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Reel-to-reel
plating process |
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Introduction
Reel-to-reel
technology
Particular
features of implementation of reel-to-reel technology
Applications
in the SOFIPEM Group |
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 Introduction
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Continuous surface treatments, which are also referred to as reel-to-reel
treatments, are in general use in most industrial sectors.
Electrical construction, connectors and associated hardware, and
electronics are fields that lend themselves to this method of metal
plating, due to the undeniable productivity savings procured.
The constraints of automated assembly of multiple electrical and
electronic components find excellent solutions wherever manufactured
products are employed and then coated in "strips" of various lengths.
Most of the treatments employed in such applications are electrolytic
coatings. |
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Reel-to-reel
technology:
The surface treatment of these products can be accomplished at two
stages of their manufacture:
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 on
the full strip used as a basis for stamping; |
| on
the pre-stamped or assembled strip. |
In both cases,
the lengths employed require that these products be packaged in
wafers (or rolls) in the first case, and reels in the second case.
Treatments are applied in special installations (production lines
or machines), consisting of a range of successive installations
through which the strip passes. The illustration below shows a standard
configuration for this type of installation, of which the main subsystems
are:
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unreeling
and rolling mechanisms; |
| chemical
or electrochemical treatment units or vats connected to electrolysis
current generators; |
| rinsing
vats; |
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systems
for feeding the strip with electric current (rotating contacts;
brushes; etc); |
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spinning
and drying systems. |
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The length of such an installation (illustrated above) is generally
between 20 and 80 metres. The strip is pulled through it at a speed
varying from 1 to 10 m per minute in the case of pre-stamped strips,
and from 5 to 100 m per minute in the case of solid strips. The
length of the vats or cells (immersed length, electrolysis length
or "active" length) varies from a few centimetres to a few metres.
The treatment duration at each station in the range is therefore
short as a general rule. Therefore, the installations and the operating
conditions applied are chosen for maximum effectiveness. The design
of the vats and the composition of the electrolyses are, in particular,
chosen in order to obtain adequate current densities (which are
obviously maintained subsequently throughout the duration of the
process). Obviously, it is the "slowest" station that establishes
the progress speed. After this, the thickness of the deposits is
directly dependent on the duration of electrolysis and is an inverse
function of the speed (which is another way of expressing the electrolysis
duration). Such installations can treat several strips of the same
or different dimensions simultaneously. |
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Particular
features of implementation of reel-to-reel technology:
These installations have to be excellently suited both to the treatment
and the product to be treated. Many of them are designed on a modular
basis in order to cater to the wide range of treatments. The quality
of the mechanisms used is essential for compliance with the dimensional
characteristics. This means that it is extremely rare that the processes
adopted for these production lines are unable to reproduce the results
obtained with other surface treatment technologies: deposition of
gold, silver, tin, tin/lead, palladium, etc, on a nickel or copper
base, on conventional substrates such as copper, brass, bronze,
cupro-beryllium, ferro-nickel and other less-conventional substrates
such as aluminium and its alloys; or even electrolytic plating of
oxides or superficial compounds, such as alumina on aluminium and
its alloys (for its insulating properties), or alumina and phosphates
on these same substrates (in order to endow them with an excellent
aptitude for bonding), or oxides on any substrates (in order to
instil them with precious surface properties). In reality, quite
the opposite is true: the additional possibilities offered by these
techniques are the criterion adopted by manufacturers for the design
of their products.
These advantages include:
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the
very low dispersal of the characteristics of the deposit from
one part to another; |
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possibility of locating treatments on previously-determined
areas ("selective" deposits) using, it is true, techniques
of varying ranges of sophistication. |
However, it
is essential that users wanting to employ this technology take account
of the constraints that it imposes:
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a
well-documented approach to the envisaged implementation.
Technical support from a well-equipped company employing the
said technology is strongly recommended; without it, the best
solution and therefore the most cost-effective may well be
overlooked. |
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quantity (length) of product employed should be, at least
and depending on the processes employed, from a few dozen
to a few hundred metres. The part for "engagement" in the
machine and "disengagement" (the length depends on the machine)
for the stabilisation of the process parameters are unusable.
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type of consideration and, very often, the complete suitability
of a machine for the product and the corresponding process
inevitably mean that only large quantities (production run,
rate or batch) are cost-effective. |
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Applications
in the SOFIPEM Group:
The SOFIPEM group has 24 reel-to-reel treatment lines (PEM: 15 lines;
ALOXEL: 9 lines).
Some of these lines are equipped for localised -- or so-called "selective"
-- treatment.
PEM has 8 of these lines, while ALOXEL has 4.
Different techniques are used for selective deposits:
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taping;
"tracks" (longitudinal locations) made by prior application
of adhesive tapes to the areas to be masked against the treatment; |
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mechanical
masking "on unrolled" product, incorporated within the treatment
line. This type of tooling allows one to obtain tracks or
spots (intermittent treatment). In the latter case, the tooling
is specific to the configuration of the deposit and the part
to be treated (existence of guidance holes in particular). |
The locating
precision is between +/- 0.5 and +/- 0.05 mm, depending on the technique
applied. This range of installations is capable of catering to an
extremely varied slate of needs:
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reels
from a few kilograms to rolls of 2.5 tonnes; |
| products
ranging from extremely fragile (a few tenths of a square millimetre
in cross section) to the most robust (around 1000 square millimetre
of cross section); |
| widths
ranging from a few millimetres to 300 mm; |
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most diverse products, varying from wire to flexible or rigid
sections or bars, to flat bars, laminates or profiled strips
(shaped strips). |
If, despite the
wide choice of products that can be handled, the necessary facilities
are not available, the engineering departments of the SOFIPEM group
(the source of the facilities in question) will be called on to
devise the most suitable solution with the client. ALOXEL and PEM
have access to the necessary inspection and testing facilities needed
to rise to the strictest quality requirements. These facilities
concern process control (electrolytic parameters, kinematics parameters,
geometric parameters, etc) and the characteristics of coatings. |
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SOFIPEM,
Siaugues St Romain 43300 SIAUGUES STE MARIE - FRANCE
Tel: +33 (0)4.71.74.29.27 - Fax: +33 (0)4.71.74.26.57
- Email : contact@sofipem.com
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