EoW November 2013

Technical article

Traditional Tinning

PlasmaPREPLATE

Multi-line tinning process with wet chemical surface preparation

Single line high-speed tinning, Dry surface treatment without fluxing

Process type

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

High – wet processes difficult to control operator experience and skills are key

Low Inline PLC-based quality control

Scrap rate

Solder wastage

High – flux contamination in tin bath

Low – flux-free production

Limited PLC with manual assistance – complex multi-line production/line-to-line reference

Fully PLC controlled production – inline PLC quality control and alarm system

Production control

Capital investment

Low

High

Production line footprint

Large

Compact

▲ ▲ Table 1 : Typical production parameters for traditional PlasmaPREPLATE tinning in PV ribbon production

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 use of wet processes adds to the number of production parameters that must be closely controlled. precision products with tight tolerances such as Production of expensive,

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.

▼ ▼ Figure 5 : PlasmaPREPLATE tinning line for PV ribbon production

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November 2013