TPT November 2010

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66 November 2010 ›
Technology Update
TUBETECH CORPORATION LIMITED
TUBETECH WUHU MANUFACTURING CO.,LTD
Clamping
unit for laser
fixtures
IN a laser welding fixture all welding seams
should be clamped with a zero gap. AWL,
The Netherlands, often uses a hydraulic
pusher to achieve this. Although this solution
works well, the fact that it uses a hydraulic
principle is a disadvantage in a laser welding
fixture, as oil spills and the risk of fire due to
sparks emitted during the welding process
are always present. Therefore, AWL has
developed an alternative solution.
AWL’s pneumatic pusher has a maximum
pressure of 16 bar, achieving a maximum
pressure force of 785N. This is more than
sufficient for the pressing of sheet metal
parts in laser welding applications within the
automotive market.
The cylinder is single-acting and, unlike
a hydraulic cylinder, does not use a return
spring. The return stroke is achieved through
vacuum. There is no loss of power and the
stroke can be increased, enabling a greater
release stroke. This release provides the
ability to auto eject the product from the
fixture, making removal of the product
easier.
The greatest challenge in developing the
cylinder was building the unit as compactly
as possible, as a lot of pushers need to
be placed close together in a laser fixture.
The solution to this problem was found by
seaming both the outer and inner cylinder.
This way, the outer size is similar to that
of the hydro cylinders. Additionally, special
mounting blocks for the hydro cylinders are
no longer needed as the pneumatic unit can
be easily connected with a tube.
Although the pneumatic pusher has the
same outer size as the hydraulic one, a
larger piston diameter can be applied, which
increases the surface and the pressure
force. With a load of 16 bar a special system
with a compressor or booster is required.
The hoses, fittings, valves and air supply
are adjusted for the workload. However, for
most applications 10-12 bar is more than
sufficient.
Use of the AWL-developed cylinder is
specifically intended for applications where
there is little space, but a need for many
pressure points. This solution offers great
perspective for welding thin plates in the
automotive industry. Besides laser welding,
AWL also expects to use the pneumatic
cylinders for gluing solutions.
To ensure that parts of a product, within
a given tolerance, are well clamped, AWL
developed a variant with a magnetic piston.
In cases were pressure points need to be
even closer than the 30mm that is normal
with a pneumatic pusher, an attachment
can be placed with a U-shaped fork anti-
twist feature, enabling clamping even closer
together.
The pneumatic pushers will be the new
AWL standard, and will replace the hydraulic
pushers from now on. The company states
that customers have already shown interest
in replacing existing hydraulic fixtures with
the AWL pneumatic principle.
AWL-Techniek BV – The Netherlands
Fax: +31 341 411822
Email:
Website:
Pipeline
brushes
LESSMANN is a leading company in
producing technical brushes. Among them
are wheel brushes, roller brushes, hand
brushes and others. Depending on the
application and the customers’ requests
different wires, abrasive nylon or diamond
filament is used.
For the treatment of weld seams in the
tube and pipeline industry special knotted
wheel brushes were developed. They are
ideal for the treatment of U- and V- weld
seams.
Due to the narrow construction with a
brush width of 5-6mm also low lying weld
seams in U- and V- welds can be reached.
Cinder, scales and other contaminations
are removed fast and efficient. Especially
after multi-layered welding processes and
to recognise asperities on the seam the
cleaning is necessary.
High tensile wires in combination with
different construction characteristics used
by Lessmann guarantee a long product
life. The spreading of the filling material
in the brush is 100% steady which helps
to create a quiet product run and an
unproblematic operation even over a long
periiod of time.
Depending on the field of application
brushes with high tensile steel wires or
high tensile stainless steel wires in different
wire sizes are deliverable. The types with
stainless steel wire have green side plates.
Different standard bores or threads
adapted to the national and international
technical requirements are deliverable ex
stock. The standard brushes are available
in the diameters 100mm, 115mm, 125mm,
150mmand 178mm. Custom-made products
are available on demand.
The brushes have a high durability due
to the high quality of the wire and they
cause an eminent brushing result.
Lessmann GmbH – Germany
Fax: +49 9082 70778
Email:
Website:
AWL’s pneumatic pusher