Automatic dimension change during polyolefin pipe production

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  • FDC (fast dimension change)
  • 4-layer polyolefin pipe at 1,500 kg/h
  • Intermediate and customized pipe sizes also possible
  • Adjustable melt gap instead of pin-and-die combination

In order to remain competitive these days, pipe manufacturers have to operate extrusion lines which are not only cost-efficient in operation, but also flexible and quickly adjustable. To address these requirements, Battenfeld-Cincinnati Germany has demonstrated for the first time its new fast dimension change (FDC) system, which allows the change of pipe dimensions automatically during production.

4-layer polyolefin pipe at 1,500 kg/h

Roughly 70 customers from Europe and the Near and Middle East attended the Battenfeld-Cincinnati customers’ events and witnessed the production of a 4-layer polyolefin pipe at a total output of 1,500 kg/h. Equipped with the FDC system, the internal pipe cooling system (EAC), as well as melt cooling integrated in the die (VSI-T+) and a special design for quick color change, this 4-layer co-extrusion line provides a high level of flexibility. Pipe dimensions can be changed automatically during production, and so can the color of the stripes or the pipe’s outer layer. The produced pipe featured a very good surface quality and an even wall thickness distribution.

On two days, about 70 customers gathered first-hand information about the new FDC (fast dimension change) line from battenfeld-cincinnati Germany.

Adjustability in a wide range of dimensions

Special features of the dimension change system are adjustability within a wide range of dimensions, an easy-to-operate water flow adjustment system in the inlet zone of the calibrating sleeve, and the the possibility to produce absolutely round pipes with very good wall thickness distribution. The latter is achieved by a calibrating sleeve made from rolled sheet metal in cylindrical design. With optional pipe die centering, the wall thickness distribution lies within the bottom third of the tolerance margin required by the DIN standard. The even water cooling in the inlet zone of the calibrating sleeve ensures a homogeneous pipe surface without water marks.

Intermediate and customized pipe sizes can also be produced

With the line on display, which was specially designed for a European customer, a range of pipe dimensions from 200 to 800 mm can be covered. This line comes with two adjustable calibrating sleeves: the first allows automatic adjustment of pipe dimensions between 200 and 355 mm, the second covers the range from 400 to 630 mm. Not only standard dimensions but also intermediate sizes and customized sizes can be produced without modification of the line. For the pipe dimension range from 710 to 800 mm, standard calibration systems are used in this customized version.

Combination of spiral mandrel die and lattice basket design

The exhibited solEX 75-40 main extruder with a processing length of 40 D provides gentle plasticizing of the polyolefin material. Due to a combination of a smooth spiral mandrel for melt pre-distribution with a compact lattice basket for detail distribution, the helix 800 VSI-TZ+ pipe die offers the advantages of low pressure build-up and functionality independent of melt viscosity. The EAC internal pipe cooling system enables the high line speeds and, together with the active melt cooling system inside the die, minimizes undesirable sagging.

Adjustable melt gap instead of pin-and-die combination

Following the pipe head, the line operates with an adjustable melt gap instead of a pin-and-die combination. A coex radial distributor is integrated in this adjustable melt gap to enable color changes to be effected quickly and with maximum efficiency. Therefore it is possible to not only change the pipe dimension with minimum waste of material, but to implement an equivalent color change of the outer layer as well. In addition, with its 4-layer co-extrusion configuration, the line can produce pipes not only for standard applications, but also for special industrial applications, for example where an oxygen barrier layer must be integrated into the pipe wall.

With the FDC (fast dimension change) technology, it is possible to produce pipes of different diameters without stopping the line. The pipe die with internal cooling ensures smooth pipe surfaces, optimal wall thickness distribution and roundness.

Vacuum tank specially designed for automatic dimension change

The vacStream 800-6 vacuum tank has also been specially designed for the automatic dimension change. It operates with a pipe support device across 180° of the pipe circumference and is steplessly adjustable across the entire range of dimensions (200 – 800 mm) without any structural changes. The flexible sealing at the end of the vacuum system stands out by its simple structure without any mechanically moving parts and has already been used many times for retrofitting on existing extrusion lines. During a dimension change, the haul-off and cutting devices are also adjusted automatically to the new dimension at exactly the right time.



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