Imported CNC equipment features and maintenance ideas

Some people think that the imported CNC equipment is easy to repair and use, which is mainly caused by the lack of understanding of its features. To repair the imported CNC equipment, it is necessary to first understand its characteristics, and to develop maintenance ideas based on these characteristics, which is beneficial to accurately and quickly judging the fault.

First, do not blindly believe in the quality of imported CNC equipment Imported CNC equipment is mostly the product of today's most cutting-edge technology applications, but due to manufacturers rush to launch, there is not enough time-efficient test, it is inevitable that there is design, manufacturing imperfections. The cylinder hole honing machine purchased from Germany GEHRING Company adopts advanced numerical control hydraulic servo technology to better solve the closed loop control of the angle, depth, cylinder bore diameter and cylindricity. The company is a world-famous company, and its newly developed laser honing technology is being tested at the Mercedes-Benz car factory and it is reported to be very successful. But it was such a device produced by a well-known company. After more than a year's use, there were frequent malfunctions such as sudden operation interruptions and equipment parking. Sometimes it will return to normal after restarting, and sometimes it will take more than one time to be normal, and sometimes there will be no problem for a period of time, and sometimes it will cause problems continuously. Alarm information shows "SYSTEM COMMUNICATION" system communication failure.

This phenomenon is generally called "soft failure." At first, it was suspected that it was caused by noise and harmonics in the power grid. The quality of the power grid was examined. The inspection report shows that the harmonics of the power grid are exceeded and it is recommended to filter them. Under normal circumstances, the harmonic quality of the power grid is mostly exceeded. Grid interference is only an external cause, and the overall anti-jamming performance of the system is an internal cause. Most of the imported CNC equipment have simple power grid noise filtering technology, and they only have problems after more than a year of use, indicating that the system is resistant to external interference. Today, either the external interference becomes stronger or the system's anti-interference performance deteriorates. From the normal operation of other imported CNC equipment in the factory, it may be a system problem. When testing the GEH A25 module, it was found that this module has obstacles in the power-on communication, the connection speed is slow, and the anti-interference performance is poor, but it is ignored by the host. After replacing a new module, the equipment runs stably and the fault disappears.

The original CNC-GOP system is a patented product jointly developed by GEHRING and SIEMENS. It has special functions, convenient control and stable performance. Because it is a newly developed system, it has not passed enough tests of timeliness, and it has poor anti-interference and stability. In fact, many manufacturers at the forefront of equipment manufacturing technology have similar problems. Therefore, we must not blindly worship the Western high technology and we must see that even advanced technology is still under development and there may be flaws. The more advanced the technology, the more likely it is to have flaws. In the maintenance of imported CNC equipment, it is necessary to recognize its technological advancement, but also to see its shortcomings in a pragmatic manner.

Second, to have an analytical reading of alarm information Imported equipment numerical control system control part of the design is rigorous, a seemingly minimal exception will also enter the alarm entry, and may stop the machine. In the process of actually repairing imported CNC equipment, reading alarm information is the most basic and most convenient method for seeking rapid repair. But not every piece of information is credible. Every piece of information can be used. In the numerous alarm messages, there are many that may be useless and may even be misleading. It is advisable to be good at extracting information from the information and eliminating it.

For example, CNC cam grinding machine produced by Germany SCHAUDT company is a CBN grinding machine with grinding cam and peach type. Each time you turn on your computer, you will see a lot of alarms. In fact, all of them are just starting up. There are many conditions for preparation that are temporarily not satisfied. There is no practical significance.

Secondly, the machine alarm indicates that the “Filter of oil dirty” static system filter is dirty. The equipment spindle slide adopts static pressure floating guide. The filter was removed for cleaning, but it was still alarmed after it was installed; another new filter was taken and the alarm could not be eliminated. A close look at the PLC alarm code, followed by the code to find that the fault condition for the static pressure floating rail pressure sensor does not work. The faulty design explanation is that when the pressure sensor does not sense pressure, it is interpreted as a filter plugged. However, through careful inspection, the filter is good. It is precisely a problem with the pressure sensor that sends a signal without sending a signal.

A given alarm message is given by the designer based on the PC simulation. It is not his experience of on-site maintenance for many years. It is often designed according to conventional logic, with the designer's personal understanding of the simulation results. However, the occurrence of failures is often unexpected, or based on fault phenomena and random data to reason and judge. The correct attitude towards the alarm information provided by the machine is: Never believe it, but do not believe it. Do not rely on alarm information and do not fall into the trap of false alarm information.

Third, when the machine tool is just starting to use it, it is necessary to make a complete backup. Imported numerical control equipment mostly uses modern microelectronics numerical control technology and uses a PC to manage. It should be said that the use of PC management CNC-PLC and OP systems, the performance of the machine tool, Maintainable performance has been greatly improved. However, if you forget to back up in time, it will cause trouble if the machine program or parameters are lost. Especially in the case of various computer viruses, backing up the PC system is more necessary.

After a holiday, an OP panel warning light flashes when an imported digital control device is turned on. Upon inspection, it was confirmed that the CNC and PLC parameters in the SIEMENS system were all lost. Immediately after the program recovery work was performed, the discs, floppy discs, and other data brought in by the imported data were entered into the system, and the machine still could not operate. Originally, most of these data were backed up by manufacturers at the time of shipment. After trial commissioning and site operation, some procedures, especially the vast majority of parameters, were greatly modified. In particular, the SIEMENS system complies with European safety standards. After the program is written, the user agreement is signed. If you do not have the latest backup on hand, and you are not familiar with the recovery system, you will be very passive.

How can we avoid the passive occurrence of lost programs? It is the worst case scenario - the preparation for a hard disk damage. After the hard disk was damaged, everything could not be done. Of course, it is possible to re-create new system hard disks, but most of the hard disks in imported CNC equipment are non-standard. Some can be replaced with notebook hard drives, but the success of this attempt is not very big. In particular, automotive manufacturers require equipment to be repaired in as short a time as possible, and it is impossible to give too much time for hard disk recovery work.

In order to cope with the sudden loss of system programs that may occur, the following methods are available:

(1) Make a complete backup of the D drive of the PC's hard disk, you must clearly mark the file name, product name, parameter type, date, and other important identification. This is the most basic and convenient backup method, and it can be immediately resumed once the machine program or parameters are lost. The disadvantage is that once the PC itself fails, program recovery cannot be performed. (2) In the D drive of the PC, make a GHOST backup to the system drive C drive. This is an easy and effective method to deal with PC system failures (including virus destruction). Sometimes all anti-virus methods do not regain the efficiency of system disk C drive GHOST recovery. GHOST chooses V 7.50 version to run better under DOS.

(3) Burn the GHOST backup of the PC hard disk contents into the disc. This method is safe and reliable. It is a good method for backing up files outside the machine.

(4) Copy the hard disk. This is the safest and most reliable method. Purchase a new hard disk that is completely consistent with the PC and save it properly. After a PC hard disk failure occurs, replace the backup hard disk immediately. The advantage is fast and reliable, the disadvantage is high cost.

Fourth, comprehensive system considerations, scientific reserve spare parts In order to ensure the normal operation of imported CNC equipment in the production, we advocate yourself to repair damaged devices. However, numerical control devices generally have high technological content. Most of them have intellectual property protection and cannot be repaired easily. Therefore, necessary spare parts must be stocked. The size and variety of spare parts reserves have always been a controversial topic. Too many reserves take up too much money and waste, and too few reserves can not meet production needs. The spare parts reserve of imported CNC equipment can be determined based on the following factors:

(1) Reserves generally do not exceed 5% of the equipment price at the time of purchase. Of course, this is a reference quantity, and the specific circumstances of the equipment should also be considered.

(2) Refer to imported CNC equipment for machine and electrical complexity. The complexity factor is large, and the corresponding reserves can be slightly larger. On the contrary, it can be slightly smaller.

(3) Choose the same manufacturer's CNC system at the time of purchase as much as possible, which can greatly save the cost of spare parts.

(4) There is a difference between the hardware and software of imported CNC equipment. For products that are developed by some manufacturers, they should be stored as full as possible according to availability. Because these spare parts usually have narrow supply channels and long procurement cycles, they are "monopolistic products" and it is necessary to be "prepared for disasters."

(5) Reserve according to market supply. Products such as SIEMENS, FANUC, etc., have a sufficient supply in the market and can be stocked according to their purchase delivery date. For short-term purchases, purchases can be postponed, and longer delivery times can be properly purchased.

(6) Determine the reserve of spare parts based on production output. In the final analysis, the reserve of spare parts is "insurance investment" to ensure the normal production is not interrupted. The larger the output, the greater the "insured amount" is, which is in line with the economic laws. Two-shift production should be greater than the production of single-shift production. Conversely, it can be considered as an appropriate reduction.