Electric Actuation Saves Milk Processor 60% in Power Consumption - A case study from our product supplier Exlar on a Butter Press required retrofitting with an Electric Actuator to replace messy, leaky hydraulics posing a contamination risk.

Mittelland Molkerei AG (Emmi) is one of the leading milk processors in Switzerland. Dairy products including butter are produced at the company’s facility in Suhr. Butter portions are produced in the weights of1, 5, and 10 kilograms, with annual production totaling around 5,500 tonnes.

To press butter in the desired quantity and shape, a hydraulic system with a feed force of approximately 155kN was necessary. However, the company’s hydraulic system had to be replaced because hydraulic oil is no longer desirable in the processing area due to potential product contamination. Additionally, more precise dosing, shorter change over time, and less equipment maintenance was desired. Emmi contacted Parkem AG, the Exlar distributor in Switzerland for ideas.

What about an electric solution?

• Exlar electromechanical actuators are ideally suited to meet the requirements governing food processing by eliminating the need for hydraulic oil, pumps, hoses and filters, etc.
• Electromechanical actuators are the very best when electromechanical actuators are the very best solution when a combination of accuracy and repeatability are required. In this case, exact butter portion control can be met.
• Electromechanical actuators are flexible; portion changes can be done quickly as mechanical conversion and/or recalibration of the system is eliminated. The user simply selects the desired product via a recipe table and the electronic system does the rest.

It quickly became clear to Emmi that anIt quickly became clear to Emmi that an electromechanical solution presented many more advantages than just hydraulic oil elimination.

So, sizing began. The hydraulic system previously in place was monitored on-site to capture cycle and load data. This is significant because hydraulic systems are usually oversized to handle instances of peak force that are typically only needed for short periods of production time.

Electric systems do not typically have to be designed to handle force this way. A design for the average production force is sufficient, as servo drives can apply two to three times the nominal force for short periods of time. The cubic mean load of the system periods of time. The cubic mean load of the system was also calculated to size the planetary roller screw necessary to achieve the required service life.

By using only the data provided from the previous hydraulic system, a new electrical system was designed for Emmi. Working together, Parkem and Emmi were able to design a system that was perfectly sufficient to handle normal production without being overbuilt.

The butter press was retrofitted with an Exlar FTX215 electric actuator, which has a feed force of 178kN. FTX actuators useExlar planetary roller screw technology. To generate the linear force via the roller screw, it is driven by a servo motor with 60Nm torque. The intermediate planetary gearbox with a reduction ratio of 5:1 increases the torque to 300Nm. A 90 KvA servo controller powers the motor.

After commissioning on-site with minor calibration, the butter press successfully resumed production. The benefits realised — in addition to the removal of hydraulic oil — were impressive:

• Accurate Dosing Quantity — Waste is reduced by 50%.
• Infinite Motion Profiles — The production speed can be adjusted on the fly, which has increased quality.
• Changeover Time Reduced — With the electrical solution, neither a mechanical adjustment nor several readjustments are necessary to achieve the exact portion weight or volume. Only the desired recipe needs to be selected in the controller.
• Significant Noise Reduction — Impact noise caused at machine start-up and on mechanical end stop does not occur with the electrical system, and the vibrations produced by the hydraulic hum of the machines are also gone.

The new system greatly exceeded all expectations. Perhaps the most important result Emmi realised upon switching from hydraulic to electric was a 60% savings in power consumption! This provides significant and ongoing cost savings over the entire service life of the butter press, in addition to conserved resources.

With increasing concerns surrounding food safety, hydraulic systems are no longer desirable in food-producing companies due to the potential risks of food contamination from oil leakage. Thanks to electric solutions, oil — and the inherent maintenance that comes with hydraulic oil systems — can be eliminated from production.

Although the initial component acquisition costs of an electromechanical system are usually higher than for hydraulics, the total life-cycle benefits make the investment worth it. Profitability increases thanks to higher productivity and significantly lower operating and maintenance costs.