COMPACT ACTUATOR FOR RELIABLE FILM WINDING

Part of British Polythene Industries, bpi.films is the UK’s leading manufacturer of shrink films, converter film and pallet stretch film. Its continuous investment in the most advanced film manufacturing technologies has allowed the company to produce an innovative and diverse range of films which package, protect and secure a wide variety of products in a host of industry sectors.

The Framo Mini 3 actuators are responsible for transferring a fully wound roll of film, weighing approximately 1,000 kg, from the process line onto a trolley for further handling. For the winding process the roll is held on an expanding mandrel which releases its grip when the roll is full. This allows the finished product to roll down guideways into moon shaped locators at the end of two radius arms.

The two Framo actuators work in parallel at either side of the machine. With the roll safely cradled in the locators, the operator initiates the actuators that expand, lowering the roll by 45° onto the waiting trolley for despatch. The actuators then return to the waiting position. They both have a 300mm stroke length, operate at a speed of 47mm/sec and with a stroke force of up to 8,000N. For this application, it is critical that both actuators travel at exactly the same speed – this is achieved by integrating an inverter between the actuator and power supply.

For bpi.films the compact nature of the Mini 3 was vital as it allowed the actuator to be retrofitted with minimal modification. Whilst many actuators have bulky external motors, the Mini employs a powerful coaxial motor to achieve the required stroke in minimum space. A number of features ensure the Mini’s reliable operation. These include a thermally protected motor, life time lubrication and integral safety switches. This reliability is complemented by economical operation, low maintenance and a long service life.