What inspection tools are used in precision machining?

In precision machining, various inspection tools are used to ensure that the dimensions, shape accuracy, surface quality, and other aspects of parts meet design requirements. Here are some common types:

  Size measuring tool

   Caliper type

Vernier caliper: 

It can measure the inner diameter, outer diameter, length, depth, and other dimensions of a workpiece, with a general accuracy of 0.02mm. Some high-precision vernier calipers can achieve an accuracy of 0.01mm. It is easy to operate and can quickly obtain measurement data, making it widely used in the machining inspection of parts with general precision requirements.

Digital caliper: 

It is the electronic version of the vernier caliper, which directly displays the measurement values on an electronic screen, making the reading more intuitive and accurate. Its precision can usually reach 0.01mm, and some models are equipped with data output functions, facilitating connection to a computer for data recording and analysis.

Micrometer: 

Includes outside micrometers, inside micrometers, etc., mainly used to measure the external diameter, internal diameter, thickness, and other dimensions of precision parts. The accuracy of an outside micrometer can reach 0.01mm. It achieves precise micro-adjustments and readings through the rotation of the thimble, and is commonly used for measuring the diameter of shaft-type parts.

  Gauge type

Go/No-Go Gauge: 

Used to measure internal dimensions such as hole diameters or slot widths. It is divided into go gauges and no-go gauges. A go gauge can pass through the measured hole or slot, while a no-go gauge cannot pass, indicating that the dimension is acceptable. It is simple and efficient to use.

Gauges: 

Mainly used to measure the outer diameter and other external dimensions of shaft-type parts. There are also go and no-go gauges. The method of judgment is similar to plug gauges, making them common tools for batch inspection of the dimensions of shaft-type parts.

  Shape and Position Accuracy Inspection Tool

Level: 

It is divided into ordinary levels and electronic levels, used to check the flatness and straightness of workpiece surfaces, as well as the levelness of equipment installation. The ordinary level reads measurements through bubble displacement, while the electronic level offers higher precision and data processing capabilities, allowing for more accurate measurement of small angle changes.

Dial indicators and micrometers: commonly used to measure the shape errors (such as roundness and cylindricity) and positional errors (such as parallelism, perpendicularity, coaxiality, etc.) of parts. The dial indicator has an accuracy of 0.01mm, and the micrometer has an accuracy of 0.001mm. The deflection of the pointer on the dial reflects the shape and positional deviations of the measured surface.

Coordinate Measuring Machine:

It is a high-precision measuring device that, through three mutually perpendicular movement axes (X, Y, Z axes), can accurately measure the three-dimensional size, shape, and position of parts. It can measure parts with complex shapes, perform contour scanning, and support reverse engineering, and is widely used in precision machining fields such as aerospace and automotive manufacturing.

  Surface quality inspection tool

Roughness meter: 

Used to measure the roughness of a part's surface. By moving a stylus across the measured surface, the microscopic unevenness of the surface is converted into an electrical signal, which is then used to obtain surface roughness parameters (such as Ra, Ry, etc.) to determine whether the part's surface meets machining requirements.

Microscope: 

Including optical microscopes and electron microscopes. Optical microscopes can be used to observe the microscopic morphology and defects on the surface of parts, while electron microscopes have higher resolution and can observe finer structures. They are often used in fields such as semiconductors and precision molds, where extremely high surface quality is required.

  Hardness testing tool

Rockwell Hardness Tester: 

Determines the hardness of a material by measuring the depth of the indentation produced by the indenter under a certain load on the material's surface. It is easy and quick to operate and is suitable for hardness testing of various metal materials.

Brinell Hardness Tester: 

It uses a steel or hard alloy ball of a certain diameter, which is pressed into the surface of the test sample with a specified test force. After holding for a specified time, the test force is removed, and the diameter of the indentation on the sample surface is measured to calculate the Brinell hardness value. It is commonly used to measure the hardness of relatively soft metal materials or rough workpieces.