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Wire & Cable ASIA – January/February 2014
Plasmait GmbH
Philipsstraße 27 / C3, 8403
Lebring
Austria
Tel: +43 3182 52 4751
Email:
Website :
The inter-metallic bond can be achieved only if the wire
surface is clean and appropriately activated. Acid cleaning
or pickling has traditionally been used to clean the wire
surface prior to surface activation, which is achieved
with fluxing. Fluxing is a dirty and environmentally
compromising process that can also be harmful to the
operators.
Figure 4 compares the process steps of the traditional hot
dip tinning to the process steps of the PlasmaPREPLATE
tinning.
PlasmaPREPLATE process anneals, cleans and activates
the surface of copper ribbon before it enters the tin bath
to allow tin adhesion without the need for fluxing. Flux-free
tinning accelerates the creation of intermetallic layer, which
in turn results in a considerably higher tinning speed when
compared to the tinning speed of the traditional process.
PlasmaPREPLATE process can be tuned to anneal the
copper ribbon to any required softness.
Complete recrystallisation with yield strengths down to
50MPa and small grain size can be achieved. Performing
annealing in-line with tinning reduces the amount of soft
material manipulation.
Less stress and mechanical deformation reduces the
potential for yield strength and camber build up on the
rolling line takeup and tinning line payoff. It is important
to recognise the need for precision handling and accurate
winding in case of super soft ribbon.
Precision transport system for handling of super soft
ribbon can be an expensive investment, which is required
on every tinning line. Faster tinning lines can therefore
reduce the capital investment in transport systems per unit
of production output.
The traditional tinning lines require acid cleaning,
rinsing and fluxing prior to tinning. These wet processes
are not only environmentally questionable, they are
also hazardous and unpleasant for the operator. Flux
contamination of tin bath leads to high cost of solder
waste. The use of wet processes adds to the number of
production parameters that must be closely controlled.
Production of expensive, precision products with tight
tolerances such as interconnect ribbon requires tight
control of the production conditions to avoid excessive
scrap rates. This is often difficult to achieve when wet
processes are involved. The differences between the two
processes can be divided into the differences related
to production efficiency and the differences in finished
product quality.
Despite higher capital investment, PlasmaPREPLATE
tinning process offers a number of benefits that translate
into considerable long-term savings:
• Production speed of up to 150m/min compared to 5m/
min-60m/min in a traditional process means fewer
tinning lines, smaller machinery footprint and less
manpower
• Process stability, increased production uptime and
less frequent spool changeovers means less material
manipulation and less operator involvement in
PlasmaPREPLATE tinning line
• Dry surface preparation with plasma replaces acid
cleaning, rinsing, drying, fluxing, waste disposal, and
water treatment used in the traditional process
• Less tin waste due to flux-free production
• Quick changeover between different products and
specifications
• Lower cost of production in terms of power, manpower,
cost of chemicals and their manipulation as well as
maintenance
• In-line quality control in the PlasmaPREPLATE tinning
process translates into consistent product quality, less
scrap and fewer returns
The key production parameters in the traditional
tinning are compared to the production parameters of
PlasmaPREPLATE tinning in Table 1.
In addition to production efficiency plasma process offers
a number of product quality advantages when compared
to the traditional tinning process:
• Superior and consistent product quality is reflected in:
• Super soft wire with yield strength down to 60 MPa on
spool and elongation over 30%
• Smooth consistent and shiny coating with tighter
thickness tolerance
• Dry, flux-free and chemical-free tinning simplifies
process control, which translates into more consistent
product quality
• In-line laser coating thickness measurement system
can be justified on a high-speed plasma line
• Computer enabled, in-line product quality control with
alarm and surface fault database simplifies quality
control activities
• Computer assisted Production Recipe Database
is an essential tool for the operator and product
manager and an integral part of production know-how
management
It is the stability of PlasmaPREPLATE process, consistency
of product quality, low cost of operation as well as low
scrap rates and tin waste that have won the confidence
of many PV ribbon manufacturers since 2007 when
PlasmaPREPLATE tinning process was first introduced to
PV ribbon production.