Trevor Osborne of Bosch Rexroth explains how Non-Contact Transfer (NCT) systems manufactured from PEEK can bring benefits to the automated handling of delicate food products and components in other industries where cleanliness is essential.
Non-Contact Transfer systems (NCTs) are a tried-and-tested method of efficiently processing fragile items weighing up to one kilogram. Using the Bernoulli principle, airflow under the NCT device creates a vacuum and lifting force. The product is lifted by this force and, if it is in danger of coming too close to the hard surface of the NCT, the streaming air can reject the product in order to protect it.
By this method, objects can be moved accurately with no need for any surface contact, which, in addition, means that the product can remain sterile if required. Crucially, the non-contact nature of the method reduces the potential for contamination or damage, thereby reducing wastage costs.
The ability of NCTs to handle fragile items has been widely accepted in the electronics, printing, telecommunication and pharmaceutical industries. In theory, this same approach would seem highly suitable for easily breakable food items that would also benefit from minimal surface contact. However, most NCT units are made from aluminium – a material that is not approved in the food and beverage industry in keeping with the standards set by the European Union (EU) and the United States Food and Drug Administration (FDA). Aluminium units are known as NCT-AL.
Benefits compared with alternatives
Alternative methods currently used in food and beverage, such as suction cups, pose other challenges, including high levels of contamination that might be a particular issue in a powdery environment, which is often the case when processing bakery products. This has exposed a requirement for an NCT system to meet both the approved material and stringent hygiene standards that are demanded in the food processing sector.
Rexroth says the answer is an NCT unit made from polyetheretherketone (PEEK), known as the NCT-PK, which is functionally identical to the aluminium version but has some crucially different characteristics. As an organic polymer thermoplastic, which is highly resistant to thermal degradation or contamination, PEEK passes all EU and FDA standards. This makes the NCT-PK excellent for use in a food and beverage environment.
Furthermore, the use of PEEK also offers performance benefits. The lifting force remains unaffected by soft, porous or dusty workpieces, thereby ensuring that its efficiency remains constant in environments where contamination of the system would result in costly downtime. PEEK is also designed to withstand daily cleaning, making it compliant with all conventional CIP (Cleaning-In-Place) and SIP (Sterilisation-In-Place) practices. The NCT-PK can also be permanently marked, which removes the need for insecure labelling.
NCT-PK devices have a minimum working press of 1 bar and a maximum of 7 bar, with a typical working press of 5 bar. Lifting force is delivered by mounted friction pads in silicone, which is another excellent material for food handling, due to its hardness. The silicone is fixed to ensure that the pads cannot accidentally fall out.
The NCT-PK, which is only available from Rexroth, is described "a unique solution for the food and beverage industry and one which can improve processing efficiency and save money through reduced waste." Thanks to the innovative application of PEEK in the place of aluminum, these benefits are now also being extended to solar, semiconductor and electronic industries.
Follow the link for more information about the NCT-PK and NCT-AL non-contact transfer systems.