What is Precision Manufacturing?
(1) Working accuracy
can be distinguished as Relative Accuracy and Absolute Accuracy
(2) Absolute degree means Tolerance
such as 200 ± 0.1mm tolerance value ± 0.1mm absolute accuracy
The relative accuracy is the ratio of the allowable tolerance value to the workpiece size
For example 0.1/200=0.0005
(3) Usually machining accuracy includes
(a) Dimension Accuracy, such as diameter, length, thickness, etc.
(b) Shape Accuracy such as Roundness, Cylindricity, etc.
(c) Surface Accuracy, such as Surface Finish, etc.
(4) In general, the so-called processing accuracy refers to the size and surface roughness (Surface Finish)

When the accuracy of the parts is usually higher than the one-ten thousandth of its own size (that is, relative accuracy), precision manufacturing can be considered. However, Micro Machining in micro-electromechanical systems (MEMS) uses absolute accuracy as a criterion for precision manufacturing. The general CNC machine tool size accuracy is 10μm, the drive is 1μm, the drive is 0.1μm, the semiconductor manufacturing equipment is 0.01μm, and the surface accuracy is one-tenth of the dimensional accuracy, if the eight standards can be achieved, It can be called precision manufacturing.

Traditional Precision Machining includes the following aspects:
Precision Casting
Precision Forging
Precision Injection
Precision Grindiry
Precision Milling
Precision Turning.

Non Traditional Precision Machining includes the following aspects:
Electron Beam Machining, called EBM
Laser Beam Machining, called LBM
Electro Discharge Machining, called EDM
Ultrasonic Machining, called USM
Chemical Machining, called CHM
Electro chemical Machining, called ECM

Macro machining includes the following aspects:
Lithography Electro forming Micro Molding, called LIGA
Chemical Vapor Deposition, called CVD
Physical Vapor Deposition, called PVD
Chemical Mechanical Polishing, called CMP
Electrolytic Polishing.

Above info is from the reference