Rotary Joints, the Servotecnica Way

Servotecnica offers the market slip rings and custom fluidic, fiber optic and hybrid rotary joints to meet machinery constructors’ needs

by Edoardo Oldrati

Rotary joints have been central to Servotecnica’s offering for more than thirty years, and its catalogue includes a vast range of solutions for this product, as well as custom versions tailored to customers’ needs, thanks to know-how widely respected on the market. These components, which as we all know are used to transfer users of various kinds (power, electric signals, fluids, optic signals) from a fixed structure to a continually rotating one, are evolving fast, with growing demand for hybrid rotary joints ( “Increasingly often,” Matteo Salgarello, Servotecnica Product Manager Rotary Joints, explains, “customers are asking us to combine fluid and electric parts in our joints, to supply a single object capable of meeting all requirements in terms of users on the rotary part of the machine. This demand also derives from the need, shared by all sectors, to minimise machines’ footprint without reducing their throughput.” In fact, we are witnessing a transition from in-line machines to machines with one or more carousels, and rotary joints are playing a more and more important part in guaranteeing these new machines’ efficiency.

“In the rotary joint sector, Servotecnica is being asked more and more often to supply integrated solutions, in particular combined electric and fluidic rotary joints, with field buses which, of course, require great care in the design stage to prevent interferences and noise coupling within the machine.

In the packaging industry in particular, this trend is accompanied by the demand for use of hybrid cables. In almost all cases, joints are located in inaccessible points, so for constructors it is fundamental to install a highly reliable component, since the machine stoppages in case of malfunctions may be very long.” To guarantee this reliability, Servotecnica draws on the experience built up in more than 30 years in the field with this type of product, and also on intensive manual and automatic testing of all rotary joints, which ensures their complete traceability.

Not just rotary joint suppliers but real partners

For a product like a rotary joint, very often designed ad hoc and thus supplied on a custom basis, it is fundamental to establish a real partnership between the supplier and customer. “A lot of people are familiar with Servotecnica and our outstanding quality,” Mr Salgarello explains, “so they trust our inputs during the machine design stage, when we provide advice on the best type of rotary joint for the customer’s needs in terms of performance and costs. Since every order presents different challenges, our experience and our engineers’ skills are essential for designing a personalised solution that will satisfy all the customer’s expectations.”

The electric part of the rotary joint is manufactured by Servotecnica, while fluidic part components are supplied by the American firm Dynamics Sealing Technologies and our specialist partner for fiber optic units is Princetel.

To guarantee that our products deliver unbeatable reliability, Servotecnica supplies a whole array of services, not just during design but also during prototyping or machine setup, to deal with any problems or criticalities which occur during the test stage.

“We provide a sample for the first stage of testing,” the Servotecnica Product Manager Rotary Joints continues, “which in the case of custom joints is just a standard product, but will enable us to acquire all the data we need for the tailored design of the personalised component, minimising lead times.” Cutting time-to-market has never been so important for manufacturers, who are asking Servotecnica to supply rotary joints in double-quick times, a big ask if we consider that these products have a high level of customisation. “Thanks to its competences and know-how, Servotecnica is able to supply effective solutions fast, and for the customer this means shortening downtimes during development and being the first on the market with an effective solution.”

Custom rotary joints, a case history

Servotecnica establishes a real partnership with its customers, starting in the design stage and culminating in the development of custom solutions with high added value. One example of this win-win cooperation is the recent supply of a fluidic joint for a home-care product filling plant. “The customer involved us right from the development phase,” Matteo Salgarello explains, “ensuring we were fully informed about all the project’s special requirements. The rotary joint we had to design and supply was intended for an environment combining a fair degree of sterilisation with the passage of highly aggressive liquids (household cleaners).” Given this mix of needs, we had to pay great attention to the chemical compatibility of the rotary joint’s construction materials, both the metal part and the polymer seals. “When it came to choosing the right material,” Mr Salgarello explained, “our in-house experience in this area was crucial, since we had to assess the materials’ behaviour during operation and not only in static conditions.” The rotary joint design process also had to cope with the object’s particularly large size, with no fewer than four inputs and almost a hundred outputs to be controlled.

“Once we had acquired all the information we needed, we began the design stage and offered the customer various solutions until we found the ideal design for what is, basically, the heart of the filling machine: a large-sized (0.5m x 0-5m) fluidic rotary joint constructed totally in AISI 316 steel and with unusual input passages, which are integral in the joint, significantly reducing overall dimensions and weight. The joint supplied by Servotecnica also guarantees the plant producer the highest reliability, vital since the rotary joint’s position inside the plant makes it very difficult to access and maintain once installed.”

Ethernet slip rings are added to the Servotecnica range

In response to the ever-increasing use of field buses, which in most cases are Ethernet based, Servotecnica has decided to include a range of standard slip rings ( in its catalogue. All available from stock, these slip rings are available in SVTS A Series capsule type (i.e. very small sized) and in the SVTS C05 Series version with 38 mm through hole. Thanks to the gold-gold technology (i.e. gold-coated brushes and rings) and a special internal structure designed to minimise interference and noise coupling, Servotecnica is able to supply both digital and analogical signal circuits and power circuits in the same slip ring. The SVTS A Series is able to accommodate up to 56 circuits with currents of 2, 6 and 8 A and voltages up to 240 VDC/AC, while the SVTS C05 Series can offer up to 48 signal circuits of 2 A, with 15 A power circuits, and voltages up to 600 VDC/AC.

Servotecnica SVTS A and SVTS C 05 Series slip rings are able to operate with 100BaseT or 1000BaseT Ethernet, at the respective speeds of 100 Mb/s and 1 Gb/s.

Media Contact
Company Name: Servotecnica
Contact Person: Simone Salgarello
Phone: +39 0362 4921
Country: Italy