With its new fibre feeder, Brabender Technologie is breaking new ground in the feeding of long and uneven fibres. While conventional feeders used to be restricted to short and compact bundles of fibres such as glass fibres, for example, the new feeder is now capable of accurately metering natural fibres, wood fibres, long carbon fibres and film chips.
New fields of application
As one of the main fields of application, the new fibre feeder can be used for shredded film strips. These are waste materials from plastic film production processes, where the film edges are cut off by film edge trimmers. This results in 10-30 % of unspoilt material, further utilisation of which has until now been difficult. The new feeder allows to refeed the remnants back into the production process as film chips so that they can be recycled. This saves resources and optimises the production process.
Feeding of natural fibres is another field of application. The fibre feeder is capable of metering them reliably, accurately and continuously in filling material or wood-plastic composites production processes. Carbon fibres are just as difficult to recycle. As reinforcement, they are laminated onto components by a roll. Materials and remnants are left over, the disposal of which is costly. The feeder is designed so that the remnants, as well as the recycled fibres, can continue to be used over and over again.
Functionality
Feeding of such long fibres is made possible by using a special fibre screw, a large steep walled hopper and a novel design and special position of the stirring agitator in the hopper. “This unique and innovative design promotes forced ingredient flow into the screw”, explains Norbert Marek, who provided the idea for the fibre feeder. Considering that the flow characteristics of the ingredients differ significantly, design details vary in each individual case. The company maintains confidentiality regarding the exact construction of the feeder.
What is no secret, however, is how important the control system is for reliable fibre feeding. The ratio of feed screw and stirring agitator speeds is essential. “Our CM plus or CB plus controllers are responsible for this”, emphasises Norbert Marek. The optimum ratio of screw and agitator speeds can be individually determined by feeding trials in Brabender’s test lab to be adjusted accordingly during feeder start-up.
