WCA January 2014

• 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.

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

Plasmait GmbH Philipsstraße 27 / C3, 8403 Lebring Austria Tel : +43 3182 52 4751 Email : info@plasmait.com Website : www.plasmait.com

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Wire & Cable ASIA – January/February 2014