Newspaper printing equipment management and maintenance

The management of printing equipment is a very important and indispensable task for every printing factory. It is a powerful guarantee for the normal production of printing plants. The management and maintenance of technical equipment are closely related. Newspaper production emphasizes timeliness, and requires high equipment integrity. Once a failure occurs, it must be repaired in the shortest possible time. It requires minimal failures and failures. Introduced separately below.

1. Management of printing equipment

Strictly speaking, technical equipment management includes two aspects, one is technical management; the other is equipment management.

1) Technical Management

Technical management is to carry out planned and purposeful scientific management of all technical activities in the production process according to the characteristics and laws of the production technology itself and in accordance with current technical policies.

The basic tasks of technology management are: to establish the necessary work order for the implementation of various technical activities, establish and improve various technical management systems, carry out research work, actively promote and adopt new technologies, new processes, new materials, and transform existing technical equipment. , Constantly tap potential, innovate and transform to improve the modernization level of printing plants; provide reliable technical basis for rational and efficient organization of production, including product design, process plan and various technical documents; at the same time, provide technical assurance for safe production .

The main contents of technology management are: formulating plant science and technology development and tapping potential, innovation, and transformation plans, and formulating and implementing relevant regulations and responsibility systems for process management, quality management, and equipment management. Scientific research and technical information collection and management, technological innovation and the introduction of new technologies, new equipment management, technical archives and technical data management, and staff technical education, training and assessment.

Technical management requires professional and technical personnel to be responsible for the establishment of specialized institutions and the application of modern scientific methods.

2) Equipment Management

Equipment management ensures that various equipments are in good condition at any time, improving the efficiency of the equipment and ensuring normal production.

The main tasks of equipment management are: according to the principle of technologically advanced and economically reasonable, the right to purchase equipment; ensure that the machinery and equipment are always in the best technical state; as soon as possible to master the repair and maintenance technology of the imported equipment, spare parts procurement and Supply and other work to ensure the normal operation of the equipment; the development of related equipment maintenance and repair system, and supervision and implementation; the establishment of equipment maintenance files.

In addition, the rational use of equipment is also an important part of equipment management. Only by rationally arranging production, can the full play of the role of equipment. It can not only obtain the best economic effect, but also reduce equipment wear, extend the service life of the equipment, and obtain long-term, stable, and greater benefits.

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? Motor cooling helium and air pump regulators;

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 electrical repair, first check the power supply voltage? Whether the current is normal, whether the air pump pressure reaches the standard, whether the hydraulic pressure of the lubrication system meets the standard, etc. If necessary, the load can be disengaged, which is favorable for judging whether the mechanical overload causes electrical failure or protection.

d) The web offset press uses a PC for automatic control, which brings a lot of convenience to troubleshooting electrical faults. Generally, there is a light emitting diode in the control cabinet for fault indication. According to the prompt, the fault location can be found. In more advanced equipment, you can look for prompts on the console display or use a laptop to “talk” with the industrial computer in the control cabinet to find the faulty system? Parts, and then rule out 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.

2 mechanical maintenance knowledge

Mechanical faults can be generally classified into accidental faults and natural faults. Accidental faults are mostly caused by improper maintenance or adjustments, or violations of operating procedures, and should be avoided as much as possible. Although natural failures are difficult to avoid, they can extend the use and maintenance levels and extend the effective working time of machinery.

There are three main failure modes of mechanical parts: fracture, deformation, and surface failure. The following describes wear, deformation, cleaning methods, and disassembly of printing machine parts.

a) Wear of printing machinery parts

In the working process of the machine, if the size of the relatively moving part surface has occurred? Changes in shape and surface quality are called wear.

The main causes of wear of parts are friction and molecular attraction. Wear can be divided into abrasive wear, mechanical friction wear and adhesive wear. The reasons that affect the wear of mechanical parts are generally: speed, pressure, lubrication, temperature, materials, processing and cooperation.

b) Deformation of printing machinery parts

In the maintenance process, wear is one of the main factors of mechanical damage, but the micro-deformation of the parts is easily overlooked. After the assembled wear parts are repaired, the technical performance of the machine does not meet the requirements. This is related to metal deformation. In the actual production, the deformation of the basic parts should be given special attention, because if the basic parts are deformed, the relationship between all the parts assembled on the basic part and the mechanical performance of the mechanism will be affected. Therefore, in the process of repairing the parts, it is necessary to check the wearing condition of the mating surface, and to check the positional accuracy of the parts (especially the basic parts). For the first time overhauled mechanical deformation, we must pay attention to whether it is deformed after 12 to 20 months under the effect of internal stress. For hot-worked parts, there should be appropriate measures to remove the internal stress.

3 Disassembly and Assembly of Printing Machinery

Mechanical repair personnel are required to face the problems of disassembly and assembly when repairing the printing machinery. In particular, assembly will directly affect the mechanical properties, and the assembly quality is not high, causing serious mechanical wear.

a) Mechanical disassembly

Due to the large number of types of printing machinery and the different shapes of parts, it is difficult to describe them one by one. Here is a general disassembly principle.

First of all, before disassembling, you must understand the structure, function, and principle of the machine. Check the relevant technical data and instructions first. From the actual point of view, to determine the demolition part, the part that can not be removed should not be removed as much as possible, but for the part that is not dismantled, it must undergo an overall inspection to ensure quality.

Secondly, in the disassembly process, disassembly shall be performed from the inside to the outside of the watch, and the external accessories, tubing, etc. shall be disassembled first, and then disassembled according to the order of the parts after the first assembly. Marks shall be made for the disassembly of the more important parts. List the numbers and avoid clutter. It is also important to use tools properly when disassembling. The tools must be compatible with the parts being disassembled. If you want to remove the threaded connector to use the appropriate wrench, remove the static fittings to use special tools, can not smash hammer, chaos and so on.

In addition, when disassembling, conditions should be created for assembly. For non-interchangeable parts, they should also be marked or placed in pairs when they are removed so that they can be reset during assembly. This will ensure assembly accuracy and reduce unnecessary wear.

b) Mechanical assembly

When assembling, it is necessary to ensure the matching precision and dimensional accuracy. To ensure the matching accuracy, the matching method, repair method, and adjustment method can be used during assembly. The dimensional accuracy mainly refers to the degree of error in the assembly dimensions of each part of the assembly. That is to say, in the assembly, it is necessary to pay attention to eliminate accumulated errors and avoid adverse effects on the machine due to the increase of accumulated errors.

The seal in the assembly is also very important. In the printing press, the seal is mainly used in the air pump, gear box and other parts. When the seal fails, air leakage and oil leakage will occur. Therefore, the sealing material used in the repair should be appropriate, and the assembly should be reasonable. The liquid sealant should be used for static sealing. According to the different nature of use, dry adhesion, dry stripping, and non-drying adhesion And semi-dry viscoelastic type and other varieties.

The preparatory work before assembly must not be overlooked. Its contents include pre-assembly inspection, assembly cleaning and assembly of components. The final step is the commissioning after assembly. The second and the first function is to check the quality of the assembly. The second is to adjust the machine.

c) Cleaning of mechanical parts

The cleaning of mechanical parts is a necessary part in mechanical repair. The cleaning content is mainly degreasing and rust removal.

The methods of degreasing and cleaning mainly include alkali solution deoiling method, organic solvent deoiling method and metal cleaning degreasing method. The alkali solution mentioned here is mainly an alkali solution added with an emulsifier, and it has a good effect on the cleaning of mineral oils and fats. The so-called organic solvents generally refer to gasoline, kerosene, etc. It can dissolve various oils without damaging parts. In addition to gasoline and kerosene, alcohol, acetone, and ether can be used for small parts and adhesive parts with high precision, respectively. And other organic solvents. Metal cleaning is a new kind of synthetic detergent. Because the surface active material reduces the interfacial tension, it produces various functions such as wetting, penetration, emulsification, and dispersion, which makes it have strong decontamination ability. The use of this cleaning agent is non-toxic, non-corrosive, non-flammable, non-explosive, and non-hazardous. It also has certain rust-preventing ability and low cost, and it has been widely used.

Rust cleaning methods mainly include mechanical and chemical methods. Mechanical derusting is generally performed with wire brushes, doctor blades, emery cloth, etc., and sometimes it can also be performed with electric grinding wheels and wire wheels. Mechanical rust removal can leave scratches on the work surface and should only be used for surface rust removal of non-essential parts. Chemical rust removal generally uses hydrochloric acid, sulfuric acid and phosphoric acid to remove basic metal oxides. The method is simple and the rust removal effect is good. When using this method to remove rust, it is necessary to master the solvent concentration ratio.