A state-of-the-art, environmentally friendly tinning line has been installed and commissioned at a cost of more than R6-million to apply tin coatings to copper conductor manufactured at the Long Street, Johannesburg, factory of Powertech company Aberdare Cables.

The tinning line, designed and manufactured in Germany, uses special chemicals to electrolytically deposit up to five microns of tin onto copper conductor at a speed of 15m/sec, ensuring the tinned copper conductor meets SABS and IEC international electrical specifications.

"The tinning line is the first of its kind to operate in Africa," said Andre Smith, general manager of the Gauteng Manufacturing Operations of Aberdare Cables. "Applying a coating of tin on to copper conductor (wire) ensures good connectivity to accessories and the high efficiency of the line makes it more cost effective"

Smith added that a further benefit of the new tinning line would be significant improvements in environmentally friendly production. "A considerable portion of the waste is re-usable, ensuring that the amount of waste for disposal is much reduced. The plant itself is made out of polypropylene plastic which also has environmental benefits from the aspects of cleaning and maintenance."

The conductor to be tinned is first degreased and passes through several stages of rinsing. The water used for this is recycled. Tin is then electrolytically discharged onto the conductor (wire) from a feedstock of 8mm dia. copper rod, drawn directly from a rod breaker which reduces the size to required diameter. Following additional rinsing and cleaning cycles the tinned conductor passes through drying stations before exiting the machine.

Once the tinning process is complete the tinned conductor is down-coiled into one-ton packs before being transferred to the various manufacturing lines at Aberdare’s manufacturing operations for incorporation into a variety of cable types.

"This investment is improving the overall quality of our products," said Smith. "It has replaced older tinning lines that are becoming obsolete while at the same time increasing our capacity to meet demand ,ensure enhanced product quality and reduce environmental impacts."

The chemicals for the tinning line are supplied by Orlik Metal Chemicals, a Chemserve Group company specialising in galvanising, tinning and plating processes. Business unit manager Ryszard Orlik said the tinning line uses a new acid technology process developed in Germany by speciality chemical and material sciences company Enthone, a division of Cookson Electronics.

"The chemistry allows the line to run at very high speeds for deposits of 2-5 microns and at the same time the process ensures smooth, fine, crystalline and even deposits of tin. The tinning chemistry is known as the ‘Stannostar’ process. The line is self-dosing and adjusts itself to the amount of current drawn."

Orlik added that full in-house testing of the line and its chemistry was conducted and Aberdare operators were fully trained on the chemical and laboratory requirements, the running of the plant and its maintenance.

Aberdare Cables Technical manager at the Long Street plant, Wayne Munilall, said that the tinning of conductors assists in preventing corrosion, makes the cable more installation friendly and increase its durability.

Munilall added that tinning finds it application, amongst others, in cables for, earth continuity conductors (ECC), drain wires in Surface wiring cables, High temperature panel wires and certain flexible type conductors, etc.