How to choose the surface roughness of parts?

How to choose the surface roughness of parts?

• Admin
• 2024/8/11

The surface roughness of the part will change after cutting, and the surface roughness of the part has a great influence on the wear resistance, corrosion resistance and mating properties of the part. How to choose the surface roughness of parts? How to perform surface roughness inspection? Today Jessie will come and learn about it with everyone.

How to perform surface roughness inspection?

The selection of surface roughness parameter values​should not only meet the functional requirements of the part surface, but also consider economic rationality. The specific selection can refer to the existing drawings of similar parts, and determine by analogy. On the premise of meeting the functional requirements of the parts, a larger surface roughness parameter value should be selected as much as possible to reduce the processing cost. Generally speaking, the working surface, mating surface, sealing surface, friction surface with high moving speed and high unit pressure, etc., have high requirements for the smoothness of the surface, and the parameter value should be smaller. For non-working surfaces, non-matching surfaces, and surfaces with low dimensional accuracy, the parameter value should be the relationship between the parameter Ra value and the processing method and its application examples.

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How to perform surface roughness inspection?

There are generally four methods for detecting surface roughness of parts: surface comparison method, test strip profiling method, surface profiler and surface roughness tester.

Surface comparison method: Use the surface roughness comparison sample to compare the newly sprayed surface with the defined surface. The comparison board has sand blasting type, shot blasting type or fine sand type, which can be compared by sight or touch. This method can quickly define the approximate range of surface roughness.

Test tape profiling method: The foamed plastic test tape on the back is pressed into the sprayed surface. Measure the test strip to determine the surface roughness. This kind of test provides a digital evaluation of roughness and can provide a test certificate, because the test tape can be included in the manual report.

Surface profiler: Surface profilers include analog and digital types. After “zero calibration”, the profile can be measured, and the instrument records the value from the top of the peak to the bottom of the valley. The digital instrument makes the intermediate error of the reading to the extreme, and the measurement is fast and accurate. The cost of the profiler is relatively high for several other methods.

Surface roughness meter: With the stylus connected to the arm, the arm automatically moves on the surface, recording and measuring contours. The instrument is very suitable for testing in the production process as a part of quality control. It is also a widely used method for measuring roughness.

If you have other better methods, you can share with us.

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