Common faults of web offset presses can be divided into three categories: paper loading faults, printing faults, and folding faults. To eliminate the fault, you must carefully read the random instructions and mechanical schematics, master the printing performance and mechanical performance of the machine, and fully understand the structure and use of each part of the machine. Only by doing these points can you have a correct fault After analysis, make correct elimination measures.
1. Common faults and troubleshooting
The upper part of the paper is to ensure the smooth and uniform speed of the whole process of feeding paper to the printing part. Common faults are: the paper tape is folded, and the paper tape is tight. Analysis of the above faults is mainly due to the quality problems of the paper tube, but in order to save raw materials, the fault can be eliminated by adjusting the paper guide roller and the magnetic powder brake. If the effect is not obvious, the direction of the paper roll movement can also be changed to eliminate such faults . When the paper roll is tightly edged, the paper tape is easily broken, which affects the normal paper supply. If this kind of phenomenon is found, the side of the tight edge can be wetted with a water brush, and the fault is eliminated.
2. Common faults and elimination of printing unit
The printing unit is the main part of the offset printing press. Whether the printing unit operates normally directly affects the key part of product quality. Common failures of printing units can be divided into three categories: water supply part failure; ink supply part failure; embossing part failure.
1. Analysis and elimination of common faults in water supply
Water supply devices can be divided into: indirect water supply and direct water supply. Indirect water supply is to atomize the water through the brush to achieve the purpose of water supply. Direct water supply means that the water rollers are in contact with each other to achieve the transfer of water and serve the purpose of water supply. No matter which method of water supply is used, the purpose is to fully Moisture keeps ink and ink balanced.
(1) Analysis and elimination of common failures of indirect water supply
The composition of the indirect water supply part: the indirect water supply part is composed of a water bucket roller, a brush roller, a string water roller, and a plate water roller.
The common faults of indirect water supply are: the water supply volume is too large or too small, and the water supply volume at one end of the printing plate is large or small, that is, the water supply volume at both ends of the printing plate is inconsistent. The above problems will directly affect the normal operation of the machine. The specific manifestations of various faults are: the excessive amount of water will make the ink color dull, gray and dull, and the ink color is not full. In serious cases, ink emulsification will occur. If the amount of water is too small, the printing plate will not be fully moistened, and graphics and text will be deformed or blurred. The specific elimination method can be adjusted according to the structure of the water supply mechanism and the function of each component. In the water supply part, the brush roller and the water roller are fixed and are not adjustable, and the water bucket roller and the plate water roller are adjustable. The depth of the water bucket roller in the sink is large, the water supply is large, and the depth is small The water supply volume is also small. The depth of the water bucket roller in the water tank is controlled by the adjustable eccentricity at both ends of the water bucket roller. According to this feature, the water supply of the printing plate can be adjusted appropriately. The gap between the plate water roller and the string water roller is adjusted by the plate water roller. The gap between the two should not be too large or too small. Excessive size cannot be fully transferred. If it is too small, some water will be squeezed out. The purpose of the transfer cannot be achieved. The gap between the plate water roller and the string water roller is consistent and balanced. It can be adjusted with 15-wire steel sheet.
(2) Analysis and elimination of common failures of direct water supply institutions
The direct water supply mechanism is composed of a water bucket roller, a water transfer roller, a string water roller, and a plate water roller.
The common faults are basically the same as the faults in the indirect water supply mechanism. The method of elimination is to adjust the pressure between the water transfer roller, the water bucket roller and the string water roller to eliminate it. The pressure at both ends of the water roller must be adjusted to a balanced position. This kind of water supply Institutions generally use water rollers, clean the water tank frequently, change the water rollers frequently, and check the pressure between the water rollers, because the pressure between the water rollers changes with the water after a period of time when the newly changed water roller fleece is used. There have also been changes, and grasping these points will eliminate the failure of the water supply part.
2. Common troubleshooting of ink supply part
The ink supply mechanism is composed of an ink fountain roller, an ink transfer roller, a tandem ink roller, and a form ink roller.
The failures are: insufficient ink supply, large ink supply, unstable ink supply, etc. Analysis of the above failures is caused by the pressure between the ink rollers not meeting the requirements. Removal method: 15-wire steel sheet can be used to adjust the pressure between the ink rollers, and the pressure balance is required. Due to the large temperature difference between winter and summer, the pressure can be appropriately increased in winter during the adjustment and the pressure can be appropriately reduced in summer.
3. Trouble shooting of imprinting part
The embossing part is the core part of the printing unit, and is also the most accurate part of design and manufacturing. Generally, the pressure and other mechanical parts cannot be adjusted. The faults include faint ink color, unclear dots, insufficient hair transfer and insufficient ink transfer, which are caused by the loss of elasticity of the rubber or the overcoat is too small. It can be eliminated by replacing the new rubber or increasing the thickness of the overcoat appropriately.
3. Failure analysis and elimination of folding unit
The folding unit is a whole that closely cooperates with each other and depends on each other. A problem with one component will affect the normal operation of the entire machine. To troubleshoot, you must understand the performance of each component, the laws of motion and the role it plays. Carefully observe and analyze the faults that occur, and then decide what method to eliminate after they are determined. Remember that you cannot analyze the faults that are inaccurate and eliminate them if they are not observed. For some faults, they appear to be problems in the next process, but they are actually problems in the previous process. If you cannot observe or analyze them, the fault It is difficult to rule out. such as:
The failure caused by improper adjustment of the machine is due to the failure of the performance, motion law, and structure of the machine. Generally, the folding does not meet the quality requirements, the paper tape is damaged, the movement time of the steel needle changes, and the folding knife and clamping plate cannot Very good coordination, 16K folding knife time changes, etc. These failures are caused by the failure to understand the movement rules of the machine parts. The main elimination method is to change the exercise time. The exercise time is generally controlled by eccentricity, and the high point of eccentricity can be changed to eliminate these faults.
Failures caused by machine parts wear: Failures caused by machine parts wear are due to insufficient lubrication of the high-speed moving parts, and the parts cannot be fully lubricated, which accelerates the wear of the parts and shortens the service life. The normal wear and tear of the machine parts were not replaced in time.
Failure caused by machine parts damage: Machine parts damage is generally due to the service life of the machine parts has reached the end of the year, or is caused by improper operation, and there is abnormal sound when the machine moves.
Pet Electronics Toys,Cat Electronics Toys,Electronics Toys
Ningbo XISXI E-commerce Co., Ltd , https://www.petspetsdoggze.com