The CNC Gantry Machining Center was manufactured by WALDRICH COBURG of Germany in 1983. The machine tool is a double gantry and can be controlled independently. The model number is 20-10-600CNC. The original machine has a total of X1 axis, XA1 axis (Double Gate Simultaneous movement), Y axis (skateboard), Z axis (ram), W1 axis, WA1 axis (beam synchronous movement), S axis (spindle), C axis (rotation work (Taiwan), A axis (accessory shaft) 9 axes, with 12 attachment heads. The original control system adopts SIEMENS8MC CNC control system. The X-axis uses a resolver for position detection and a mechanical synchronous drive bar to ensure the synchronization requirements of the column movement. Other control shafts use induction synchronizers as position detection elements. The cross beam movement uses a DC motor in series and is equipped with a mechanical synchronous drive bar to keep the drive synchronized. An AC fine-tuning motor is also provided on one side for adjustment. The drive of the machine tool is controlled by an analog DC servo system.
Machine specifications and parameters:
X axis stroke: 0--27000mm, speed: 5--10000mm/min;
Y axis stroke: 0--8000mm, speed: 5-6000mm/min;
Z axis stroke: 0--1000mm, speed: 5-3000mm/min;
W axis stroke: 0--3900mm, speed: 5-2000mm/min;
The spindle has a directional function, two gears, one gear speed is 6-275r/min, and second gear speed is 17-750r/min.
The transformation of CNC system
Siemens 840D CNC system was selected to reconstruct the SINUMERIK 8MC CNC system of the original CNC milling machine. The new system includes a "10.4" color TFT (OP031) display and MMC103 with a hard disk. MMC software version is 5.3, WINDOWS95 operating system, "3.5" floppy drive, R232 standard communication port. The NCU is a 572.3 system and the software version is version 5.3 of the 840D. The PLC adopts S7-300 input/output modules, and at the same time, 13 S7-ET200B PLC modules (including two analog output modules) are installed on the PROFIBUS interface of the 840 CNC system to establish 4 remote control substations. The data transmission speed of this interface is 1.5 Mbaudrate, which is much higher than the transmission speed of the X122 interface of 187.5 Kbaudrate, which improves the data transmission speed. Siemens dedicated communication cables are used between substations for data communication with the CPU. This saves the number of control cables and reduces the electrical failure rate. The machine also has a gantry axis function and master-slave function (mainly to solve X1, XA1, W1, WA1 synchronous operation) and five-axis linkage function, Chinese display, the standard canned cycle, with 840D standard system functions.
Drive system and motor configuration
Siemens 611D digital servo drive system and 1FT6 series AC servo motor were selected to transform the X1 axis, XA1 axis, Y axis, Z axis, W1 axis, WA1 axis and S axis. Siemens 611D digital modules were selected for control.
PLC section
Siemens S7-300 and S7-ET200B were selected to retrofit the original S5-PLC. Using SIEMENS 840D standard machine tool control panel and user operation panel to achieve some of the machine's auxiliary actions and functions.
Machine tool standard function setting
First, according to the original machine tool standard functions, self-designed electrical schematics, and on-site installation and commissioning for PLC, NC online debugging.
The original Y axis, Z axis, W1 axis, WA1 axis measurement system was replaced by HEIDENHAIN linear scale (LB382C). Replace the original X-axis position encoder, spindle orientation encoder with HEIDENHAIN incremental encoder (ROD485). The X-axis synchronization function utilizes two incremental encoders (ROD485). The gantry axis function of the 840D is used to realize synchronous operation of the two motors X1 axis and XA1 axis. The W-axis synchronization function uses the LB382C linear encoder (one linear encoder and one left and one right). The gantry axis function of the 840D is used to realize synchronous operation of two motors on the W1 axis and the WA1 axis, and a fine-adjustment motor is provided on the WA1 side as a manual beam horizontal adjustment.
The spindle is different from the proximity switch installed on the milling head of the ram. It can be programmed by PLC program to automatically and manually install the attachment head and different attachments. Different power limits of the milling head can be used to protect the attachment. Super power for workpiece cutting.
Machine data configuration
For a standard CNC gantry machining center, the following machine data configuration was made according to the actual working requirements of the machine tool.
X1, XA1, Y, Z, W1, WA1, S axis NC parameter configuration;
X1, XA1, Y, Z, W1, WA1, S axis drive parameter configuration;
X1, XA1, Y, Z, W1, WA1, S axis drive optimization;
Pitch compensation for X1, XA1, Y, Z, W1, WA1 axes.
Through the PROFIBUS bus, each user's operation station on the machine tool is configured for hardware configuration and connection. The establishment and display of the set-top user alarm information and operation information, the programming of the attachment head loading and unloading, and the realization of the standard functions of the 840D control system.
PLC control program design and online debugging
In addition to designing the PLC program for various functions required for the normal operation of the machine tool, the following PLC program design and debugging were also performed for the special functions of the CNC gantry machining center.
Using two incremental encoders, X-axis gantry axis synchronization PLC program design and debugging. Using two LB382C linear encoders, W axis gantry axis synchronization PLC program design and debugging. W-axis beam automatic, manual leveling PLC programming and debugging. Spindle and accessory milling head power limitation PLC program design and debugging.
According to different combinations of proximity switches installed on the ram and attachments on the milling head of the attachment, automatic programming and commissioning of various attachment milling heads, and PLC programming and debugging of the loading and unloading; Design and debugging; PLC program design and debugging of beam forward and backward tilt (blade cutter device); PLC program for each axis limit, reference program design and debugging of each axis; user alarm information and operation according to machine tool requirements PLC programming and debugging of information.
The failure alarm of CNC machine tools plays a significant role in the operation and maintenance of machine tool operators and maintenance technicians. Therefore, the fault alarm classification level of the machine tool is designed as follows: the emergency stop of the machine tool, the corresponding and related actions are stopped, and the corresponding action is stopped after the alarm prompt is delayed. , alarm tips. The machine tool is designed to automatically detect the power used by the spindle accessory and generate an alarm message when the maximum set load is reached. When the maximum set load is exceeded, the corresponding feed action is stopped. Use simple Chinese language to describe alarms and provide related fault diagnosis information. To protect the machine tool, the corresponding faults and diagnostic information after the alarm must not be automatically eliminated without manual removal. The above information is displayed in Chinese on the CNC display.
Bed safety protection, operation interlocking PLC program design and debugging. Including spindle shifting PLC program design and debugging; each user operating station manual function of the PLC program design and debugging, CNC panel and extended machine tool panel debugging; other auxiliary functions of the PLC program design and debugging.
Through the configuration of SIEMENS 840D CNC system, Siemens 611D digital servo drive system and 1FT6 series AC servo motor and use of Siemens 611D digital modules, S7-300 digital input and output modules, ET200B modules and other hardware. Using Siemens' exclusive TOOLBOX software, the PLC program design and the 840D CNC system NC machine data were correctly configured. Once the commissioning was successful, the original machine tool design function was achieved, and the test was successful in a very short time and put into production use. At the same time, it also enabled us to understand the superior performance of the SIEMENS 840D CNC system and accumulated experience in the design and commissioning of CNC machine tools.