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Traceability not only on the production line
Cross-line solutions are designed to help identify bottlenecks in electronic assembly manufacturing, to avoid errors and to inform if the target throughput is achieved. The original factory of the future requires fluid production processes. This requires a certain degree of mutability from each actor along the manufacturing value chain, ultimately leading to resource efficiency and ergonomics. Thus, complete traceability helps to optimize processes.
But the companies bundled in the RFID consortium (currently eleven companies) are not going far enough. Although established identification and labeling technologies in products such as barcodes, dot-matrix code or laser marking certainly have their advantages, they do have “they do not allow flexibility,” says Alexander Schmoldt the point. Murata Europe’s Manager Business Innovation & Incubation has been involved in the topic of “RFID in electronics production” for almost ten years and therefore understands the users’ needs: “Identification is the key to the necessary transparency of production and logistics processes. Not only can important data be stored in the RFID chip, but also continuously updated. This makes it possible to map the entire product lifetime, which can be called up at any time. “In concrete terms, this means that RFID can function as product memory and data storage, which is becoming increasingly important given the increasing complexity of the integration of different systems. Processes are independently influenced or monitor themselves. ”
How this can look in practice is explained by Thomas Mückl, Deputy Director of Zollner Elektronik. He is active in global engineering and is responsible for all planning processes and product realization. According to him, the complex topic of Industry 4.0 involves two topics: “Firstly, I have to design the production intelligently, but this is only possible if – secondly – I bring an intelligent product, which also offers the possibility to follow the production flow or the sequence “What good is a self-regulating process, if the production of a” stupid label “, he asks the rhetorical question and refers to the known problems such as confusion or variant formation and high costs in logistics. “For me, the end-to-end value-added chain that already starts with the PCB manufacturer is important.
Complete traceability does not start at the goods receipt or even on the SMT line. “Previously we had the problem that we did not know what history the circuit board has, so what relevant data before the first application of the label already existed.” In case of error – and thus in the case of complaint – there were quite difficulties to correctly assign the error, About outsourcing in the warehouse, you can extrapolate the approximate delivery, but then you had ultimately only a delivery note number as relevant information. Here, RFID can exploit its advantages, is Thomas Mücklfrom Zollner Elektronik: “If the information in the RFID chip is stored in the printed circuit board, the PCB manufacturer has the opportunity to play back in production and then evaluate whether or not more customers are affected by this printed circuit board batch. Thus, logistics plus intelligence is the deciding factor in the production flow and also for Industry 4.0. ”
This agrees with Claus Heller. Nokia Networks’ Senior Quality & Technology Specialist works in manufacturing and drives technology development there. For him, it is clear: “The quality requirements require clear labeling of the products.” Why a tag or label quickly reaches the limits of feasibility, he also explains: “In an RFID, I can also deposit, for example, that the product is broken and, ideally, what exactly is broken. I could also enter a link where I find that in the production system. “This ensures that the product is no longer included in the production cycle. After all, the machine could promptly respond to the error message stored in the defective module and forward the module to post-processing: “The operator.
RFID embedded in the board
Not a few associate RFID labels that are difficult to remove on wine bottles. One can confidently say goodbye to this idea, assures Gernot Seeger, Managing Director of Beta Layout. The PCB manufacturer specializes in prototyping and small batch production and since 2010 has been involved in the embedding of RFID chips in printed circuit boards. “The technology is easy to embed in the PCB. The most effective form of source tagging is the most effective form of source tagging. “After all, the circuit board in the electronic assembly manufacturing chain is the first link, he argues. “By birth, so to speak, of the printed circuit board or assembly, RFID technology can be used to store and read information relevant to production. And the RFID chip is all that’s needed to give the PCB a digital ID. ”
Embedding the RFID module in the printed circuit board is not a very big effort. In essence, machines are in use that is anyway available at the PCB manufacturer. However, separate production steps are still necessary; he explains: “Of course there is a step where the module is pushed into the circuit board – by the way, not in the individual circuit board, but in the manufacturing benefits. This happens in a very early production step. “For this purpose, Beta Layout has developed a machine with the acclaimed name Proof-of-Concept. Also, the system can easily be scaled up also to be able to realize series production. On the other hand, the embedded mini-tags are not limited to specific printed circuit board techniques. In the smallest form these are just 1.2 mm x 1, Gernot Seeger of Beta Layout: “With our technology, we can embed RFIDs in any board. These can be single-layer printed circuit boards, double-sided multilayers or HDIs – there are no restrictions. ”
Limiting factors are metal surfaces. However, there are now RFID metal tags that can be applied to metal. The built-in spacer to the metal surface allows readability, Claus Heller from Nokia has learned: “These metal surface-suitable tags can also be implemented by drilling small cavities in the metal. It is important to ensure that there is a certain amount of free space. “The distraction of legibility through ground plains has also lost its horror, confirms Alexander SchmoldtMurata: “Using the ground plane as a tag antenna simply reduces the range with a smaller ground plane, but the functionality is always there.” After all, more than 90 percent of the boards contain an extended layer of copper. This obstacle could be to the advantage of coins by instead of a dipole antenna, the metal surface of the circuit board itself acts as a booster antenna. He adds: “In problematic situations, there is still the possibility of developing a specific antenna. It always comes with a minimum of effort to a solution. “For example, could think about an edge metallization, whereby the circumference of the board would be available as an antenna. It is also possible to make a loop via vias.
Challenge soldering technology
However, a not insignificant task still has to be mastered in the hottest field of SMT production: to fully exploit the potential of the RFIDs in the reflow soldering systems. Wireless temperature measurement systems have already paved the way for data acquisition. For Paul Wild, Deputy Head of R & D at Rehm Thermal Systems, the end of the flagpole is far from over. In its area of responsibility for plant and process development, RFID-bound data communication in the peak zone is an ambitious goal, with many challenges. Nevertheless, we are making very fast progress. “The fact that Rehm will be able to teach the soldering machines to communicate with the products during the entire process has been a target for years, which is now within reach.
It is not just about measurement parameters, but above all on which level they are tapped. Rehm has already integrated temperature measuring systems for thermal processes such as Procap Kic or WPS2.4 into the processes and systems. In thermal processes such as soldering, drying or curing of electronic assemblies, a reliable and reproducible temperature profiling is important to obtain reliable information about the introduced thermal energy. Temperature detection, therefore, has a particular significance in the demanding soldering process. For example, in cooperation with Pro-Micron, a wireless temperature sensor has been developed that is tailored to the specific requirements of condensation soldering with the Condenso-X series from Rehm Thermal Systems. Thus, a complete monitoring of soldering processes up to 300 ° C is ensured, but: “The temperature sensors measure the temperature only in the atmosphere within the soldering system,” he exclaims and draws clearly the comparison in which he shakes hands with his neighbor Gernot Seeger from Beta Layout stretches out: “If I hold my hand like this, do you feel my temperature? No, certainly not. Only when I touch you, we know more about our thermodynamic state. ”
It would be perfect if the temperature could be measured directly on the product, especially in safety-critical applications. “At the moment we always have a distance of about 20 mm to the assembly in the atmosphere.” The procedure with the temperature sensors is established and works very well for the current requirements, emphasizes Paul Wild, also to continuous traceability: “It can help each assembly a soldering profile or temperatures are assigned. But as I said: there is still a gap in between. This distance is associated with a certain risk for higher demands. “Until a consistent RFID solution is possible, there will be a transitional solution of both technologies – temperature sensors and RFID. Nevertheless, work is underway although the initial conditions are not very simple with little space and high temperatures: “First, the hurdle in the lead-free soldering with peak temperatures of up to 300 ° C to take. If we have bridged that, and the gap in the peak area is closed, we can move into other areas. Due to the high process temperatures, we have to do some pioneering work to achieve these goals: if we manage to reliably transfer the data from the assembly surface in the soldering area, this will make using RFID in areas with lower temperature stress much easier. ” Paul Wild estimates that the project team at Rehm will be ready to communicate with the products via RFID in just three years, not just in the preheating and cooling zones.
On the way to CPS-based production
The communication is initiated by an RFID read-write unit (reader). In the RFID module, a mini-UHF tag (transponder) is integrated. The technology for this – from the transponder to the software package – comes from Harting. It is possible to capture up to several 100 objects without – in contrast to the barcode – requiring a line of sight connection. The data collected are immediately available throughout the company for further processing. In the field of an electronic assembly, the RFID consortium endeavors to enable continuous data exchange from the beginning of the board production to assembly and connection technology, testing techniques and post-processing, as well as after-sale, maintenance and end-of-life of the product.
Olaf Wilmsmeier is the Business Development Manager responsible for the RFID division at Harting, which means he is also involved in embedded platforms. For him, it is clear: “Ultimately, technology must be applicable and be able to solve problems. What is very important is that we do not want to create anything that somehow works in isolation, but that you can integrate the technology into the existing systems. “It was important to bring added value into the existing machinery and IT landscape. “No one wants to give up his MES or database-based system in which all sales orders and production planning are stored. Rather, we want to increase flexibility as well as production accuracy, process stability and traceability, “adds Wilmsmeier also.
RFID must be integrated into existing production processes and environments. Setting up and converting production lines with plants and machines is anything but trivial. Processes have to be adapted; libraries have to be rewritten or supplemented. Ideally, the current production should not be affected. “We have now designed an RFID reader equipped with a coaxial antenna that can do more than just read RFID tags. This means that complete RFID data processing can be carried out directly on the machine in line with standards, “explains Wilmsmeier. This uniquely identifies printed circuit boards and securely exchanges data such as status information and processing times bidirectionally between product and machine or MES. “This allows the first steps to take place without IT integration. For example, it is possible to install the reader parallel to the machine. At the same time, however, it is always possible to create an integrated, both about the machine and to existing MES, database systems or higher-level software systems such as clouds. That creates a high degree of flexibility. ”
Olaf Wilmsmeier immediately gives another argument: “The second thing is that we also thought about how the data on the printed circuit board would be stored. Here, too, we agreed in the consortium that we want to set standards. Because only if you standardize here, you have the opportunity to grow here and set up the whole modular. “In practice, this could be such that you attach to the system an additional limit switch, which can be monitored, where and when perhaps a hood or window was opened and feed this information into the RFID technology.
IDENTIFICATION IN THE SMART FACTORY
RFID is a wireless identification technique that uses radio communication with the transponder (object). The connection is initiated by an RFID read-write unit (reader). The transponder is embedded directly in the object. This provides the required real-time transparency and uniqueness. Also, it provides contextual information that is used in the process of the plant but at the same time supports humans as a central player in production. RFID thus plays a central role. It gives products the necessary identity using tags, enables bi-directional communication between the object and the IT world.
But is RFID the only relevant data platform? When the use of RFID makes sense, explains Thomas Mückl of Zollner electronics. A specially developed MES suite and the RFID platform are a good tandem for flexible and efficient production, which ultimately allows high process reliability, he reports: “We see the main benefit of RFID in reducing data traffic on the network line. Thus, we map the track and trace information and the module status via RFID and later write the process data for this module into the MES platform. “Especially with 20 to 25 SMT lines in one location, an enormous volume of data would quickly come up, that could not be handled easily via MES. Also, Olaf Wilmsmeier notes on Harting: “We use an RFID reader here, which already has a certain logic and can communicate in milliseconds to initially reduce traffic.” Finally, the MES or SAP is event-based. This means that the relevant MES-relevant events are transmitted via web services, while the RFID platform is sufficient for M2M communication. “With RFID, I can not only work well but also relieve the network – so the SAP or MES to decouple a bit far,” says Wilmsmeier.
Is protection against hacker attacks possible?
The topic of protection against hacker attacks in a networked world is also demanding. After all, it is about efficiently protecting an “open system” and thus embedding additional IT equipment or computer systems in an IT landscape. “I think that’s just what companies need IT for. Just as I usually integrate my machine into my network, I also have to see where I can integrate the RFID technology “, Olaf Wilmsmeier von Harting raises in the discussion and warns:” As a user, you just have to be aware that Build IT security accordingly. ”
Broken down to the RFID chip on the board, Wilmsmeier recommends: “Here, too, I have to use the possibilities of technology to protect such an ID appropriately and not clone it.” An example: If the circuit board really could tell a robot which Movements he should perform, then the board could also say what program he should run – to the committee. So where are the boundaries? “Of course, I have to be really sure that this information, which is on the circuit board, is also stored in such a way that it can not simply be copied and outsiders can suddenly activate the robot via RFID tag,” he advises and notes “The techniques are there, but you also have to use them properly to protect yourself from such attacks effectively.”
RFID vs. established solutions
In what context is RFID technology related to Industry 4.0 and Smart Factory? After all, electronics production with cross-line software solutions such as Pulse from Asys or the de facto standard of M2M communication “The Hermes” is quite a big step towards the optimization screw. “I would say that we are one step ahead with our RFID technology. We create the basis for the whole, “argues Alexander Schmoldtfrom Murata. Finally, there is the talk of cyber-physical systems in which products and machines are communicatively connected. “We need a reliable connection between the digital world, the digital standards we have, and our objects,” he concludes. The technology of choice is RFID, because: “our products do not have their energy supply in the as yet unfinished state or even in the event of a defect. Thus, a technology is needed that goes beyond normal identification and provides the flexibility to store data. This technology must work even when power is not available. And that’s only possible with RFID. ”
RFID can also make a valuable contribution to the product lifecycle. After all, the electronics manufacturing industry has a great deal of responsibility for the technologies of the future. Therefore, consideration should be given to the life and service life of electronic products and what will happen to them at end-of-life. The intelligent and sustainable use of raw materials, such as rare earth, is a central macroeconomic task. High-tech products and short-lived consumer and production goods, in particular, contain innumerable raw materials whose extraction is more costly than recycling, which is why Alexander SchmoldtMurata emphasizes: “To reuse the valuable materials that dormant in the devices, the tag function can provide important information from the manufacturer on material compositions.” The use of secondary raw materials is becoming more and more important the fewer resources are available. For example, according to the Mining.com platform, 200 copper mines will close worldwide by 2035. Market experts agree that existing mine production will drop from the current 20 million tonnes of copper per year to less than 12 million tonnes in 2034.
Against this background, Schmoldt argues that tagged products could significantly advance the rationalization of material and material flows: “What is missing is the link to the objects and thus the information about which valuable substances are contained in which quantity in the products. This information about it – that is, what it contains and has been installed – can already be included in the RFID tag or could be stored in the databases of the OEMs or EMS. For the end-of-life, getting reliable information about material compositions and content is crucial – with a reliable and clear link to the objects. And that’s just what we’re doing now. “Nokia’s Claus Heller thinks that way. It’s more like a locked or “private” cloud database, to which the recycler gets access. “The recycler then receives a summary record of what it is picking up, which is within a batch of printed circuit boards or electronic waste. From this, he learns which substances are contained and he also learns how these substances are linked together. ”
With electronic waste in the classical sense, however, it is not yet enough for Heller. He goes a step further: “The recycler also learns if there are components that can be recycled again. This is particularly interesting if these components are no longer manufactured, but could be used for a long-term repair process. “In this way, it is possible with RFID, from the birth of a product to the end of its life, a complete, data-rich and Process optimizing traceability based on a – sometimes lively – bidirectional M2M communication.