Four-axis CNC refers to which four axes, and what is the fourth axis used for?

Four-axis NC refers to X, Y, Z and rotation axis, and the fourth axis is used to rotate around other axes.

Types of axis machine tools: cradle type, vertical type, horizontal type, CNC workbench+CNC dividing head, CNC workbench+90 B axis, CNC workbench+45 B axis, CNC workbench+universal horizontal five-axis CNC machine tool A axis, two-axis CNC spindle, etc.

There are two ways to rotate the shaft of a vertical five-axis machining center. One is the workbench axis, and the workbench arranged on the lathe bed can rotate around the X axis, which is defined as the A axis. The general working range of axis A is +30 degrees to-120 degrees.

There is also a turntable in the middle of the workbench, which rotates around the Z axis, defined as the C axis, and the C axis rotates 360 degrees. The advantages of this arrangement are that the structure of the spindle is relatively simple, the rigidity of the spindle is very good, and the manufacturing cost is relatively low.

However, in general, the workbench can't be designed to be too large and its bearing capacity is small, especially when the A-axis rotates 90 degrees or more, the workpiece will bring great bearing torque to the workbench when cutting.

Extended data

No matter whether the system works in MDI mode or memory mode, the NC system treats the part program as a program segment, and explains all kinds of part contour information (such as starting point, ending point, straight line or arc, etc.). ), machining speed information (F code) and other auxiliary information (M, S, T code, etc. ) according to certain grammatical rules, it is converted into a data form that can be recognized by the computer, and stored in a specified special storage unit in a certain data format.

In the process of decoding, we should also complete the grammar check of the program segments and call the police immediately if grammatical errors are found.

Tool compensation includes tool length compensation and tool radius compensation. Usually, the part program of NC device is programmed with the outline trajectory of the part, and the tool compensation function is to convert the outline trajectory of the part into the tool center trajectory.

In a good numerical control equipment, the workpiece of tool compensation also includes automatic switching of program segments and overcutting discrimination, which is called C-tool compensation.

Programming the given tool moving speed is the speed of each coordinate synthesis direction. The primary task of velocity processing is to calculate the component velocity of each motion coordinate according to the synthetic velocity. In some numerical control equipment, the limit of the minimum and maximum speed allowed by the machine tool and the automatic acceleration and deceleration of the software are also handled here.

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