EoW November 2013

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Technical article
November 2013 59
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.
Traditional Tinning PlasmaPREPLATE
Process type Multi-line tinning process
with wet chemical surface preparation
Single line high-speed tinning,
Dry surface treatment without fluxing
Production speed 5-60m/min, subject to ribbon softness 150m/min – super soft ribbon
No of lines/output 4-25, subject to quality, ribbon softness 1 – super soft high-quality ribbon
Annealing type furnace/resistive/induction (off-line) Plasma (inline with tinning)
Surface preparation
for tinning
Acid, rinsing, fluxing prior to tinning
Expensive and harmful to operator
Dry, chemical-free plasma treatment
Low cost and operator friendly
Production cost High – labour, chemicals, energy Low
Production continuity More frequent changeover – 50kg spools Less changing over – 500kg spools
Scrap rate High – wet processes difficult to control
operator experience and skills are key
Low
Inline PLC-based quality control
Solder wastage High – flux contamination in tin bath Low – flux-free production
Production control Limited PLC with manual assistance – complex
multi-line production/line-to-line reference
Fully PLC controlled production – inline
PLC quality control and alarm system
Capital investment Low High
Production line footprint Large Compact
▲ ▲ Table 1: Typical production parameters for traditional PlasmaPREPLATE tinning in PV ribbon production
▼ ▼ Figure 5: PlasmaPREPLATE tinning line for PV ribbon production