Examples of the hottest CNC machine tool maintenan

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Numerical control machine tool maintenance example

numerical control machine tool adopts digital control system, which can realize multi axis linkage, realize the processing of three-dimensional shape, and process parts with complex geometry, so it is favored by people. In recent years, with the wide application of numerical control machine tools, people have a considerable understanding of numerical control technology, and can eliminate some common faults, thus improving the utilization rate of machine tools, but they still feel thorny about some uncommon faults. Here are a few examples of PolyOne's colorants that also add vibrant colors to the materials, such as Superman Blue, watermelon red, lime green and bright orange. The author has encountered in the maintenance of CNC machine tools in recent years for your reference

as we all know, rotary encoders or grating rulers are generally used as position feedback elements on CNC machine tools. After the machine tool is turned on each time, it is necessary to find a reference point to determine the coordinate point of the machine tool, that is, we often say "return to zero". After the rotary encoder fails, the "zero return" operation cannot be carried out generally, and the alarm will be given because the correct reference point cannot be found. Here are some special faults encountered

fault phenomenon - CNC lathes made in Taiwan adopt fanuc-0 system. When the tool touches the workpiece during processing, it will generate 400# alarm (i.e. servo alarm)

diagnosis and troubleshooting check that the processing program is correct, and check that the mechanical transmission part of each shaft is not obstructed, and the movement is flexible. The diagnostic parameters show that the x-axis is overloaded, so check all parts of the motor, but they are normal, and the supply voltage and holding brake coil voltage are also normal. All cables and connectors are normal. Replacing the servo unit, axle card and power supply unit still cannot eliminate the fault. Later, contact the manufacturer to replace the encoder in the motor and troubleshoot

fault phenomenon 2. A turning unit using Siemens sinumeriksystem 840C, after starting up, the upper plane of the X foundation should be flat, and the axis cannot return to the reference point. The X axis can decelerate but does not stop during the "return to zero" process. The maximum stroke of each action does not exceed 40mm until the hard limit is pressed, the coordinate value of the surface plate changes suddenly, and the display value is very large. At the same time, the alarm "x axis SW limitswitch minus" is displayed

diagnosis and troubleshooting check that the parameter settings in the machine tool are correct, and no faults are found in peripheral devices such as cable connections. Under the manual mode, the machine tool can act and display coordinate values. The machine tool can be positioned, which means that the grating ruler should not be damaged. After checking that the grating ruler is a German "Heidenhain" product, we learned that the zeroing method adopted by Heidenhain grating ruler is different from that of other company products. In order to avoid looking for reference points in a large range, the reference mark is encoded by distance, and a notch is added next to the grating scribe line. The reference position can be found through two adjacent reference marks, That is, the "zero point" can be found within any 40mm (or 80mm, depending on the model of the grating ruler). After removing the shield of the machine tool, it was found that due to the long use time, the oil mist entered the grating ruler, the zero mark was blocked, and there was no zero pulse output, so the machine tool could not find the zero. Because the device is maintenance free, the manufacturer was contacted to replace it and the fault was eliminated

fault phenomenon Sany machine tool cannot return to the correct reference point

diagnosis and troubleshooting this machine tool adopts fanuc-0m system. There is no deceleration bump block on the machine tool, but only a hard limit stop device. For the work of "returning to zero" of the machine tool, it was originally weighed with a precision analytical balance to confirm the amount of wear. It is clear to everyone that it generally moves in the axial set direction. When the zero switch is pressed, it decelerates, and when it is separated from the zero switch, the CNC system presses the first zero pulse received, It is determined as the reference point of the machine tool (there are roughly three specific ways to return to zero). After contacting the manufacturer, the fault was solved in the following way. After starting the machine, manually move the shaft to the hard limit position, remove the "limit alarm", then swing the shaft to 5mm away from the limit switch, change the parameters 20 and 21, and then shut down the machine. After starting the machine again, the fault is eliminated

for machine tool failures caused by sudden power failure, interference or misoperation of the machine tool, we don't need to carry out cumbersome operations in sequence. Sometimes as long as we master the basic laws, we can solve them in an easy way

the tool change mechanism of general CNC machine tools is composed of four parts: the cutter head is pushed out, the cutter head rotates, the cutter head is pushed in, and the cutter head is clamped. When the tool change mechanism is disordered or the tool fails to be positioned and clamped, it can be restored by manually following the above steps, but it is quite troublesome. In fact, sometimes we can find the law as long as we observe it carefully

fault phenomenon four knife control system: it mainly includes the part of the disc controlled by the computer that is turned in place but not clamped

diagnosis and troubleshooting. According to the electrical schematic diagram of the machine tool, find the corresponding solenoid valve wiring. The i/o display of the machine tool shows that the cutter head of the machine tool is in place but not clamped. Open the electrical cabinet and find the solenoid valve wiring pushed by the cutter head. It can be seen from the relay that it is not powered on at present. Find a temporary line to quickly connect the solenoid valve to solve the fault

therefore, when dealing with the faults of CNC machine tools, we should consider both their universality and particularity. After the fault occurs, both of them should be considered comprehensively in order to solve the problem accurately and quickly. (end)

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