Some examples of the most popular ME810S machining

2022-07-31
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Several cases of ME810S machining center failure

at present, there are more and more machining centers using Siemens 840D system and 611D digital servo module. Compared with other systems and digital servo units used in our factory, 840D and 611D have the highest failure rate. Since the external use conditions of the machining center (such as power supply quality, environmental conditions, operator quality, etc.) are basically the same, the reason for the high failure rate may be the problem of 840D system and 611D digital servo or the problem of electrical design and parameter matching of the manufacturing plant of the machining center. The following is a list of common failures of ME810S machining center for the reference of peers in maintenance

example 1 in the process of machining, the CRT suddenly shows no display, and the LED indicator of some functions of the operating keyboard is on. The CRT is powered by the external 24VDC switching power supply, and the information flow is NCU unit - MPI bus - machine tool control panel - mmc100 - CRT. Check that the LED indicator on the interface of NCU unit and machine tool control panel displays normally, the manual operation of each axis is normal, and check that the CRT 24VDC voltage is normal

mmc100 interface board has an external VGA socket, which can be attached with a general-purpose computer VGA display, and can be used to determine the fault location. When an external VGA monitor is connected, the display is normal. Suspect the CRT display. It is normal after replacement

example 2: the external computer and the machine tool cannot normally transmit data. Check that the communication protocol of the computer side communication software is completely consistent with the machine tool side settings. Moreover, the data transmission has been carried out normally before. Therefore, it is suspected that the machine tool plant's debugging personnel randomly plug and unplug the communication cable during on-site operation and burn the communication part of the mmc100 interface board. After the mmc100 was replaced, the communication was normal. Therefore, when the machine tool communicates with an external computer, be sure not to plug and unplug the communication cable

example 3 during the machining process of the machine tool, the LCD display suddenly shows no display, but the LED indicators of some function keyboards on the control panel of the machine tool are on. Open the electric cabinet of the machine tool, and it is found that the relevant LED indicators of e/r module, NCU module, MSD (spindle) module and FDD (x/y axis, Z axis) module have no indication, and the s PLC indication is normal. Measure that the bus voltage of e/r unit is 0V, and it should be 600vdc normally. Turn off the power supply of the machine tool according to the shutdown sequence, start the machine after 5min, and measure the 600vdc voltage of the e/r module while starting the machine. It is found that the voltage is about 30VDC when the machine tool is started, and then it drops to 0V. Therefore, it is suspected that a load of the e/r power module has short circuit or serious overload

when the machine tool is powered off, unplug the device bus cable plug (x351 plug) on the z-axis module, x/y dual axis module, MSD module and NCU module from right to left. Every time you unplug the x351 plug of one module, restore the x351 plug of other modules, and then power on the machine tool to observe whether the fault phenomenon is eliminated. It is confirmed that there is a problem with the x/y dual axis module. The module is composed of x/y dual axis signal interface panel and power amplifier module. Replace the signal interface panel, and the fault remains. Replace the x/y dual axis power amplifier module, and the machine tool returns to normal

in less than two years, three groups of x/y dual axis modules have failed. The main fault causes are: ① poor external power quality; ② the drive module selected by the machine tool factory is not necessarily optimal. For example, whether the power of the servo module matches the load of the machine tool, and the optimization of the machine tool parameters and shaft parameters; ③ poor working environment: ① improper startup and shutdown sequence of the machine tool. Since the Siemens servo module uses regenerative voltage to feed back external power, improper switching on and off sequence can easily destroy the feedback path and damage the module

when starting the machine, first turn on the main power supply of the machine tool, then release the emergency stop button, and then press the spindle enable and feed enable keys respectively. The carbon fiber reinforced thermoplastic composite (CFRTP) prepared by combining the advantages of engineering plastics, such as corrosion resistance, low specific gravity, impact resistance, easy forming, and two-time use, makes each servo module in the enabled state. When shutting down, first press the spindle enable and feed enable keys to make each servo module in the non enable state, press the emergency stop button, and then turn off the main power supply of the machine tool

example 4: the self-test of the machine tool is normal after startup. After self inspection, press the spindle enable key and feed enable key, and then press the automatic return to origin key of the machine tool. The machine tool has no action to enhance communication and exchange in the industry. The LCD displays no axis enable information. It is found that after each enable key is pressed, the corresponding LED indication is normal. After pressing the auto home key, the LCD displays the message "no feed enable signal". Open the door of the electrical cabinet and find that the green LED on the e/r module is on, while the normal state should be yellow LED. The green LED on indicates that the equipment is not ready due to the loss of external enabling signals (terminal numbers 63, 64, 48)

according to the electrical drawings provided by the machine tool manufacturer, check that terminal 63 of x121 socket on the e/r module is directly short circuited with terminal 113 of the module: terminal 64 of x121 socket is connected with terminal 9 through the normally open contact of relay K19; terminal 48 of x161 socket is connected with terminal 9 of x121 socket through the normally open contact of time relay KT. Check that the above connection signals are normal

after carefully reading the relevant materials, it is found that the e/r module is connected with the external 1 The test knowledge required by the descent tester is connected to two groups of terminals: one group is terminal 72 and 73.1 of x111 socket, and the two terminals are connected to a normally open contact of the relay inside the e/r module. External 72 of the module is connected to e32.1 point of PLC input module, input e/r overload signal, and 73.1 is connected to +24v external power supply: the other group is terminals 5.1 and 5.3 of x121 socket, and the internal e/r is connected to the normally open contact of another relay. External 5.1 of the module is connected to e32.0 point of PLC input module, input e/r module ready signal, and 5.3 is connected to +24v. With the help of the PLC diagnosis screen of LCD, it is checked that the internal output overload signal of e/r interrupts the Nck and no enable output. Replace the e/r module and the machine tool returns to normal

example 5 after the machine tool is started, the LCD displays 4050 NC code identifier @ can not be reconfigured to alarm. The alarm prompts that there are characters "@" that the NC system cannot recognize in the data stored in the NC system parameters, programs and other memories. Since there is no input key with "@" character on the operation panel of the CNC system, it can not be caused by misoperation, and some data may be changed due to some interference. To check all parameters and programs, the workload is too large, so it is decided to initialize the CNC system, and then use an external computer to load the original backup data. The Nck initialization steps of s 840D numerical control system are as follows: ① turn the S3 rotary switch on the NCU module panel from 0 to 1 (start-up mode): ② press the reset switch on the NCU module panel, and the extruder products fluctuate in export and Nck is restarted. When the NC software initialization is completed, the 7-segment status display on the module panel displays "6". At this time, the data stored in RAM (SRAM) has been erased, and the standard machine tool data has been loaded: ③ turn the S3 rotary switch from 1 to 0; ④ load the backup machine tool data, processing programs, etc. with an external computer; ⑤ run the pitch compensation programs of X, y, z axes. The machine tool returns to normal. (end)

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