How to measure productivity in copper wiredrawing – Part 3
Supplier technical support
A wiredrawing factory should choose a lubricant supplier that can provide the correct and required technical support to enhance the process and assist the customer in times of change, such as when experience leaves the industry, which is particularly important in the current economic situation. A supplier should be able to train, educate and help new staff in procedures and emulsion maintenance practices to comply with quality, health and safety requirements, and serve as a partner and be able to answer all questions with technical credibility. See Fig. 8.
Technical support has to be more than condition monitoring analysis. It should include:
- product selection
- emulsion preparation and water quality advice
- comprehensive emulsion condition monitoring
- emulsion lubrication, evaluation and advice
- health and safety advice
- emulsion disposal advice
- system design and filtration recommendations
- equipment recommendations
- technical help lines
- local stock, expertise and support
Much has been written about methods for emulsion disposal. As disposal costs will inevitably continue to rise, this aspect is as important as the product selection. All emulsions should be disposed of in accordance and with advice from the local legislation in any country. Before any disposal process is adopted, every factory should evaluate their waste products and consider the likely toxic metals that may have accumulated.
Disposal costs are based on emulsion volumes and Chemical Oxygen Demand (COD) values. One method for copper wiredrawing emulsion disposal, ultrafiltration, separates the oil and water parts of the emulsion, a technique that can reduce emulsion disposal costs by as much as 80 to 90%, providing significant cost savings. With ultrafiltration, which is widely used in other metal manufacturing companies, the emulsion is passed through a membrane filter that separates the oil and water layers. See Fig. 9. The oil layer, typically 10-20%, can be disposed of through a waste oil contractor. The remaining water permeate layer is further processed through a reverse osmosis system to reduce the dissolved copper level to a very low level. See Fig. 10. The end result of the process is clean water that can be disposed of safely in accordance with the local legislation or reused in the factory for emulsion make up-or treatment systems. The cost savings are substantial, as much as an 80-90% reduction.
Fig. 11 shows the potential reduction results for different techniques. The data in Fig. 11 show the condition of Germ-Allcard Priamus X7 emulsion that is 24 months old and has had no filtration and exposure to bacteria and tramp oil. The emulsion has a high conductivity, high chemical oxygen demand and high copper content. For copper wiredrawing factories, copper is the key “toxic” metal which is the costly part of the disposal, and the further elements in yellow show the classic “toxic six” (copper, chromium, cadmium, nickel, lead and zinc) where the sum of the parts per million for all six metals should not be above 10 ppm. Local conditions and specifications may apply so do check with your local legislative authority.
The Ultrafiltration water permeate is shown where the copper content is reduced from 1594 ppm to 93 ppm, and with further reverse osmosis the water permeate is reduced to 0.28 ppm, which is a trace level. The processed water is suitable for re-use for emulsion make-up, saving metered costs of water or normal disposal. Note: all emulsion systems at the end of their life will vary in the elements present, but it is fair to comment that with rising disposal costs the payback time for disposal equipment technology can normally be measured in less than two years. Overall, reducing disposal costs by up to 80-90% is also dependent on emulsion disposal volumes.
This series of articles discussed how productivity cost savings can be achieved specifically with care, attention and maintenance of wiredrawing emulsions. Some techniques are common sense, some are simple advice to improve the operating conditions of the wiredrawing emulsion and some are more complex, but all have a contributing factor to reduce the cost of the process and increase productivity. Many techniques and much experience has been lost from the industry through factory personnel changes, and the need for the supplier to support their customers and highlight cost saving options is ever more important. A wiredrawing lubricant may be the smallest cost item in the process but it remains one of the most influential. Think productivity: how do you measure it? Are your procedures correct, and is your machine and copper wire drawing emulsion running to its maximum output? We hope this information promotes the thought in your mind.