The NUM CNC system features multi-axis groups and multi-channel functionality, capable of controlling up to 8 axis groups. Each axis group can control up to 9 interpolation axes, 32 servo axes, and 4 spindles, and each channel can be operated and controlled independently. We modified a Japanese OKUMA dual-axis lathe using the NUM1040T and achieved satisfactory results. 1. Machine Overview The Japanese OKUMA dual-axis lathe has relatively independent left and right sides, each with its own X, Z axes, spindle, turret tool post, cooling system, and automatic safety door. The lubrication system, hydraulic system, and chip removal system are shared. 2. Dual-Axis Group Control Method The NUM1040T CNC system can control up to 2 axis groups, with each axis group controlling up to 4 interpolation axes, 6 servo axes, and 2 spindles. Dual-axis group control means the system has two relatively independent channels, each with its own PLC and NC information exchange area, M-code, T-code, PLC variables, and flag bits. The system can switch between common axis group mode and independent axis group mode. When the system operates in common axis group mode, both axis groups have the same operating mode. When the system operates in independent axis group mode, the two axis groups have different operating modes and can be operated and controlled independently. By setting the corresponding system parameters and writing the PLC control program, dual-axis group control can be achieved. 3. System Parameters Related to Dual-Axis Groups **P97:** Defines the number of axis groups in the CNC system. **PO:** Defines the axis displayed in the CNC system. **P2:** Defines the measuring axis of the CNC system. **P3:** Defines the servo control and interpolation axis. **P5:** Defines the machine tool type of the axis group. **P9:** Used to associate the axis name with the actual address. **P6:** Configures the spindle with measuring function and specifies the spindle type. 4. PLC Variables Related to Dual-Axis Groups **%W2.2:** Switches between common axis group and independent axis group. **%W17.B:** Axis group selection. Used to display the corresponding axis group data. **%Wg03:** Selects the operating mode of the independent axis group. (g-1～8 are axis group numbers, the same below) 口%wsoo. 5 - M function response signal of axis group g. 口%wgoL2 - Cycle start request of independent axis group g. 口%Wg0t. 1 - Cycle stop request of independent axis group g. 口%wg02. B - Feed rate of axis group g. 口%RglE. w - M function code required for response of axis group g. 口%Rg7C. L_ - Tool number of axis group g. 5 User program for dual axis groups (1) Program description The machining program of a multi-axis group is composed of programs corresponding to each axis group. Each program has a common basic sequence number, followed by an index number for a specified axis group. Subroutines in the machining program do not need an index number. For example: %6.1 Program sequence number of axis group 1 %6.2 Program sequence number of axis group 2 (2) T function index number is. 1 The tool number TXT in the program can have the same sequence number as the tool in other programs, but does not have to be the same tool. (3) Tool calibration values: All programs share the same tool calibration table. (4) Program variables: Variables Lo～L19, L100～L999, Lg00～L959. Each axis group can use these variables. Using the multi-axis group function of the NUM CNC system, a control method for composite machine tools is provided for users, enabling one composite machine tool to have the functions of multiple single machine tools.