machinery | Extruder technology
Right: Tecno- matic says that innovations in screw and
motor design
have enhanced the perfor- mance and energy
efficiency of its Zephyr
extrusion series
screw concept that consistently applies the theory of dispersive melting, and a feed zone with a completely revised geometry that is fitted with spiral grooves. The SolEx NG extruder series is available in
four sizes – 60, 75, 90 and 120mm – with outputs of 1,000-2,500kg/h. This is an increase of up to 25% for each machine size, compared to the original SolEx series. One benefit of the new design of processing unit is an increase in melt capacity, along with gentle and energy-efficient processing. Melt temperature in the extruder is reduced by up to 10°C for comparable outputs, while melt homogene- ity remains at a high level. Modifying the conveying mechanism has reduced the
axial pressure profile in the feed zone and barrel – cut- ting pressure across the system and enabling an increase in the specific output level. Overall energy cost savings of up to 15% are also
possible – partly through needing less drive energy, and partly due to the cooling of barrel and grooved bush, which reduces heat discharge.
Enhanced extrusion Tecnomatic has developed an enhanced version in its Zephyr extrusion series in L/D 40, in both a gearless and a traditional version (with gearbox). The company says that the latest versions offer higher performance and energy efficiency due to innovations in the screw and motor designs, and a new spiral grooved bush. The new feed bush reduces the friction generated by raw material transport, which helps to increase throughput. Redesigning the screw to optimise and enhance its torque and shearing elements has boosted output and allowed the material to be processed at lower melt temperatures. In addition, the machines are equipped with torque
or water-cooled motors – in this case with a one- or two-step gearbox – and compact water-cooled invert- ers. This delivers high power consumption, low noise, reduced maintenance, high efficiency and faster dynamic response, says Tecnomatic. Zephyr extruders are offered in four screw diam- eters, with a maximum output of 1,700kg/h.
Screw improvements Davis-Standard recently upped its game to deliver a new feedscrew to a US-based customer in around half the normal time. Tempo Products had noticed falling output rates –
and material inconsistency – on its Davis-Standard extruder, and realised that it needed a new feedscrew.
32 PIPE & PROFILE EXTRUSION | July/August 2017
However, it could not wait for the normal eight- or nine-week delivery time – as it often promises same- day shipping to its customers. “We are so engaged in keeping up with business that
we overlook periodic feedscrew maintenance,” said Rael Sacks, founder and co-owner of Tempo Products. “We pulled the feedscrew once since buying the extruder in 2012, and didn’t have any issues until recently, so we didn’t think about it.” Tempo uses the extruder to process linear low-den-
sity polyethylene (LLDPE) and flexible PVC tubing for drip irrigation products, which are sold to major retailers throughout the USA. The company has a same-day shipping policy, making consistent, high-rate production a necessity. Davis-Standard managed to deliver and install the
new feedscrew – a replica of the original, but with a harder finish – within five weeks, restoring production rates and keeping production timelines on track. “Once the new screw was installed, everything was
back to normal in five minutes,” said Sacks. “We definitely plan to do more frequent feedscrew and barrel checks to avoid this issue in the future.” Davis-Standard recommends inspections at 90- to 180-day intervals, using either the accurate method or approximation method. The accurate method compares current screw output with production benchmark output. The approximation – which requires around 24 hours of downtime – involves pulling and cleaning the screw, and measuring screw and barrel clearance.
Service plan Polyhose India, which manufactures a range of hoses for automotive and industrial applications, has signed a service level agreement (SLA) with Maillefer, for the maintenance of some of its machines. “The agreement targets the three lines delivered by Maillefer in 2011,” said SJ Ali Asger, Director of
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