How to select cutting fluid?

1. General steps for cutting fluid selection

The selection of cutting fluids in general steps must be determined by considering comprehensive factors such as machine tools, cutting tools and processing technology. Before choosing cutting fluids according to machining methods and required precision, some restrictive items, such as safety and waste liquid treatment, have been set. Through these items, it can be determined whether to use oil-based cutting fluids or water-based cutting fluids.

If fire protection and safety are emphasized, water-based cutting fluids should be considered.When water-based slurry cutting is selected, the discharge of waste liquid should be considered. Enterprises should have facilities for waste liquid treatment.In some processes, such as grinding, only water-based cutting fluids are generally used.Oil-based cutting fluids are generally considered for cutting with cemented carbide tools.

Some machine tools use oil-based cutting fluids according to high time requirements, so they should not easily change to water-based cutting fluids to avoid affecting the performance of machine tools.By balancing these conditions, it is possible to determine whether oil-based cutting fluid or water-based cutting fluid should be used.After determining the main cutting fluid items, a second step can be made according to the machining method, the items requiring machining accuracy, surface roughness, etc. and the characteristics of the cutting fluid, and then the selection and the ability of the cutting fluid to meet the expected requirements can be identified.Identify if there is a problem, then feedback back, identify the cause of the problem, and improve, and finally make a clear choice. 

2. Applications of Oil-based and Water-based Cutting Fluids

At present, there are many kinds of cutting fluids and their properties are good or bad. If they are not selected properly, they will cause adverse consequences.Water-based cutting fluids should generally be selected under the following questions:

• Potential fire hazards of oil-based cutting fluids;

• High speed and large feed cutting make the cutting area higher than high temperature, smoke is fierce, and there is a risk of fire.

• Where water-based cutting fluids are required, considering the flow of the front and rear processes.

• Hope to reduce the contamination and dirt around the machine tool caused by oil splash and oil mist and diffuse surface, so as to keep the operating environment clean.

• Considering the price, general water-based cutting fluids can be used for cutting of some easy-to-process materials and workpieces with low surface quality requirements, while greatly reducing the cost of cutting fluids.

  
  

3. Oil-based cutting fluids should be considered for the following situations

When the durability of the tool has a large proportion to the economy of cutting (e.g. the cost of the tool is very high, it is difficult to grind the tool, the time of loading and unloading assistance is long, etc.).Machine tools with high precision must never be mixed with water to avoid corrosion.Where the lubrication system and cooling system of the machine tool are easily interlinked and the waste liquid treatment equipment and conditions are not available.

4. Precautions for Cutting Fluids

Cutting fluids shall have no irritating odor and contain no harmful additives to the human body to ensure the safety of the user.

 Cutting fluids shall meet the requirements of lubrication and protection management of equipment, i.e. cutting fluids shall not corrode the metal parts of the machine tool, damage the seals and paints of the machine tool, and leave no hard gum-like deposits on the guide rails of the machine tool, so as to ensure the safety and normal operation of the equipment.

Cutting fluids shall ensure that the rust-proof oil between work processes rusts the work piece.Sulfur-containing cutting fluids should not be used when processing copper alloys.PH neutral cutting fluid should be selected for machining aluminium alloys.

Cutting fluids should have excellent lubricating and cleaning properties.Choose the cutting fluid with high PB value and low surface tension of maximum non-seizing load and evaluate the effect by cutting test.

Cutting fluids should have a long service life, when the machining center is particularly important.

Cutting fluids shall be suitable for various machining methods and workpiece materials as far as possible.

Cutting fluids should be low in contamination and have waste treatment methods.

Cutting fluids should be suitable in price and easy to prepare.

In conclusion, when choosing cutting fluids, the user can select 2-3 cutting fluids with better comprehensive performance according to the specific processing conditions. After trial application in the factory, the cutting fluids with suitable price and satisfying processing process requirements are determined.