A. the purpose and significance of CNC machine tool maintenance
As we know, CNC machine tools are high-tech products that comprehensively apply advanced technologies such as computer technology, automatic control technology, automatic detection technology and precision machinery design and manufacturing, and are typical mechatronics products with high technical density and high degree of automation. . Compared with ordinary machine tools, CNC machine tools not only have the characteristics of high machining accuracy, high production efficiency, stable product quality and high degree of automation, but also can process complex surfaces that are difficult or impossible to process by ordinary machine tools, so CNC machine tools play an increasingly important role in machinery manufacturing. We can even say that in the machinery manufacturing industry, the grade and quantity of CNC machine tools is an important symbol reflecting the manufacturing ability of an enterprise.
However, we should be soberly aware that whether CNC machine tools can achieve the goals of high machining accuracy, stable product quality and improved production efficiency in enterprise production depends not only on the accuracy and performance of the machine tools themselves, but also on whether the operators can correctly maintain and use CNC machine tools in production.
At the same time, it should also be noted that the concept of CNC machine tool maintenance can not be simply understood as that when the CNC system or the mechanical parts of CNC machine tools fail, it only depends on how the maintenance personnel troubleshoot and repair them in time, so that CNC machine tools can be put into use as soon as possible, which should also include correct use and daily maintenance.
To sum up, only by adhering to the daily maintenance of machine tools can we prolong the service life of parts, prolong the wear cycle of mechanical parts, prevent the occurrence of unexpected and vicious accidents and strive for the long-term stable operation of machine tools; Only in this way can we give full play to the machining advantages of CNC machine tools, achieve the technical performance of CNC machine tools, and ensure that CNC machine tools can work normally. Therefore, the maintenance of CNC machine tools is very important for the operators and maintenance personnel of CNC machine tools, and must be highly valued.
B. Basic requirements for maintenance of CNC machine tools
After we understand the purpose and significance of CNC machine tool maintenance, we must also make clear its basic requirements. Mainly includes:
1, we should attach great importance to the maintenance of CNC machine tools, especially for the operators of CNC machine tools. We can't just pay attention to the operation and ignore the daily maintenance of CNC machine tools.
2. Improve the comprehensive quality of operators.
The use of CNC machine tools is more difficult than using ordinary machine tools, because CNC machine tools are typical mechatronics products, involving a wide range of knowledge, that is, operators should have a wider range of professional knowledge such as machinery, electricity, liquid and gas; Moreover, because the numerical control system in its electrical control system is updated quickly, it is impossible to master the application of new numerical control system skillfully without professional theoretical training and irregular study. Therefore, the quality requirements for operators are very high. Therefore, it is necessary to train CNC operators and systematically learn the principle, performance, lubrication parts and methods of machine tools, so as to lay a foundation for better use of machine tools. At the same time, in the use and management of CNC machine tools, a series of practical and effective measures have been formulated.
3, create a good environment for the use of CNC machine tools.
Because there are a lot of electronic components in CNC machine tools, I am most afraid of direct sunlight, humidity, dust and vibration. , can make electronic components corrosion or cause short circuit between components, resulting in the machine tool can not work normally. Therefore, the use environment of CNC machine tools should be kept clean, dry, constant temperature and vibration-free; For power supply, the voltage should be stable, and generally only 10% fluctuation is allowed.
4, strictly follow the correct operating procedures.
No matter what type of CNC machine tool, it has its own operating rules, which is not only one of the important measures to ensure the personal safety of operators, but also an important measure to ensure the safety of equipment and the quality of products used. Therefore, users must operate correctly according to the operating procedures. If the machine tool is used for the first time or not for a long time, it should be idling for a few minutes. And in use, special attention should be paid to the sequence and precautions of starting and shutting down. See 6.5 below for the operating procedures of various CNC machine tools.
5, in use, as far as possible to improve the operation rate of CNC machine tools.
In use, it is necessary to improve the running rate of CNC machine tools as much as possible. Newly purchased CNC machine tools should be put into use as soon as possible, and the failure rate of equipment in the initial stage of use is often relatively large. Users should make full use of the machine tools within the warranty period, expose their weak links as soon as possible, and solve them within the warranty period. If there is a lack of production tasks, we cannot be idle. Start the machine regularly, idling about 1 hour at a time. Use the heat generated when the machine tool is running to remove or reduce the humidity in the machine.
6, to treat machine tool failure calmly, not blindly.
Some faults will inevitably occur during the use of machine tools. At this time, the operator should treat it calmly and not blindly, so as not to cause more serious consequences. Pay attention to keeping the scene. After the maintenance personnel come, they will truthfully explain the situation before and after the fault, and participate in the analysis of the problem to eliminate the fault as soon as possible. If the fault is caused by operation, the operator should learn from the experience in time to avoid making the same mistake again.
7, formulate and strictly implement the rules and regulations of CNC machine tool management.
In addition to the daily maintenance of CNC machine tools, it is also necessary to formulate and strictly implement the rules and regulations of CNC machine tool management. Mainly includes: personnel, posts and responsibilities "three fixed" system, regular inspection system and standardized handover system. This is also the main content of management, maintenance and maintenance of CNC machine tools.
C. Inspection and management of maintenance of CNC machine tools
Because CNC machine tools integrate many technologies such as machinery, electricity, hydraulic and pneumatic, their maintenance should be managed scientifically and corresponding rules and regulations should be formulated purposefully. Hidden dangers found in the maintenance process should be eliminated in time to avoid downtime for repair, thus prolonging the mean time between failures of equipment and improving the utilization rate of machine tools. Implementing spot inspection is an effective method to maintain CNC machine tools.
Equipment maintenance based on routine inspection is a routine inspection management system developed by Japan on the basis of introducing American preventive maintenance system. Spot inspection refers to the fixed-point and regular inspection and maintenance of equipment according to the provisions of relevant maintenance documents. Its advantage is that it can eliminate the deterioration of easy-going performance in the bud and prevent over-repair or under-repair, but its disadvantage is that the workload of regular spot inspection is large. This modern maintenance management system with spot check as the core in the equipment operation stage can achieve the purpose of reducing failure rate and maintenance cost and improving maintenance efficiency.
Since the early 1980s, Japanese equipment maintenance system has been introduced into China, organically organizing equipment operators, maintenance personnel and technical managers. According to the specified inspection standards and technical requirements, the parts of the equipment that may have problems are inspected, maintained and managed at fixed points, fixed personnel, fixed quantity, fixed time and fixed points, which ensures the continuous and stable operation of the equipment and promotes the development of production and the improvement of operating efficiency.
The spot inspection of CNC machine tools is the basis of condition monitoring and fault diagnosis, which mainly includes the following contents:
(1) Fixed-point First, determine how many maintenance points a CNC machine tool has, scientifically analyze this equipment, and find out the parts that may fail. As long as you "stare" at these maintenance points, you will find faults in time.
(2) The calibration standards, such as clearance, temperature, pressure, flow and sealing, should be formulated for each maintenance point one by one. And there must be clear quantitative standards. As long as it does not exceed the prescribed standards, it is not a fault.
(3) How often do you check it regularly? Determine the inspection period. Some points may be inspected several times per shift, and some points may be inspected once a month or several months. It depends on the specific situation.
(4) Determine which items should be checked at each maintenance point. Each point can check one or several items.
(5) Who will carry out the inspection, whether it is the operator, maintenance personnel or technical personnel, according to the inspection site and technical accuracy requirements.
(6) How to check the method should also be specified, whether it is manual observation or instrument measurement, ordinary instrument or precision instrument.
(7) The environment and steps of inspection shall be specified, whether it is inspection in production operation or shutdown inspection, disintegration inspection or non-disintegration inspection.
(8) Record inspection shall be recorded in detail, and filled out clearly in the prescribed format. Fill in the inspection data and their differences with the specified standards, judge the impression and handle the opinions, and the inspector shall sign and indicate the inspection time.
(9) If it can be handled and adjusted in the process of processing inspection, it shall be handled and adjusted in time, and the processing results shall be recorded. Without the ability or conditions to deal with it, it is necessary to report to the relevant personnel in a timely manner and arrange for handling. But anyone, at any time, must fill in the processing record.
(10) Regularly and systematically analyze the analysis, inspection and treatment records, find out weak "maintenance points", that is, points with high failure rate or links with large losses, put forward opinions, and submit them to the designers for improving the design.
The spot inspection of CNC machine tools is divided into two levels: daily spot inspection and full-time spot inspection. Routine spot check is responsible for the spot check of the general parts of the machine tool, handling and checking the faults in the process of machine tool operation, which are carried out by the machine tool operators. Full-time spot check is responsible for key spot check, equipment condition monitoring and fault diagnosis of key parts and important parts of machine tools, making spot check plans, making diagnostic records, analyzing maintenance results, and putting forward suggestions for improving equipment maintenance management, which are carried out by full-time maintenance personnel.
As a working system, the spot check of CNC machine tools must be seriously implemented and continued to ensure the normal operation of the machine tools.
Judging from the requirements and contents of spot checks, spot checks can be divided into full-time spot checks, daily spot checks and production spot checks. Schematic diagram of routine inspection and maintenance process of CNC machine tools.
1. Full-time spot check
Be responsible for regular spot checks on key parts and important parts of machine tools, make inspection plans for intact rate monitoring and fault diagnosis, make diagnosis records, analyze maintenance results, and put forward suggestions for improving equipment maintenance management.
2. Daily routine inspection
Responsible for checking the general parts of the machine tool, handling and checking the faults in the operation of the machine tool.
3. Production inspection
Responsible for the inspection of CNC machine tools in production and operation, and responsible for lubrication and fastening.
As a working system, spot check must be carried out seriously and persistently to ensure the normal operation of CNC machine tools.
D. Maintenance and maintenance of CNC machine tools
The key to preventive maintenance is to strengthen daily maintenance. The main maintenance work includes the following contents:
1. Check frequently.
Its main projects include hydraulic system, spindle lubrication system, guide rail lubrication system, cooling system and pneumatic system. Daily inspection is based on the normal situation of each tested system. For example, during the process inspection of the spindle lubrication system, the power light should be on and the oil pump should operate normally. If the power light is not on, the spindle should be stopped and contact the mechanical engineer. For maintenance.
Step 2 check every week
Its main items include machine tool parts and spindle lubrication system, which should be checked correctly every week, especially the machine tool parts should be cleaned of iron filings and external sundries.
3. Monthly inspection
Mainly check the power supply and air dryer. Under normal circumstances, the rated power supply voltage is 180V-220V, and the frequency is 50Hz. If it is not normal, it must be measured and adjusted. The air dryer should be disassembled once a month, then cleaned and assembled.
4. Quarterly inspection
The quarterly inspection is mainly carried out from three aspects: lathe bed, hydraulic system and spindle lubrication system. For example, checking the lathe bed mainly depends on whether the accuracy and level of the lathe meet the requirements in the manual. If you have any questions, please contact the mechanical engineer immediately. When checking the hydraulic system and the spindle lubrication system, if there are any problems, please replace them with new oil 6oL and 20L respectively and clean them.
5. Check once every six months.
After half a year, check the hydraulic system, spindle lubrication system and X axis of the machine tool. If there is a problem, replace it with new oil and then clean it.
After being fully familiar with and mastering the knowledge of preventive maintenance, we must also have a deeper understanding and necessary grasp of the causes and treatment of abnormal phenomena in the oil pressure system. For example, the oil pump does not spray oil, the pressure is abnormal, and there is noise. You should know what the main reason is and what the corresponding solution is. The causes and treatment of abnormal phenomena in oil pressure system should be understood from three aspects:
(1) The oil pump does not inject oil.
The main reasons may include low oil tank level, reverse rotation of oil pump, low rotating speed, high oil viscosity, low oil temperature, filter blockage, excessive oil suction pipe volume, air intake, shaft and rotor damage, etc. The main reasons have corresponding solutions, such as refueling, confirming signs, and replacing the oil pump when it is reversed.
(2) Abnormal pressure
That is, the pressure is too high or too low. The main reasons are various, such as improper pressure setting, bad action of pressure regulating valve coil, abnormal pressure gauge and leakage of oil pressure system. The corresponding solutions include dismantling and cleaning according to the specified pressure setting value, replacing a normal pressure gauge and checking each system in turn.
(3) There is noise
Noise is mainly produced by oil pumps and valves. The valve is noisy because the flow rate exceeds the rated standard, so the flow rate should be adjusted appropriately; When the oil pump is noisy, there are many reasons and corresponding solutions, such as high viscosity and low oil temperature. The solution is to increase the oil temperature. When there are bubbles in the oil, the air in the system should be released and so on.
In a word, if you want to do a good job in preventive maintenance of CNC machine tools.
E. Maintenance and maintenance of mechanical parts
The maintenance of mechanical parts of CNC machine tools mainly includes the maintenance of spindle components, feed transmission mechanism and guide rail.
1. Maintenance and maintenance of spindle components
Spindle component is an important part in the mechanical part of CNC machine tool, which is mainly composed of spindle, bearing, spindle quasi-stop device, automatic clamping and chip removal device. Lubrication, cooling and sealing of spindle parts of CNC machine tools are several problems worthy of attention in the use and maintenance of machine tools.
First of all, good lubrication effect can reduce the working temperature and prolong the service life of bearings; Therefore, attention should be paid to circulating lubrication with grease and oil at low speed; Oil mist and oil-gas lubrication are used at high speed. However, when grease lubrication is used, the sealing capacity of the spindle bearing is usually 10% of the bearing space volume, so it is forbidden to fill it at will, because too much grease will aggravate the spindle heating. Oil circulation lubrication, check the spindle lubrication constant temperature oil tank every day to see if the oil quantity is sufficient. If there is not enough oil, add lubricating oil in time. At the same time, pay attention to check whether the temperature range of lubricating oil is appropriate.
In order to ensure the good lubrication of the spindle, reduce friction and heat, and take away the heat of the spindle assembly, a circulating lubrication system is usually adopted, with a hydraulic pump supplying oil for lubrication and an oil temperature controller controlling the oil temperature of the oil tank. The spindle bearing of high-grade CNC machine tools is lubricated by high-grade grease seal, which can be used for 7 ~ 10 years every time grease is added. The new lubrication cooling method should not only reduce the temperature rise of the bearing, but also reduce the temperature difference between the inner and outer rings of the bearing to ensure the small thermal deformation of the spindle.
There are two common methods of spindle lubrication. Oil-gas lubrication method is similar to oil mist lubrication method, but oil mist lubrication method is to supply oil mist continuously, while oil-gas lubrication is to send oil mist into bearing gap regularly and quantitatively, which not only realizes oil mist lubrication, but also avoids polluting the surrounding air due to excessive oil mist. Spray lubrication method is to spray a large flow of constant temperature oil (3 ~ 4L/min per bearing) on the spindle bearing to achieve the purpose of lubrication and cooling. Here, the oil injected with a large flow rate must be forcibly discharged by the oil drainage pump, instead of flowing back naturally. At the same time, a special high-capacity and high-precision thermostatic oil tank should be used, and the oil temperature change should be controlled at 0.5℃.
Secondly, the cooling of spindle components is mainly to reduce the bearing heating and effectively control the heat source.
Thirdly, the sealing of spindle parts should not only prevent dust, chips and cutting fluid from entering the spindle parts, but also prevent the leakage of lubricating oil. The spindle parts have contact and non-contact seals. For the contact seal with linoleum ring and oil-resistant rubber sealing ring, attention should be paid to check its aging and damage; For non-contact seal, in order to prevent leakage, it is important to ensure that the oil return can be discharged as soon as possible and the oil return hole is unobstructed.
Sealing structure of spindle front bracket
To sum up, in the use and maintenance of CNC machine tools, we must attach great importance to the lubrication, cooling and sealing of spindle components and do this work well.
2. Maintenance and maintenance of feed transmission mechanism
The electromechanical components of the feed transmission mechanism mainly include: servo motor and detection element, deceleration mechanism, ball screw nut pair, screw bearing, moving parts (workbench, headstock, column, etc.). ). This article mainly explains the maintenance of ball screw nut pair.
(1) Adjustment of axial clearance of ball screw nut pair
In addition to the feed accuracy in one direction, the ball screw nut pair also has strict requirements on the axial clearance to ensure the reverse transmission accuracy. Therefore, attention should be paid to the axial clearance caused by the wear of lead screw and nut pair in operation, and the adjustment method should be used to eliminate it.
Clearance elimination of double nut washer type
As shown in the figure,
This form has simple and reliable structure, good rigidity and the widest application. The form of adding a gasket between the double nuts can be done by professional students.
The factory adjusts the pre-tightening force in advance according to the user's requirements, which is very convenient for loading and unloading when using.
Clearance elimination of double nut thread
As shown in the figure,
Using the external thread on one nut, the relative axial position of two nuts is adjusted through the round nut to realize pre-tightening, and the other round nut is locked after adjustment. This structure is easy to adjust and can be adjusted at any time during use, but the pre-tightening force cannot be accurately controlled.
Tooth difference type backlash elimination
As shown in the figure,
The flanges of the two nuts are respectively provided with cylindrical external gears, which are respectively meshed with the internal gear rings fixed at both ends of the sleeve, and the number of teeth is Z 1 and Z2, respectively, with a difference of one tooth. When adjusting, first remove the internal gear ring, let the two nuts rotate one tooth in the same direction relative to the sleeve, and then insert the internal gear ring. At this time, the two nuts will have relative angular displacement, and the axial displacement is:
Where Z 1 and Z2 are the number of teeth of the gear, and Ph is the lead of the ball screw.
(2) Daily inspection of sealing and lubrication of ball screw nut pair
The daily inspection of sealing and lubrication of ball screw nut pair is a problem that we should pay attention to in operation and use. For the sealing of the lead screw nut, it is necessary to check the sealing ring and protective sleeve to prevent dust and impurities from entering the ball screw nut pair. Lubrication of screw nut, if grease is used, should be lubricated regularly; If lubricating oil is used, always pay attention to injecting oil through the oil injection hole.
3. Maintenance and maintenance of machine tool guide rail
The maintenance of machine tool guide rail is mainly the lubrication and protection of guide rail.
(1), lubrication of guide rail
The purpose of rail lubrication is to reduce friction resistance and friction and wear, so as to avoid crawling at low speed and reduce temperature rise at high temperature. Therefore, the lubrication of guide rail is very important. For the sliding guide rail, use lubricating oil; Lubricating oil or grease can be used for the rolling guide rail. Commonly used lubricating oil brands of CNC machine tools are: L-AN 10, 15, 32, 42 and 68. The oil lubrication of guide rail generally adopts automatic lubrication. During the operation, we should pay attention to check the reversing valve in the automatic lubrication system. If it fails, the guide rail will not lubricate automatically. Besides, it must be done every day.
Check the oil quantity in the lubricating oil tank of the guide rail. If the oil quantity is insufficient, add lubricating oil in time. At the same time, pay attention to check whether the lubricating oil pump can start and stop regularly, and check whether the lubricating oil can be provided when it is started regularly.
(2), guide rail protection
Attention should be paid to prevent chips, abrasive particles or cutting fluid from scattering on the surface of the guide rail, otherwise it will aggravate the wear, abrasion and corrosion of the guide rail. Therefore, we should pay attention to the daily inspection of the guide rail protection device to ensure the protection of the guide rail.
4. Maintenance and maintenance of turntable
The circular feed motion of CNC machine tools is generally realized by turntable, which has become an indispensable part of machining center. Therefore, attention should be paid to the correct operation and use in strict accordance with the requirements of the operating instructions and operating procedures of the turntable. Pay special attention to the lubrication of the transmission mechanism and guide rail of the turntable.
F. Maintenance and maintenance of auxiliary equipment
The maintenance of auxiliary equipment of CNC machine tools mainly includes the maintenance of CNC dividing head, automatic tool changing device and hydraulic pneumatic system.
1. Maintenance of CNC dividing head
The CNC indexing head is a common accessory of CNC milling machines and machining centers. Its function is to make rotary indexing or continuous rotary feed movement according to the instructions of CNC devices, so that CNC machine tools can complete the specified machining accuracy. Therefore, attention should be paid to the correct operation and use in strict accordance with the requirements of the instruction manual and operating procedures of the CNC dividing head.
2. Maintenance and maintenance of automatic tool changing device
Automatic tool changing device is a characteristic structure of machining center which is different from other CNC machine tools. It has the function of automatically replacing the required tools according to the processing technology requirements, thus helping the CNC machine tool to save auxiliary time and meet the requirements of completing multi-process and step-by-step processing at one installation. Therefore, attention should be paid to regularly check whether the mechanical structure of each part of the automatic tool changer works normally and whether there are abnormal phenomena during operation; Check whether the lubrication is good, etc. , and pay attention to the reliability and safety inspection of tool changing.
3. Maintenance and maintenance of hydraulic system
(1) Check, filter and replace the oil in the oil tank regularly;
(2) Check the performance of the cooler and heater and control the oil temperature;
(3) Check and replace the seals regularly to prevent the hydraulic system from leaking;
(4) Regularly inspect, clean or replace hydraulic components and filter elements, and regularly inspect and clean oil tanks and pipelines;
(5) Strictly implement the daily inspection system to check whether the leakage, noise, vibration, pressure and temperature of the system are normal.
4. Maintenance and maintenance of pneumatic system
(1) Select a suitable filter to remove impurities and moisture in compressed air;
(2) Check the oil supply of the oil mist device in the system to ensure that there is a proper amount of lubricating oil in the air to lubricate the pneumatic components, so as to prevent air leakage and component action failure caused by corrosion and wear;
(3) Maintain the tightness of the pneumatic system, and regularly check and replace the seals;
(4) Pay attention to adjusting the working pressure;
(5) Regularly check, clean or replace pneumatic components and filter components.
G. Use inspection of numerical control system
Numerical control system is the core of electrical control system of CNC machine tools. After the CNC system of each machine tool runs for a certain period of time, some parts will inevitably be damaged or broken. In order to prolong the service life of parts as much as possible and prevent all kinds of faults, especially vicious accidents, it is necessary to carry out daily maintenance and maintenance of CNC system. Mainly includes: the use of CNC system inspection and daily maintenance of CNC system.
In order to avoid some unnecessary faults in the use of CNC system, operators of CNC machine tools should read the relevant operating instructions carefully before using CNC system, know the performance of CNC system in detail, and master the functions of buttons, keys and switches on CNC system and machine tool operation panel as well as matters needing attention in use. Generally speaking, the numerical control system should be checked before and after power-on.
1. Inspection of CNC system before power on
In order to ensure the normal operation of the CNC system, when the CNC machine tool is installed and debugged for the first time or powered on for the first time after machine tool handling, the CNC system can be checked in the following order:
(1), confirm whether the specifications of the AC power supply meet the requirements of the numerical control device, and mainly check the voltage, frequency and capacity of the AC power supply.
(2) Carefully check whether all the connecting cables between the CNC device and the outside world are correctly and reliably connected according to the attached technical manual. The connection of the CNC system is carried out through the pointer to the CNC device and its supporting feed and spindle servo drive unit, mainly including the connection of external cables and the connection of the power supply of the CNC system. Before connection, carefully check the numerical control system device, MDI/CRT unit, position display unit, paper tape reader, power supply unit, printed circuit board and servo unit. Find the problem and take measures or replace it in time. At the same time, we should pay attention to check whether the connector and printed circuit board are fastened, inserted in place, whether the plug is loose and whether the fastening screws are tightened, because failures caused by poor performance are the most common.
(3
These hardware settings include various shorting bar settings and adjustable potentiometers.
(4), carefully check the protective grounding wire of CNC machine tools. CNC machine tools should have good grounding wires to ensure equipment and personal safety and reduce electrical interference. Protective ground wire should be connected between servo unit, servo transformer and high voltage cabinet.
Only after the above inspection and confirmation, the numerical control device can be powered on.
2. Check the numerical control system after power-on.
After the numerical control system is powered on, the inspection contents include:
(1), first check whether the fan in the numerical control device works normally, otherwise it will affect the heat dissipation of the numerical control device.
(2) Confirm whether the DC power supply on each printed circuit or module is normal and within the allowable fluctuation range.
(3
(4) When the numerical control device and machine tool are powered on-line, be prepared to press the emergency stop button while turning on the power supply, so as to cut off the power supply at any time in an emergency.
(5) In manual mode, move each axis at a low speed, and observe whether the moving direction of the machine tool and the display of coordinate values are correct.
(6) Return to the reference point of the machine tool for many times, which is used to check whether the CNC machine tool has the function of returning to the reference point and whether the position of the reference point is exactly the same each time.
(7), CNC system function test. According to the instruction manual of CNC system of CNC machine tools, the function of CNC system should be tested manually or by compiling CNC program. For example: quick point positioning, linear interpolation, circular interpolation, tool diameter compensation, tool length compensation, fixed cycle, user macro program and other functions, as well as M, S and T < /span auxiliary functions.
After the above inspection and confirmation, the numerical control device can be officially operated.
H. Daily maintenance and maintenance of numerical control equipment
Numerical control system is the core of electrical control system of CNC machine tools. After the CNC system of each machine tool runs for a certain period of time, some parts will inevitably be damaged or broken. In order to prolong the service life of parts as much as possible and prevent all kinds of faults, especially vicious accidents, it is necessary to carry out daily maintenance and maintenance of CNC system. Mainly includes: the use of CNC system inspection and daily maintenance of CNC system.
The daily maintenance of CNC system mainly includes the following aspects:
1. Strictly formulate and implement the rules and regulations for daily maintenance of CNC system.
According to the performance characteristics of different CNC machine tools, the rules and regulations of daily maintenance of CNC system are strictly formulated and strictly implemented in use and operation.
2. Try to open the doors of CNC cabinet doors and high-voltage cabinets as little as possible.
Because the air in the machining workshop often contains oil mist and dust, once it falls on the printed circuit board or electrical components of the numerical control system, it is easy to cause the insulation resistance of the components to drop, and even lead to the damage of the circuit board or electrical components. Therefore, in the work, try to open the doors of CNC cabinet doors and high voltage cabinets as little as possible.
3. Regularly clean the cooling and ventilation system of the numerical control equipment to prevent the numerical control equipment from overheating.
Heat dissipation and ventilation system is an important device to prevent numerical control equipment from overheating. So check whether the cooling fan on the numerical control cabinet works normally every day, check whether the air duct filter is blocked every six months or every quarter, and clean it in time if it is blocked.
4. Pay attention to the regular maintenance of input and output equipment of CNC system.
Such as cleaning the magnetic head in the input device of the numerical control system.
5. Check and replace the brush of DC motor regularly.
In 1980s, most CNC machine tools used DC servo motors, which led to the problem of brush wear. Therefore, DC servo motors need to be inspected and replaced regularly.
6. Regularly monitor the grid voltage of numerical control equipment.
The numerical control system has strict requirements for the working grid voltage. For example, the numerical control system produced by FANUC allows the grid voltage to fluctuate within the range of 85% ~ 1 10% of the rated value, otherwise the numerical control system will not work normally and even damage the electronic components inside the numerical control system. Therefore, it is necessary to regularly detect the grid voltage and control it within the range of–15% ~+10% of the rated value.
7. Check and replace the stored batteries regularly.
In general, the storage contents in some CMOS memory in CNC system are saved by battery power supply when power is cut off. Lithium batteries or rechargeable nickel-cadmium batteries are generally used. When the battery voltage drops to a certain value, it will cause data loss, so check the battery voltage regularly. When the battery voltage drops to the limit value or battery voltage alarm occurs, the battery should be replaced in time. When replacing the battery, it is usually carried out when the numerical control system is powered on, which will not cause the loss of storage parameters. Once the data is lost, you can re-enter the parameters after replacing the battery.
8. Maintenance of CNC system when it is not used for a long time
When the CNC machine tool is idle for a long time, the CNC system should be maintained regularly. When the machine tool is not powered on, use the spare battery to supply power to the chip and keep the data unchanged. When the battery voltage on the lathe is too low, an alarm prompt is usually given on the display screen. When not used for a long time, always turn on the machine to check whether there is an alarm prompt, and replace the spare battery in time. Machine tools that have not been used for a long time, such as electrical components being wet or printed boards being short-circuited or open-circuited, should be electrified at least twice a week. The specific approach is:
First of all, the numerical control system should be energized frequently, and the machine tool should idle when locked. Secondly, in the rainy season when the air humidity is high, the numerical control system should be electrified every day, and the moisture in the numerical control cabinet should be driven away by the heat of electrical components to ensure the stable and reliable performance of electrical components. Production practice has proved that if CNC machine tools are not used for a long time, they often break down as soon as they are turned on in rainy days.
In addition, for CNC machine tools equipped with DC servo motor, if it is not used for more than half a year, the brush of the motor should be taken out to avoid the corrosion of the commutator surface due to chemical corrosion and ensure the commutation performance.
9. Maintenance of spare printed circuit boards
For the purchased spare printed circuit board, it should be installed on the numerical control equipment regularly and powered on for a period of time to prevent damage.
10. Troubleshooting of CNC system
Once the CNC system fails, the operator should take emergency stop measures to stop the system operation and protect the site. And assist maintenance personnel to make preparations for early maintenance.
That's basically it. It is ok to organize and print these materials for training new operating employees by yourself!