Examples of the most popular fault detection metho

Examples of commonly used fault detection methods for numerical control equipment

now numerical control equipment is used more and more widely, followed by how to ensure the tensile test of the material of the equipment. We choose Jinan Sida WDS series models for effective utilization. When the equipment fails, we should restore the equipment to normal use as soon as possible. In order to solve this problem, first of all, maintenance personnel should have high quality. They should not only have rich professional knowledge, such as electromechanical integration technology, computer principle, numerical control technology, PLC technology, automatic control technology, drag principle, hydraulic technology, etc., but also master common sense of mechanical processing and simple programming of numerical control devices. In addition, they should have a certain level of English and be able to read English technical materials. There should be sufficient data, including mechanical, electrical and hydraulic drawings, machine tool parameter backup, system operation and maintenance manual, PLC ladder diagram, etc. There should also be a certain amount of spare parts. In addition, maintenance personnel need to have certain experience and master certain maintenance methods. The author has been engaged in the maintenance of numerical control equipment for many years, and has accumulated some experience. A set of methods for the maintenance of numerical control equipment are summarized as follows for reference

to find out the fault phenomenon

when the numerical control equipment has a fault, we must first find out the fault phenomenon, understand the situation of the first fault from the operator, observe the process of the fault when possible, and observe under what circumstances, how and what consequences the fault occurs. Only when we know the first-hand situation can we eliminate the fault. If we clarify the fault process, the problem will be solved in half. After finding out the fault phenomenon, we can start from one production line, and then according to the working principle of machine tool and CNC system, we can quickly diagnose the problem and eliminate the fault, so that the equipment can return to normal use

for example, when a CNC cylindrical grinder using the teachable III system of American Bryant company is used for automatic machining, the grinding wheel will grind off a piece of the dresser. In order to observe the fault phenomenon and prevent accidents from happening again, dismantle the grinding wheel and operate the machine tool. At this time, observe the fault phenomenon again. It is found that in the automatic grinding process, the grinding is normal and there is no problem. After the workpiece is grinded, when the grinding wheel is trimmed, the grinding wheel feeds normally, and the grinding wheel dresser rotates very fast, and soon press the upper limit switch. If the grinding wheel is not dismantled at this time, it is sure that the grinding wheel will hit the dresser again. According to the working principle of the machine tool, the grinding wheel dresser is driven by the e-axis servo motor, and the rotary encoder is used as the position feedback element. Under normal circumstances, when the dresser trims the grinding wheel, the z-axis sliding table drives the e-axis dresser to move to the dressing position, and the dresser swings 30 ~ 120 to trim the grinding wheel. We have observed the fault phenomenon for many times and found that when pressing the upper limit switch of axis E in the future, the coordinate value of axis E on the screen is only about 60, while the actual position is about 180. Obviously, there is a problem with the position feedback, but the replacement of the position control board and encoder did not solve the problem. After repeated observation and test, we found that when the e-axis dresser is at the edge of the z-axis, there is no problem in returning to the reference point and rotating and swinging, and the alarm information of the system should be used

now the self diagnosis ability of the CNC system is becoming stronger and stronger. Most of the faults of the equipment can be diagnosed by the CNC system, and corresponding measures, such as shutdown, can generally produce alarm display. When the numerical control equipment fails, sometimes the alarm information is displayed on the display, and sometimes there are alarm indications on the numerical control device, PLC device and drive device. At this time, these alarm information should be analyzed according to the manual. Some of them can directly confirm the cause of the fault according to the alarm information. As long as the content of the alarm information is clear, the faults of the CNC equipment can be eliminated

for example, a CNC channel grinder with German Siemens 810 system will generate No. 1 alarm display battery alarm power supply after starting up, which obviously indicates that the CNC system is powered off to protect the battery. After replacing the new battery (Note: the battery must be replaced when the system is powered on), reset the fault and restore the machine tool to use. Another CNC grinder with Siemens 3 system was determined by Heilongjiang provincial government. The screen did not display after startup. After checking the CNC device, it was found that a light-emitting diode on the CPU board flickered. According to the instructions, the flickering frequency was analyzed and it was confirmed that the power-off protection battery voltage was low. After replacing the battery, the restart system fault disappeared

for example, a CNC lathe using the FANUC 0tc system in Japan gives an alarm No. 2043 and displays hyd Pressure down indicates that the hydraulic system pressure is low. According to the alarm information, the hydraulic system was checked, and it was found that the hydraulic pressure was indeed very low. The hydraulic pressure was adjusted to restore the normal use of the machine tool

the alarm information of other faults can not reflect the root cause of the fault, but the result of the fault or other problems caused by it. At this time, the cause of the fault can be determined only after careful analysis and inspection. The following methods are effective for the detection of such faults and some faults without alarm