Global manufacturer finds perfect fit with Siemens solution

Battenfeld-cincinnati manufactures energy-efficient, high-performance extruders and complete extrusion lines according to customers’ specifications and has found practical, innovative solutions for developing components and tooling.

Battenfeld-cincinnati is the market and technology leader in polyolefin (PO) pipe extrusion, particularly for large diameter pipes. Numerous projects for lines with diameters of up to 2.6 meters at a wall thickness of 100 millimeters (mm) have already been realized and successfully placed in the field. Other products include extrusion lines for smaller pipes which are used in telecommunications, where the smallest dimensions can be up to a diameter of 4mm at a wall thickness of 0.5mm with an extrusion speed of up to 200 meters per minute, building services (such as underfloor heating), and automotive applications, among others. These can have several different layers and various color stripes.

Figure 1b: Battenfeld-cincinnati offers a variety of co-extrusion solutions and multilayer pipe heads for special applications.

Energy efficiency, conservation of resources and reduction of material consumption have long been a focus for battenfeld-cincinnati. As a member of the Mechanical Engineering Industry Association’s (VDMA) Blue

Competence Initiative, they play a part in promoting sustainable economic development. Battenfeld-cincinnati’s vision is to provide leading performance and energy efficiency solutions to their customers.

For over a decade, Simcenter™ FLOEFD™ software has supported battenfeld-cincinnati engineers in their product development. Simcenter is a part of Siemens Xcelerator business platform of software, hardware and services.

“The current short project lead times between ordering and hot-commissioning require the use of advanced simulation tools like Simcenter FLOEFD,” says Heinrich Dohmann, head of research and development (R&D) pipe heads and mechanical engineering downstream, battenfeld-cincinnati.

Designing and building large diameter pipe heads is a huge challenge. Battenfeldcincinnati is driven by a customer-centric approach to design solutions, whereby customers can select the most suitable pipe head for their specific application from a wide range of tooling options. In the early days, battenfeld-cincinnati used Simcenter FLOEFD for melt distribution optimization. The increasingly complex geometries could not be calculated with the available tools, making the implementation of a 3D simulation tool necessary. In addition, a confidential development project in cooperation with an established pipe manufacturer was successfully developed using Simcenter FLOEFD.

Since then, battenfeld-cincinnati has applied Simcenter FLOEFD to a wide range of applications to achieve a uniform velocity distribution in the annular gap at the melt die outlet. The challenge here is to optimize the pressure drop simultaneously. This can amount to up to 400 bar for the entire line, creating a significant impact on the overall efficiency and the installation space required. The shear flow and the material dwell times have to be considered accurately at the same time.

Figure 1c: Five-layer PE-RT pipe with EVOH oxygen barrier layer.

One of battenfeld-cincinnati’s innovative products is the high performance “helix VSI-T+” pipe die. With its two-step distribution concept, it is a highly efficient solution that has proven itself in more than 600 dies worldwide. It consists of a spiral mandrel and a lattice basket distributor element, for which battenfeld-cincinnati holds the patent. Thanks to the two-step concept the melt is ideally distributed and optimally homogenized. This allows a smaller design for the distribution component, while at the same time ensures excellent pipe quality and high outputs. With the help of Simcenter FLOEFD, the battenfeld-cincinnati engineers give the pipe heads their ideal dimensions. Material flow channel and steel parts are designed compactly and efficiently.

Figures 3a, b, c: Melt flow through the melt die.

Figure 4: Melt die cooling.

Battenfeld-cincinnati’s helix VSI-T+ die features active internal melt cooling to reduce melt temperatures already in the die and a reduced sagging effect, which is a big advantage in producing pipes with large wall thicknesses and a high line output.

The pipe head is a key factor for customers. Its design and features ensures the production of large pipes with even wall thickness distributions and reduced pipe ovality. It also reduces sagging significantly (figure 2).

Figure 2

The efficient cooling concept allows for shorter cooling lengths in the line and enables space savings. The complete line of components are custom-made and produced at battenfeld-cincinnati’s manufacturing facilities.

Another application for the Simcenter FLOEFD flow simulations is in the development of multilayer (co-extrusion) tools. In this process, several different layers are produced. In direct extrusion up to seven layers and, in coating, up to five layers can be produced. Various color stripes can be introduced into the pipe. The quality requirements are also very high. Even the slightest deviations of the tone and thickness of the color stripes are not accepted.

“In addition to the time optimization, the simulation supports us in terms of product quality and reliability, such as at the color stripes,” says Carsten Bulmahn, mechanical engineering pipe heads, battenfeld-cincinnati. “The detailed engineering is carried out within our development processes by the same team.”

With computer-aided design (CAD) embedded in Simcenter FLOEFD, the battenfeld-cincinnati engineers can directly use the native 3D CAD data. The fluid space is automatically captured and the mesh is generated automatically from just a few settings within the software. Special calculation models for non-Newtonian fluids are applied for the simulation of the used materials. In this specific case, the Carreau model is applied. The parameters for the non-Newtonian fluid model are determined on the basis of customer supplied material samples.

Future applications where Simcenter FLOEFD might be used include granulate preheating and pipe cooling. Both are examples of the process’ energy optimization. For granulate preheating the waste heat can be re-used in the process. The pipe cooling can already be ensured, but there may be potential to further reduce energy consumption and increase efficiency.

Figures 5c, d: Melt distribution at the die outlet.

Figures 5a, b: Inner layer, middle layer (gray and black) and two-color stripes (blue and red, depending on operating status).

In all of these challenges, Simcenter FLOEFD supports battenfeld-cincinnati’s development engineers early in the development process. Efficiency simultaneously saves electricity and raw materials.