Four-axis CNC refers to X, Y, Z, and rotary axis, with the fourth axis used for rotation around other axes.
Types of axis machine tools include: swivel head, vertical, horizontal, NC worktable + NC rotary head, NC worktable + 90° B axis, NC worktable + 45° B axis, NC worktable + universal horizontal five-axis linkage CNC machine tool A axis°, two-axis NC spindle, etc.
In vertical five-axis machining centers, the rotary axis has two methods. One is the worktable rotary axis, set on the bed's worktable for rotation around the X-axis, defined as the A axis, with a general working range of +30 degrees to -120 degrees.
There is also a rotary table in the middle of the worktable, rotating around the Z-axis, defined as the C axis, with a full 360-degree rotation. The advantage of this setup is that the spindle structure is relatively simple, with excellent rigidity and lower manufacturing costs.
However, the worktable generally cannot be designed too large, with a relatively small load-bearing capacity, especially when the A-axis rotation is greater than or equal to 90 degrees, which can impose significant torque on the worktable during workpiece cutting.
Regardless of whether the numerical control system operates in MDI mode or memory mode, it processes part programs in units of program segments. Various part contour information (such as start point, end point, straight line or arc, etc.), processing speed information (F code), and other auxiliary information (M, S, T codes, etc.) are interpreted into computer-readable data format according to certain syntax rules and stored in designated memory units.
During the decoding process, syntax checks for program segments are conducted, and any syntax errors are immediately alarmed.
Tool compensation includes tool length compensation and tool radius compensation. Typically, the part program of a CNC device is programmed with part contour trajectory programming, where the tool compensation converts the part contour trajectory into the tool center trajectory.
In advanced CNC devices, tool compensation for parts includes automatic transition between program segments and overcutting detection, known as C tool compensation.
The tool movement speed given in programming is the speed in the composite direction of all coordinates. The first step in speed processing is calculating the individual speeds of each motion coordinate based on the composite speed. Some CNC devices also handle restrictions on the lowest and highest speeds allowed by the machine, automatic acceleration and deceleration in the software in this process.
