities for process monitoring systems or process control but the complexity of the process itself, meaning the dependence of the processing result on several process input parameters, does not facilitate their use. As only continuous supervision of the manufacturing process can guarantee the high demands on the quality of the produced parts, process monitoring systems have become more and more standardized devices in laser applications. There is no doubt that the basis for reliable on-line process monitoring systems is the possibility to measure significant indicators, which demonstrates the instantaneous condition of the interaction zone and/or neighboring areas.
This contribution to the Photonics West 2017 LASE conference on the one hand will demonstrate an approach using chromatic coded line sensors for post-weld inspection, on the other hand will show a sensor, based on interferometric principle, which is capable to in-situ measure keyhole depth during deep penetration laser welding and further potential of this sensor approach.
The essential basis for a reliable and target-aimed process control is the understanding of the interaction between the laser beam and the treated material and this was gained by thorough research on the influence of the process input parameters on the interaction sub processes and on the treatment result. The main players conducting this research over the decades have been research facilities and institutes and this research is still in progress. Since the moment when it was possible to achieve the necessary power density to start the process of deep penetration welding, accompanied by a keyhole, there is hope - and need - to measure e.g. the depth of this vapor channel. In the decades in which the technology of deep penetration welding has been used, various approaches have been developed that allow a message about the depth of the keyhole. The aim of this contribution is to show a compact overview on the different approaches to monitor and/or control micro and macro laser welding processes and especially bring out those which successfully have been transferred from laboratory to serial production in the recent past and will in the near future. Further use includes the acquisition of 3D images around the laser process itself, allowing for coaxial integration of pre- and post-process sensors.
The introduction of inline coherent imaging technologies as a sensor for the laser materials processing is accompanied by the integration into several applications. One of these is the measurement of the depth of the vapor capillary for laser welding applications, now allowing to keep record of the welding depth with an accuracy of micrometers and a sub millisecond temporal resolution. The broader achievement is the closed-loop control of the welding depth that was not available in industrial environments till now due to the lack of an adequate sensor. Further use includes the acquisition of 3D images around the laser process itself, allowing for coaxial integration of pre- and post-process sensors. These applications are demonstrated by using the In-Process Depth Meter (IDM).
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