WCA May 2010

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Improved housekeeping = Increased productivity Stuart Duff and Mike Philips offer extracts from their presentation to the Istanbul Cable & Wire 2009 conference, “New Technology for Global Markets” held in November 2009, organised by the IWMA, WAI, ACIMAF and CET.

Emulsion performance Throughout emulsion life the factory should monitor and record production data and keep records of the emulsion condition monitoring and maintenance. The consumption rate of emulsion can be measured and then used as a benchmark target. Data of tonnage drawn, top up rates, wire break analysis and emulsion analysis should be recorded and monitored. Typically the consumption rate of an ideal process should be 0.1 to 0.25 litres of emulsion per tonne of copper wire drawn. The litre per tonne value is dependent on emulsion chemistry and working practice of the factory, and every system will have its own figure. Emulsion disposal The cost of disposal will continue to rise so the disposal of the emulsion is as important as the product selection. All emulsions should be disposed of in accordance with local legislation in any country. Before any disposal process is adopted, every factory should evaluate its waste products and consider the likely toxic metals that may have accumulated. One example of copper wire drawing emulsion disposal is by separating the oil and water parts of the emulsion by passing it through a membrane filter; this technique is known to reduce emulsion disposal costs by 80% to 90% hence providing significant cost savings as emulsion disposal costs are based on Volume of Emulsion and Chemical Oxygen Demand values (COD). This separation technique, known as Ultrafiltration, is widely used in other metal working sectors. The oil layer, of typically 10-20%, can be disposed of through a waste oil contractor and the remaining water permeate layer is further processed through a reverse osmosis system to reduce the dissolved copper level. The resulting water is clean and pure, and can be disposed of safely in accordance with local legislation or reused in the factory for emulsion make up or treatment systems. Kuwait Petroleum International Lubricants – UK Website : www.q8oils.com

will harm the concentrate. The ideal storage position is to place the drums on their side with bungs at the quarter to three position. Mixing The emulsion mixing process can also affect the long-term stability and lifespan of the wire drawing emulsion so it is vital to always add the concentrate to water rather than the other way around to avoid instability. The use of mixing units is recommended and especially the positive displacement mixing units which will inject the concentrate into the water. Water The water quality used for make up is important for the life and long-term stability of the wire drawing emulsion. The water should be medium hardness for emulsion make up and low hardness for emulsion top up. It is also beneficial in certain applications to use demineralised water but the use of salt softened water is not recommended. Machine cleaning Cleaning and preparing machines prior to emulsion fill is important for removal of debris, fines and deposits in used systems and also for removal of anti-corrosives in new machines as these can promote initial emulsion foaming. Maintenance It is important to protect wire- drawing emulsions from biological contamination: Keep the drawing emulsion • above minimum recommended concentrations and use a refractometer to record the concentration Sterilise and clean the system • before introducing a fresh emulsion Avoid emulsion make up using • contaminated water Never discard waste into the • emulsion Minimise metal fines by effective • filtration Maintain temperature between • 35ºC and 45ºC Avoid tramp oil contamination • Simple measures, together with emulsion general condition monitoring, can increase emulsion life, save costs and improve the working environment of the drawing machine resulting in cleaner drawing dies and longer die life, and increased speed and machine output.

To increase the productivity of a copper wire drawing emulsion several points need to be considered: Drawing lubricant technology • Housekeeping of the emulsion • system Performance of the drawing • emulsion Evaluation of disposal techniques • and cost Drawing lubricant technology It is important to understand the technology in the product. The operator who understands the physical and chemical properties, will better manage the emulsions and appreciate why precautions should be observed and procedures followed. Copper wire drawing lubricants are highly specified soluble oils designed for mixing into water at concentrations from 2% to 15% dependent on the specific application. A soluble oil concentrate for wire drawing will typically contain the following chemical additives: Mineral oil (oxidation stable pure • base oil) Emulsifiers • Surfactant detergency additives • Surfactant coupling agents • Corrosion inhibitors • Lubricity additives • Extreme pressure performance • additives Bactericides, biocides and fungi- • cides Antifoams • Water • Wire drawing lubricants provide both boundary and hydrodynamic lubrication. Boundary lubrication is a thin film used at slow speeds at the wire/die interface and the wire/ capstan interface. Hydrodynamic lubrication is thin film lubrication used at high speeds at the wire/die interface. Wire drawing lubricants can be conventional, semi-synthetic or fully synthetic. The most common type of wire drawing lubricant for copper is semi-synthetic, where oil lubrication droplets of around 0.8 to 1 micron in diameter are suspended in water. They have a simultaneous lubricating and cleaning action. Housekeeping of the emulsion Storage All soluble oil concentrates should be stored indoors and protected from extremes of temperatures of frost and direct sunlight. The drums should be stored to avoid water ingress, as this

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Wire & Cable ASIA – May/June 2010