While highly useful in many different industrial processes, neat oil can be a challenging substance to handle. The fact that it is a fire hazard is widely known, but the general awareness surrounding its aerosol emissions is generally much lower.
What are neat oils, and how are they used?
Neat oils (also known as neat cutting oils or straight oils) are water-undiluted mineral or vegetable oils blended with certain additives in order to generate certain beneficial properties. Their excellent lubrication and cooling properties make them particularly useful for reducing frictional heat, for example when a machine tool is processing a workpiece. This, in turn, contributes to giving the workpiece an appropriate surface finish, and helps prolong the life of the machine tool as well. As such, there are numerous industrial processes where neat oils are applied, ranging from light machining to heavy-duty operations. Among the more common applications are broaching, cutting, drilling, grinding, hardening, honing, milling and rolling (hot and cold).
Neat oil smoke can cause damage to both humans and equipment
As the neat oil is heated up from the friction, an aerosol known as oil smoke is formed. Increased production intensity, with a high oil pressure, leads to more aerosols being released. As the oil does not contain any water, the oil smoke emitted from it poses a potential fire hazard. If the temperature inside the machining process becomes too high, or if it starts generating sparks, the aerosols may cause a fire in the machine, or even an explosion (depending on the circumstances).
Oil smoke particles are smaller than one micrometer in size, which makes them difficult for most filters to collect. They affect both their physical surroundings – electronics, machinery, surfaces – and human health negatively. You can read more about this in our article on How FibreDrain technology streamlines oil mist and oil smoke filtration.
Special oils, MQL and sharp tools may help reduce oil smoke emissions
The greater the quantity of oil smoke, the greater the risk of an incident. Low viscosity oils tend to produce more and smaller droplets, compared to oils with a higher viscosity. Some oils are blended so as to release less smoke than the average neat oil, but these special variants are in turn more expensive.
A more economical way of reducing oil smoke is by reducing the volume of oil itself. This is made possible thanks to a method known as MQL – Minimum Quantity Lubrication. In the MQL process, very small amounts of high-quality lubricant are applied directly to the tool or workpiece, rather than flooding it with a gush of cooling neat oil.
Also, worn out machine tools cause more friction than sharp ones, leading to an increased risk of overheating. Blunt tools should thus be sharpened or replaced on a regular basis, for the sake of production efficiency, quality and safety.
Extracting the oil smoke from the machining process
Once the oil smoke is formed, it should ideally be removed as quickly as possible in order to reduce the risk of a fire or explosion. An efficient oil smoke/oil mist collector will capture the aerosols in a filter that, in turn, drains and collects the droplets. While there are many filters that are able to clean the air from oil mist, only a select few have the capability of draining the fine droplets of the oil collected, and thus provide years of additional filter life. In most cases, these collectors need to be able to run continuously, and they often require a certain degree of customization in order to comply with different customer needs, standards and equipment.
The importance of adequate extraction systems is often underestimated
Insufficient extraction systems are, regrettably, common among industry machinery, as manufacturers often underestimate the amount of oil smoke or oil mist emitted from their products. Generally speaking, the effectiveness of the extraction system is often much too weak. In addition to being completely leakproof, the dimensions and the speed of the ducting system must be designed so as to be able to handle the amount of smoke or mist being transported through it, or else the oil may accumulate in the duct.
Increased awareness, and use of MQL, bodes well for the future
As machining tools become able to perform tougher and more complex duties, they usually require both higher concentrations of neat oil and a higher neat oil pressure. This in turn leads to the release of more oil smoke particles, which obsolete filtration techniques and cheap collectors are not able to properly collect, posing risks to factories and the people who work in them. However, with the growing popularity of MQL, the amount of particles can probably be reduced, due to the method’s economical and highly local use of lubricant.
Awareness of the risks involved with neat oil usage, oil mist and oil smoke is something that differs widely between industries and, perhaps even more so, between countries. Fortunately, as new factories are built, modern filtration equipment keeps replacing older, insufficient systems, becoming a new industrial norm in the process. Neat oil applications, by their very nature, force companies to understand the risks involved with insufficient oil mist and oil smoke collection, and the necessity of a safe and reliable collector system.
Nederman’s Oil Mist Filter FibreDrain is an example of a product that has been developed specifically to handle the complex filtration and drainage challenges of neat oil applications and MQL applications (where both oil and solid particles are present), faced by so many industries. It is a complete oil mist collection system, effectively collecting the mist close to the source, draining it of its oil droplets, and preventing the risk of a fire or explosion.
Feel free to contact me at firstname.lastname@example.org if you wish to know more about FibreDrain, and how we can help you and your company ensure neat oil application safety. You can also read more about how to identify an oil mist problem, as well as plenty of other articles related to air filtration safety and solutions, here at the Nederman Knowledge Center.