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Yaskawa controller optimizes chocolate production
Many industries are feeling the effects of ever shorter product life cycles, and upstream processes are also required to adapt to this development. One area particularly affected by this trend is the food industry including, as in this case, the chocolate industry. Knobel AG in Felben (Switzerland), a world-leading supplier of machines and systems for the production, forming and processing of pralines and chocolate, is tackling this issue with flexible, modular systems.
Machines manufactured by Knobel are used across the globe – be it in corner bakeries or in chocolate factories with large-scale plants for the mass production of chocolate bars. In all cases, the availability of the machines is of utmost importance. Every fault and downtime results in costs that are disproportionate to the price of the system. Overall machine availability is also dictated by the availability of the installed components, including the fitted drive technology.
SwissDrives AG, a partner of Knobel AG, is a system vendor for drive technology-based in Tübach (Switzerland) and only ever uses highest quality components from Yaskawa. Daniel Züger, motion specialist at SwissDrives, has nothing but praise for the reliability and accuracy of the employed servo drive systems: “We have supplied over 1000 servo axes for systems in permanent use throughout the world, and not once has the drive technology failed”.
Use of a modular handling system
As an enhancement to the modular components used in the production of chocolate (depositing machines), Knobel AG and SwissDrives AG jointly created the HighFlex handling system, which perfectly complements Knobel’s modular production approach. In creating the system, particular importance was attributed to its flexibility and minimal servicing requirements. In chocolate production, the depositing moulds must be implemented and the chocolate formed at high cycle rates. Knobel satisfied these requirements with a patented procedure, ingenious design and the use of high-quality components.
At the heart of the HighFlex system are two linear motors from Yaskawa, both of which use the same guide. The head module, which is mounted according to the scissor principle, travels in x- and z-direction based on the absolute or relative movements. Depending on the application, a grabbing, vacuum, cutting, turning or other tools can be fitted to the same head.
A teach-in function enables the programming of different processing positions. By means of a transformation, the values from the “head coordinate system” are transferred to the “motor coordinate system”. The head load is then moved from one processing position to the next via the time-optimized path on the basis of a mathematical curve calculation. This prevents any jerking movements and allows the motion dynamics to be adapted to the individual products. In some movements, the product (praline/chocolate) travels with the machine. These special circumstances can be addressed by means of adapted motion dynamics.
Sophisticated solutions minimize service support
Thanks to the clever mechanism, oscillation and vibration are largely eliminated. The residual machine resonance is suppressed by innovative control algorithms in the servo amplifiers of the linear motors. The entire system is characterized by its extremely high control quality, thus achieving great accuracy across the whole motion sequence without overshooting at the end of the movement.
The entire motion sequence is coordinated by a Yaskawa motion controller, which enables position-specific generation of all necessary pre-signals. This allows a pneumatic grabber, for example, to start its motion once the head module has passed a specific position. The movements thus begin to “converge”, which results in an enormous boost in performance.
Where cycle times were previously around 10 cycles per minute, the new systems can achieve up to 30 cycles per minute – and the machine movements are buttery smooth. Mechanical strain is minimized, the service life of the machine is increased and servicing/maintenance requirements are all but eliminated, largely thanks to the use of linear motors. In this system, the linear motor functions as a direct drive without mechanical power transmission, while the positioning system takes the form of a non-contact optical reading system. All that is required is regular lubrication of the linear guides.
With the newly implemented system, Knobel AG can plan, manufacture and deliver comparable, finished machines within a minimal time frame. To avoid the need for software adjustments, SwissDrives has configured the motion controller software as an open system and developed it to the point that the user can perform not just the parameterization but the entire hardware configuration at the machine control level. As a result, the same controller can operate up to six complex, interpolating systems at the same time.
Daniel Züger is convinced of the system’s abilities: “With this system, Knobel AG has developed the ideal means for chocolate producers to create their product with a sophisticated and innovative machine and provide chocolate lovers with their favorite treats at consistently high-quality levels”. And there was one more reason to opt for Yaskawa: “The entire drive system was created and put into operation in a record time of just three weeks, with Yaskawa application engineers providing invaluable on-site support throughout the planning and programming of the system”.