Extrusion: High-Output Stretch Film Line
New ‘hands-free’ die control is said to permit fast and easy product changes.
In operation during October’s K 2019 show in Dusseldorf, the PowerCast XL stretch film line from SML has a net film width of 4500 mm. Without increasing the trim ratio, the new line is able to produce 400-, 450-, 500- and 750-mm wide rolls, said to be a key advantage to serve market requirements. The 13-layer system running at K was equipped with eight extruders, a 5435-mm wide Cloeren Reflex die, a 1600-mm diam. chill roll that’s 5500-mm wide, and a double turret winder, W4000 4S 2T, with 4 shafts per turret.
SML’s newly introduced "hands-free" operation of the extrusion die reportedly makes product changes on the new PowerCast XL line fast and straightforward. With Cloeren’s new Reflex die, used in combination with SML’s “Booster” regulation, the line operator does not need to make manual cross-profile adjustments during product changes any more. Using a conventional system, it takes sometimes 30-45 min until the required product quality is reached. The available hands-free and Booster regulation can do this in approximately 10 min, completely automatically, SML states.
The automatic mapping of the die bolts is another innovation from SML to minimize both personnel costs and waste production. With conventional equipment, the operator needs to do a manual die mapping at every product change to ensure the good regulation of the thickness gauge. With the new automatic version developed by SML, a special software constantly regulates the expanding and contracting of the die bolt at a defined position to the film. The thickness measuring unit recognizes the position of the bolt and automatically readjusts the mapping.
All of SML’s stretch film lines can measure the real temperature of the extruded film directly on the chill roll. This feature gives processors the ability to predict the quality of the film with regard to its elongation already inline during production. The operator then knows immediately if he needs to modify or readjust anything to achieve the right properties.
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