RPC bpi Stretchfilms Removing Metal Using Drawer Magnets

By Paul Fears | 09 July 2019

Stretchfilms RPC bpi in Leominster use a series of Bunting Drawer Magnets to capture ferrous metal contamination in the process.  This prevents equipment damage and reduces production downtime.

LP FF Drawer Magnets

LP FF Drawer Magnets

RPC bpi was using Hoppergrids, a very basic type of Ferrite magnetic separator that simply sits loosely inside a hopper.  However, they found that these were not operator friendly or very effective.  The RPC bpi team contacted several magnetic separator suppliers, but none of the recommended solutions met their requirements.  During a visit to the K Show in Germany [international plastics trade fair], the RPC bpi team met Bunting.  One of the Bunting sales team visited the Leominster site to assess the application and determine the best solution.

RPC bpi Stretchfilms produces agricultural and industrial stretch film, with three sites in the UK and one in Belgium.  Despite already using low powered Ferrite magnetic separators, metal contamination remained a serious problem and concern.  If metal found its way through to delicate processing equipment, such as the screws and the barrels, then it could cause significant damage that would be both costly in terms of equipment repair and production downtime.  BPI was processing small 3mm plastic beads that was used to produce the plastic film and occasionally metal would be found in the beads.

Special Low Profile FF Drawer Filter Magnets

After the initial assessment, Bunting quoted on the same day and RPC bpi placed orders for three FF model, high strength Neodymium Rare Earth Drawer Magnets.  However, when the drawings of the FF model were passed to RPC bpi for approval, it became apparent that there were significant space limitations.  Bunting UK engineers reassessed the installation and proposed the low profile (LP model) Drawer Magnets, which fitted perfectly into the key location.  The new Magnetic Separators were supplied to RPC bpi later that week.

The LP Model Drawer Magnets were only approximately 183mm high and 210mm square, which were the perfect size for the limited available space in the ideal location for the Magnetic Separation.  Each Drawer Magnet had three high powered Rare Earth Tube Magnets, which could be easily removed from the front for cleaning.  The unit was also fitted with a top slide plate that was pushed into position prior to cleaning to stop the flow of material and thus prevent spillage.  On the front of the unit are two large, easy to turn knobs for quick access.

Drawer Magnet Grid

Fine iron contamination captured on the Tube Magnets

The Drawer Magnets are cleaned every four days.  Not long after the installation, part of a screwdriver was found firmly attached to the magnets.  This would have caused significant damage and downtime if the magnets had not been installed.  The cost of the equipment damage alone would total several thousand pounds.

Following the installation of the first three units, RPC bpi purchased an additional six.

For further information on removing Metal from a plastics processing plant using Magnetic Separators and Metal Detectors, please contact the Bunting technical sales team on:

Phone: +44 (0) 1442 875081
Fax: +44 (0) 1442 875009
Email: sales.berkhamsted@buntingmagnetics.com
Via the website

All photographs taken by Paul Fears Photography

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