Introduction

Rosendahl Maschinen GmbH, Austria, manufactures wire and cable equipment systems for a variety of applications. From core extrusion onward, the company supplies a comprehensive range of high-end cable manufacturing systems for telephone, LAN, mini-coax, CATV, RF-coaxial, and optical fibre, as well as automotive and low-voltage power cables. Rosendahl also offers extrusion, physical foaming, SZ-stranding, buffering, and sheathing lines; fibre optic and testing equipment; and process technologies.

Ongoing demand for new insulation materials and production flexibility which moreover satisfy high quality standards are challenges which automotive wire extrusion equipment must meet. As a global supplier of turnkey extrusion equipment, Rosendahl presents a wide range of equipment for automotive wire applications, including single-core extrusion lines with quick-colour-change systems, battery cable extrusion lines, multi-conductor cable jacketing lines, and plastic optical fibre (POF) cable jacketing lines.

Single-core extrusion lines

Rosendahl provides the automotive industry with standard lines equipped with two extruders, as well as quick-colour-change lines with three and four extruders. The auxiliary extruders are available as either vertical (Figure 1) or horizontal (Figure 2) units. The operating range of a typical automotive wire extrusion line is from 0.22 to 7.00mm2.

Figure 1: Extruding line for automotive wire

Masterbatch Dosing Systems
For standard materials such as PVC, PP, and Sioplas-XLPE, volumetric dosing systems are used. For special materials Rosendahl recommends the use of a gravimetric dosing system (Figure 2).

Figure 2: Three groups of extruders with gravimetric dosing system

ROCOMAT Quick-Colour-Change System
The patented ROCOMAT system from Rosendahl features a quick-colour-change shaft integrated into the crosshead (Figure 3). This design ensures maximum compactness. The ROCOMAT system can also serve the bypass function in all extruders on the system. As a result, the length of the adaptors (Figure 4) can be kept very small. The colour change is hydraulically activated.

Figure 3: ROCOMAT crosshead

Figure 4: ROCOMAT with adaptors

Figure 5 gives a cross-sectional view of a 0.50mm2 product from a three-extruder ROCOMAT colour-change system. The conditions immediately before the colour change are evident. After the colour change, these characteristics prevailed:

• Main colour: blue;
• Stripe colour: white;
• Non-visible stripe: red.

With all three extruders contributing to the cable, there is no purging scrap.

Figure 5: 0.50mm2 single wall product

Figure 6 gives a cross-sectional view of a 0.35mm2 product from a four-extruder ROCOMAT colour-change system. Again in this case, all four extruders are producers of the cable. This sample was taken prior to a colour change. After the colour change, these characteristics prevailed:

• Main colour: brown;
• Stripe colour: green;
• Inner layer: white;
• Non-visible stripe: red.

Figure 6: 0.35mm2 dual-wall product

For sensitive colour combinations which do not permit the use of a dual-layer design, an additional unused layer bypass (ULB) shaft is available from Rosendahl.

Scrap Marker
Rosendahl lines can be equipped with a special scrap marker (Figure 7). This module generates spark faults which help in tracing the source of weldings and other quality faults. The scrap marker is placed between the crosshead and the cooling trough.

Figure 7: Scrap marker

Cooling Trough
The design of the Rosendahl cooling trough allows easy access. Downtime after wire breaks can be significantly reduced with the use of brake systems for the deflection pulleys in the multi-pass cooling trough. Highly efficient cable dryers ensure proper function even at top line speeds. Cable dryers are equipped with blowers and thus do not require compressed air.

Figure 8: Cooling trough and cable dryer

Line Control
The RIO line control system (Figure 9) from Rosendahl is a powerful operating system available in three versions: basic, standard, and enhanced. A feature of all three versions is the remote service management (RSM) module. This permits remote operation, servicing, and installation of software upgrades direct from Rosendahl headquarters.

Figure 9: RIO line control system

The automatic batch control (ABC) module permits definition of production batches. For example, order number, product type, product colour, batch length, etc. can be stipulated and put into sequence for automatic processing. In combination with the ROCOMAT quick-colour-change system, the ABC module is an efficient tool that reduces scrap and increases productivity. The quality management system (QMS) module is designed to monitor and record production parameters and quality parameters. Collected data can be stored for later analysis.

Take-up Systems
Rosendahl single-core extrusion lines are available with various take-up systems (double spoolers, barrel coilers, ring coilers, Niehoff NPS take-ups, etc.) depending on customer requirements.

Plastic optical fibre cable jacketing lines

Increasing demand for multimedia digital applications has led Rosendahl to develop media orientated systems transport (MOST), which is a digital data bus standard. It operates at 24Mbit/s over plastic optical fibre. Commercially available POF features the design dimensions shown in Figure 10.

Figure 10: Plastic Optical Fibre (POF)
Overall diameter: 1.00mm
PA coating
POF (PMMA)

Rosendahl produces plastic optical fibre cable jacketing lines which can be used to manufacture single-layer jacket cables (Figure 11) featuring a POF of 1.00mm Ø and a PA jacket (coloured) of 1.60mm Ø. It also produces dual-layer jacket cables (Figure 12) featuring a POF of 1.00mm Ø, a PA inner jacket (natural) of 1.30mm Ø, and a PA outer jacket (coloured) of 2.20mm Ø.

Figure 11: Single-layer jacket cables

Figure 12: Dual-layer jacket cables

The basic parameters of a Rosendahl plastic optical fibre cable jacketing line are:

• POF pay-off reels: 500mm Ø;
• Pay-off tension for POF: 0,5 - 5 N;
• Take-up reel size: 800mm Ø;
• Jacketing materials: PVC, PA;
• Line speed: 500m/min max.

Summary

With more than a decade of experience in serving demanding customers world-wide, Rosendahl has developed the finest extrusion and stranding technology. The company offers high-productivity, properly sized, and customised manufacturing systems for a versatile product range of plastic optical fibre cable designs. With its core competence in the fields of extrusion technology, quick-colour-change systems, and intelligent line control systems, Rosendahl makes an ideal partner for companies active in automotive wire applications.