Abstract : This paper briefly introduces the implementation plan and debugging method of synchronous axes of CNC machine tools using SINUMERIK 840D system and SIMODRIVE 611D servo drive system. Keywords : synchronous axis; leading axis; synchronized axis; DB (data block); referencing point Due to the structural requirements of the machine tool itself, to ensure the overall rigidity of the machine tool and the stability of long guideways, synchronous motor drive is a common method used by machine tool manufacturers today for the same coordinate. It helps improve the rigidity of the servo system, overcome positional deviations caused by single leadscrews, avoid elastic deformation, and ensure high precision of the machine tool. II. Function Introduction The synchronous axis function is generally used in machine tool coordinates with two or more mechanical connections, where there is no mechanical offset. A synchronized coordinate is defined based on programming. During synchronized movement, the system detects the current position value to see if it is within the system's set error range. When the synchronized auxiliary axis deviates from the position range of the drive axis, the system stops all coordinate movement, effectively preventing damage to the machine tool's mechanical parts due to asynchrony. The purpose of the synchronous axis function is to strictly detect the movement accuracy of the coordinates on the guide rails. III. Application The synchronous axis function is used for the gantry synchronization function of large gantry milling machines, with each side having its own position measurement cycle system. Due to the mechanical hardware connection requirements, the two drives must be absolutely synchronized to ensure mechanical stress deformation. A synchronization group consists of one master axis and up to two slave axes. IV. Hardware Organization and Synchronization Definition Large CNC gantry milling machines are composed of multiple coordinate units (see the figure below). Each coordinate drive is an independent drive system with its own measurement cycle, forming a complete coordinate system. When the mechanical coordinates move, as shown in Figure 2, the two sets of coordinates X and X1, Z and Z1 must be completely synchronized; otherwise, it will damage the mechanical components. 4.1 Keyword Meaning: ① Synchronous Axis Group: A synchronous axis group consists of at least one pair of coordinates, including one driving axis and one driven axis, all of which are mechanically connected. Movement must be simultaneously controlled by the NC. The difference is that the two coordinate position detection systems are separate. ② Driving Axis: A driving axis is a common mechanical coordinate controlled by the NC, a linear or rotary axis that can be programmed for parts. The axis name is defined by the synchronous group. ③ Driven Axis: The driven axis is also controlled by the NC, but it always moves along with the driving axis. The axis name is also defined by the synchronous group. 4.2 Coordinate Definition: Coordinate definition is defined by the machine tool data GANTRY_AXIS_TYPE: defining whether the coordinate belongs to the synchronous group, and whether it is a driving axis or a driven axis. Each synchronous axis group consists of one driving axis and a maximum of two driven axes. 4.3 Conditions for Synchronous Axis Groups A synchronous axis group cannot contain a main spindle; the driven axis cannot be a positioning axis; the driven axis cannot be the name of another synchronous axis group. The coordinates of each coordinate in a synchronous axis group, such as matching speed, acceleration, and dynamic response time, must be consistent. 4.3 Monitoring of Actual Coordinate Values ​​of Synchronous Groups Synchronous Axis Warning Limits When the main axis and driven axis exceed the warning range, the NC system outputs an alarm message: "Exceeding the limit range." Simultaneously, the PLC outputs a signal to stop the machine tool from automatic operation. Synchronous Axis Travel Limits When the synchronous axis group exceeds the travel range, the NC system outputs an alarm message: "Exceeding the limit range." Simultaneously, the PLC outputs a signal to stop the machine tool from automatic operation. Synchronous Axis Travel Limits When the synchronous axis group exceeds the travel range, the NC system outputs an alarm message: "Exceeding the limit range. " V. Reference Points and Synchronization Settings for Synchronous Axes 5.1 Method for Setting the Reference Point of the Main Axis The reference point setting for the coordinates is done by the PLC's DB block. The PLC's specified return-to-reference point programming must be performed according to the coordinate drive type. Activate this function. The activation method is to set the PLC's "Activate referencing" = 1 and "Active machine function REF" = 1, and "Traversing key +/-" (DB31, ... ; DBX4.7/4.6) to 1. 5.2 Method for Setting the Reference Point of the Driven Axis After the driving axis returns to the reference point, the driven axis will automatically return to the reference point. The reference point of the driven axis is determined by the driving axis. The driven axis cannot be manually returned to the reference point independently. 5.3 After returning to the reference point, the synchronous axis group will automatically run according to the NC programming requirements. VI. Machine Tool Data Related to Synchronization 6.1 MD NO. 37100 GANTRY_AXIS_TYPE This machine tool data is used to define two sets of basic synchronous characteristics: whether the coordinate belongs to the coordinate within the synchronous group, and which coordinate (driving axis or driven axis). Specific bit settings are shown in the following figure: For the 840D system, a maximum of three synchronous groups can be configured. A synchronous group must consist of one driving axis and at least one driven axis. Axes within the same group cannot be reused. If the definition is incorrect, the control system will output the message "INCORRECT GANTRY MACHINE DATA," indicating an error in the machine tool synchronous group configuration. The configuration example is as follows: 0 No synchronous axis 1 Driving axis 11 in synchronous axis group 1 Driven axis 2 in synchronous axis group 1 Driving axis 12 in synchronous axis group 2 Driven axis 3 in synchronous axis group 2 Driving axis 13 in synchronous axis group 3 Driven axis 6.2 MD NO. 37110 GANTRY_POS_TOL_WARNING and 37120 GANTRY_POS_TOL_ERROR These two data are for machine tool synchronization, ensuring the normal synchronization accuracy of the machine tool coordinates to complete the synchronous movement of the machine tool, and related output information to indicate whether it exceeds the machine tool synchronization range. After defining these data, the machine tool synchronization can be tested. VII. Synchronous axis signal description 7.1 NC control coordinate axis signal description 1. Start synchronization group signal DB 31, ... DBX29.4 ; Start gantry synchronization Starts the machine tool synchronization operation and ensures that the synchronization error is within the allowable range; otherwise, this signal is set to 0. 2. Start automatic synchronization signal DB 31, ... DBX29.5; Start automatic synchronization. This signal starts the automatic operation of the synchronization group, similar to the previous signal. 7.2 Signal descriptions from the coordinate axes: 1. Synchronization trip limit DB 31, ... DBX101.2; Gantry trip limit exceeded. A synchronization signal issued by the system. Received and processed by the PLC. 2. Synchronization warning limit DB 31, ... DBX101.3; Gantry warning limit exceeded. Same as above. 3. Synchronization axis synchronization started DB 31, ... DBX101.4; Gantry synchronization ready to start 4. Synchronization axis group is synchronized DB 31, ... DBX101.5; Gantry grouping is synchronized The specific coordinate synchronization signals are shown in the table below: [table][tr][td=1,1,103]DB Number[/td][td=1,1,144]Bit[/td][td=1,1,228]Content[/td][/tr][tr][td=3,1,475]General Signals[/td][/tr][tr][td=1,1,103]11-14[/td][td=1,1,144]5.2[/td][td=1,1,228] [Start machine tool REF function] [td=3,1,475]Channel signal[/td][/tr][td=1,1,103]21-28[/td][td=1,1,144]33.0[/td][td=1,1,228]Reference point start[/td][/tr][td=3,1,475]Coordinate signal[/td][/tr][td=1,1,103]31, ... ;[/td][td=1,1,144]60.4, 60.5[/td][td=1,1,228]Synchronization Reference Point[/td][/tr][tr][td=1,1,103]31, ... ;[/td][td=1,1,144]29.4[/td][td=1,1,228]Start Synchronization Signal[/td][/tr][tr][td=1,1,103]31, ... ;[/td][td=1,1,144]29.5[/td][td=1,1,228]No Automatic Synchronization[/td][/tr][tr][td=1,1,103]31, ... ;[/td][td=1,1,144]101.2[/td][td=1,1,228]Synchronization Travel Limits[/td][/tr][tr][td=1,1,103]31, ... ;[/td][td=1,1,144]101.3[/td][td=1,1,228]Synchronization Warning Limits[/td][/tr][tr][td=1,1,103]31, ... ;[/td][td=1,1,144]101.4[/td][td=1,1,228]Synchronization Ready[/td][/tr][tr][td=1,1,103]31, ... ;[/td][td=1,1,144]101.5[/td][td=1,1,228]Synchronization group synchronized[/td][/tr][tr][td=1,1,103]31, ... ;[/td][td=1,1,144]101.6[/td][td=1,1,228]Synchronization group axis ready[size=1][/size] [/td][/tr][/table] VIII. Establishing a Synchronization Axis Group Group Definition: Coordinate 1 = Driving axis using incremental measurement feedback loop; Coordinate 3 = Driven axis using incremental measurement feedback loop. Step 1: Modify the following machine tool data. Step 2: Set the NCK PLC interface signal. PLC program settings: axis1 settings: DB31, ... ; DBX 29.4 = 0 DB31, ... ; DBX 29.5 = 1 Axis3 settings: DB31, ... ; DBX 29.4 = 0 Machine tool ready signal settings: DB31, ... ; DBB101 Step 3: Set MD 37110: GANTRY_POS_TOL_WARNING and 37120: GANTRY_POS_TOL_ERROR as the maximum reference point for coordinates. Set MD 37130: GANTRY_POS_TOL_REF. The size and relationship of this coordinate data are as follows: Step 4: Setting complete, adjust machine tool parameters for matching. [b]IX. Conclusion[/b] Machine tool coordinate synchronization is a practical and fundamental technology in actual applications. Different configurations must be adopted according to the rigidity and structure of the machine tool to achieve the required machine tool accuracy. References [1] SINUMERIK 840D/840Di SINUMERIK 810D Special Functions…………………………SIEMENS [2] HMI/MMC SINUMERIK 840D/840Di/810D…………………………………………………SIEMENS [3] SINUMERIK 840D/840Di/810D Extended Functions………………………………………SIEMENS [4] SINUMERIK 840D/840Di/810D Measuring Cycles…………………………………………SIEMENS Zhang Fen: Female, born in September 1980, Master's degree; Work unit: Teacher of Department of Automation Engineering, Xi'an Aeronautical Vocational and Technical College, Postcode: 710089; Research direction: Motion control Tel: 13572816930 E-mail: [email protected]