Compact linear actuators retrofitted to roll transfer machinery

When bpi.films needed to replace worn out and obsolete actuators at the end of a process line the company was faced with a few problems. The replacements needed to match the fixing centres and diameter of the failed mechanisms and be sufficiently compact so as not to impinge on the nearby drive system. The Framo Mini 3 actuator from R.A. Rodriguez proved to be suitable and was also available on a very short lead time. Within ten days the process was restored to full automation.

Part of British Polythene Industries, bpi.films is described as the UK's leading manufacturer of shrink films, converter film and pallet stretch film. Its continuous investment in advanced film manufacturing technologies has enabled the company to offer an innovative and diverse range of films for packaging, protecting and securing 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 1000kg, from the process line onto a trolley for further handling. For the winding process the roll is held on an expanding mandrel that releases its grip when the roll is full. This enables the finished product to roll down guideways into moon-shaped locators at the end of two radius arms.

Synchronised motion

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 degrees 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/s and with a thrust of up to 8000N. For this application, it is critical that both actuators travel at exactly the same speed - and 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 enabled the actuator to be retrofitted with minimal modification. While many actuators have bulky external motors, the Mini employs a powerful coaxial motor to achieve the required stroke in the minimum of space. A number of features ensure the Mini's reliable operation. These include a thermally protected motor, lifetime lubrication and integral safety switches. This reliability is complemented by economical operation, low maintenance and a long service life.

Follow the link for more information about the Framo Mini 3 actuator.