The best quality measurement ensures flatness

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High quality measurement ensures flatness

in order to closely cooperate with rotating or linear parts, the industry has put forward some functional requirements for many parts. When design engineers integrate these requirements into the parts, they will set the necessary tolerance dimensions for the straightness, roundness and even cylindricity of the parts, and cylindricity reflects the comprehensive performance of straightness and roundness

when the Design Engineer considers straightness as the main factor, the tolerance range is generally limited to the measurement plane through two parallel lines at a certain distance. Generally, the flatness is determined by the tolerance area of the whole surface, for example, "the flatness tolerance is determined within the range of 0.001in (1in=25.4mm)."

Mr. George Schuetz, marketing manager of measuring and cutting tools Department of mahr federal company

most measurement methods are based on straight lines or planes. When measuring straightness, the situation is exactly the same. However, when measuring straightness, it generally does not need any data. It is measured relative to the shape of the part itself. However, something is needed as a baseline for comparison. The required reference line is very simple, which can be a ruler, or a height measuring instrument or forming machine for measurement and calibration

the most direct and basic method of measuring straightness is to use a ruler with certain accuracy. In many application fields, it is acceptable to use a ruler to measure the test surface, or use a thickness gauge or light gap method to measure the gap. In the absence of relatively new measuring equipment, sometimes a precision ruler can be used to measure the ground surface through the light gap method. Generally, it is easy to see a light gap less than 0.0001in through observation with a good light source. When the optical gap reaches 70~50 μ In, the light starts to turn red. When the optical gap reaches 30 μ In, the light turns blue. The discoloration effect of light is caused by the diffraction of light. This method is very effective for testing these small distances, but there are also some problems, including environmental problems and operator changes

high quality measurement ensures flatness

there is a better measurement method to obtain better measurement results, which is to use electronic height measuring instrument or forming system. These two kinds of measuring instruments have high measurement accuracy. Therefore, this method does not use a ruler to compare with the part, but uses a gauge to compare the part with an internal reference surface. The basic measuring functions and methods of height measuring instruments and forming machines are the same. There are many types of impact testing machines on the market

the above two measurement methods, Honeywell's three business groups have all settled in China. They all use an internal measurement benchmark and a sensor measuring head that moves with the measurement surface, and compare the changes of the measurement surface and the reference surface with the improvement of technology through the sensor. The deviation between the two is the measurement result or the flatness of the measured surface. After knowing the deviation value, the tolerance range can be applied and the surface measurement results of parts can be determined according to the required tolerance dimension

like other measuring systems, the measuring instruments used must meet the requirements of parts. Some height measuring instruments have an accuracy of 0.0002in, while others, including some forming systems, have a measurement accuracy of 0.00001in. The sensing and measuring head can be a simple digital indicator or a precise digital encoder probe

according to different height measuring instruments or forming systems, you can compare the length of the surface and the number of measuring points on this length, and set various parameters. In almost all cases, under small deformation conditions, as long as a start command is sent to it, the measurement can start immediately. As the system normalizes the lines and automatically removes the angular deviation, the measurement results can be displayed automatically

the final measurement result is a black-and-white image of the measured straightness, without red or blue shadows, so users can more easily understand the result

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