The electric cylinders of the CMS... series are precise and powerful. When combined with a MOVIDRIVE® drive inverter, they ensure high process reliability.
Creating a high-quality and visually attractive chocolate product requires complicated process engineering. This is where the electric cylinders from SEW‑EURODRIVE come into play. With their compact size, high power, and suitable displacement curves, they ensure that the chocolate is injected evenly into the molds.
Combined process steps for tasty results
The company Böhnke & Luckau GmbH in Wernigerode, Germany develops and constructs machines and complete systems for the chocolate industry. Whether in the D-A-CH region, Eastern Europe, the Middle East or East Asia, machinery from Böhnke & Luckau is used in many countries around the world. The specialty of this Wernigerode-based company is its molding lines. These lines create chocolate products in any shape imaginable. The block line from Böhnke & Luckau features a high power rating and is suitable for injecting chocolate into large molds up to 5000 grams. The system mixes, tempers, doses, vents and cools the chocolate. The system uses various mold sizes and a long cooling time to prevent weak spots or cracks from forming in the large blocks. The molds circulate within the system and can be exchanged. The XXL system can therefore fill between 15 and 22 molds per minute (depending on the mold sizes) and produce up to 2500 kg per hour. The block filling system from Böhnke & Luckau has a modular design. The casting machine injects the raw chocolate into the mold. The mass of raw chocolate enters through a heated funnel with an agitator. A shaking unit then evenly distributes the liquid chocolate into the mold. This shaking ensures that the chocolate mass has a homogeneous structure and prevents air pockets. A PLC controls all the processes in the system. A touch panel is used to operate the system.
The chocolate is injected into the mold through a distribution plate with milled cavities, i.e. hollow spaces running through it. An SEW‑EURODRIVE electric cylinder is connected via a crank to a shaft, to which a comb-shaped piston base is attached. This base is attached to the individual pistons that travel laterally into the injector head. This head contains pneumatic rotary valves. These rotary valves are cylinders with an L-shaped cutout and act as stoppers. They rotate by 90°. This closes off the residual flow from the filter. The pistons come in from the side and press the mass through a distribution plate with channels that is located below the mass. The channels collect the chocolate mass and distribute it evenly among the nozzles, which are screwed onto a nozzle plate. The motion of the pistons causes the chocolate to be injected into the polycarbonate mold.
Block filling system
Paternoster cooling cabinet
MOVIDRIVE® drive inverter
MOVITRAC® LT frequency inverter
Controlled application of force
"Creating a high-quality and visually attractive chocolate product with a fine texture requires complicated process engineering," explains Ronny Krebs, Director of Purchasing at Böhnke & Luckau. The chocolate must reach specific temperatures at defined time points. The chocolate is slowly cooled to about 2° C to 4° C. Approximately five to seven molds are collected and then run through the paternoster cooling cabinet together. This principle allows Böhnke & Luckau to save significant space.
The chocolate molds take about an hour and a half to run through the cooling cabinet. Depending on the product and the block size, the molds can then be run through a second paternoster cooling cabinet. These cooling cabinets have a modular design and are installed in the systems according to the particular customer requirements. The paternoster is sanitary in its design and is well insulated to ensure energy efficiency.
The last stage in the production process is the demolding station. This system is equipped with a loosening station, a mold-turning station and two knocking stations. The mold is twisted using a pneumatic cylinder so that the cooled chocolate can be more easily separated from the mold. This is done by twisting the sides of the mold in opposite directions. Before the molds travel back to the start of the system, they must also pass through an automatic unit to check that the molds have been emptied, a sorting station and a mold magazine. The automatic shakeout station transports the chocolate blocks on a conveyor belt out of the machine and into a packaging machine.
Because of the space restrictions of the machine, the customer needs components that take up little space. Since the block line must operate at high powers, the customer requires drives that can generate large forces. The system must also operate reliably.
The compact size of the SEW‑EURODRIVE electric cylinders and the large forces they can generate are perfect for the requirements of the customer's machine. When combined with our MOVIDRIVE® drive inverters, they constitute a cost-efficient solution that ensures high process reliability for the system.
... says Ronny Krebs, Director of Purchasing at Böhnke & Luckau. He continues: "The displacement curve of these cylinders is such that the chocolate is evenly distributed and homogeneously formed." According to Volker Schulz, "this is a significant advantage over pneumatic or hydraulic drives." Schulz heads the Magdeburg Technical Office for SEW‑EURODRIVE and has worked with Böhnke & Luckau for over 20 years. During this time he has helped the customer realize a great number of innovations, as they regularly employ SEW‑EURODRIVE drives in their machines. Not only does SEW‑EURODRIVE meet the customer's requirements for a supplier, we also offer development services to provide custom-tailored solutions.
The CMS.. series of electric cylinders are equipped with permanent magnet rotors. These integrated servomotors are extremely precise and powerful. When combined with drive electronics—the MOVIDRIVE® drive inverter from SEW‑EURODRIVE for this application—they constitute a cost-efficient solution that ensures high process reliability for the system.
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