The role of grating scale on CNC machine tools - News - Global IC Trade Starts Here.

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As the position detecting component of the linear axis of the CNC machine tool, the grating ruler is equivalent to the "eye" of the human being, that is, "monitor" the linear axis after the execution of the movement command of the numerical control system, whether the linear axis is truly accurate to the requirements of the numerical control system command s position. If the NC machine tool is not installed grating, when the move command is issued after the system is linear axis, linear axis CNC system can reach the required position, entirely on the accuracy and precision CNC mechanical transmission system debugging to protect. After using the CNC machine for a period of time, due to the modification of the electrical debugging parameters and the increase of the mechanical error, the linear axis is likely to be much different from the position required by the CNC system command. At this time, the CNC system does not know, repair and operate the machine tool. The personnel do not know, in order to know the gap, the maintenance personnel must carry out the accuracy test on the machine tool. Therefore, the CNC machine tool does not have a grating ruler. It is necessary to check the accuracy of the machine tool regularly. If you forget to check the accuracy of the CNC machine tool, it may lead to the accuracy or even scrapping of the processed product.

If the linear axis of the CNC machine tool is equipped with a grating ruler, the above problem does not need to be taken care of, and the grating ruler is used to accomplish this mission. If the linear axis does not reach the position accurately due to mechanical reasons, etc., the scale as a position detecting component will issue an instruction to the numerical control system to enable the linear axis to reach a more accurate position until the resolution of the grating is not resolved. At this time, the scale acts as a supervising function independent of the machine tool. Like the human eye, it always "monitors" the position of the linear axis, ensuring that the linear axis can reach the position required by the numerical control system.

The accuracy of the grating depends on its resolution, the resolution is different, and the price is different. The grating ruler has a glass grating ruler and a steel tape grating ruler. At present, the length of the glass grating that can be made in the world is about 3 meters long, and the steel ruler is used for the grating ruler over 3 meters.

In the production of new or old machine tools, the purpose of the grating ruler is to increase the accuracy of the linear axis. However, the ability to increase the scale does not depend entirely on whether or not the grating is purchased, mainly depending on the geometrical accuracy of the mechanical part of the linear axis. The grating ruler cannot replace the precision of the machine, it can only be "added to the icing on the cake". Many people have deviations in the understanding of this issue. If the geometrical accuracy of the linear axis of the machine tool is very poor, for example, some Z-axis of the lathe is driven by a straight rack, the backlash is very large, even if the shaft is used after the grating ruler, when the axis reaches the running command position of the numerical control system, due to The linear axis's transmission accuracy is not high, not only does not achieve the purpose, but will be oscillating before and after the exact position.

Which linear axis of the CNC machine is installed with the grating scale depends on the actual situation. In general, the X-axis of CNC machine tools must be equipped with a grating ruler. When the CNC grinding machine has a tapered surface in the grinding product, the Z-axis is also installed with a grating ruler to ensure the accuracy and surface quality of the processed cone. The Z-axis of the boring and milling machine is usually equipped with a grating scale, and the other axes depend on the precision of the processed product.

In the numerical control machine tool, the function of the grating ruler is as the position detecting component of the numerical control system, and it is detected whether the actual displacement of the linear axis of the machine tool coincides with the command issued by the numerical control system.