The influence of temperature error on measurement results
The temperature has
a very significant influence on measurement accuracy. Everyone knows that
thermal expansion and contraction, but the expansion coefficients of different
objects have great differences, so significant errors will occur during
measurement. Generally, it is stipulated that the temperature of the measuring
tool itself should be equal to the temperature of the measured object. Of
course, the temperature requirements for measurement are different in different
regions. The temperature required in our country is 20°C. The flow rate between
the temperature and the measurement result can be summarized as the following
points:
(1) When the
temperature of the workpiece and the measuring tool are the same and equal to
20°C (that is, under laboratory conditions), the temperature error is zero.
(2) When the
temperature of the workpiece and the measuring tool is the same, but not equal
to 20°C (that is, under certain conditions), the temperature error is
proportional to the difference between the size of the workpiece, the
temperature of the workpiece and the measuring tool, and their linear expansion
coefficients.
(3) When the
temperature of the workpiece and the measuring tool are the same, and the linear
expansion coefficients of the two are also the same (equivalent to the
situation that the workpiece and the measuring tool have passed the temperature
balance, and the materials of the two are also the same), the temperature error
is zero.
(4) When the
linear expansion coefficient of the workpiece and the measuring tool is the
same, the temperature error is proportional to the size of the workpiece, the
linear expansion coefficient of the workpiece or the measuring tool, and their
temperature.
(5) When the
workpiece temperature is 20℃ and the measuring tool temperature is not 20℃, the
temperature error is only proportional to the workpiece size, the difference
between the measuring tool temperature and the standard temperature, and the
linear expansion coefficient.
(6) When the
temperature of the measuring tool is 20℃ and the temperature of the workpiece
is not 20℃ (equivalent to the case where the measuring tool in the constant
temperature room is used to measure the workpiece without isothermal), the temperature
error is only the difference between the workpiece size, the workpiece
temperature ,and the standard temperature. The coefficient of linear expansion
is directly proportional.
Therefore, when
we measure the size, we must pay attention to the error effect caused by
temperature, then how should we reduce the error effect caused by temperature.
In order to
minimize the impact of temperature error, we can try the following methods:
1) Measure when
the temperature is close to the standard temperature. But in actual work, in
order to make the work orderly, we can artificially control the temperature and
some other environmental factors in a specific space to make it meet the
standards we require.
2) Before using
the measuring tool, it can be placed on top of the measuring object to achieve
an isothermal effect.
3) For the inspector, when using a specific measuring tool for measurement, the insulation pad of the measuring tool should be held. If it is found that heat has been transferred to the measuring tool, it should be placed for a period of time before measuring.
The influence of
temperature on the measurement results is very important. Nowadays, many
laboratories have dedicated to controlling the temperature and other environmental
factors together, which also provides a guarantee for the measurement results.
