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PC: Oemeta Chemische Werke GmbH

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COOLANTS & LUBRICANTS Five overlooked TCO aspects of metalworking fluids

Oct 16, 2020

Oemeta Chemische Werke GmbH develops, produces and deliveres high-quality lubricants for processing metal, glass and ceramics. From being profitable to bringing in high efficacy, manufacturing companies see to it that the coolants they use are properly efficient and lead to top productivity. From its role in waste treatment to sustainability, the article discusses some lesser considered topics concerning metalworking fluids that nevertheless prove to strongly impact a machine shop’s overall costs. - Walied Henschel, Senior Application Technologist, Oemeta Chemische Werke GmbH

With various coolant suppliers and product philosophies, the market for metalworking fluids is buzzing. Plenty of choices are offered. Coolants might or might not contain boron, biocides, mineral oil, ester oil, formaldehyde releasers or chlorinated paraffins. While all must comply with the Globally Harmonized System of Classification and Labelling of Chemicals (GHS), some don’t. Others would even offer approval of machine manufacturers or OEMs. Ultimately, each coolant will provide a unique set of advantages as well as disadvantages.

Understanding the differences in coolants and being able to choose their properties, depending on the according machining process, proves to be a bold venture. Hence, most commonly, the coolant’s price per kg remains the single important factor for decision making. Anyhow, widening the scope for coolant selection often results in significant overall cost reduction. For purchasers, a trustworthy supplier offering, reliable advice and support is crucial.

Cooling lubricants are complex

Cooling lubricants are complex mixtures of up to 30 ingredients. These ingredients might be mixtures themselves. Typical water miscible metal working fluids include base oils, emulsifiers, lubrication performance improving additives, corrosion inhibitors, flushing agents and defoamers. Each substance provides advantageous and disadvantageous properties at the same time. Tensides, for example, act as emulsifiers and improve the coolant’s wetting and flushing characteristics. Unfortunately, tensides form foam bubbles. This effect is negated by anti-foaming agents. However, those are lost via filtration due to their molecule size. Adjusting one property will tip off another, hence, hampering the balance of the coolant. A truly ideal, universal coolant cannot exist. Thus, understanding the machining process as well as the production plant’s characteristic demands is crucial for coolant choice.

Co-operation with a manufacturer on a partner level is worthwhile

Picking and maintaining the appropriate metalworking fluid requires knowledge in metallurgy, machining, process engineering and chemistry. Ideally, experts of all fields meet to understand which of the plant’s requirements are to be prioritised highest. Often, coolant manufacturers advise as early as in the planning phase of a new plant.

Taking the time to think about the diversity of metal working fluids, apparently impacting the overall process in various ways reveals the careful consideration required. A wrong coolant choice could increase the unnecessary consumption of additives or even impair the machining process. The cooling lubricant influences the processing parameters, such as cutting parameters and material removal rates which have a direct relation to a plant’s productivity. However, at this point, things get a bit more complex and many consumers are happy to push forward blindly. Therefore, having a supplier who acts as a partner becomes even more important.

Various machining problems can be solved on the long run by joint forces of coolant suppliers and customers machining experts, as striving for the best performance requires a comprehensive understanding of the whole process. Optimisation of the processing parameters bears higher rewards compared to small occasional savings on coolant per kg prices.

Waste treatment

Waste treatment always accounts for a fair share of overall costs. Understanding the coolant’s impact on those spending is worthwhile.

Regulations as well as costs of waste treatment will differ, depending on the respective country and even state. However, the waste’s composition usually impacts the treatment costs the most. Certain substances are not easily recycled or combusted, especially if environmental protective measures are in place. Especially heavy metals, dangerous substances and mineral oil require a high level of processing as well as care whilst transportation. Any reduction of those waste’s quantities will result in plain savings on the economic side.

Three mechanisms reducing disposal costs will be elaborated on –

  1. Reducing the total quantity of waste is the best practice and often required by law. Unfortunately, there is a limit on that front. However, separating different classes of waste and even reducing the quantity of costly substance classes is an effective way to achieve precious savings. Choosing coolants incorporating no harmful substances or mineral oil will often effectively reduce the overall disposal costs.

  2. A coolant with a low consumption and drag out rate will not only result in clean machines but lower overall quantities of waste.

  3. Multifunctional coolants enable a further reduction of waste. Filling the same oil in the hydraulics, using it to prepare the metalworking fluid and to lubricate the slideway avoids cross contamination and reduces required top up rates of coolants.

Health and safety

Being most likely one of the least quantifiable aspects, the employees’ health and safety remains remarkably hard to pin down economically. Nevertheless, its impact on productivity should not be denied. Ultimately, each plant’s success can be described via the amount and value of parts produced as well as the total costs per part.

Coolants are technical fluids composed of various chemicals, their foremost purpose being the increase of surface and dimensional quality as well as the reduction of machining cycle times. Anyhow, a capable coolant manufacturer keeps the workers’ safety in mind and refrains from the usage of harmful substances as much as possible. Workers falling sick will often not be immediately replaced with colleagues just as capable. Recovering measures are often expensive and tedious. As a result, machine downtimes and time consuming trainings for new colleagues are to be expected. In addition, manufactured part’s quality is likely to suffer, decreasing the parts value. As the workers union’s focus falls upon recurring cases of sickness, opposition arises and productivity becomes impaired.

Even though all local governmental regulations are fulfiled, a close examination of this aspect is likely to prove beneficial. With the economy being globally intertwined and health & safety and as well as environmental sustainability concerns rising, a clear demand for suppliers’ compliance, with all sorts of global regulations, is observed. One of the mechanisms in place to ensure human and environmental health & safety is the European regulation of Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH). Ensuring one’s chemicals compliance with REACH is a significant step towards a smoothly running plant.

Sustainability aspect

Not only health and safety of humans but also the state of the environment is economically important. As workers might seem replaceable to some economists, a point that we strongly disagree on, the environment undoubtedly supports each plant with the required resources for a sustainable economy. Whereas, some resources should be kept unharmed in order to sustain a business in the long run, others should be used as little as possible. Saving resources almost always saves money. Especially consumables, such as energy, water and raw materials – including metals or chemicals – which are acquired at high costs and used in large quantities. As obvious as the impact of the reduction of these resources is, as unnoticed is the effect of less obvious resources, such as cleanliness or waste. Waste is usually gathered in containers, tanks or piles, until getting disposed by waste treatment facilities. The costs are usually significant.

Cleanliness, on the other hand, is only achieved by removing various forms of waste from e.g. the machine, the workplace or the plant in general. Not only does cleanliness affect the well-being of the workers but also the performance of the plants’ processes significantly and the quality of the produced goods. Cleaning itself is an expensive process and different coolants generate significantly differing amounts of pollution. This ranges from coolants containing extremely high mineral oil contents with ineffective tensides to coolants with low or no mineral oil & extremely effective tensides, causing a washing effect themselves.

We believe that state-of-the-art coolants with a low impact on the environment are supporting plants all over the world with a sustainable performance. The same process can be ensured with the same quality, today and in the future.

Image Gallery

  • (Clockwise) total cost efficiency, lifecycle assessment, process optimisation, & occupational safety

    PC: Oemeta Chemische Werke GmbH

  • The environment undoubtedly supports each plant with the required resources for a sustainable economy

    PC: Oemeta Chemische Werke GmbH

  • Walied Henschel

    Senior Application Technologist

    Oemeta Chemische Werke GmbH

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