Eight mechanical failures and remedies common to gravure printing machines

The structure of the gravure printing machine is relatively complex and professional in maintenance. In addition to normal operation and maintenance, equipment adjustments and repairs should be commissioned by professional technicians. When a failure occurs, the technician should be able to perform a simple analysis and take appropriate measures to protect personal safety, product quality, and the protection of corporate assets.

one. High failure rate of unwinding machine A/B reel

1 It is necessary to check whether the A/B reels are synchronized, whether the transmission components (synchronous belts) are effectively driven, 2 whether to measure the actual diameter of the material coil, whether it is compared with the self-test of the system, and whether the reel diameters are the same; 3 whether the reversal position of the docking arm and the reel is reversed normal. Whether the radio eye and the reflex eye are working properly and the detection position is correct; 4 whether the connection of the cutting knife and the pressure roller is smooth and consistent; if there is any advance or hysteresis, whether there is water vapor in the trachea or the air pressure is too low, which will affect the normal operation of the cylinder. 5If the roll is slippery, it will affect the electric eye detection (this problem will directly lead to large finishing tension fluctuations, poor color registration accuracy). When checking whether to install the material roll, the power side and the operation side operation thimble do not fix the tight material roll; 6 set ring surface oxidation or the carbon brush wears badly, the electric signal output, the input are weak, influences the component electricity action and the feedback. Need to be dealt with accordingly, make this part electrify, the contact is normal, the maintenance needs to cut off the electricity to operate; 7 Adhesive tape adhesiveness is insufficient, need to change sticky tape.

Second, traction device failure

(1)Steel roller traction is not synchronized

1Check whether the rubber roller presses against the steel roller, whether the rubber roller rubber layer is aged; 2 whether the pressure is up to the specified air pressure, whether there is leakage or obstruction in the air circuit; 3 whether the speed of the steel roller and the device speed are synchronized, and the transmission components ( Whether the synchronous belt) effectively transmits power; 4 whether the motor encoder works normally (the traction does not synchronize will directly affect the tension and color accuracy).

(2) Poor cooling effect

1 whether the cooling water temperature is maintained at 20 ~ 25 °C, or use cooling water 5 ~ 15 °C; 2 whether the amount of water meets the requirements, there is enough cooling water circulation; 3 whether the cooling roller within the long-term use of scale, plug the cooling roller inside, The high-pressure cleaning pump can be used to perform high-pressure dissolving and cleaning with an acidic solution and maintain a good cooling water pipe flow.

Third, no shaft loading mechanism failure

(1) Gear box heating

1 It is necessary to check the condition of oil in the gearbox in time. Lubricating oil can effectively maintain the lubrication of the transmission components in the gearbox and the cooling components are ineffective. 2 When the gearbox heats up and the noise of the gearbox increases, there may be a transmission component inside the gearbox. Wear or damage, need to stop the inspection in time; 3 check whether there is ink or solvent from the gear box cone top rod into the gear box, resulting in bearing damage or other transmission parts damage.

(2) The accuracy of horizontal axis registration is poor

1 The power-side cone plugging structure is a cylinder cone top form, and the manual valve is rotated under the condition that the cylinder is withdrawn (intake). Whether the cone plugging is in good contact with the stencil tube or if there is a slippage gap, check whether the taper plug and the plate cylinder are in contact with each other, whether scratches or heat occurs, and whether the permanent magnet low speed motor in the transverse axis mode of the 2nd version is working properly and whether there is an abnormal phenomenon. ; 3 can be manually checked by color to check the action, but also can be adjusted by manually adjusting the color after adjusting the color automatically, to observe the color change; 4 printing plate or plate loading accuracy reasons.

Fourth, the embossing mechanism failure

(1) poor ink transfer effect

1 Impression force. Check whether the actual imprinting force is consistent with the pressure value of the regulating valve, and calculate the cylinder output pressure corresponding to the corresponding pressure gauge value through the cylinder bore. If they are inconsistent, check the pneumatic components, main air pressure, and whether there is mechanical resistance or other factors. 2 If the quality of the impression cylinder is bad and the surface adheres to impurities, replace the roller.

(2) color registration accuracy problem

1 The impression roller is a passive component. In the pressed state, the roller and the printing plate should be in a synchronized state. If it is not synchronized, it is necessary to detect whether the rolling bearing is flexible and whether it is stuck; 2 Check whether the operation of the impression cylinder is normal during the start of printing; 3 check whether the impression cylinder and the plate cylinder are in good contact.

Fifth, scraper mechanism problems

When the squeegee effect deteriorates, the following problems can be checked and eliminated: 1 Check whether the screws, bolts, fixed handwheels, handles, and blade clamps of the squeegee mechanism are all locked and tightened; 2 Check the blade lift, before and after, Whether there is wear in the screw rod, worm gear and worm gear pair of the operating parts such as swinging and swinging, and whether there is a gap; whether there is a transmission, a transmission member is stuck, and the work is not flexible. Whether sliding bearings, transmission parts, rotating parts, etc. are adequately lubricated; 4 Whether the doctor blade works without ink. The ink acts as a lubricant between the doctor blade and the plate cylinder, but when the doctor blade is in rigid contact with the plate cylinder without the ink state, it will cause the blade to have a large frictional force and heat, and also cause damage to the plate cylinder; 5 Whether the doctor blade swings Smooth. The squeegee oscillation transmits blade oscillating power through the output shaft below the gear box. This position is converted from a circular motion to a linear motion, and the part is easily ignored. Special care must be taken to keep the part flexible. The use of equipment for a long time can easily cause mechanical resistance due to grease aging or dust accumulation.

Sixth, ink plate lifting failure

The lifting and lowering of the ink tray is achieved through the cooperation of the worm gear and the rack and pinion for lifting and self-locking. Usually the failure of the lifting device is due to lack of lubrication, lifting resistance is large, the power side, the operation side of the lift is not synchronized, etc., can be used to maintain the flexibility of the transmission parts by lubricating or cleaning the dust and ink on the transmission. This part must be installed at the same level at both ends.

Seventh, the ink roller failure

1 Ink roller rotation failure. If the motor is overheated, the noise is heavy, the ink roller is shaken (eliminating the rubber quality problem of the ink roller, and the problem of the ink roller itself jumping), and inspection and maintenance can be started from the transmission components.

2 Ink roller pressing failure. The pressure/off state of the inking roller depends on the action of the cylinder, and the working height of the inking roller can be adjusted by the limiting nut on the cylinder. There is a problem with this component that needs to check whether the air path is obstructed, whether the air pressure meets the requirements, whether the limit is correct and whether the moving parts are flexible.

3 Ink roller speed failure. The gear ratio in the ink roller mechanism is a fixed value. The speed is adjusted by the potentiometer. The potentiometer control source is the inverter. The inverter controls the motor frequency to meet the required speed. Can understand the relevant electrical data, according to the electrical instructions overhaul.

Eight, longitudinal correction mechanism failure

Longitudinal correction is driven by a low-speed permanent-magnet motor, and the signal is transmitted to the trapping system encoder, which feedbacks each other to guarantee overprint accuracy. Longitudinal color registration accuracy is poor (because the non-color registration system results) When the corrective reaction is not flexible, you can check from the following aspects: 1 check whether the color coded encoder is faulty; 2 check whether the low-speed permanent magnet motor has a fault; 3 check whether the film route is normal ;4 Check whether the worm and the worm gear work flexibly, whether there is stuck and high resistance. Whether the ball screw is flexible and effective, whether the left and right ball screws are in the horizontal state, whether the two ends of the motor driving the screw at both ends rise or fall at the same time has no obvious obstruction or the action is not smooth. Worm gear and worm gear should pay attention to maintenance and lubrication; 5 can set the color system to select the manual position, adjust to the color after the pass to select automatic color registration, watch color deviation and longitudinal correction work.