Newspaper Printing Equipment - Maintenance (1)

2 . Printing equipment maintenance knowledge

In the maintenance of printing equipment, it is necessary to adhere to the idea of ​​maintenance-oriented, prevention-oriented, and take effective measures from the organizational form and system to ensure the implementation of this work. The following describes the maintenance and repair knowledge of the equipment.

1) Maintenance of printing equipment

Generally can be divided into four categories:

1 Routine maintenance, also called routine maintenance, is to clean, lubricate, fasten loose fasteners, and check the integrity of components.
2 Level 1 maintenance, regular (eg once per week) inspection of equipment: clean dampening system water buckets, water tanks, tighten loose parts, internal and external cleaning of the machine, transmission system, lubrication system, pneumatic system and imprinting Part and so on.
3 Secondary maintenance, mainly for the internal cleaning of the equipment (including water glue, ink glue) and lubrication, targeted dismantling inspection of key parts, adjustments to the machinery and equipment (including level, etc.), replacement of wearing parts.
4 three levels of maintenance, the main part of the equipment for dismantling inspections and adjustments, including motor cleaning, inspection of technical conditions, replacement of lubricating oil, etc.; for some parts to achieve the specified wear limit replacement, such as bearing keys, electrical and pneumatic components Wait.

For air pump and maintenance, please pay attention to the following points:

a) Clean the air pump inlet filter every week, the motor heat sink and the air pump regulator;
b) refuel the bearing every three months,
c) Perform a major overhaul every year (or 2500 hours) of work and inspect major wear parts?
The following points should be noted for the maintenance of air compressors:
a) check the compressor oil level daily, not below the safety mark line;
b) Daily discharge of condensate from the tank;
c) Clean the air inlet filter every week;
d) Check the belt tension every month to clean the motor and heat sink;
e) Change the oil every 3 months and thoroughly clean the oil chamber;
f) Check the pressure drop (leakage) every 1 year. If the pressure drops by more than 10%, check the replacement of the damaged compressor seal in time;
g) Overhauled once every two years, to open a comprehensive inspection?

Each printing factory must, based on the actual conditions of the existing equipment, proceed from the actual production, and formulate the best maintenance system and maintenance rules that meet the existing equipment and production requirements.

2) General knowledge of maintenance of printing equipment

The maintenance of the equipment and the maintenance of the equipment are different in content and function. The repair is mainly to find faults, troubleshoot, repair and replace damaged or worn, corroded parts, so that the equipment can operate normally. Equipment repairs are divided into electrical and mechanical parts.

1 Electric part maintenance knowledge

In the daily printing equipment repair work, the electrical part occupies a large proportion. With the continuous development of printing technology equipment, the degree of automation control is getting higher and higher, and the control system is also more complicated. Therefore, electrical maintenance personnel are required to have a high level of technical skills and quality, and to understand computer principles and operations. For print maintenance electrical personnel, the following points should be noted in daily maintenance work:

a) Carefully read the electrical schematics and related documents of the equipment, and master the electrical principles and control system principles of the equipment in principle. Find out where electrical components are located, how they are routed, and how they are numbered and routed.

b) For machinery and equipment failures, carefully analyze the parts that may have this failure, and look for components and circuits that may cause failures based on electrical schematics, wiring diagrams, etc., and diagnose and eliminate them one by one.

c) In the electrical repair, first check the power supply voltage and current, whether the pump pressure reaches the standard, the lubrication system oil pressure meets the standard, etc. If necessary, the load can be disengaged, which is helpful to determine whether the overload is caused by mechanical overload. Electrical fault or protection.

d) The web offset press adopts a PC for automatic control. This brings a lot of convenience to troubleshooting electrical faults. Generally, there are light emitting diodes in the control cabinet for fault indications. The fault location can be found according to the prompts. In the equipment, you can find the prompt on the console display screen, or use the laptop computer to “talk” with the industrial computer in the control cabinet, find the faulty system parts, and then eliminate them one by one.

e) Frequently encountered electrical faults can be summarized as: fuse damage, contactor, relay contact damage, loose wiring, poor contact, failure of the button, limit switch, safety control system, a certain position control switch is not reset, In the tension control system and the paper break system, some photoelectric detection failures, electromagnetic valve leakage, damage, etc.

f) The motor is the source of power in the printing equipment. The following describes the common faults of the DC motor and the AC motor.

The common faults in DC electric operation are mechanical and electrical. Mechanical failures are mainly manifested as bearing heating, motor vibration, armature colliding with the stator core, and abnormal noise emission. It is generally caused by the rotation of the armature. When checking, manually rotate the armature to observe whether the armature collides with the stator and determine whether the vibration is caused by the motor itself or due to a poor transmission. The motor is less likely to vibrate due to its own poor balance. Frequently, the concentricity of the transmission is not good enough to cause vibration. This phenomenon can easily cause damage to the motor bearings and even cause deformation of the armature output shaft.

The most common electrical fault of DC motors is the spark between the brush and the commutator. During normal operation, the spark between the brush and the commutator is pale blue, faint and fine, and the contact surface of the brush is smooth and bright. A red-brown oxide film forms on the surface of the commutator. When the motor is not operating normally, the spark size and color will change. When the fault is slight, the spark will appear yellow-red and bright, and the commutator will have a black surface with burning marks. If the spark is severe, it will spray red and green sparks in a large amount, mixed with flash fire, and accompanied by a buzzing sound. If the machine is not stopped in time, the commutator, brush and brush holder will soon be burnt out. When the brush position deviates from the geometric centerline, there may be serious sparks when the armature winding is open and short circuited. In addition, brush brands, performance does not match, brush pressure is too large, too small, the brush is not well ground, the contact area is too small and other reasons, will cause failure.

The mechanical failure of an AC three-phase asynchronous motor is basically the same as that of a DC motor. Here is a brief introduction to common electrical faults. First, single-phase operation fault, that is, one phase winding in the three-phase winding of the motor is disconnected. At this time, the motor torque is significantly reduced, the speed is slow, the sound is abnormal, and the time is longer. Severe fever and burnout; Second, the motor has a serious fever, and even issued a paste smell, this failure may be due to the load is too heavy, it may be caused by the power supply voltage is too low, too high.