Inspection skills of heavy machinery parts in maintenance process
Main contents of parts view
In mechanical maintenance, parts should be checked one by one, and the main contents can be divided into the following aspects:
- Check the precision of parts
Several precision includes scale accuracy and shape orientation accuracy, but sometimes maintenance work is not to pursue a few dimensions of a single part, but requires relative cooperation accuracy, which is often an important part of inspection work.
Roundness, cylindricity, concentricity, coaxiality, parallelism and straightness are common in the maintenance of shape and orientation accuracy.
- Inspection of surface quality
The inspection of the surface quality of parts in maintenance is not only limited to the inspection of surface finish, but also the inspection of the defects such as scratch, burning and scuffing on the surface of used parts.
- View of mechanical function
According to the characteristics of mechanical maintenance, in addition to checking the hardness of the mechanical function of the part data, other indicators are generally not checked, but some functions encountered in the process of parts manufacturing and maintenance, such as balance, spring stiffness, etc., can not be ignored.
CNC machining
- Shadow defect check
In the process of manufacturing parts, there may be some original defects, such as slag inclusion and cavitation, and micro cracks may occur in the process of use. These shortcomings can not be found directly from the general investigation and measurement, but they may have severe consequences on machinery. Therefore, in the maintenance of machinery, it is necessary to have a comprehensive view of some parts.
How to check parts
There are many ways to view parts, and new viewing skills are developing rapidly. However, starting from the practice of mechanical maintenance, it can be summarized as follows:
- Feeling check method
This is a way to identify the skill of parts by the intuitive feeling of the inspector without having to check the equipment. This method is simple, and in the mechanical maintenance, it is also relatively simple to distinguish the shortcomings of many parts to be disassembled and inspected. Therefore, this method is still useful. However, this method can not be used to view parts with high precision requirements, and requires the inspector to have rich experience.
- Instrument and things check method
A lot of homework is done with instruments and things. Due to the different working principles and types of instruments and things, they can be divided into general measuring tools, special measuring tools, mechanical instruments and meters, optical instruments, electronic instruments, etc.
- Physical view method
This is a method to detect the skills of parts by using the changes caused by electrical, magnetic, optical, acoustic, thermal and other physical quantities through the workpiece. The realization of this method is also combined with the instrument and the method of viewing things. This method is usually used to check the hidden defects inside the parts without damaging the parts themselves. It is widely known as non-destructive inspection. In recent years, nondestructive inspection technology is increasingly developed. Magnetic powder method, penetration method, ultrasonic wave and ray method are widely used in production.
About the author