TPT November 2009

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Technology Update
70 November 2009 ›
THE EMMEDI & Annealing Division of
SAET GROUP has installed an advanced
MOSWELD solid-state HF Welder 200kW
output power at ZPT JSC Bulgaria.
ZPT is a factory located in Straldzha,
manufacturing carbon steel tubes. The
new MOSWELD is installed on a tube mill
producing tubes from 60mm to 150mm
and WT up to 4mm.
THE development of the new CNC contour
turning unit by Wolf opens up previously
unsuspected fields of application as far
as the production of small turned parts
is concerned. This new CNC contour
turning unit is already an integral part of
the machine programme of Wolf and it is
successfully used as an element of the
TSM 280 rotary table transfer machine.
Thanks to the reduction of costs
and integration of particular production
sequence in the hydraulic two axial
CNC contour turning unit expensive and
complicated form tools can be dispensed
with. The use of simple, economic and
standardised tools makes a quick tool
change possible, whereby complex set
ups are minimised.
The TSM 280 rotary table transfer
machines are machines of very high
The solid-state welder generation
MOSWELD, based on a MOSFET-type
inverter is able to work up to 450kHz.
As typical working frequencies in tube
welding process are in the range 300–
45kHz, MOSFETS are one of the most
cost-effective choices for this application,
the company claims.
A system control board communicates
with the inverter through optical fibres
that are provided on the unit. The inverter
is a current fed type and the output
oscillating circuit is directly connected to
the inverter.
The company says MOSWELD has
the following advantages: high efficiency;
modular design; easymaintenance; it is short
circuits proof; it has much lower voltages
inside the cabinets compared with oscillator
precision owing to their structural
and modular construction. Repeated
positioning and accuracy of 0.01mm in
the axial direction and of 0.005mm in the
radial direction are achieved.
The hydraulic two axial CNC contour
turning unit is operated by means of
a newly-developed CNC control in
conformance with the ISO standard. The
operation and handling of this CNC control
can be learned thanks to special easily
and logically arranged programs, so that
the machine operators can quickly and
simply become acquainted with it and safe
operation of the machine is achieved.
Wolf – Germany
Fax: +49 713593 69866
Email:
Website:
tube technology; power components are not
subject to obsolescence; it uses the same
coils as the classic oscillator tube welder;
and it offers long-term reliability.
The modular structure and a complete
diagnosis system allow quick and easy
maintenance in order to reduce production
stops. A special digital control system
has been developed for an optimum
phase locking (and then for an efficiency
increasing) with the possibility to follow
the change of frequency due to load
variation in any working condition.
EMMEDI Welding & Annealing Division
of SAET GROUP – Italy
Fax: +39 011 9974328
Email:
Website:
Solid-state
HF welder
New two-axis hydraulic
CNC contour turning unit
 A solid-state HF welder has been
installed at ZPT JSV Bulgaria