I. Necessity of High Pressure Coolant

Recent interest on high pressure fluid grew as machine tools tend to become high speed and high precision.
Low pressure (below 14kgf/cm²) cutting fluid is blocked by the vapor barriers created by machine tool..s cutting speed. It loses cutting fluid function before it enters the cutting zone because of evaporation.
On the other hand, high pressure (over 20kgf/cm²) cutting fluid can reach the cutting zone to achieve the following :

1. Smooth lubrication and cooling effect
2. Improvement in cutting capability
3. Improvement in tool lifetime by removing the phenomenon of chip re-cutting
4. Improvement in cutting surface roughness
5. Smooth chip removal effect
6. Deburring effect
7. Smooth cutting and cutting capability improvement in special processes such as deep hole processing and difficult-to-cut material processing

In case 70kgf/cm² high pressure cutting fluid is used in the cutting of difficult-to-cut materials, the tool manufacturer test shows the following results compared with the use of common cutting fluid.

1. 20% reduction in cycle time because of an improvement in cutting speed and feed
2. 50% improvement in tool lifetime

II. Hole Processing (Drilling , Boring and etc.)

Low Pressure Cutting Fluid / Flood Coolant
	Cutting fluid cannot reach a processing point and almost not cutting fluid is supplied to the tool. Peck cycle is used because chip discharge is difficult. Re-cutting often occurs because thread like chip surrounds the tool and tool holder.
High Pressure Cutting Fluid / Through Tool Coolant
	Cutting fluid is supplied to a processing point at the highest pressure. Chip is discharged effectively from a deep hole by reflected pressure and cutting fluid. The drill can perform more difficult processing therefore reducing work hour. The tool's lifetime is significantly increased compared with the use of low pressure cutting fluid.

III. Turning

High Pressure Coolant
	Highly reduced heat zone is created through the direct spray of cutting fluid to a processing point. Cutting hydraulic wedge effect can be produced depending on the usage. Wearing of the tool is reduced by cooling the contact zone between chip and tool. Cutting chip into small pieces increases chip discharging capability. This prevents recutting by chip and increases tool lifetime.

IV. Application