There are two main types of machining, one is to make a mold and then make a large number of copies, and the other is to use various tools and specific materials to make the required shapes. Individual processing includes the following three major categories.

一、Cutting: drilling, milling, turning

二、Grinding: Surface grinding, cylinder grinding

三、Electrical Discharge: Electrical Discharge Processing, First Cut Processing

This article refers to precision machining with the main focus on tool precision cutting.

Opportunities for Precision Cutting

It is generally used for workpieces that require high precision, high reliability, high strength, free form, and small lot sizes:

（1）Components that support high-speed motion: airplane engines

（2）Components in manufacturing tools and devices:Semiconductor devices

（3）Parts for low volume devices and machines: Space related parts.

Precision machining applications include tool shape, material, action and strength.

Differences in the shape of a tool affect its life and rigidity.

Front cutter angle size

Large angle, good tool condition, less heat generation, but the tool is thin and less rigid and prone to chipping.

The angle is small and the tool condition is poor, but it is not easy to produce chipping.

Rear blade angle size

Large angle, small wear range of the rear cutter surface, can be used for a long time, especially suitable for cutting aluminum, which is easy to stick to the material.

Smaller angles result in a wider range of wear on the back face, but heat generation also accelerates tool wear.

Sharpness of the front of the blade

Generally, a tool will have a small R or C angle at the tip of the blade, which is called the cutting edge.

Small blade: Knives are in good condition, but prone to chipping.

Bigger blade: The knife is in poorer condition, but it is less likely to be chipped.

Blade Chip Breaker

Each manufacturer will have a different pattern in order to rapidly curl the chips produced after cutting, making them curly and crumbly.

Sharpness of End Mills

More blades: better rigidity, but smaller and easy to block, not suitable for groove machining.

Low number of blades: Enough space for chip chut

Helix angle of end washer

Large spiral angle: less rigid, suitable for side finishing.

Small spiral angle: better rigidity, suitable for deep groove machining.

Commonly used tool materials

1.Diamond Sinter

2.cBN Sinter

3.ceramics

4.Metal Ceramics

5.Hard Alloy

6.High Speed Tool Steel (HSS)

It is selected according to its hardness, toughness, heat resistance, solubility, and the material to be used for the chip. (e.g. Diamond is hard but not suitable for cutting carbon steel, it will react with the carbon of carbon steel and shorten its life).

Operation of the tool

Cutting speed is the speed at which the tool acts on the tool. Generally speaking, the unit is expressed in m/min. Rotary tool cutting, the outer diameter of the tool rotates one cycle of the circumferential speed is the cutting speed, because the material rotation will become the cutting point of the circumferential speed, so the cutting speed is also known as the circumferential speed.

Cutting is divided into continuous cutting and interrupted cutting. Continuous cutting impact is small but continuous machining process will accumulate heat; intermittent cutting impact is large (because the process of multiple feeds) but the machining process is not as much as continuous cutting abrasion generates so much heat.

Tool Strength

If the rigidity of the tool is too small, it will cause vibration during the machining process, which not only accelerates the wear of the tool but also prevents the machining from achieving the required machining accuracy.

The rigidity of the support that holds the tool, the machine itself and the workpiece are also important. If the rigidity of the workpiece is insufficient, the effect can be minimized by means of a clamping system. If the structure cannot be clamped, it is necessary to use tools with good sharpness as much as possible in order to reduce the cutting load and to suppress the deformation of the workpiece.