Cutting fluids are a key lubricant in machining

The Importance of the Right Cutting Fluid

Selecting the right cutting fluid is extremely important. Large amounts of heat are generated during the metal machining phase due to friction. To counteract this, cutting fluid is needed as it is designed specifically to act as a lubricant and coolant during metal fabrication. It is added to remove friction between the tool and the workpiece while at the same time carrying heat that is generated away. The heat is removed extremely fast, keeping the temperature range within an acceptable limit meaning the operation can continue.

There are 4 main types of cutting fluid available today:

Straight OilsDrilling Machine in Factory Workshop

These oils are non-emulsifiable (emulsifiers are substances which cause the suspension of tiny oil droplets in water) and very beneficial in machining operations where they operate in an undiluted form. Their composition is of a base mineral or even petroleum oil and they will usually contain polar lubricants like vegetable oils, fats and esters. They may also have extreme pressure additives including sulphur, chlorine, and phosphorus. Straight oils are usually considered to have the best lubrication, but on the other hand, they may have poor cooling characteristics which will mean the tool and environment will heat quicker.


Synthetic Fluids

Synthetic fluids do not contain mineral oil base or petroleum. Rather, they are developed from alkaline organic and inorganic compounds. Additives are also added to prevent corrosion. They function well in their diluted form but of all the various types of cutting fluids, they offer the best cooling performance.


Soluble Oils

Most of the time, soluble Oils will form an emulsion after mixing them with water. The resulting composition contains emulsions and a base mineral oil which in turn creates a stable emulsion. They function well in their diluted form and offer great lubrication in addition to heat transfer performance. They are the lowest costing cutting oil and are the most widely used in the industry.


Semi-Synthetic Fluids

These fluids are basically a combination of soluble oils and synthetic fluids. The lubrication, cooling performance and cost of the semi-synthetic fluids fall between those of the soluble and synthetic fluids.


Functions of Cutting FluidLubrication and Cooling, the key functions of a cutting fluid

  1. Heat Removal: The key function of cutting fluid, they cool down both the tool and workpiece. This reduces thermal stress and expansion, increasing cutting accuracy.
  2. Lubrication: Cutting fluids also act as a lubricant, reducing the friction. This also reduced tool wear and increases longevity.
  3. Temperature Stability: The workpiece is kept at a constant, stable temperature reducing thermal distortion also improving cutting accuracy.
  4. Reduced Power Consumption: As the friction is reduced, cutting force is also reduced meaning that less power generation is required.
  5. Cost Savings: By applying cutting fluid, the time is taken, and the cost of production is reduced as the fluid allows for the maximum cutting speed to be used.
  6. Corrosion Resistance: Cutting fluids prevent the components from corroding.
  7. Chip breaking & Removal: As the tool creates chipping and breaks them into smaller pieces, the cutting fluid will also wash it away from the tool.
  8. Anti-Welding: Substances such as chlorine are added to cutting fluids to stop welding of the chip onto the tool.


Characteristics of a Good Cutting FluidCoolant and lubrication

Choosing the right cutting fluid is extremely important as it has a direct impact on tool life, productivity and even costs. The biggest problem is that the selection can vary depending on the different methods of machining and operating conditions

  1. A cutting fluid must be chemically stable, even in extreme conditions such as high temperature and pressure.
  2. They must be able to help disperse the heat created at the cutting zone quickly, especially as the heat is generated between the tool and material.
  3. On the other side of this, cutting fluids must be less evaporative while being stable. Cutting fluids that evaporate quickly are not worth using in relation to both cost and performance.
  4. It is extremely important that cutting fluids have excellent lubricating properties, ensuring the free flow of fluid. A low viscosity will also help to settle chip and dirt quickly
  5. Cutting fluids must have a high flash point to ensure that the risk of fire is reduced.
  6. It is preferable to use a clear/transparent cutting fluid so you can see the full area that you are cutting.
  7. Regarding its chemical structure, cutting fluids should be neutral and harmless to both the machine and operator. This also means that it should be non-toxic and odourless.
  8. Molecules must be much smaller than other lubricants to allow easier cutting fluid penetration.


Total Valona Range of Neat Cutting Oils

Eco-Friendly and chlorine free, Valona oils are intended for cutting and grinding operations guaranteeing high performance and optimised production costs. The level of performance of these oils (and cutting fluid in general) is indicated by a figure that ranges from 1,000 to 9,000. These figures highlight the lubrication capacity with the choice of product dictated to by factors such as the type of material machined and/or the machining operation that is being performed. View our full range of Valona products today.

View our Full Range of Cutting Fluids Today


Total Spirit Soluble Cutting Fluids

The Spirit range of semi-synthetic, soluble cutting fluids is designed to surpass the highest technological requirements for your application. In conformity with European Legislation, the Spirit range is also designed to provide maximum safety for operators, containing no boric acid or formaldehyde. View the full of Spirit products today.