Our working environment is very important, and it can play a big role. In ordinary life, often use to precision mechanical parts, so it is more familiar with it. In the actual machining production process in a variety of heat sources (friction heat, cutting heat, ambient temperature, thermal radiation, etc.) under the action of machine tools, tools, workpieces being machined and other temperature changes will produce thermal deformation, which affects the relative displacement between the workpiece and the tool, resulting in processing errors, and then affect the machining accuracy of the parts. Such as the coefficient of linear expansion of steel 0.000012 / ℃, for the length of 100mm steel parts, when the temperature rises 1 ℃ will elongate 1.2μm. temperature changes in addition to directly affect the expansion of the workpiece, the accuracy of machine tools and equipment also has an impact.
In the precision machining, the machining accuracy of the workpiece and the stability of the accuracy put forward higher requirements. According to relevant statistics, in precision machining, the processing error caused by thermal deformation accounts for 40%-70% of the total processing error. Therefore, in the high-precision precision machining, in order to avoid the expansion and contraction of the workpiece due to temperature changes, the reference temperature of the environment is generally strictly defined. And the deviation range of temperature change is set, 20 ℃ ± 0.1 ℃ and 20 ± 0.01 ℃ of constant temperature processing has appeared.
In general, for precision processing with constant temperature and humidity laboratory, in order to avoid the processed workpiece in the processing and measurement of temperature changes due to expansion and contraction, generally strict provisions of the benchmark temperature of the room, and the development of temperature changes in the range of deviation, while the requirements for the relative humidity of the air is not as strict as the precision requirements of textile testing. Such as a national ultra-precision processing laboratory, the required temperature is 20 ℃ ± 0.2 ℃, while the relative humidity is 45% ± 5%.