1、 Accuracy levels of different grades of CNC lathes
Ordinary CNC lathe
Positioning accuracy: ± 0.005mm (i.e. 5 microns)
Repetitive positioning accuracy: 0.002-0.003mm (2-3 microns)
Suitable for processing conventional mechanical parts and meeting the tolerance level requirements of IT7-IT8.
Precision CNC lathe
The positioning accuracy can reach ± 0.001mm (1 micron), and some domestically produced high-precision equipment has achieved a full range accuracy of 0.6 microns and a repeated positioning accuracy of 0.4 microns.
Widely used in industries such as automobiles, molds, aerospace, etc. that require high dimensional consistency.
Ultra precision CNC lathe
The machining accuracy is controlled within 5 microns, and some advanced equipment such as the high-speed and high-precision machine tool developed by Jiangxi Jiashite has achieved a positioning accuracy of 0.6 microns and a repetitive positioning accuracy of 0.4 microns.
Some domestic enterprises have achieved a roundness accuracy of 0.2 microns through technologies such as thermal deformation compensation and full static pressure spindle, approaching the international top level.
With the assistance of artificial intelligence, the latest intelligent numerical control system can control errors at the 0.1 micron level.
2、 Key factors affecting machining accuracy
Machine tool structure design: The high rigidity bed, linear guide rail, and ceramic bearing spindle can effectively reduce vibration and thermal deformation, and improve stability.
Environmental temperature control: A temperature fluctuation of 1 ° C can cause a length change of approximately 12 micrometers in a 1-meter steel component, therefore a constant temperature workshop (20 ± 0.5 ° C) is a prerequisite for ensuring micrometer level processing.
Tool and process matching: A small tool tip radius (such as 0.1mm) combined with a low feed rate (<0.02mm/revolution) is necessary to ensure surface quality and dimensional accuracy.
Calibration and maintenance: Regularly use testing tools that are one level higher than the accuracy of the machine tool for calibration (such as nanometer level instruments calibrating micrometer level machine tools) to ensure long-term stable operation.
3、 Domestic technological progress and breakthroughs
In recent years, China has made significant breakthroughs in the field of high-end CNC machine tools:
Shandong Leiou Machine Tool has successfully developed a high-speed and high-precision CNC machine tool with a positioning accuracy of 0.5 microns and a repeated positioning accuracy of 0.5 microns, breaking the foreign technology blockade.
The large gantry boring and milling machine of Beiyi Machine Tool has a machining accuracy of 5 microns and a repeat positioning accuracy of 2 microns, reaching a world-class level.
The precision coordinate boring machine of Kunming Machine Tool has a positioning accuracy of 2.5 microns (full stroke), with repeated positioning entering the sub micron level, representing the high-end strength of "Made in China".