subcon scene focus
WITHIN the automotive industry, lasers
are becoming the preferred method for
cutting and trimming interior trim
components such as door panels. However,
there have always been limitations, and whilst
lasers are used on interior components and
also on BIW applications, use on finished
surfaces has been restricted due to the
potential for marking or damage to the
surface finish and cut edge from the heat
generated.
Conventional laser cutting removes the
molten material from the cutting path in one
pass. With heat sensitive or non-homogeneous
materials, high heat input can lead to
problems of the edge melting and the creation
of burrs. These problems are eliminated by the
StarDisc Laser, broadening the application
range of the laser. The operation of the
StarDisc is greatly enhanced by the use of a
Galvo Deflection Head, which ensures rapid
and precise beam positioning in two
dimensions. The material is ablated at speed
using multiple passes, with very high peak
laser power, achieving rapid material removal
rates. The StarDisc laser does not normally
require assist gas and the multiple pass process
provides efficient material removal, which is
expelled upwards with minimal melt creation.
As a result, it can be used to process a wide
range of materials across applications
previously considered unsuitable for laser
cutting.
One new application is the customising of
Style-sensitive marking
Technology development makes new laser cutting and drilling applications
possible, with special significance for the automotive sector.
Rapid removal
- of metal and heat
car, van or truck bodies by laser after final
painting and lacquering. Many vehicles have
numerous optional accessories, and whilst
most are easily fitted during the vehicle build
process some, eg additional aerials or body
styling kits and spoilers, are fitted when the
vehicle is fully painted and lacquered. When
the StarDisc laser is applied to painted and
lacquered panels, a cutting speed of
approximately 2.0mm/second is achieved on a
typical material thickness of 0.68mm. The
result is a clean cut, with no damage to the
painted surface, and no dross or debris on the
inside of the panel which has been cut. The
cut component does not fall inside the panel,
but remains attached to the parent material,
ready for removal using a vacuum or
magnetic gripper.
These benefits should enable the StarDisc to
be used on a wide range of thin sheet metal
cutting applications not only within the
automotive industry, but also in applications
such as the production of electronic
enclosures where metal particles within the
panel are unacceptable.
WHEN leading loudspeaker manufacturer KEF Audio created its 7-foot tall, top of the range, Muon speakers it needed
a way of marking them which was true to the original design concept. The shape of the super-formed polished
aluminium cabinets had been styled by leading industrial designer Ross Lovegrove and the purity of the shape could
not be compromised - and at £70k a pair, nothing as mundane as an adhesive label could be considered. Only laser
marking of the actual aluminium case would fulfil the requirements of brand, designer and owners.
The problem was finding a company that could accommodate such large objects. Most laser marking is used on
small components and so the laser machines have a very small working area. KEF found Surrey-based Fimark,
prominent in the subcontract laser marking sector and using their own laser benches which can accommodate a wide
variety of component shapes and sizes.
The KEF loudspeakers are only one of a range of large components including carbon fibre dashboard panels and
engine covers, lift panels, graduated tubes, oil industry test equipment and large aluminium sample cases that Fimark
has laser marked, alongside the smaller components that are normally associated with laser marking. With a 600 by
300mm X/Y table, rotary axes and lenses up to 330mm diameter working area, Fimark can process larger components
than would normally be laser marked. Larger lenses provide an increased field of focus able to tackle curved and
irregular surfaces such as the KEF speakers. www.fimark.co.uk
98 MWP november 2007
Laser specification and background
StarDisc is a Q-switched disc laser and
provides material removal rates which are
unrivalled by any other laser source. This is
achieved by high average power, excellent
beam quality, (TEM00 - Gaussian Mode),
and an unusually long Q-switch pulse
length.
The performance capability of the StarDisc
can be illustrated by making a comparison of
this laser with another Rofin Laser -
PowerLine E-20. Both are Single Mode/
TEM00/Gaussian lasers, with Average and
Peak power levels as follows :-
Average Peak
Power Power
StarDisc 60W 2kW (Approx)
PowerLine E-20 18W 250kW (Approx)
If average power levels are considered, one
might expect the StarDisc to outperform the
PowerLine Laser, as the StarDisc has the
higher average power level. This assumption
is then reversed if the peak power levels are
considered, with the PowerLine laser having
a much greater peak power level than the
StarDisc Laser. However it is the
combination of the high average power,
together with the unusually long pulse
duration, which enables the StarDisc Laser
to achieve ablation rates which are an order
of magnitude greater than other Q-switched
lasers of a similar power.
www.rofin-baasel.co.uk
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