As for our precision machinery parts processing industry, sufficient accuracy is often a more intuitive reflection of the processing strength of the workshop. We know that temperature is a major factor affecting the processing accuracy. Here is a brief introduction from Xiaobian:
In the process of essential machining, under the action of various heat sources (conflict heat, cutting heat, environmental temperature, thermal radiation, etc.), the temperature change of machine tool, cutter, workpiece to be processed will generate thermal deformation, which will affect the relative displacement between workpiece and cutter, form machining deviation, and then affect the machining accuracy of parts. For example, if the linear expansion coefficient of steel is 0.000012 / ℃, for steel pieces with a length of 100m m, the elongation will be 1.2 μ m when the temperature rises by 1 ℃. In addition to directly affect the expansion and contraction of the workpiece, temperature transformation also has an impact on the accuracy of machine tools and equipment.
In precision machining, higher requirements are put forward for the machining accuracy and the stability of the precision. According to the statistics of related materials, the machining deviation caused by thermal deformation accounts for 40% – 70% of the total machining deviation in the precision machining. Therefore, in the high-precision machining, in order to prevent the expansion and contraction of workpieces due to the temperature change, the reference temperature of the environment is usually strictly regulated, and the deviation boundary of the temperature change is formulated. The constant temperature machining at 20 ℃ ± 0.1 ℃ and 20 ± 0.01 ℃ still appears.
In general, for the constant temperature and humidity test room for precision processing, in order to prevent the expansion and contraction of the processed workpiece due to temperature change during processing and measurement, the reference temperature in the chamber is usually strictly regulated, and the deviation boundary of temperature change is formulated, while the requirements for air relative humidity are not as strict as the accuracy requirements for textile testing. For example, a national ultra precision machining laboratory requires a temperature of 20 ℃ ± 0.2 ℃ and a relative humidity of 45% ± 5%.
In the future, with the development of society and the progress of technology, precision parts processing temperature control technology will be more and more developed.
About the author