Foundries are increasingly adopting data-driven process automation to achieve long-term goals of higher quality, less waste, maximum uptime and minimal costs. Fully integrated digital synchronization of pouring and molding processes (seamless casting) is especially valuable for foundries facing the challenges of just-in-time production, reduced cycle times and more frequent model changes. With automated molding and casting systems that seamlessly link together, the casting process becomes faster and higher quality parts are produced more consistently. The automated pouring process includes monitoring the pouring temperature, as well as feeding inoculation material and checking each mold. This improves the quality of each casting and reduces the scrap rate. This comprehensive automation also reduces the need for operators with years of specialized experience. Operations also become safer because fewer workers are involved overall. This vision is not a vision of the future; This is happening now. Tools such as foundry automation and robotics, data collection and analysis have evolved over decades, but progress has accelerated recently with the development of affordable high-performance computing and advanced Industry 4.0 networked sensors and compatible control systems. Solutions and partners now enable foundries to create a robust, intelligent infrastructure to support more ambitious projects, bringing together multiple previously independent sub-processes to coordinate their efforts. Storing and analyzing process data collected by these automated, integrated systems also opens the door to a virtuous cycle of data-driven continuous improvement. Foundries can collect and analyze process parameters by examining historical data to find correlations between them and process results. The automated process then provides a transparent environment in which any improvements identified by the analysis can be thoroughly and quickly tested, validated and, where possible, implemented.
Seamless Molding Challenges Due to the trend towards just-in-time production, customers using DISAMATIC® molding lines often have to change models frequently between small batches. Using equipment such as an Automatic Powder Changer (APC) or a Quick Powder Changer (QPC) from DISA, templates can be changed in as little as one minute. As high-speed pattern changes occur, the bottleneck in the process tends to shift toward pouring—the time required to manually move the tundish to pour after a pattern change. Seamless casting is the best way to improve this step of the casting process. Although casting is often already partially automated, full automation requires seamless integration of the control systems of the molding line and the filling equipment so that they operate completely synchronously in all possible operating situations. To achieve this reliably, the pouring unit must know exactly where it is safe to pour the next mold and, if necessary, adjust the position of the filling unit. Achieving efficient automatic filling in a stable production process of the same mold is not that difficult. Each time a new mold is made, the mold column moves the same distance (mold thickness). In this way, the filling unit can remain in the same position, ready to fill the next empty mold after the production line is stopped. Only minor adjustments to the pour position are required to compensate for changes in mold thickness caused by changes in sand compressibility. The need for these fine adjustments has recently been further reduced thanks to new molding line features that allow pouring positions to remain more consistent during consistent production. After each pour is completed, the molding line moves one stroke again, placing the next empty mold in place to begin the next pour. While this is happening, the filling device can be refilled. When changing the model, the thickness of the mold may change, which requires complex automation. Unlike the horizontal sandbox process, where the height of the sandbox is fixed, the vertical DISAMATIC® process can adjust the thickness of the mold to the exact thickness needed for each set of models to maintain a constant sand to iron ratio and account for the height of the model. This is a major benefit in ensuring optimal casting quality and resource utilization, but varying mold thicknesses make automatic casting control more challenging. After a model change, the DISAMATIC® machine begins to produce the next batch of molds of the same thickness, but the filling machine on the line still fills the molds of the previous model, which may have a different mold thickness. To combat this, the molding line and filling plant must work seamlessly as one synchronized system, producing molds of one thickness and safely pouring another. Seamless pouring after pattern change. After pattern change, the thickness of the remaining mold between the molding machines remains the same. The pouring unit made from the previous model remains the same, but since the new mold coming out of the molding machine may be thicker or thinner, the entire string can advance at different distances in each cycle – to the thickness of the new form. This means that with each stroke of the molding machine, the seamless casting system must adjust the casting position in preparation for the next cast. After the previous batch of molds is poured, the thickness of the mold becomes constant again and stable production resumes. For example, if the new mold is 150mm thick instead of the 200mm thick mold that was still being poured previously, the pouring device must move 50mm back towards the molding machine with each stroke of the molding machine to be in the correct pouring position. . In order for a pouring plant to prepare to pour when the mold column stops moving, the filling plant controller must know exactly what mold it will be pouring into and when and where it will arrive in the pouring area. Using a new model that produces thick molds while casting thin molds, the system should be able to cast two molds in one cycle. For example, when making a 400mm diameter mold and pouring a 200mm diameter mold, the pouring device must be 200mm away from the molding machine for each mold made. At some point the 400mm stroke will push two unfilled 200mm diameter molds out of the possible pouring area. In this case, the molding machine must wait until the filling device has finished pouring the two 200mm molds before moving on to the next stroke. Or, when making thin molds, the pourer must be able to skip the pour completely in the cycle while still pouring thick molds. For example, when making a 200mm diameter mold and pouring a 400mm diameter mold, placing a new 400mm diameter mold in the pouring area means that two 200mm diameter molds need to be made. The tracking, calculations and data exchange required for an integrated molding and pouring system to provide trouble-free automated pouring, as described above, have presented challenges for many equipment suppliers in the past. But thanks to modern machines, digital systems and best practices, seamless pouring can be (and has been) achieved quickly with minimal setup. The main requirement is some form of “accounting” of the process, providing information about the location of each form in real time. DISA’s Monitizer®|CIM (Computer Integrated Module) system achieves this goal by recording each mold made and tracking its movement through the production line. As a process timer, it generates a series of time-stamped data streams that calculate the position of each mold and its nozzle on the production line every second. If necessary, it exchanges data in real time with the filling plant control system and other systems to achieve precise synchronization. The DISA system extracts important data for each mold from the CIM database, such as mold thickness and can/cannot be poured, and sends it to the filling plant control system. Using this accurate data (generated after the mold is extruded), the pourer can move the pouring assembly to the correct position before the mold arrives, and then begin opening the stopper rod while the mold is still moving. The mold arrives in time to receive the iron from the pouring plant. This ideal timing is crucial, i.e. the melt reaches the pouring cup accurately. Pour time is a common productivity bottleneck, and by perfectly timing the start of pour, cycle times can be reduced by several tenths of a second. The DISA molding system also transfers relevant data from the molding machine, such as current mold size and injection pressure, as well as broader process data such as sand compressibility, to the Monitizer®|CIM. In turn, Monitizer®|CIM receives and stores quality-critical parameters for each mold from the filling plant, such as pour temperature, pour time, and the success of the pour and inoculation processes. This allows individual forms to be marked as bad and separated before mixing in the shaking system. In addition to automating molding machines, molding lines and casting, Monitizer®|CIM provides an Industry 4.0-compliant framework for acquisition, storage, reporting and analysis. Foundry management can view detailed reports and drill down into data to track quality issues and drive potential improvements. Ortrander’s Seamless Casting Experience Ortrander Eisenhütte is a family-owned foundry in Germany that specializes in the production of mid-volume, high-quality iron castings for automotive components, heavy-duty wood stoves and infrastructure, and general machinery parts. The foundry produces gray iron, ductile iron and compacted graphite iron and produces approximately 27,000 tons of high-quality castings per year, operating two shifts five days a week. Ortrander operates four 6-tonne induction melting furnaces and three DISA molding lines, producing approximately 100 tons of castings per day. This includes short production runs of one hour, sometimes less for important clients, so the template has to be changed frequently. To optimize quality and efficiency, CEO Bernd H. Williams-Book has invested significant resources in implementing automation and analytics. The first step was to automate the iron melting and dosing process, upgrading three existing casting furnaces using the latest pourTECH system, which includes 3D laser technology, incubation and temperature control. Furnaces, molding and casting lines are now digitally controlled and synchronized, operating almost completely automatically. When the molding machine changes model, the pourTECH pour controller queries the DISA Monitizer®|CIM system for the new mold dimensions. Based on the DISA data, the pour controller calculates where to place the pour node for each pour. It knows exactly when the first new mold arrives at the filling plant and automatically switches to the new pouring sequence. If the jig reaches the end of its stroke at any time, the DISAMATIC® machine stops and the jig automatically returns. When the first new mold is removed from the machine, the operator is alerted so that he can visually check that it is in the correct position. The benefits of seamless casting Traditional hand casting processes or less complex automated systems can result in lost production time during model changes, which is inevitable even with rapid mold changes on a molding machine. Manually resetting the pourer and pour molds is slower, requires more operators, and is prone to errors such as flare. Ortrander found that when bottling by hand, his employees eventually became tired, lost concentration, and made mistakes, such as slacking off. Seamless integration of molding and pouring enables faster, more consistent and higher-quality processes while reducing waste and downtime. With Ortrander, automatic filling eliminates the three minutes previously required to adjust the position of the filling unit during model changes. The entire conversion process used to take 4.5 minutes, Mr. Williams-Book said. Less than two minutes today. By changing between 8 and 12 models per shift, Ortrander employees now spend about 30 minutes per shift, half as much as before. Quality is enhanced through greater consistency and the ability to continuously optimize processes. Ortrander reduced waste by approximately 20% by introducing seamless casting. In addition to reducing downtime when changing models, the entire molding and pouring line requires only two people instead of the previous three. On some shifts, three people can operate two complete production lines. Monitoring is almost all these workers do: other than selecting the next model, managing sand mixtures and transporting the melt, they have few manual tasks. Another benefit is the reduced need for experienced employees, who are difficult to find. Although automation requires some operator training, it provides people with the critical process information they need to make good decisions. In the future, machines may make all decisions. Data dividends from seamless casting When trying to improve a process, foundries often say, “We do the same thing the same way, but with different results.” So they cast at the same temperature and level for 10 seconds, but some castings are good and some are bad. By adding automated sensors, collecting time-stamped data on each process parameter, and monitoring results, an integrated seamless casting system creates a chain of related process data, making it easier to identify root causes when quality begins to deteriorate. For example, if unexpected inclusions occur in a batch of brake discs, managers can quickly check that parameters are within acceptable limits. Because controllers for the molding machine, casting plant and other functions such as furnaces and sand mixers work in concert, the data they generate can be analyzed to identify relationships throughout the process, from sand properties to the final surface quality of the casting. One possible example is how pour level and temperature affect mold filling for each individual model. The resulting database also lays the foundation for the future use of automated analysis techniques such as machine learning and artificial intelligence (AI) to optimize processes. Ortrander collects process data in real time through machine interfaces, sensor measurements and test samples. For each mold casting, about a thousand parameters are collected. Previously, it only recorded the time required for each pour, but now it knows exactly what the level of the pouring nozzle is every second, allowing experienced personnel to examine how this parameter affects other indicators, as well as the final quality of the casting. Is the liquid drained from the pouring nozzle while the mold is being filled, or is the pouring nozzle filled to an almost constant level during filling? Ortrander produces three to five million molds a year and has collected a huge amount of data. Ortrander also stores multiple images of each pour in the pourTECH database in case of quality issues. Finding a way to automatically rate these images is a future goal. Conclusion. Simultaneous automated forming and pouring results in faster processes, more consistent quality and less waste. With smooth casting and automatic pattern changing, the production line operates effectively autonomously, requiring only minimal manual effort. Since the operator plays a supervisory role, fewer personnel are required. Seamless casting is now used in many places around the world and can be applied to all modern foundries. Each foundry will require a slightly different solution tailored to its needs, but the technology to implement it is well proven, currently available from DISA and its partner pour-tech AB, and does not require much work. Custom work can be carried out. The increased use of artificial intelligence and intelligent automation in foundries is still in the testing phase, but as foundries and OEMs gather more data and additional experience over the next two to three years, the transition to automation will accelerate significantly. This solution is currently optional, however, as data intelligence is the best way to optimize processes and improve profitability, greater automation and data collection is becoming standard practice rather than an experimental project. In the past, a foundry’s greatest assets were its model and the experience of its employees. Now that seamless casting is combined with greater automation and Industry 4.0 systems, data is quickly becoming the third pillar of foundry success.
—We sincerely thank pour-tech and Ortrander Eisenhütte for their comments during the preparation of this article.
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Post time: Oct-05-2023