If you turning aluminum without any coolant and lubricant, there may be various problems to interfere with the process and affect product quality, to ensure the machining success, right aluminum cutting fluid is necessary. Follow us to learn about how to select a cutting fluid for aluminum and other metals.

What is Cutting Fluid?

Cutting fluid, also called cutting oil or cutting compound is a kind of coolant and lubricant used in metalworking process, including oils, oil-water emulsions, pastes, gels, aerosols (mists), and air or other gases. As aluminum is a common CNC machining material and the characteristics of processing, there is a great demand for aluminum cutting fluid.

How to Select a Cutting Fluid? 

A cutting fluid should be effective in metalworking, there are many factors you should think about.

- Cutting tool: notice the tool material and details, like coating and grinding abrasives, some cutting oil additives will not work effectively with particular coatings, and causes serious problems.

- Metal types: aluminum is easy to machine with general-purpose cutting oils, while some metals like stainless steel, exotic alloy and hard metal have high demand for the performance of cutting fluid.

- Machining process: CNC turning, milling, drilling and other easy machining operations can be performed at high speed, lower viscosity, needs excellent coolant and modest EP, lower viscosity and lightly additized fluids are ideal, while difficult machining like thread-cutting or broaching needs a great deal of anti-weld protection, requires oil higher in viscosity and loaded with EP additives like active sulfur and chlorine.

- Chemical restrictions: the chemical composition in the cutting oil should be healthy to person and compliance with environmental protection regulations.

How to Select an Aluminum Cutting Fluid? 

When selecting cutting fluid for aluminum CNC turning and machining, the properties of aluminum and problems may occur in the processing should be considered.

1. The chemical properties of aluminum are relatively active. It is easy to oxidize in air and acid /alkaline environment. 

2. The thermal expansion coefficient of aluminum alloy is large, the cutting heat can be quickly extended to the workpiece, which is easy to cause thermal deformation, the part size will be difficult to control, and machining accuracy reduced. 

3. Aluminum alloy is soft and easy to stick to the tool during cutting and form chip accretion. In high-speed cutting, it is more likely to produce fusion welding on the cutting edge, resulting in the tool lose cutting ability, machining accuracy and surface roughness being influenced. 

4. Aluminum has high ductility, which may form long strip cracks, which will block the cutting area, making the cutting process difficult. At the same time, the cut debris is difficult to be taken away by the cutting fluid. 

5. The corroded aluminum alloy is mainly presented as surface discoloration and pitting, the surface may be from brown to black, pitting is small and deep, but sometimes connected with each other to form large holes, precipitated white powder.

In order to avoid the difficulties and problems in aluminum machining, choosing an aluminum alloy cutting fluid should meet the following requirements:

1. The pH of aluminum alloy cutting fluid should not be too high, and it is better to between 8.0-8.5. 

2.Good cleaning ability.

3.Able to take away formed chip from the cutting zone. 

4. Excellent cooling performance, ensure the shape, size and processing accuracy of the aluminum machined part. 

5. Aluminum alloy cutting fluid should have excellent lubrication and anti-friction characteristics, improve the smoothness and accuracy, and extend the service life of the tool. 

6. The added anti-rust agent needs to have the ability of corrosion inhibition and maintaining pH value stability. It is better to select those anti-rust agents that can form a protective film on the surface of the workpiece, such as phosphate, sodium silicate, etc. 

7. Outstanding corrosion resistance, the extremely sensitive aluminum will not produce corrosion spots. 

8. Can suitable for water quality of various hardness and aluminum alloy processing. 

9. Excellent biological stability, long service life, not easy to stink.

10. Environmental friendly. The aluminum cutting fluid is free of sulfur, chlorine and nitrite, no harm to people. 

Best Cutting Fluid for Aluminum

Generally, the aluminum cutting fluid needs to have good lubricity, cleanliness, anti-rust and cooling. Recommended cutting oil for different machining processes:

- Best cutting fluid for turning aluminum: Soluble Oil

- Best cutting fluid for milling aluminum: Soluble Oil, Lard Oil or Mineral Oil

- Best cutting fluid for drilling aluminum: Soluble Oil, Kerosene or Lard Oil

- Best cutting fluid for threading aluminum: Soluble Oil, Kerosene or Lard Oil

- Best cutting fluid for reaming aluminum: Soluble Oil, Kerosene or Mineral Oil

- Best cutting fluid for tapping aluminum: Soluble Oil or Mineral Oil