Introduction and setting of the coordinate system and coordinate points in CNC machine tools, basic part one
To machine a part on a CNC machine, we must first determine the position of the workpiece relative to the tool so that I can accurately process the part. So today I will show you how to determine the coordinate system and coordinate points in NC programming.
The coordinate systems in CNC machine tools are divided into two categories: machine tool coordinate systems and workpiece coordinate systems.
Machine tool coordinate system: We can understand the machine tool zero point. Before the machine tool leaves the factory, the manufacturer sets the machine tool zero point for each machine tool. The coordinate system with the machine tool zero point as the coordinate origin is called the machine tool coordinate system. In our vertical machining center, the origin of the machine tool coordinate system is generally at the upper right corner of the machine tool. The table is in the third quadrant of the coordinate system.
Workpiece coordinate system: The workpiece coordinate system exists under the machine tool coordinate system. The position of the workpiece coordinate system is determined by setting a point in the machine tool coordinate system as the origin. We can set it through the program G92 X .Y .Z. But under normal circumstances, this kind of setting cannot realize the tool compensation, so we will set the coordinate system in the MDI panel. There are 6 coordinate systems such as G54-G59 which can be set, which is usually enough. The calling method is very simple, just write G90G54 in the program.
Before establishing the coordinate system, let the machine tool return to the reference point. We can press the pos key on the machine tool panel, and you can see the absolute, relative, and comprehensive on the display. In the comprehensive option, we can see the entire machine coordinate system and the position of the workpiece coordinates. The relative position is only used as a reference and has no effect on the control of the machine tool. In order to observe our cutting position more intuitively, I will explain the usefulness of the tool in detail later.
In addition, in the workpiece coordinate system, we can also establish a local coordinate system, the command is G52 X.Y.Z. I will not introduce it in detail here because it is not commonly used, everyone knows that this function is just fine.