EuroWire March 2020

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PhotocourtesyMesseDüsseldorf/CTillmann ©

wire 2020 Exhibitors

di erent temperatures and, by means of an intermediary tool, the diameter of the ller layer can be calibrated to just cover the stranded cable. The simultaneous application of the outer sheath secures the stranded core and eliminates untwisting of SZ-strands.

2M-Tech GmbH Stand: 10 C52-06

For the manufacture of installation cables, usually two di erent polymers are used. The stranded core is lled with a low-adhesion compound, mostly a highly lled rubber elastomer. This ller layer is applied to enable easy stripping of the outer sheath, up to a length of 500mm. The compound for this layer is usually extruded at temperatures of 70°C and less. The material for the outer sheath is, depending on speci cation, PVC, PE or an HFFR compound. All these materials are extruded at mass temperatures of 180 to 220°C. Because conventional co-extrusion heads cannot operate with good results with such a high temperature di erential, the two processes – extrusion of ller and outer sheath – are usually done in tandem. However, the tandem extrusion process has disadvantages that include generation of more scrap at start up, and greater space requirement. In the case of SZ-stranded cables, the ller does not secure the strand, so thicker wall ller is required, using more material. 2M-Tech o ers a crosshead that enables co-extrusion of two materials at widely

2M-Tech GmbH www.2m-tech.at

a de ned smaller diameter over a freely adjustable length. The machine achieves roundness tolerances as low as two to three hundredths of a millimetre. The demand for electric bikes results in bicycles operating at higher speeds and with heavier-weight riders. As a result of these trends, the spoke ends connecting with the hub have to cope with increasingly higher loads, especially during braking. At the same time, the opposite ends of the spoke may have the same diameter as common in non-electric bikes because the connection with the rim is not a ected by the extra load. Consequently, there is a growing demand for spoke blanks with ends of di erent diameters. The new AMBA machine is servo- controlled. The length and position of the area with reduced cross section can be ▲ Double thick end spokes, which are thinner in the middle than at the ends, are mainly used for high-end bikes

Aachener Maschinenbau GmbH Stand: 16 E50

wire 2020 will see the unveiling of the new DD-350 spoke-blank reducing machine developed by Aachener Maschinenbau GmbH (AMBA). With a throughput rate of up to 40 pieces per minute, the machine achieves higher e ciency than machines of conventional designs. Double thick-end spokes – thinner in the middle than at their ends – are predominantly used in high-end bicycles. They save weight and reduce windage. The blanks for this type of spoke cannot be manufactured by drawing or upsetting. The new spoke-blank reducing machine developed by AMBA reduces the spoke diameter between the ends by rolling to

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March 2020