Machine coordinate origin setting

The origin of machine tool coordinates is the reference point of machine tool processing movement. The correct machine origin is the prerequisite for reliable machine tool processing. The AC servo motor of the drive shaft of the CNC machine tool has two kinds of relative position encoder and absolute position encoder. The importance of the machine reference point to the machining process and the precautions under these two configurations are explained as follows.

(1) Relative position encoder. When the AC servo motor of the CNC machine tool is a relative position encoder, the speed block, travel switch and servo motor rotation signal are usually used to complete the machine tool's return to origin operation. After confirming the validity of the overtravel limit switch, attention should be paid to the machine tool returning to the origin.

Before the processing operation, if the machine does not return to the machine origin, or the position of the machine is incorrect, the machine coordinates will be offset. When the program is running, it is easy to cause the processing size to be inaccurate or crash.

If the installation position of the deceleration block at the machine origin is incorrect, or the deceleration distance is not enough, the position of the deceleration block at the machine origin may be wrong every time. The faster the machine tool returns to the origin, the longer the block length. Otherwise, due to numerical control acceleration and deceleration, machine tool inertia and other reasons, the speed of the trawler will not decrease after passing the stop, which will directly affect the accuracy of the machine tool returning to the origin. Generally, the origin of the machine tool return to the deceleration block is installed within the maximum stroke close to the axis, and the effective stroke of the origin of the return block is more than 25 caffeine to ensure sufficient deceleration distance, and the speed of returning to the origin can be reduced to ensure that the machine returns to the origin accurately.

(2) Absolute position encoder. When the servo motor system with absolute encoder is powered off, the servo motor or servo drive is equipped with a battery, and the position of the machine tool can be saved in the memory. Therefore, when the machine is powered off, it is not necessary to return to the origin of the machine, which is convenient to use. But it should be noted that when the battery of the absolute encoder is low, the battery should be replaced in time to avoid the loss of the machine position. For example, for Fanucbeta series servo motors, the battery needs to be replaced when the machine is powered on, otherwise the machine coordinates will be lost. When the coordinate position is lost, the corresponding relationship between the mechanical position and the absolute encoder must be re-established. After rebuilding the coordinates, when using the machine tool, you must check whether the program coordinates and various compensation data are correct. When the machine tool leaves the factory, the machine tool manufacturing plant has been established