Advances in film processing technology
New design drives space saving extruders
Reifenhäuser is treading a new path in extruder construction with the development of special drive technology. The REItorque direct drive used in a new design series of single screw extruders features very high torque ranging from 300 –11,000Nm, that can be achieved even at low speeds.
“Compared to conventional mechanical engineering efficiency, is increased by about six per cent, which offers a considerable reduction in energy costs on a production line,” says the company. The technology also means a 30 per cent smaller footprint. Instead of using gearboxes, couplings and belt drives, the compact design is achieved by a motor directly driving the screw shaft. Size is a particular advantage in the arrangement of multi layer coextrusion lines.
Wear to moving parts is reduced too. “The REItorque drive technology is almost maintenance free,” adds the company. The screw can be changed easily, it is claimed, as it can be removed both in the extrusion direction to the front and to the rear through the drive unit.
Sculpted die design helps boost productivity
With a shape that differs dramatically from conventional dies, a flat extrusion die launched at the recent NPE 2003 show is said to enable film, sheet and coating processors to improve productivity and product quality by eliminating a longstanding trade-off between gauge uniformity and streamlined melt flow.
The new Contour die, which was introduced by EDI, has a tapered, sculpted shape instead of the standard block-like configuration. The new system exhibits die-body deflection that is uniform across the width of the die yet avoids the sacrifice of meltflow streamlining incurred by earlier ‘constant deflection’ dies, according to John Ulcej, EDI’s executive vice president of engineering and technology.
The key advantage of uniform die deflection is said to be a reduction in the amount of time that is required to adjust the gauge profiling system. “Operators can achieve target gauge several minutes sooner after startup or changes in the extrusion rate,” he explains.
More BOPP capacity for Moscow
The British consortium on behalf of HilltonGate, London, has recently signed a contract with Brückner for a further BOPP film production line for the Russian market. The ordered line will have a nameplate capacity of 18,000t/year. The first line will start production within the first quarter of 2005 in a region close to Moscow.
Jointly developed line technology and design places particular emphasis on the ability to attain maximum productivity and reliability as well as ensuring product flexibility. The building design has been planned to house two production lines both capable of attaining the same output at the same time.
Cast stretchwrap winder boosts productivity for wider lines
Davis-Standard’s Model 2300 winder has been upgraded to include a new chucking mechanism that permits 3,000mm finished roll widths at claimed production speeds of up to 460m/min. This is accomplished without the need for a centre shaft support.
Primary advantage of the chucking mechanism is that it increases line speed by reducing shaft deflection and shaft whipping, which previously limited speeds to 300m/min at this winder width, explains the company. It adds: “This constraint forced machinery builders to implement a double-wide winder configuration, using two 2,000mm or two 2,500mm winders, which is costly and confines slitting schedules due to a fixed centre slit.” The new model enables maximum flexibility using in-line slitting for accommodating six 500mm rolls, four 760mm rolls, three 1,000mm rolls and other width combinations. Without a centre support, processors have more flexibility to produce several widths simultaneously without incurring waste.
Money saving monitoring
NDC Infrared Engineering has developed a high speed film thickness gauge, the FG710, which uses near infra red (NIR) technology to help achieve advantages in quality, accuracy, productivity and competitiveness.
The gauge is said to offer more consistent high quality production, enabling flatter cross-web film thickness profiles and improved streak detection. Because more of the product is produced correctly first time and raw material usage and wastage is reduced, both product and cost efficiency is improved, boasts the company.
Detection of streaks sometimes caused by die blocks is critical to any plastics film manufacture because of its effect on product appearance and quality. The gauge makes it possible to monitor and detect streaks effectively, claims NDC. Tests show a 1mm wide streak can be detected with a 15 per cent change in gauge output, with a scanning speed set at 6m/min and a response time of 30ms. The gauge can measure across a thickness range of 12-5mm and be used in multiple on-line locations. For ultra thin film products, the TFG-710 gauge allows measurement down to five microns or less.
“Based on our extensive web experience, the FG710 responds to the broadest needs of the industry, whether it be the sophisticated ‘lights out’ fully networked factory, or smaller installations of a few stand-alone gauges,” comments marketing manager James Millard.
Precise layer ratios achieved in S Africa
A newly installed yield control system from Maguire has made possible outstanding product quality and consistency in a three layer blown film coextrusion line operated by Johannesburg based Coextruded Film Technologies (CFT), according to Bob Boden, managing director of this relatively new producer of polyolefin packaging and industrial films.
“The LineMaster system has enabled us to maintain extremely precise layer ratios and to produce rollstock with weights that are virtually identical from one roll to the next,” he said. “Our control over layer ratios has resulted in films with consistent heat sealing and mechanical properties – an achievement which has proved invaluable for supplying quality film for high speed wicketted bag production.”
While Maguire’s Extrusion Control Network controls product thickness by monitoring the weight of raw material metered to the extruder per unit of time and using this data to adjust extruder throughput, LineMaster software provides more advanced control by adjusting both extruder throughput and line speed to maintain target yield.
Extrusion innovations geared to quality
Windmöller & Hölscher placed great emphasis on its film extrusion systems during an open house earlier this year. Three different specification Varex three and seven-layer blown film systems with working widths of 1,600 and 2,200mm were demonstrated with production including tissue film, film for automatic packaging systems and blown stretch, as well as barrier film for thermoforming applications. In addition, a Filmex cast film line was shown producing a PP multi layer film at high output speeds, as well as an asymmetrical seven-layer high barrier film with a PA outer layer and a PA/EVOH/PA middle layer.
Innovations included the Maxicone blown film die for five and seven layers. Very short melt flow paths and reduced melt residence times combine with minimized melt volumes in the die, the elimination of ‘dead zones’ and minimized pressure loss to allow for trouble-free high quality production even of the most critical barrier films, claims W&H.
A new film sizing cage – the non contact Nostic Air Cage – is said to give perfect alignment and support of the blown film bubble after leaving the die. It also ensures flow mark free production, even when sticky film or films with two frost lines are processed, adds the company.
One of the blown film lines was demonstrated in conjunction with the newly developed Filmatic S dual winder. This surface winder features automatic taper tension and contact pressure control to match the increasing diameter of the film roll. It can be optionally equipped with reverse winding capability by incorporating a vacuum contact cutter drum and/or be extended for centre/gap winding.
The Filmatic R winder, developed by the W&H daughter company Reinhold, was another first. A single wind unit was demonstrated downstream of a Varex. It features reverse winding capability using a vacuum contact cutter drum and is suited to all wind modes, including surface, centre and gap. Right angled web cut and splicing without tail foldback are among its characteristics, as are centre drive from the very beginning of a new reel and an integrated automatic reel shaft refeeding system. A laser marker serving as a core positioning aid is optional.
Treater ignites industry
Enercon has developed a new flame plasma treater in response to requests from many industry leaders who rely on flame surface treatment. The system is claimed to be capable of handling webs reliably at very high speeds and to deliver exceptionally consistent treatment levels. It features “innovative burner design” and an easy to use electronic control system which “allows users to produce repeatable results without needing a degree in surface treating physics or combustion control”.
Kampf has taken over the business establishments of KKA Kleinewefers Anlagen in Munich and Krefeld, Germany. The integration of KKA calender technology will provide an excellent foundation in achieving Kampf’s goal of strengthening its turnkey business, reports the company. And the KKA converting technology will “enhance Kampf’s product line, reinforcing its worldwide position as a market leader in the field of film and foil converting”. All product lines will continue to be supported by sales, engineering and service, at their present locations.
Specialist static management distributor WLT has added dedusters from Pelletron to its range. Designed for the removal of dust and debris during the production or recycling of plastics, unlike conventional equipment the deduster can be integrated into pipework used for the transportation of plastics granules, allowing dust to be removed whilst the beads are ‘en-route’.
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