Injection molding machine fault analysis and troubleshooting III

1. Failure problems and solutions of mold locking:
(1): No clamping:
Solution:
1):Check the travel switch in front of the safety door, and fix it.
2): Check the 24V5A power supply in the electrical box, replace the fuse and power box.
3): Check whether the spool is stuck and clean the spool.
4): Check whether the I/O board has output and whether the solenoid valve is live.
5): Check whether the hydraulic safety switch is pressed and whether the mechanical lock rod baffle is opened.
(2): Mold opening and closing machine twisting:
Solution:
1): Check whether the lubricating oil pipe is disconnected, if so, the oil pipe must be reconnected.
2): The amount of lubricating oil is small, increase the amount of lubricating oil, it is recommended to make 50 molds of oil once or add enough lubricating oil manually.
3): The clamping force is large, check whether the mold needs a large clamping force, and adjust the clamping force.
4): The current of the amplifier plate is disturbed, check whether the current parameters meet the acceptance criteria, and readjust the current value.
5): The parallelism is out of tolerance, check whether the parallelism of the first two plates is greater than the acceptance standard with a dial gauge, and adjust the parallelism.
(3): Wait a few seconds before opening the mold:
Solution: 1): The starting speed is slow, check whether the screw damping is too large, and adjust the screw damping hole.
2): The middle hole of the damping screw is too large, check whether the damping of the Y-hole screw is too large, and replace the damping nail with a thin center hole.
(4): Unlocking and crawling:
Solution:
1): The two-plate guide rail and the corinning column are worn out, check the two-plate guide rail and the corinning column, replace the two-plate copper sleeve, the corinning column, and fill the lubricating oil.
2): improper adjustment of the clamping speed and pressure, set the flow rate of 20, the pressure of 99 when the clamping plate should not crawl, adjust the flow proportional valve hole, or the pilot valve hole, adjust the linear current value of the proportional valve.
3): There is air in the pipe and oil cylinder, exhaust.
(5): The mold is not opened:
Solution:
1): Increase the speed of unlocking, the pressure flow is too small and not adjusted, check the unlocking speed, whether the pressure is appropriate, and increase the unlocking pressure and speed.
2): The zero position of the clamping electronic ruler is changed, check whether the clamping and straightening machine is terminated in the zero position after twisting, and readjust the zero position of the electronic ruler.
3): Check whether it is reversed.
(6): In automatic production, the mold adjustment will become tighter and tighter or looser:
Solution:
1): Mold-adjusting solenoid valve leakage, check whether the solenoid valve is "O" type, model 4WE6E or 0810092101, replace the solenoid valve or whether the solenoid valve does not work with 24V electricity.
2): Whether there is a mold adjustment action when manually playing other actions, and see whether the valve is stuck.
(7): When other actions work after clamping, the mold is opened slowly and automatically:
Solution: 1): If the oil plate is leaking, check or replace the express clamping valve and replace the oil plate.
2): The mold opening valve is leaking, start the oil pump and terminate the mold locking, press the injection table or the injection action, whether the second plate is moved back, and replace the mold opening oil valve. Normal is to unlock the mold and do not move.
(8): When locking the mold, there is only the action of opening the mold:
Solution: 1): Connect the wrong wire, check whether there is 24VDC to the valve, check the line and wiring.
2): Clamp the valve or install the wrong valve core, check whether the valve core is wrongly installed, or blocked, reinstall the valve core or clean. Under normal circumstances, the unlocking action is immovable.
(9): Poor clamping:
Solution:
1): Improper adjustment of holes A and B, when the system flow rate is set to 20 and the pressure is 99, observe the clamping movement
Whether to creep, readjust or change the valve.
2): There is air in the oil circuit, listen to whether there is air sound in the oil circuit, check whether there are bubbles in the oil, need
Exhaust.
3): Improper adjustment of the amplification plate up and down, observe whether the current value of the ammeter changes with the rise and fall or whether it is proportional to the speed, and adjust the magnifying plate.
(10): The clamping does not have high pressure, and the stroke is exceeded:
Solution: 1): The limit switch exceeds the limit, check whether the mold adjustment is appropriate, adjust the appropriate mold thickness, and check whether the motor is in a normal state.
2): The hydraulic limit exceeds the stroke, whether the stroke position of the electronic ruler is appropriate, check whether the mold adjustment is appropriate, and the appropriate mold adjustment is forward.
(11): Manual mold opening termination, semi-automatic mold opening termination:
Solution: 1): The mold opening valve is leaking, manually hit the injection table after the action, observe whether the second plate is retreating, and replace the mold opening valve.
2): Check the maximum stroke and pressure flow rate of the electronic ruler.
(12): Thimbleless action:
Solution:
1): If the thimble limit switch is broken, check whether the 24V proximity switch is on with a multimeter. Replace the ejector pin limit switch.
2): Card valve, use a hexagonal key to press whether the ejector pin spool is movable, clean the pressure valve
3): The thimble limiting rod is broken, and the limiting rod is taken out by hand after the shutdown is stopped, and the limiting rod is replaced.
4): The thimble switch is short-circuited, check the 0 voltage of the thimble switch to the ground with a multimeter, and replace the thimble switch.
5): The position of the electronic ruler is set improperly.
(13): Semi-automatic thimble out of control:
Solution:
1): The thimble board is broken, check whether the circuit is normal, and the normal voltage DV24V. Repair of the ejector pin plate.
2):The wire is broken, check the switch connection line comprehensively, and the connection line on the I/O board. Check the wiring and rewire.
3): Check whether the mold is out of position.
4): Whether the cylinder piston rod sealing ring is damaged.
(14): Loud sound when opening the mold:
Solution:
1): Proportional linearity difference, poor adjustment of pressure and flow at the time and position of mold opening and closing, check the ramp up and drop in the parameters, and adjust the ramp up and drop in the parameters.
2): Poor lubrication of the reaming of the clamping machine, check the lubrication of the corinth column, the second plate slippery foot, and the hinge lubrication, increase the lubrication, and increase the number of oiling.
3): If the mold clamping force is too large, check the clamping force when the mold is stressed, and reduce the clamping force according to the user's product situation. Check if the time location is appropriate.
4): The parallelism deviation of the two plates of the head plate, check the parallelism of the two plates of the head plate. Adjust the parallel error of the second plate and the head plate.
5): The setting position of slow speed to fast mold opening is too small, and the speed is too fast. Check whether the position of slow mold opening to fast mold opening is appropriate, and whether the slow mold opening speed is too fast. Lengthen the slow mold opening position and reduce the slow mold opening speed.
(15): Semi-automatic has 2 times of clamping action
Solution: 1): The clamping valve core is not completely reset, check whether the next action is too continuous after the clamping action is completed.
2): Increase the delay time of the next action.
2. Failure problems and solutions for mold adjustment part:
(1): Can not adjust the mold:
Solution:
1): The mechanical level and parallelism are out of tolerance. Check with a spirit level. Adjust the parallelism and level. (For large models, small models have little impact)
2): The gap between the pressing plate and the die adjusting wire mother is too small. Measure with feeler gauge. Adjust the gap between the pressing plate and the nut, and the gap between the adjusting nut and the pressing plate (the gap ≤ 0.05mm).
3): Burn the nut: check whether the nut can be rotated to heat up and whether there is iron powder coming out. Replace the nut.
4): Adjustment of upper and lower support plates. Disassemble the plate lock nut and inspect it. Adjust the adjustment nut.
5): The I/O board is broken. Check the output point on the computer page for a signal. Repair electronic boards.
6): The mold adjustment valve spool is stuck. Remove the valve to check. Cleaning valves.
7): Bad mold adjustment motor: check the oil motor. Replace or repair oil motors.
Three: injection part of the fault problem and treatment methods:
(1): No glue shooting:
Solution:
1): There is a foreign object blocking the nozzle. Check if the nozzle is blocked. Clean or replace the nozzle.
2): Break the glue nozzle. Disassemble the flange to check whether the dispensing tip is broken. Replace the dispensing nozzle.
3): The injection direction valve is stuck. Check whether the directional valve has a voltage of 24V and a coil resistance of 15-20 ohms, if it is normal, the valve is blocked. Clean the valve or replace the directional valve.
4): The injection piston rod is broken. Loosen the clamping mother of the injection piston rod and check whether the piston rod is broken. Replace the piston rod.
5): The temperature of the barrel is too low. Check whether the actual temperature reaches the desired melting point temperature of the material. Reset the barrel temperature.
6): The injection piston oil seal is damaged. Check whether the piston oil seal is broken. Replace the oil seal.
(2): Loud starting of glue shooting:
Solution: 1): The injection speed starts too fast. Observe the change of the starting speed of the injection. Adjust the injection flow rate and speed.
2): There is air in the oil circuit. Observe whether there is vibration in each movement.
(3): Loud sound when the injection terminates and turns to melt:
Solution: 1): The action conversion speed is too fast when shooting. Check whether the injection has increased the holding pressure. Increase the holding pressure, adjust the injection grade, and add melt lag.
(4) Unstable injection volume:
Solution:
1): The oil seal of the cylinder is worn. Observe the pressure gauge pressure holding. Replace the oil seal.
2): Glue nozzle and rubber ring wear. Detected with 2 shots. Replace the three-piece tip set.
3): The barrel is worn. Detect with 2 shots, and check the wear and tear of the material dismantling. Replace the melt cartridge.
(5): Semi-automatic non-injection action.
Solution:
1): The advance of the firing table is not terminated. Check whether the front of the injection table or the clamping travel switch is normal. Check the line and travel switch.
2): Disconnection. Check the line. Rewire.
3): Clamping to zero. The position of the hinge is 0 when it is straightened. Readjust the zero position of the electronic ruler.
(6): When semi/fully automatic work, the temperature of the barrel gradually exceeds the set value.
Solution:
1): The melting speed is too fast. Use a tachometer to test whether the screw speed is too fast. Reduce the melt speed.
2): Excessive back pressure. Observe the product, the back pressure gauge value, and reduce the back pressure as much as possible.
3): The screw rubs against the barrel. Disassemble the screw, barrel and check the wear. Replace the barrel or screw.
4): Improper temperature setting. Check if the actual temperature is too low. Reset the temperature.
5): Plastic, the shear heat is too large. ,, Check the temperature rise in the anterior section, ,, in the middle section. Reduced melt speed, back pressure.
(7): The screw rings when the glue is melted.
Solution:
1): Improper installation of the transmission shaft. Separate the screw to rotate to check whether there is any sound, and if so, remove the flat bearing. Reassemble.
2): Plane bearing is broken. Separate the screw and check that there is a sound in the rotating part. then replace the flat bearing.
3): Screw bending. Remove the screw for inspection. Replace the screw.
4): The screw has iron filings. Disassemble the screw for inspection. Clean the screw.
5): Check the coaxiality of the adjustment screw with a dial gauge. The runout of about 0.05mm is normal.
(8): No melting.
Solution:
1): Burn the bearing or the transmission shaft burst. Separate the screw and melt the glue and observe the sound.
2): There are iron filings in the screw. Separate the screw from the barrel and check whether the screw has iron filings. Dismantle the screw for cleaning.
3): The melt valve is blocked. Use the hex key top spool to see if it moves. Clean the solenoid valve.
4): The melt motor is damaged. The melt motor is separated, and the melt does not turn. Replace or repair the melt motor.
5): Burn out the heating ring. Use a multimeter to check if it is normal. Replace the heating coil.
6): Loose plug. Check whether the melt oil plug is in poor contact. Plug in tightly. And check if there is a 24 power supply.
(9): The back pressure cannot be adjusted when melting.
Solution: 1): The back pressure valve is broken. Blanking increases back pressure. Check if the screw is backing up. Clean the back pressure valve.
(10): The product has black spots.
Solution:

1): The screw has carbon deposits. Check the cleaning screw, barrel.
2): The barrel has carbon deposits and the auxiliary machine is not clean. Check the loader for dust. Polishing barrel and cleaning auxiliary.
3): Corrosion of the sub-nozzle assembly. Check the dispensing nozzle. Replace the dispensing nozzle assembly.
4): Flange, nozzle with carbon deposit. Clean up and replace.
5): The raw materials are not clean, check the raw materials. Replace raw materials.
6): The temperature is too high, and the back pressure of the melt is too large. Check the temperature of each section. Cool down and reduce back pressure.
(11): Poor color mixing of screws.
Solution:
1): Inter-material questions. Check the toner quality. Replace the material.
2): The temperature is too low. Check the actual temperature and the required temperature of the material. Increase the temperature.
3). If the back pressure is too low, check the back pressure. Increase back pressure.
4): Short mixing time. Extend the mixing time or replace it with a mixing head.
5): The rotational speed is too low. Check the screw speed. Increase the speed of the screw.
(12): No glue extraction.
Solution:
1): High back pressure. Check the speed of the nozzle dispensing when manually melting. Lowers back pressure.
2): Disconnection. The glue withdrawal valve is disconnected.
3): The spool of the directional valve is not flexible. Press the spool with an Allen wrench to check if it is free to move. Clean the spool.
(13): When melting, the motor swings its tail.
Solution:
1): Bad bearing. Observe whether there is any abnormal sound when melting. Replace the bearings.
2): Improper adjustment of oblique ball bearing. Observe whether the transmission shaft swings. Readjust the gap.
3): Screw deformation. Separate the screw to observe the rotation of the transmission shaft. Replace the screw.
4): The copper sleeve of the back plate of the injection table is worn, and the guide rod is deformed or the fixing screw is loose. Observe whether the copper sleeve of the second plate is ground out of copper powder. Replace the copper sleeve.
(14): Shoot twice for glue
1): The nozzle aperture is too small, and the resistance is too great when shooting.
2): If the heating ring of the nozzle is broken, check the heating ring or replace it.
3): Check whether the pressure flow output is reduced or not.
(15): Cause of screw breakage
1): The shot is out of sync, adjust the shot time synchronization ±0.05
2): The injection cylinder is out of sync, adjust the synchronization ± 0.05 of the injection cylinder
3): The raw material does not match the performance of the screw of the injection molding machine.
4): The temperature does not reach the melting point of the material used.
5): Wait until the temperature has just reached and turn the screw.
6): The heating cylinder is burned out and not heated, check whether there is an anti-cooling function, and replace the heating cylinder.
Fourth: Hydraulic part failure problems and solutions:
(1): Hydraulic oil pollution:
1): Mixed with air in the oil. Mainly due to the poor density of pipe joints, hydraulic pumps, hydraulic cylinders, etc. Manifested in the presence of air bubbles on the fuel tank.
2): Mix water in the oil. It will make the oil milky white. The main cause is a leaking cooler or a humid environment.
3): Solid impurities are mixed into the oil. Mainly chips, welding slag, rust flakes and metal powder.
4): Colloidal substances are produced in the oil. The main feast is that the seal is etched or deteriorated by the oil, so that the gelatinous substance in the oil is produced, which often clogs the pores.
(2): What is the effect of temperature on the viscosity of hydraulic oil:
Effects: 1): When the temperature increases, the viscosity of the oil decreases. Changes in oil viscosity have a direct impact on the performance of the hydraulic system and the amount of leakage. (Normal temperature between 30~50°C)
(3): Creeping fault:
Causes:
1): Poor lubrication conditions. There is a "pause-glide-pause". Increase the amount of lubrication.
2): Immersion in air in the hydraulic system. Exhaust is required.
3): Mechanical rigidity. The parts are worn and deformed, causing changes in friction and creeping. Replacement parts.
(4): After starting the production for a period of time, the oil pump sounds.
Solution:
1): The quality of the suction pipe is not good or the throat code is not tightened. Disassemble the filter to check whether it is deformed. Whether the suction pipe is layered. Replace the oil pipe, strainer.
2): The filter is not clean. Whether there are too many impurities in the hydraulic fluid. Wash the strainer.
3): Oil pump wear: check the wear of the oil distribution plate and rotor end face of the oil pump. Replace the oil pump.
(5): After the motor starts, the pressure gauge has pressure and no flow.
Solution: 1) :D A board is broken, repair the DA board.
2): The relief valve is jammed. Remove the relief valve for inspection, clean the relief valve or replace the pressure gauge for inspection.
(6): No pressure flow
1): Check whether the rotation direction of the motor oil pump is normal.
2): Check for oil leakage.
3): Check whether there is current in the pressure flow valve.
4): There is an inner hexagon to resist the pressure valve core whether it is pressurized, replaced or cleaned.
6. Injection molding machine debugging operation procedures:
(1): Installation conditions of injection molding machine:
The foundation requirements of our company's injection molding machine are divided into three levels:
A, 600T and below models:
(1) THE BEARING CAPACITY OF THE FOUNDATION IS REQUIRED TO BE MORE THAN 10T/M2.
(2) Lay 250-300mm terrazzo workshop floor.
(3) Install it with a shock-absorbing pad.
B, 750T~1000T model (according to the foundation drawing):
(1) THE BEARING CAPACITY OF THE FOUNDATION IS REQUIRED TO BE MORE THAN 10T/M2.
(2) After excavation, lay a layer of Φ8-150×150mm steel mesh.
(3) Water the 300mm thick terrazzo ground.
(4) Use adjustable diagonal iron to pad the feet.
C, 1000T or more models (according to the foundation drawing construction).
(1) THE BEARING CAPACITY OF THE FOUNDATION IS REQUIRED TO BE GREATER THAN 12T/M2.
(2) The bottom layer is laid with Φ12-Φ18, 150×150 steel mesh.
(3) Pour C25 concrete and reserve anchor screw holes. (The anchor screw hole is poured in situ after the foot nail is laid).
(4) Leveling the mounting surface.
(5) Use adjustable oblique iron to pad the foot, and pad the δ10-δ15mm steel plate (twice the area of the bottom of the foot).
(6) After the whole machine is fully installed, it should be allowed to stand for seven days, and the level of the whole machine must be adjusted before starting, and the force of each foot should be balanced, and the C25 concrete should be poured and the anchor screw hole should be reserved. (The anchor screw hole is cast in situ after the anchor screw) to level the installation surface.
(2): Rack level adjustment requirements
The purpose of adjusting the level is to avoid the distortion of the frame of the clamping part of the clamping part, so that the clamping mechanism cannot be used normally. The clamping part is 1000mm: 0.05mm, and the injection table part is 1000mm: 0.03mm.
(3) On-site installation and inspection of injection molding machine;
When the machine arrives, protect the Corinth with soft objects before hoisting to avoid scratching the Corinth. If it is transported in pieces, the clamping device is first padded on the ground with wooden planks, and then assembled, and placed horizontally only on the Corinth column. And adjust by adjusting the adjusting screws of the shock absorber feet until the frame is horizontal in the transverse and longitudinal directions.
(4): Installation of water and electricity for injection molding machine:
1): There are two parts of external water: (1) melt cylinder, water transport ring and mold. (2) The lower part of the oil cooler is the water inlet, and the upper part is the drain port.
2): Three-phase, four-wire, power supply, 380V, and ground wire.
(5): Install hydraulic oil and lubricating oil.
1): Open the oil tank filler cap and inject 46# anti-wear hydraulic oil until the oil level is higher than the middle scale of the oil level gauge. After adding hydraulic oil, do not start the motor for three hours to facilitate the discharge of gas in the oil.
2): Lubricating oil, 150# gear oil for extension reaming lubrication. Lithium-based grease for injection table guide rods and bearings. Molybdenum disulfide for tail plate mold adjustment.
(6): Check the direction of motor operation
Inspection before operation: 1): Check the power cord first, and whether the grounding wire is firm.
2): Whether the hydraulic oil is injected into the oil level of the oil tank, and whether the lubricating grease is added to each lubrication point.
3): Check whether the pressure pipes are connected. Whether the screws are tightened or not.
Check the running direction: 1): Remove the rear sealing plate of the injection table to facilitate the inspection of the running direction of the oil pump motor
2): The motor can only be started in manual mode. The motor shaft can be rotated by hand, except for the variable pump.
3): After about 3-5 seconds of the oil pump motor, press the "emergency stop" and turn off the power supply, and observe whether it rotates clockwise from the shaft end of the oil pump.
4): If the oil pump motor runs in the wrong direction, the power supply of the electric box and the power supply in the plant should be turned off first, and the two power cables should be reversed on the power terminal of the electric box, and the wiring of the motor should not be replaced.
5): Start and stop the motor alternately several times (not less, more than 5 times) to remove the air from the oil pump.
6): Stop the motor about 20 seconds after running.
(7): Inspection and testing of mechanical safety devices:
1): The mechanical safety device is a direct safety device. When the safety door is opened, the mechanical lock rod baffle becomes separated, and the baffle falls downward, and the template is moved at this time, and the mechanical rod touches the baffle, and the clamping action stops immediately.
(8): Inspection and testing of electrical safety devices:
1): It is to control the clamping signal by opening and closing the safety door. When the front safety door or the rear safety door is opened, the two safety limiters respectively input the signal that the front or rear safety door is not open and closed to the computer, so as to cut off the clamping signal and make the mold unable to open and close. Steps:
(1): Start the motor and close the safety door.
(2): Press the "clamp" button to lock the mold.
(3): When the template moves forward, open the safety door to confirm whether the moving template stops moving.
(9): Hydraulic safety device:
1): The safety valve is installed below the front door of the safety door, when the safety door is opened, the cam on the device presses the control valve, cuts off the hydraulic circuit of the clamping, and can not lock the mold.
(10): Mold selection and installation:
Mold selection: 1): Colin column spacing, maximum, small modulus, maximum mold opening stroke, need to refer to the specification table.
2): Adjust the appropriate mold opening position according to the mold thickness.
Installation of the mold: 1): Press the "debug button", select "mold thickness" or "mold thin" to adjust the distance between the die locking head plate and the second plate.
2): Confirm whether the ejector pin position matches the mold hole.
3): Manually move the thimble to the front position and remove the unneeded thimble rod.
4): Confirm whether the ejector pin stroke is sufficient, and tighten the ejector rod screw. Screws are used to adjust the length.
5): Clean the mold and the first two plate surfaces, lift the mold with a lifting ring or steel wire, put it between the two heads, align the positioning ring of the mold with the center hole of the head plate, and close the safety door.
6): Press the "debug button" to cancel the "express" clamping operation on the function page, so that the second plate advances until the mold is pressed. Stop the motor and use the mold clamp and screws to fix the mold on the template.
7): Remove the wire rope, start the motor, manually open the mold slowly until it is opened to a suitable position, and check whether the thimble stroke is sufficient.
8): Adjust the clamping force required for the mold, and the adjustment of the clamping force is better to the pressure of the molded product without burrs.
9): After the mold is installed, the low-pressure clamping must be adjusted to test whether the mold can be clamped to the end position when there is a foreign object in the mold, and an alarm will be issued.
10): Connecting the mold cooling water.
(11): Selection of nozzles:
The head of the nozzle is spherical, and its size should be matched with the concave spherical surface of the mold, and under normal circumstances, the spherical radius of the nozzle is slightly smaller than the spherical radius of the mold by 0.5-1mm.
(12): Adjustment of injection volume:
The injection amount needs to be adjusted several times, generally according to the weight of the finished product and the nozzle, plus a rough estimate of the amount of glue to hold the pressure.
(13): Adjustment of melt volume:
The melt amount must be greater than the actual injection amount, otherwise the product is prone to instability and shrinkage.
(14): Regulation of cooling water:
1): Improper cooling of the mold will affect the quality of the product and cause difficulty in demoulding, pay attention to adjust the amount of water.
2): The cooling water at the end of the melt cylinder should be kept smooth and low temperature to prevent the rubber particles from melting at the blanking port, resulting in difficulty in blanking.
3): The pressure oil temperature should be kept between 30 and 50 degrees.
Seven: injection molding machine maintenance operation process:
(1) Tools required for maintenance:
1): Multimeter (required to have temperature test function).
2): A set of Allen wrenches.
3): Adjustable wrench 6 inches, 8 inches, 12 inches.
4): Slotted screwdriver (Ф2.5-100. Ф3.5-250.)
5): Phillips screwdriver (ibid.).
6): Electric ferrochrome (220V-50W).
(2): Safety matters to be paid attention to in maintenance:
1): When the equipment is operated, the fixed door must not be removed for convenience.
2): When the fault needs to be repaired, the emergency stop switch should be pressed first, and the power supply should be cut off if necessary
Switch.
3): When the hand needs to enter the moving mold, the safety door must be opened. Shut down when necessary, ensure
Safe.
4): When the body enters the operation between the dynamic clamping, the motor must be stopped in advance and the emergency must be pressed
Discontinued.
5): When touching the nozzle, wear protective gloves and pay attention to the face not close to the nozzle.
6): When the heating ring is maintained, the heating electric heating should be turned off to prevent electric shock.
7): Before the maintenance operation, when the main switch of the power supply needs to be turned off, the "no closing" card should be placed at the main switch.
8): In the maintenance of electrical systems, pay attention to whether there are short circuits, open circuits, all kinds of wiring, whether the grounding screws are loose,
(3) Precautions after the completion of maintenance:
1): After maintenance, put the used tools back in their original places, not on the machine.
2): Restore the machine to its original state after repair, and clean up the site to ensure the cleanliness around the machine.
3): Power on the machine and actually operate it several times, and leave it only after the machine is working normally.
4): Do a detailed record of the fault phenomenon.