The structure of the tool changer and tool changer is complicated and frequently moves at work, so the failure rate is higher. At present, more than 50% of the faults on the machine tool are related to it. Such as knife movement failure, positioning error is too large, manipulator clamping handle unstable, manipulator error is too large and so on. These failures eventually result in a tool change card bit, the whole machine to stop working. Therefore, the maintenance of the magazine and tool changer is very important.
1. Maintenance points for tool changers and tool changers
1) Do not overweight, long tool into the magazine, to prevent the knife in the robot when the knife or knife and workpieces, fixtures and other collisions.
2) The order of the knife selection method must pay attention to the tool placed in the magazine in the order to be correct, other tool selection method should also pay attention to the tool for the same tool and the required tool to prevent the wrong tool lead to accidents.
3) When loading the knife manually to the magazine, make sure that it is securely attached and that the locking device on the knife holder is reliable.
4) Regularly check the magazine back to zero position is correct, check the machine tool spindle back to replace the knife position is in place and found that the problem should be promptly adjusted, or can not complete the tool change action.
5) Care should be taken to keep the tool holder and holder clean.
6) When turning on the machine, run the magazines and robots first to check whether the work of each part is normal, especially if the limit switches and solenoids can operate normally. Check the pressure of the hydraulic system of the manipulator is normal, whether the tool is reliable in the locking of the manipulator and should be dealt with promptly when it is abnormal.
2. Tool magazine failure
The main fault of the magazine are: the magazine can not rotate or turn in place; the cutter sleeve can not clamp the cutter; the cutter sleeve is not up and down and so on.
(1) The magazine can not be rotated or not rotated. The reason that the magazine can not be rotated may be: ① the coupling between the motor shaft and the worm shaft is loosened; ② the inverter is faulty, the inverter's input and output voltage should be checked; ③ PLC no control output, the interface board may be the relay failure; ④ mechanical connection is too tight; ⑤ grid voltage is too low.
Reasons for the tool magazine may not turn: motor rotation failure, transmission error.
(2) The tool holder can not clamp the tool. The reason may be that the adjustment screw on the tool holder is loose or the spring is too loose, resulting in insufficient clamping force or the tool is overweight.
(3) the knife is not up and down the place may be due to improper device adjustment or machining errors caused by excessive fork position is not correct; limit switch installed incorrectly or improperly adjusted and cause the feedback signal error.
3. Tool changer malfunction
(1) the tool holder is not tight off the knife may be due to the clamping jaw spring pressure is too small; or loose nut behind the spring; or tool overweight; or manipulator card lock does not work and so on.
(2) The tool can not be loosened after clamping. The reason may be that the loose spring is pressed tightly and the jaws are not retracted. The nut should be adjusted so that the maximum load does not exceed the rated value.
(3) When the tool is exchanged, the headstock does not return to the tool change point or the tool change point when the tool is changed. When the robot grasps the knife, it will start to pull the knife, which will cause the knife to be removed when the tool is changed. In this case, you should move the headstock again to return to the tool change point and reset the tool change point.
8.4.5 automatic tool change device repair 10 cases
Examples 371 to 373. Manipulator fault repair
Example 371. Symptoms: a machining center using cam manipulator tool change, robot structure and tool change procedures as shown in Figure 2-22, Figure 2-23 below. During the tool change, the motion is interrupted and an alarm 2035 # is issued, indicating that the robot has reached a point of failure.
Analysis and processing: According to the alarm content, the machine tool is unable to execute the next step "remove the tool from the spindle and the magazine," leaving the tool change process interrupt and alarm.
Manipulator failed to extend the completion of the spindle and the magazine from the knife action, the cause of the malfunction may be:
(1) "loose knife" sensor switch failure In the tool change process, the completion of each action signal sent by the sensor switch, only the last action can be carried out after the next action. The third step is the "spindle loose knife", if the sensor switch is not signaling, then the robot "pull knife" will not move. Check the two sensors switch, the signal is normal.
(2) "loose knife" solenoid valve failure Spindle "loose knife" is the electromagnetic valve connected to the hydraulic cylinder to complete. If the solenoid valve failure, the hydraulic cylinder is not into the oil, the tool is "loose" can not. Check the spindle "loose knife" solenoid valve movements are normal.
(3) "SONG DAO" hydraulic cylinder will not move due to lack of hydraulic system pressure or oil leakage, or the stroke is not in place. Check the knife and knife hydraulic cylinder, the action is normal, the stroke is in place. Open the headstock (Figure 8-2) , Check the spindle loose knife hydraulic cylinder and found that it has reached the loose knife position, hydraulic pressure is normal, no leakage of hydraulic cylinder phenomenon.
(4) robotic system problems, can not afford to establish the "pulling knife" conditions The reason may be: motor control circuit problems. Check the motor control circuit system is normal.
(5) Spindle system problems Spindle structure diagram shown in Figure 8-2. The knife is by the disc spring through the lever and the spring chuck and the tail end of the tool handle taut tension; release knife, the hydraulic cylinder piston rod pressure top rod, push rod through the hollow rod push rod, on the one hand the spring chuck Unclamp the tool pull nail, on the other hand Dingding move pull the nail, so that the right tool and the spindle taper in the hole become "loose."
Spindle system is not loose reason is estimated to have the following 4 points: ① tail length pull the nail is not enough, resulting in the hydraulic cylinder has moved in place, but still not the top of the tool "loose"; ② rod tail hollow screw position has changed, So that the hydraulic cylinder stroke can not meet the "loose knife" requirements; ③ mandrel out of the question, has been deformed or worn; ④ spring chuck failure, can not open: ⑤ spindle assembly adjustment, the tool moves too small, Resulting in the use of some comprehensive factors can not meet the "loose knife" conditions.
Treatment: Remove the "loose knife" hydraulic cylinder, inspection found that: This fault is the manufacture and assembly, Hollow screw "stick out" adjusted too small, so "loose knife" hydraulic cylinder stroke in place, and the tool in the spindle Cone hole "pressure" is not enough, the tool can not be removed. Adjust the hollow screw "extension" to ensure that the spindle "loose knife" hydraulic cylinder stroke in place, the shank taper in the spindle out of the amount of 0.4 ~ 0.5mm. After the above adjustment, troubleshooting.
Example 372. Symptoms: JCS-018A vertical machining center (Beijing Precision Machine Tool Plant production) manipulator failure; arm rotation speed uneven, gas-oil converter speed oil loss, manipulator rotation is not in place, the arm movements do not move or arm reset is not spirit. Adjustment SC-15 throttle manual adjustment, can only maintain a short period of normal operation, and the exhaust sound gradually cloudy, unlike the normal action clear, and finally to the tool change.
Analysis and processing process:
1) Turn the arm 75º to grasp the tool on the spindle and the tool holder, you must hold firmly in place to drop the knife. After the action is in place, rotate 180º, change the knife position, respectively, insert knife, arm and then reset, knife sleeve. Arm 75º, 180º rotation, the power transmission is compressed air source to promote gas-liquid converter into hydraulic oil controlled by the electronic control program, the rotation speed by the SC-15 throttle adjustment; commutation by 5ED-IONl8F solenoid valve control . Under normal circumstances, the life of these components is very long, you can rule out the existence of such components problems.
2) Because the upper and lower arms and arm up and down are independent of the gas source to promote exhaust is independent muffler exhaust port, so arm rotation force transmission; but not in place, the arm lift is impossible. According to this principle, focusing on checking the arm rotation system components to perform the necessary work.
3) Observe that when the 75º, 180º arm rotates or does not rotate, the hydraulic cylinder expands and contracts corresponding to the gas-liquid changeover of the oil level. If the left-right paired gas-liquid converter is found, the upper limit on the left is the lower limit, and vice versa The common exhaust port has a larger amount of oil discharged. Analysis of gas-liquid converters, nylon pipes are sealed installation, so the cause of the malfunction should be in the implementation of the device cylinder.
4) Remove the manipulator hydraulic cylinder, disintegration inspection and found that the piston bearing ring O-ring linear wear, can not be sealed. Rough cylinder wall, ring knife obvious, poor accuracy. Replacement of Beijing Precision Machine Tool Plant production of 80 cylinder, heavy equipment failure to adjust after adjustment, normal operation has been 7 years, no further robotic tool change failure.
Example 373. Symptoms: FANUC11 system supporting a BX-110P machining center, JOG mode, the robot arm in the transfer tool, can not shrink the claw. When the machine tool is processing the workpiece in the JOG state, the manipulator removes the tool from the main magazine and sends it into the delivery box, and the claw can not be retracted, but the alarm is not alarmed; the method is selected to the ATC state and the manual operation is normal.
Analysis and processing process: The ladder diagram, the original limit switch LS916 and no lamination; adjust the limit switch position, the machine back to normal. However, after some time, this failure occurred again, check LS916 did not loosen, but did not press together, thus suspect that the manipulator's hydraulic cylinder rod did not reach the place. The investigation found that the top of the cylinder rod locking nut locking screw loose, so that the hydraulic cylinder telescopic stroke has changed; adjust the lock nut and tighten the set screw, this troubleshooting.
Example 374. Tool change is not in place for fault maintenance
Symptom: Automatic tool change knife chain is not in place. When the automatic tool change to the program, the magazines start running, but need to change the tool is not in place, the magazine stopped running. 3min machine alarm.
Analysis and processing process: MPA-H100A machining center is produced by Mitsubishi Corporation's Hiroshima Works & Machinery Co., Ltd., equipped with a CNC system FANUC6M-MODELB and a worktable of 1000mm × 1000mm and 60 tools. It is known from the above fault alarm that the tool change time is exceeded. In MDI mode, the magazine will not operate no matter whether the tool is rotated clockwise or counterclockwise by manual input. Check the electrical control system, did not find any abnormalities; PLC output indicator light-emitting diode, indicating PLC has output, clockwise and counterclockwise movement of the electromagnetic valve on the counterclockwise side of the light-emitting diode lit, indicating that the electromagnetic When the valve is energized and the tool magazine is not moving at this time, the problem should occur in the hydraulic system or in other ways. However, the normal pressure of the hydraulic system, the oil flow are smooth and no blockage; check the various hydraulic valve hydraulic device did not find any problems, it is estimated that the fault may be in the hydraulic motor. To this end, demolition of the protective cover, remove the hydraulic motor, the site can be disassembled, have been examined, did not find any problems; hydraulic motor will be sent to Dalian Institute of Machine Tools to identify the test conclusion Hydraulic motor is intact. After a careful analysis and study conducted by comrades present, there can be only one problem, that is, a mechanical fault. However, there are no obvious signs of damage to various parts and parts of the magazine, so mechanical failure can be ruled out. Finally, The problem boils down to the point that the knife load is too heavy, or there are parts of the block, and even caused by the hydraulic motor does not move.
In fact it is true. We are processing 10t forklift box, due to the complexity of the workpiece, more processing surface, the use of tools up to 40, and the big tool, long tool (the longest tool up to 550mm), heavy tool (the heaviest Of the tools up to 25kg) a large amount, and we ignore the distribution of the tool in the magazine, heavy and long tool in the magazine is not evenly distributed, but rather in a period, as well as causing the chain of the magazine Local pull too tight, large deformation, and may have blocked the phenomenon, so the machine hydraulic motor with no movement. In the end we made the adjustable parts of the magazine chain a little loose and everything returned to normal, indicating that the problem was indeed mechanical.
Note: the chain of the magazine can not be adjusted too loose, otherwise there will be "flying knife" danger. Once the manipulator grabbed the knife on the magazine side, when the tool was pulled out and then raised and then turned 180º again, the knife suddenly thrown out, almost causing disaster. Analysis of the reasons for the failure, it is because the magazine chain is too loose reason. The two jaws of the machine tool manipulator are pushed downward by the downward thrust and are clamped by the tension of the spring. When the manipulator grasps the knife downward, because the chain is too loose, the chain strap also droops downward with the downward thrust of the manipulator. As a result, the claw of the manipulator only grips the handle half and does not grasp completely. Grip, when the robot rotation, due to the heavy tool, the role of centrifugal force, the tool thrown out along the tangential direction. With the strap slightly tightened, there was never a similar situation.
Maintenance experience: no more than two types of drive system knife, a mechanical transmission, a hydraulic transmission. MPA-H100A machining center is a product of the early 1980s, the use of hydraulic transmission, that is, the use of hydraulic motors, solenoid valves, flow control valves to drive the operation of the magazine. Compared with the magazine driven by the variable frequency speed regulating motor, its electrical control system is much simpler and more intuitive, and generally not prone to failure. However, it may also vary depending on the environment in which the equipment is used, the machining conditions, the complexity of the work piece, and the number of tools used, in particular the length of the tool, the weight of the tool and the distribution of the tool in the magazine, Possible factors.
Example 375 ~ Example 377. Rotary turret fault repair
Example 375. Symptom: SAG210 / 2NC CNC lathe turret motor does not move, the turret can not move.
Analysis and processing process: SAG210 / 2NC and CKD6140 and CNC lathes, with the supporting tool holder LD4-I four-position electric tool holder.
Analysis of the cause of the fault may be reversed motor phase sequence or the power supply voltage is low, but adjust the motor armature line and power supply voltage, the fault can not be ruled out. The fault is caused by mechanical reasons. Remove the motor cover, rotate the motor blades and found that the resistance is too large. Take the motor further examination found that the worm bearing damage, the motor shaft and worm clutch quality is poor, so that the motor resistance.
Replace the bearings, repair the clutch, troubleshooting.
Example 376. Symptom: SAG210 / 2NC CNC lathe turret knife body raised but not in place.
Analysis and processing process: The lathe supporting the same turret. According to the mechanical principle of the electric turret, the upper cutter body can not be rotated may be coarse positioning pin in the tapered hole stuck or broken. After disassembling the electric tool holder to replace the new dowel pin, the upper blade body still can not be rotated into position. When disassembling, it is found that when assembling the cutter body, it should be aligned with the four sides of the cutter body, and the gear rack must be engaged. After being assembled according to the above requirements, the trouble is solved.
Example 377. Symptom: Hungary EEN-400 CNC lathe turret positioning is not allowed.
Analysis and processing: The EEN-400 CNC lathe is produced by SEIN Hungary with a knife holder made in Bulgaria for 6 knives. The main reason for the investigation is not allowed to locate the main part of the turret mechanical wear more serious, can not be adjusted by conventional, knife backlash compensation and other means to solve the need to consider the overall replacement. It is understood that the domestic manufacturer of CNC turret has been able to produce the same horizontal 6-knife turret, for proper treatment, you can use.
In Shaanxi Province Machinery Research Institute produced JYY horizontal CNC electric tool holder replacement of the original tool holder, the restoration of the positioning accuracy, the use of more than a year song, has been normal.
Example 378. Processing size out of control of the failure of maintenance
Symptom: Nanjing JN CNC machining system size can not be controlled.
Analysis and processing: The machine is an economical CNC lathe modified by JN series CNC system of Nanjing Jiangnan Machine Tool Numerical Control Engineering Co., Ltd. Its tool holder is LD4-I electric tool holder.
The machine tool in the processing of the product, the size of its processing can not control the phenomenon, each time the operator to modify the parameters in the system, the size of the digital display and the actual processing out of the size of a large difference, and the size of the irregular changes Can be found, even if the system does not modify the processing parameters, the size of the processed products are constantly changing. Because the machine is mainly for bore processing, so the size of the main reaction in the X-axis changes. In order to determine the fault location, using the substitution method, the X-axis drive signal and the Z-axis drive signal exchange, that is, with 2-axis control signal to drive the X-axis, and X-axis control signal to drive the Z-axis. After the replacement fault still exists, indicating that the X-axis drive signal without fault, but also shows the source of the fault should be in the X-axis stepper motor and its transmission, ball screw and other hardware.
Check the transmission, ball screw and other hardware are no problems, further inspection X-axis axial repeat positioning accuracy is also within its technical indicators. What causes X-axis processing size can not control it? Thinking to examine and analyze the idea of failure, we found that in the analysis and inspection of an important part ignored - electric knife holder.
Check the electric knife turret repeated positioning accuracy of each tool and found that electric knife positioning is not allowed. Analysis of the reasons for the positioning of the electric knife holder is not allowed, if the electric knife holder's own mechanical positioning is not allowed, the fault should be fixed, there should be no processing size can not control the phenomenon, there are other causes for the failure phenomenon. Check the rotation of the electric turret and found that when the electric turret raises, there is a scrap of iron stuck in it. Iron scrap positioning is not allowed, this is the source of the fault.
Disassemble the electric knife holder, use compressed air to position the electric knife holder on the iron plate to clean the iron pieces, reassemble the electric knife holder after the trouble shooting.
Example 379 ~ Example 380. Tool magazine can not rotate the fault repair
Example 379. Symptom: Automatic tool change knife chain is not in place. When the automatic tool change to the program, the magazines start running, but need to change the tool is not in place, the magazine stopped running. 3min machine alarm.
Analysis and Processing Process: The chain-type magazine used by TH42160 gantry machining center is shown in Figure 8-20. Its supporting CNC system is SIEMENS840D.
It is known from the above fault alarm that the tool change time is exceeded. In MDI mode, the magazine will not operate no matter whether the tool is rotated clockwise or counterclockwise by manual input. Check the electrical control system, did not find any abnormalities; PLC output indicator light-emitting diode lit, indicating that PLC has output, then the problem should occur in the mechanical transmission. It is estimated that the fault may be on the reducer. Therefore, the protective cover was removed, the servo motor was removed, the reducer was disassembled, and the coupling key on a transmission shaft in the reducer was found to fall off, resulting in the interruption of the power transmission path and the rotation of the magazine. After repair reducer, troubleshooting.
Example 380. Symptom: Automatic tool change knife chain operation is not in place, the magazine stopped running, the machine automatically alarm.
Analysis and Processing Process: The chain-type magazine used by TH42160 gantry machining center is shown in Figure 8-20. Its supporting CNC system is SIEMENS840D.
It is known from above fault alarm that the servo motor of the magazine is overloaded. Check the electrical control system, did not find any abnormalities, the problem should occur in the mechanical transmission or other aspects: ① knife chain or reducer with foreign objects stuck: ② Tool chain on the tool too heavy: ③ poor lubrication: After checking the above Three normal. Remove the servo motor and found that the servo motor inside a lot of cutting fluid, resulting in short circuit caused by the coil. Observe the reason is that the motor and the gear reducer coupling wear Department, resulting in penetration of cutting fluid into the motor. After replacing the seal and servo motor, troubleshooting.
