What are the general inspection methods for precision mechanical components?

What are the general inspection methods for precision mechanical components?
During component processing, it is necessary to continuously inspect and verify to ensure that the processed product is qualified. What are the general inspections required during component processing? Let's take a look together with precision component processing manufacturers.
1. Basic dimensions and shape inspection of precision stamping parts
a. Measurement of outer diameter
When measuring the outer diameter, it is necessary to measure and record it in two circumferential areas. When the length of the same diameter of the part is greater than 50mm, a straightness inspection should be conducted. The working surface of the knife edge ruler should be in contact with the outer diameter busbar to observe the width of the building, and then the judgment should be made based on the standard light gap.
b. Measurement of inner diameter of precision stamping parts
When measuring the inner diameter size of a part, it is only necessary to measure in three circumferential areas and keep records. When the length of the same diameter is greater than 40mm, cylindricity inspection should be conducted, and measurements should be taken at two positions with large intervals within the length direction of the same diameter. Calculate the error in cylindricity.
c. Length measurement
External thread measurement: The pitch diameter of the external thread is measured using a thread ring gauge or three needle gauge, while the minor diameter is measured using a thread ring gauge (through gauge).
Internal thread measurement: The outer diameter of the internal thread is inspected using a thread plug gauge (through gauge), and the pitch diameter is inspected using a thread plug gauge.
The large, medium, and small diameters of threads should be inspected according to the accuracy level required by the drawing.
The effective length tolerance of the thread shall be in accordance with the requirements of HY/QT001 Fastener Inspection Specification.
2. Detection of surface planes
a. Surface roughness detection: Use sample comparison method for comparison and judgment.
b. Flatness inspection: Use the marking method for inspection (directly machine tool marking inspection after finishing the parts).
Precision mechanical parts are mainly precision, and in the actual production process, we must ensure that their precision meets relevant standards and be improved as much as possible. How to improve the accuracy of precision mechanical parts has become a key issue for related enterprises.