Foodjet uses Beckhoff's PC-based control technology to open and close the nozzles of its MDL food 3D printers with lightning speed. Foodjet customers can use it to dispense and deposit a variety of sauces with maximum precision, whether it's applying the perfect layer of tomato sauce to a pizza on a moving conveyor belt or decorating donuts with seasonal patterns using icing.
Microsecond-precision quantitative dispensing of seasoning sauce
and perfect repeatability
How do you spread tomato sauce on a pizza base or garlic sauce on pita bread when handling continuous product flows? How do you quickly decorate Christmas or Easter cookies? Foodjet, a company headquartered in Radboud, Netherlands, has developed a variety of food dispensing systems to address these challenges, one of which is the Large Mobile Deposit Unit (MDL).
“The advantage of our MDL metering system is that it allows for the flexibility to adjust the printing pattern according to the size and shape of each product,” explains Dirk Schindler, Sales and Marketing Director at Foodjet. For example, as more suppliers opt for handmade pizza dough, traditional round pizza bases are gradually being replaced by non-standard round ones. In fact, many food items are not perfectly round, yet these products still need to maintain clean edges. “This means we have to precisely scan every pizza stand on the assembly line so our printhead knows exactly where to deposit the sauce,” Schindler points out, highlighting the first challenge. After all, ensuring uninterrupted equipment capacity is crucial.
There will be no more unpopular manual labor on the assembly line.
“MDL helps customers solve one of their pain points,” Dirk Schindler emphasized. While some processes are fully automated, in many cases, someone still needs to stand on the assembly line and use a spoon to spread the sauce around the crust. “This work is not only stressful, but the amount spread is also inaccurate, causing weight fluctuations.” If needed, Foodjet can easily quantify this cost pool for interested buyers.
The return on investment for decorative items is also difficult to calculate: How much sales do decorative items actually contribute? Is it really an effective way to gain more market share? "Maybe." This is the answer Dirk Schindler has heard most often.
Foodjet noted that this is a topic of great interest in the market right now, as the first food manufacturers have already made the changes, and no one wants to, and should not, be left behind. Therefore, businesses must now be able to adjust ingredients seasonally and flexibly decorate their products, such as with Christmas stars, Easter bunnies, and Valentine's Day hearts, and so on. Beckhoff's PC-based control technology helped Foodjet overcome these technical challenges.
For example, to keep the pizza production line running at high speed, Foodjet's equipment must be able to determine the topping pattern with lightning speed. The distance between the camera system and the dispensing head is typically 85 centimeters, leaving only half a second for the necessary calculations. "The camera must capture the pizza in a single frame," explains Ed de Leur, a control system engineer. Only after the entire pizza base has been scanned can the pattern be created and the individual points on the print head calculated to synchronize everything with the running conveyor belt.
The AM8800 stainless steel servo motor, controlled by the AX8000 multi-axis servo system, reliably pumps the sauce to the printhead.
Individual control of 48 printheads with microsecond precision
The second challenge was the need for high repeatability. “We studied servo pumps to ensure the desired amount of sauce was pushed through the nozzles at the exact moment,” said Ed de Leur. Precisely controlling these nozzles within the milliliter range has a significant impact on droplet shape, and therefore on the uniformity of sauce deposition. “With the Beckhoff control system integrated into the MDL, this accuracy can reach 20 μs,” Ed de Leur explained.
Furthermore, the special layout of the printheads must be considered: up to 48 printheads can be deployed across multiple planar printing rows, tilted towards the direction of the conveyor belt's travel. This allows for improved resolution by shortening the effective working distance between the nozzles; however, the nozzles in the front row must begin working earlier than those in the back row. This means, "We must control each nozzle individually while ensuring that each nozzle receives the same amount of sauce," explains Ed de Leur.
Replacing mechanical devices with software functions
“We often see manufacturers coming up with all sorts of creative ways to neatly arrange the dough bases on a conveyor belt,” Dirk Schindler revealed. With MDL, all that work is unnecessary, as the shape and orientation of the dough bases become irrelevant. When creating a recipe using Foodjet Food Designer software, only the distance parameter between the sauce and the edge of the dough base needs to be set. The system then precisely layers each product. Ed de Leur explained, “For customers, they no longer need to teach the equipment various patterns, which is a major victory.”
If needed, even pizzas and baguettes can be randomly fed one after another on the conveyor belt, and toppings can still be added. More importantly, MDL can identify non-compliant crusts during the scanning process and can sort them out before adding toppings. "This control method has become part of our standard workflow," said Dirk Schindler.
MDL systems must calculate various patterns in real time. Ed de Leur is very clear on one point: "The control technology must come from Beckhoff. I am familiar with all the competitors, but because our application is very specific, few controller manufacturers offer products that we really need. Beckhoff products not only provide sufficient computing power, but can also be programmed directly on the Windows kernel, which is something other PLC manufacturers simply cannot offer, or even if they could, the price would be too high to afford." Nikolas Eimer, Business Development Specialist at Beckhoff Netherlands, added: "Not every customer needs to use our embedded controller products on such a large scale. Foodjet's process is one of the fastest high-end applications."
Foodjet used a CX2040 embedded controller equipped with an Intel® Core™ i7 quad-core processor to ensure that the calculation process was completed within 150 μs and the results were transmitted via EtherCAT to complete the most important actual printing task. Filling the buffer in the printhead may take longer, and Ed de Leur estimates that the motion control task for the servo pump requires 500 μs. Finally, there are some routine tasks such as HMI, safety functions, and pressure measurement, for which a cycle time of 50 milliseconds is sufficient. Ed de Leur is very satisfied with the freedom of choice offered by the Beckhoff platform: "Beckhoff has a very rich variety of I/O products, including not only standard terminal modules for controlling valves or pumps, but also some special models."
For the HMI, Foodjet decided to develop a visual application in C# and run it in a Windows environment. The advantage of PC-based control technology is that, despite the high real-time requirements for the printhead, the application can run on the same control computer because the HMI runs on a different CPU core. “Another real advantage of PC-based control technology is that software developers can freely run different applications on the same hardware platform,” said Ed de Leur. The automation expert also praised the collaboration with Beckhoff: “I’m a typical software engineer who likes to get hands-on and try to solve problems.” Due to the short delivery cycle, problems often arise after delivery. Therefore, for Ed de Leur, quickly obtaining solutions and support is paramount. “The collaboration with Beckhoff has also been very effective in this regard,” Ed de Leur emphasized.
Foodjet's vision system currently uses a separate PC; however, their goal is to integrate the image processing system into the Beckhoff platform as well, because timing synchronization between the two systems can be quite complex. "Beckhoff technology is ready for integration, we just haven't had time to implement it yet," explained Ed de Leur.
Ed de Leur, an engineer at Foodjet, is setting up the MDL system. “We have to push the right amount of sauce through dozens of nozzles at the exact right time. I can’t think of anything better suited for this challenging task than PC-based control technology.”
From full-surface painting to complex drawing
“The next logical step is to apply MDL technology to food garnishing as well, but this will involve different speeds, resolutions, and yields,” said Dirk Schindler, highlighting the current challenges. Foodjet has successfully developed equipment to meet this market demand and has decided to equip all of these devices with PC-based control technology. Our goal is to develop a universal control platform for all industries and applications.
Foodjet is also exploring mixing different sauces using two sequentially placed MDL systems. The first MDL prints tomato sauce, while the second adds ricotta cheese, French white sauce, or olive oil. “It’s already working quite well,” says Dirk Schindler, “but there’s room for improvement.” For example, adding a small amount of tomato sauce after the cheese has been spread on the pizza base would ensure a consistent flavor. Alternatively, the toppings could be split in half, with tomato sauce on one side and a spicier version on the other. These changes, tailored to various personalized needs, are possible with Foodjet Designer Studio software and PC-based control technology.
