Economical production
of TWP®-plate-sections
Foto: Hero Lang
überreicht von der
GRAEBENER Maschinentechnik GmbH & Co. KG, 57250 Netphen-Werthenbach
und der
Schuler Held Lasertechnik GmbH & Co. KG, 63128 Dietzenbach
Sonderdruck aus HANSA 9/2004
Schiffahrts-Verlag Hansa C. Schroedter GmbH & Co.
Striepenweg 31 · 21147 Hamburg · Tel. [phone] · Fax [phone] · www.hansa-online.de
SHIPBUILDING
Production
Meyer Werft restructured their construction procedure completely and started to produce
plate-panels by using newly developed laser-welding lines as well as tailor-welded-plates.*
Economical production
of TWP®-plate-sections
erman shipyard Jos. L. Laser Hybrid Welding are:
Meyer GmbH, Papen- " The panels no longer have to be
Gburg, and their project turned for a root penetration
partners Schuler Held Lasertech- weld, a process, which becomes
nik GmbH & CO. KG and more and more difficult as the
Graebener Maschinentechnik prefabricated blocks and panels
GmbH & CO. KG revolutionised get bigger.
shipbuilding within recent years " Welding rates are much higher
(see HANSA 9/2002, S. 82) by in- than pure MIG welding  but
stalling Laser-welding (LASER also higher than pure laser weld-
= Light Amplification by Stimu- ing.
lated Emission of Radiation) sys- " Because of the deep penetra-
tems which are really based to tion, the side angle can be re-
light-beams. The core compo- duced to 6°, which helps to make
nents of this new prefabrication dramatic reductions in the quan-
of the shipyard are laser systems tity of extra wire needed, com-
produced by Schuler Held pared with conventional weld-
Main plate-panel-line at Meyer s new technology hall: Laser 1
Lasertechnik and plate milling ing processes.
on blue portal right; Laser 2 on blue portal behind yellow gird-
systems by Graebener Maschi- " Reducing the side angle also re-
er-portal Photo: Schuler Held
nentechnik. duces the milling volume when
With the help of a laser hybrid process, Meyer Werft uses a laser-hybrid process preparing the weld.
these systems automatically weld together (see HANSA 6/2002, S. 66) that the com- " Reducing the area affected by heat also
the panels and walls, first vertically and then pany itself perfected. With the aid of MIG reduces the energy input applied per
horizontally. The major advantages are: welding, filler metal and the seam edge unit length, resulting in tangible re-
1. The process is fully automated despite the are fusion-welded while the focused spot ductions in panel distortion. This en-
different configurations of the panels. of the laser (following directly behind) en- sures that the welding process can be
2. The size of the system and the quality sures fusion into the root of the seam by automated. Moreover, costly and time-
of the welds permit prefabrication of means of deep penetration welding effect. intensive reworking is reduced and the
sections as large as 20 x 20 m without In this way the laser produces a weld that assembly of the blocks in the dock sim-
ever having to turn the panel. is as good as a conventional root pene- plified.
In shipbuilding, such component size, tration seam even though it is processing " By using a MIG welding source to apply
welding precision, and the level of au- from just one side and with a very low energy in areas near the surface, the laser
tomation amount to a revolution  espe- angle of beam spread. The weld edge is made available solely for deep pene-
cially for processes that typically have been preparation is the key factor to success. tration welding, i.e. for the process ur-
done manually before. Instead of using plasma cut edge, Meyer gently dependent on the laser s qualities.
is using a milled edge. The advantages on Energy costs are almost halved, com-
Welding Process
pared with pure laser welding.
Just as in the automobile in-
Plate edge preparation
dustry, shipbuilders also try to
by means of milling
reduce material consumption
and weight in order to keep op- Milling technology, in contrast
erating costs as low as possible. to grinding or even plasma re-
In shipbuilding they also make spectively flame cutting, be-
use of the technique known as comes more and more accepted
Tailor Welded Plates« (TWP®) in the field of plate edge prepa-
that is, joining panels made of ration. The main advantages are:
plates of varying thickness as " High milling speed of up to
required by the specifications 8 m/min can be reached.
of the ship s hull. Panel di- " Due to the parallel processing
mensions, in this case, can of plates the very small gap
reach 20 x 20 metres. widths can be achieved, and af-
terwards most modern weld-
Authors: Ralf Möller, (Schuler Held La-
sertechnik GmbH & Co. KG, Dietzen- ing technologies such as laser-
bach), Marc Decker and Ulrich Weber
(Graebener Maschinentechnik GmbH &
TPW®
Laser 2 on blue portal in main plate-panel-line Photo: Schuler Held  Registered by GRAEBENER
Co. KG; Netphen-Werthenbach)
HANSA  Sonderdruck
2
SHIPBUILDING
Production
ters are used for the edge preparation.
For the milling process the plates are hy-
draulically clamped onto the support ta-
bles over the total milling length. By means
of this, a possible waviness of the plates
can be compensated. Furthermore, the
tension has a positive effect on the milling
result and the life of the cutting tools. High
precision guiding systems of the plate edge
milling machines as well as the possibili-
ty to simultaneously process the plate
edges to be joined ensure the compliance
with the small form and gap tolerance for
the laser-hybrid-welding. The arrangement
of the milling tips in the cutter guarantees
a processing almost free of burst.
In order to reduce the production times
and the adherence to small tolerances, the
plates in the same clamping are milled at
first and than joined until to the necessary
View into milling-drain of milling-portal; right
gap distance are reached. Last, they are
and left hydraulic plate clamping devices; laser-
welded by means of the laser-hybrid-
hybrid welding head in background
Laser-hybrid-welding head with MIG torch
process. For this purpose, the machine
Photo: Schuler Held
cleaning station Photos: Schuler Held
bed of the plate edge-milling machine can
or laser-hybrid-welding can be applied. be moved back and forth and the welding
" The creation of various seam types equipment is integrated into the plate combinations by welding. The machine
(I,Y,V,U, etc.) can be achieved without edge-milling machine. concept of the plate edge milling machines
problems. The requirement of a TWP® process is allows a segmental adjustment of the plate
" No heat is transmitted into the compo- to provide the possibility to join different supporting tables in height. Therefore the
nent during the milling process. Due to individual plates in various variations and plates can be clamped by means of indi-
this fact there are no tensions inside the vidual hydraulic clamping elements. The
component. production sequence is as follows: First
" After the milling process the compo- individual plates are joined to a plate strip
nents show a clean and metallic surface. at the cross edges, then the plate strips are
" The edge preparation by means of milling welded to panels respectively plate fields.
can also be applied for thicker plates.
Equipment
" In contrast to the traditional processes
chips produced during the milling process At the heart of the system are welding
can be recycled without any problem. machines from Schuler Held Lasertech-
" Milling is a non-polluting process. There nik, two butt-joint welding machines for
is no toxic gas or hazardous dust. Ven- the production of panels in connection
tilation units as used for the tradition- with two plate milling systems from
al processes are not necessary. Graebener Maschinentechnik. The first
Plate preparation by milling meets the re- butt-joint welder joins individual plates to
quirements which are related directly to stripes, which will be welded to panels in
the laser-hybrid-welding such as high pre- the second butt joint welder. Here for the
cision and reproducible plate edge prepa- first time anywhere butt-welded seams are
ration according to the given edge type as applied continuously over a length of 20 m.
Full penetration in stiffener weld seam
well as a processing almost free of burst. Indeed, the machines used for this pur-
Milling also meets the requirements pose are the most ambitious systems that
which are related to the TWP® process. Schuler Held Lasertechnik and Graeben-
Here, different dimensions of the indi- er Maschinentechnik have ever built.
vidual plates as well as individual varia- The Graebener Maschinentechnik
tion and combination possibilities, when milling system, with integrated clamping
joining the plates to a panel or plate field, device, does the edge preparation of the
have to be considered. Especially when weld seam. While the plates are clamped
joining plates of different thickness cor- the welding is performed directly after
responding transitions between the indi- milling operation is done. The welding
vidual plates have to be provided. process itself uses an RF-excited C02-laser
Furthermore, the reductions of the man- with a peak output of 12 kW and a MIG
ufacturing and cycle times as well as an welding current source of 450 A.
economic manufacturing process are re- A major influence on the quality of the
quirements, which have to be met by the weld is how accurately the distance be-
process applied for the plate preparation. tween the laser focus and the MIG current
Edge milling is used above all because of head can be maintained relative to the weld
the high precision edge preparation and seam root and how well the parameters of
the high advance speeds, which can be the laser and the MIG processes are coor-
achieved. Correspondingly designed cut- Butt and fillet joint dinated. These welding parameters are es-
HANSA  Sonderdruck
3
SHIPBUILDING
Production
tablished in a comprehensive series of tests and one small), fillet joint welding unit,
and stored in the machine s control system plate handling und plasma cutting unit
in the form of a technology database. for a total price of approx. 9,200,000 E1).
The butt joint welder uses a light sec- If the steel works per ship are calculated
tion sensor to trace the weld line. This with 350 kh and if the hourly rate is 65 E/h
sensor registers any horizontal weld de- the result would be costs of 22,750,000 E.
viation or tramping. The axes of the MIG This calculation is based on an estimated
and laser head are subsequently adjusted, inaccuracy outlay of 20 %, i.e. that this
in accordance with the sensor signal. De- would be costs of the amount of 4,550,000 E.
pending on the size of the deviation, the When using a TWP® line 50 % of this costs
technology parameter records are modi- could be saved, here 2,275,000 E.
fied to comply with the programmed func- Graebener plate milling machine In this case the TWP® line in contrast
tions of this deviation. Overall a central to the conventional line has paid out after
monitoring station on which all status in- one ship (9,200,000 E + 2,275,000 E =
formation for the individual machines can 11,475,000 E > 11,300,000 E). Expenses for
be displayed performs control and moni- the air ventilation, cleaning of the work
toring of the manufacturing line. surroundings, etc. which occur due to the
application of grinding, flame cutting, sub-
Summary
merged arc welding, etc. have not been
By means of combining plate edge taken into account yet.
preparation by milling and laser welding, Additional advantages are better and safer
shipbuilding can achieve an unprece- working conditions for the staff since many
dented manufacturing accuracy and at the tasks can be avoided due to the fact that
same time save costs. In order to give a only few adjustment works are necessary.
first hint about the investment and the These are additional reasons for the appli-
cost situation the following example can cation of a TWP® line.
be consulted: Just as it happened some years ago in
" TWP® line consisting of: 3 laser sources the automotive industry, this technology
with 12 kW each, 3 laser machines of tailor welded plates will make its way
(2 butt joint welders; one 4 m wide and to the manufacturers. By means of this
one 20 m wide as well as one fillet joint technology, ships can be especially de-
welder 20 m), two plate edge milling signed for their respective application and
machines, plate handling and plasma therefore result in a cost reduction for the
cutting system for a total price of ap- shipbuilder as well as for the ship operat-
prox. 11,300,000 E. ing company. ß
" Conventional line consisting of: Sub-
1) This line must be calculated twice in order to achieve
merged arc welding units (2, one large
Milling head the same output as a TWP® line.
GRAEBENER Maschinentechnik GmbH & Co. KG
Am Heller 1 · 57250 Netphen-Werthenbach
Tel. [phone] · Fax [phone]
www.graebener-group.com
Schuler Held Lasertechnik GmbH & Co. KG
Assar-Gabrielsson-Str. 3 5 · 63128 Dietzenbach
Tel. [phone] · Fax [phone]
www.schulergroup.com
HANSA  Sonderdruck
4