17/03/06
Press Release - New small footprint carton sealer suits Twinings to a ‘tea’



Sewtec Automation of Dewsbury, West Yorkshire, has designed, developed and commissioned three, top load, four flap carton sealing systems that enhance the flexibility and productivity of the Twinings tea production facility at North Shields, Tyne & Wear. The Sewtec ‘four flap’ carton closers are used on Twinings’ black tea products, which include traditional afternoon teas, English Breakfast, Earl Grey and Lady Grey blends.

The Sewtec carton closers were installed over a 12 month period commencing April 2005 and are incorporated within two separate production lines; one line producing 50-bag cartons, the other producing 100-bag cartons. Two carton closers are stationed on the 50’s line, while one carton closer is on the 100’s line. Each Sewtec carton closer is downstream of a tea bagging machine, running at 2,000 bags per minute, which manufactures and fills the teabags, before dropping them in to the inner, four flap cartons. Filled and open cartons are then conveyed to the Sewtec indexing carton closer, which effects the closing and sealing of the carton flaps by means of flap kickers, guides, hot melt glue application and pneumatic top flap closure.

Due to the limited space within the existing plant, the new lid closure system was also required to possess a very small footprint, without compromising on quality or efficiency.

The machine uses indexing motion for carton transportation, generated by a single AC drive motor coupled with a precision cam motion indexing drive and timing belts. The drives are mounted beneath the main machine bed, separated from the carton closing area to give protection against dust ingress.

Cartons are transferred, by a pair of pneumatically activated driven side belts, from a queue, into a series of fore and aft lugs at each side of the carton to maintain carton squareness, during the flap closing operations. As the cartons are indexed through the machine the leading and trailing flaps are folded down by means of a top guide and rotary kicker, which is linked by timing belts to the main drive. The carton closers incorporate Dyna-Tech, hot melt gluing systems, which were the preferred choice of Twinings, with glue blades and guns applying lines of glue to the appropriate areas of the main top flap, during the carton index cycle prior to closure. The final closure is by means of a pivotal top flap, spring loaded tamper plate, driven via timing belts from the indexing unit and timed to operate during the stationary period of the machine cycle, thus resulting in a perfectly square flap closure. Nominal speed is 40 cartons per minute, with a maximum speed of 55 cartons per minute. A change of carton size or a change from new to old type carton, and vice versa, can be carried out quickly utilising change parts with a few adjustments – should the need arise.

After the inner cartons have been closed and sealed by the Sewtec carton closer, they are conveyed downstream to another machine which fits the outer carton packaging.

Control of the machines is by Allen Bradley MicroLogix PLC-based systems, which operate on multi-functional levels, via PanelView 300 operator interface. Operators have a simple interface for stop/start and control of feed rates, while higher functions such as maintenance and programming are accessed through a password protection system.

The requirement for the new Sewtec carton closers came about through a design change of product packaging. A new carton design was proposed, initiated to improve cost efficiency, which incorporated a new inner carton with an additional flap to seal the carton across its front. The Sewtec machines were designed to operate with both types of cartons, old and new, so that a phased introduction of new packaging could be carried out.

Commenting on the impact that the new Sewtec carton closers have had, Twining’s project engineer Paul Robertson says: “Since their introduction, the Sewtec carton closers have reduced waste significantly and added to the flexibility of black tea packaging operations. We’ve used Sewtec in the past on various small projects and it was felt that this application was typical of their expertise. It’s a special purpose machine, with a small footprint, and ideally suited for the limited available space on the factory floor. “

He adds: “We spent some time with the Sewtec designers and project engineers, and were quite surprised at how quickly the project was progressed from initial concept. On our first progress visit, the concept had been developed into clear 3D images, from various different views, so that we could get a very good understanding of how exactly the system would work. This fast rate of progress, aided by excellent communication and collaboration between supplier and customer, has been a significant feature throughout the project. Due to the success of this project, and the cost savings and added flexibility we have gained, we are planning to introduce a further three Sewtec carton closures into our operation in the very near future.”

Sewtec application engineer, Steve Levitt, comments: “As a special purpose machine manufacturer, Sewtec thrives on the challenges set by our customers. The Twinings application allowed us to demonstrate our ‘complete solution provider’ abilities throughout the design and build process, and deliver a cost competitive and well engineered solution that fully meets the demands of the application.”



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