Difference between ink roller and water roller of printing press machine and cause of wear

The rubber rollers of printing press machine play an important role in the printing process, but in actual production, many printing companies will soon need to replace the original rubber rollers. Due to insufficient cleaning and maintenance of the rubber rollers by most manufacturers, the original rubber rollers are prematurely aged, causing printing failures and cost loss.

Ink roller
Ink roller refers to the rubber roller in all ink supply systems. The role of the ink roller is to quantify and uniformly transfer the printing ink to the printing plate, which can be divided into three types: ink, ink transfer, and printing plate.
The ink is used to extract a fixed amount of ink from the ink fountain and then transfer it to the transfer roller. The ink transfer roller receives these inks and distributes them evenly to form a uniform ink film. It is then passed to the platen roller, which is responsible for distributing the incoming ink on the printing plate. At this point, the task of the ink roller is completed.

In offset presses, rubber rollers and hard rollers are always spaced apart to form a soft-hard alternate arrangement. This arrangement is more conducive to ink transfer and uniform distribution. The function of the ink roller can further strengthen the axial distribution of the ink. When it is working, it also rotates in the axial direction and performs a series of axial translation. Therefore, it is called an ink roller.

The ink roller is used to transfer ink, so the rubber must be ink-friendly. Due to the long-term contact between the adhesive layer and the ink, it must have certain resistance to ink corrosion. At the same time, the speed of the offset press is very high, and the speed of the ink roller is also very high, which causes serious heat generation of the adhesive layer, thereby accelerating the aging of the rubber. Therefore, to make the rubber roller durable, the requirements on the rubber material are also very high.

Water roller
The water roller is a rubber roller in the water supply system, similar to the ink roller, and its function is to uniformly transport water to the printing plate. Water rollers also have water, water, and plate. At present, there are two types of water supply methods for water rollers. One is the continuous water supply method. The water supply amount is achieved by adjusting the speed of the bucket roller, which is suitable for high-speed printing. The other is intermittent. The platen roller is covered with a fleece cover, and the water roller swings back and forth to supply water.

The water roller is used to transfer water, so it must be hydrophilic and resistant to water corrosion, and its hardness is usually lower than that of the ink roller.Ink rollers and water rollers of offset printing presses traditionally use nitrile rubber, but they have their own emphasis on the formula of rubber compounds. Of course, other materials can also be used as long as they meet the requirements for use.

Causes of Rubber Roller Wear
1. Improper pressure adjustment of the ink roller will cause wear of the ink roller, especially if the pressure is heavy on one side and light on the other, it will easily cause damage to the rubber roller.
2. Forgetting to close the handles on both ends of the water bucket roller will cause the colloid of the metering roller to tear and damage. If one end is not closed or the other end is not in place, the metering roller and the plate-type water roller will be worn.
3. During the plate loading process, the PS plate is not installed properly, the bite of the PS plate and the tension screw at the end of the plate are not tightened. The PS plate will wear out the rubber roller due to the untensioned part and the protruding protrusions; The plate is too tight or the top plate is too powerful, which causes the plate to deform or rupture and damage the ink roller, especially because the plate water roller has low rubber hardness and its damage is also * obvious.
4. In the printing process, when printing a long order, the running conditions of the two ends and the middle are different, which will cause the two ends of the ink roller to wear.
5. Poorly printed film. The powder and sand particles falling off the film will cause the ink roller and copper roller to wear.
6. Use a sharp tool to draw a gauge line or make other marks on the printing plate, resulting in damage to the ink roller.
7. During the printing process, due to the poor local water quality and high hardness, and the printing plant did not install a proper water treatment device, the surface of the ink roller accumulated calcium compounds, which increased the rubber hardness and increased friction. This problem not only causes wear of the ink roller, but also causes serious print quality problems.
8. The ink roller is not regularly maintained and recycled.
9. The ink on the surface of the metering roller will not cause abrasion if it is not washed for a long time.
10. Special processes, such as printing gold and silver cardboard, stickers or films, require special inks and special additives, which will accelerate the cracking and aging of rubber rollers.
11. The roughness of ink particles, especially the roughness of UV ink, has a direct impact on the wear of rubber rollers.
12. The speed of wear of rubber rollers in different parts is different. Such as the ink transfer roller, because its action is stationary → high speed → stationary continuously reciprocating, its wear degree is faster than ordinary.
13. When the rubber roller is stationary for a long time when it is stopped for a long time, the rubber diameter of the rubber roller is uneven, and the rotation and deformation of the rubber roller are different, which exacerbates the wear of the rubber roller.
14. The temperature control of the working environment is not good. It exceeds the physical properties of the rubber roller and increases the wear of the rubber roller.

How To Design Cleverly LED Waterproof Power Supply?

In a wide range of applications of power supplies, as a professional power supply for LEDs, most of them require a certain waterproof function, and have high requirements for the level of waterproofing. Regardless of whether the requirements are waterproof, but also the ability to adapt to the ambient temperature and the operating conditions of equipment in severe weather have high requirements.
Waterproof power supply must have certain requirements for its insulation and working temperature. The working temperature of the led waterproof switching power supply is generally -40 -80 ° C (outer surface temperature of the case), the storage temperature is -40 -85 ° C, and the working humidity is 10-90% relative humidity.
LED waterproof switching power supply has great requirements for the working environment and has been widely used in daily life. So, what characteristics does it have?
1. High reliability: Especially the driving power sources like LED street lights are at high altitude, so it leads to inconvenience of maintenance, and the cost is even greater.
2. High efficiency: LED is an energy-saving product, and the efficiency of the driving power supply must be high. For the power supply, the structure placed in the led lamp is very important.
The luminous efficiency of LED will decrease with the increase of LED temperature, so the heat dissipation of LED is especially important. When the efficiency of the power supply is high, the power loss of the power supply becomes smaller, the heat generation in the LED lamp will also be reduced, and the temperature of the lamp will be reduced accordingly, which is beneficial to delaying the light decay of the LED.
3. High power: The power factor is the load requirement of the grid. Generally, there are no mandatory indicators for electrical appliances below 70 watts.
4. Driving mode: one constant voltage source provides multiple constant current sources, and each constant current source supplies power to each LED individually. Its advantage is that the combination is flexible, and the failure of all the LEDs will not affect the normal operation of other LEDs, which will be higher for cost.
The second type is direct constant current power supply, and the LEDs are operated in series or in parallel, but there is a obvious disadvantage that it is poor flexibility.
These two forms coexist for a period of time, and multiple constant current output power supply methods will be better in terms of cost and performance.
5. Surge protection function: LED's ability to resist surge is relatively poor, especially its ability to resist reverse voltage. For example, led lamps installed outdoors, due to the start-up of the grid load and the induction of lightning strikes, various surges can be invaded from the grid system, and some surges can cause damage to LEDs. Therefore, the LED drive power must have the ability to suppress the intrusion of the surge and protect the LED from damage.
6. Protection function: In addition to the normal protection function of the power supply, it is best to add negative feedback of LED temperature to the constant current output to prevent the LED temperature from becoming too high.
7. Protection: The type of the lamp is externally installed, the power supply structure should be waterproof and moisture-proof, and the shell should be resistant to sunlight.
8. The life of the drive power must be adapted to the life of the LED.
9. To meet the requirements of safety regulations and electromagnetic compatibility.
LED waterproof power supply supplies are mostly used to provide driving capabilities for various LED lamps, such as LED spotlights, LED street lights, LED underground lights, LED ceiling lights, and LED panel lights. The biggest feature of the led power supply is that it is waterproof and can be used outdoors. At the same time, it is not afraid of bad weather such as rain, fog and direct sunlight.

Refrigeration Equipment Type Introduction(1)

Refrigeration equipment

Refrigeration equipment is a combination of a chiller and a facility that uses cold capacity. Refrigeration units are designed and constructed to efficiently use cold quantities to refrigerate food or other items; to perform product performance tests and scientific research tests at low temperatures; to achieve certain cooling processes in industrial production, or to perform air conditioning. When the item is cooled or frozen, a certain amount of heat is released, and the enclosure of the refrigeration unit also introduces a certain amount of heat when it is used. Therefore, in order to maintain the low temperature conditions in the refrigeration unit, it is necessary to install a refrigerator to continuously remove the heat, or to absorb the heat by melting the ice or sublimation of the dry ice.



Condenser

The high-pressure high-temperature refrigerant vapor sent from the compressor is condensed into a liquid. There are three types of commonly used condensers: 1 water-cooled. With water as the coolant, there are tube condensers, sleeve condensers and spiral plate condensers. 2 spray type. At the same time, water and air are used as coolants, there are spray condensers (air is natural convection) and evaporative condensers (air is forced convection). 3 air-cooled. Air is used as a coolant, ie an air condenser.







Tag: Refrigeration Equipment

The Necessity And Inspection Method Of PCBA Detection

As a platform for the transmission of many components and circuit signals, the printed circuit board (PCB) has always been regarded as a key part of electronic information products, and its quality determines the quality and reliability of the final product. Due to the development trend of high density, lead-free and halogen-free environmental requirements, if professional and timely inspections are not completed, various failure problems may occur, such as poor wettability, cracks, delamination, etc.
Detection Technology
Generally, PCBA assembly inspection technology is divided into two types: visual inspection and automatic process inspection.
A. Visual inspection
After a large number of steps in the PCB assembly process, visual inspection can be used, and the visual inspection equipment is selected according to the position of the inspection target. The effectiveness of the visual inspection depends on the competence of the inspectors, the consistency and applicability of the inspection standards.
Inspectors must be fully aware of the technical requirements for each type of solder joint, as each type of solder joint may contain up to 8 defect criteria, and there may be more than 6 solder joints on different assembly equipment. Therefore, visual inspection is not suitable for quantitative measurement of effective structural process control.
B. Structural Process Test System (SPTS)
Digitization and analysis systems for real-time and automatic video capture can significantly improve the tolerance and repeatability of visual inspection. Therefore, structural process test systems rely on certain forms of emitted light, such as visible light, laser beams, and X-rays. All of these systems process images to obtain information to identify and measure defects related to solder joint quality.
C. Automatic / Automatic Optical Inspection (AOI)
The AOI system relies on multiple light sources, a programmable LED library, and some cameras to illuminate the solder joints and shoot. Under reflected light, the leads and solder joints reflect, reflecting most of the light, while PCB and SMD reflect very little light. The light reflected from the solder joint does not provide actual height data, while the pattern and intensity of the reflected light provides information about the curvature of the solder joint. A professional analysis is then performed to determine if the solder joints are complete, whether the solder is sufficient, and if wetting has not occurred.
D. Automatic laser test (ALT) measurement
ALT is a more direct technique for testing height and shape solder joints or paste deposits. When the image of the laser beam is focused on one or more position-sensitive detectors at an angle to the laser beam, the system is used to measure the height and reflectance of some surface parts.
During the ALT measurement, the surface height is determined by the position of the light reflected by the position-sensitive detector, and the surface reflectance is calculated from the power of the reflected beam. Due to the secondary reflection, the beam may illuminate a position-sensitive detector at multiple locations, which requires a solution to distinguish the correct measurement.
In addition, when traveling along the light of the position sensitive detector, the reflected light beam may be shielded or interfered by interfering materials. To eliminate multiple reflections and prevent shielding, the system should test the reflected laser beam along an adjusted independent optical path.
How to determine the PCB assembly inspection method?
Despite the variety of detection methods, there is a big difference between AOI inspection and X-ray inspection. The three factors to consider when determining the inspection method are defect type, cost, and inspection speed. When it comes to defect types AOI and X-ray coverage, AOI is usually used for inner layer testing before lamination. Defect items include solder paste amount, component location, missing and polarity, and solder joint defects.
The above is a detailed introduction to the common methods of testing printed circuit boards. If you have any questions about our answer, you can contact us.

The Necessity And Inspection Method Of PCBA Detection

As a platform for the transmission of many components and circuit signals, the printed circuit board (PCB) has always been regarded as a key part of electronic information products, and its quality determines the quality and reliability of the final product. Due to the development trend of high density, lead-free and halogen-free environmental requirements, if professional and timely inspections are not completed, various failure problems may occur, such as poor wettability, cracks, delamination, etc.
Detection Technology
Generally, PCBA assembly inspection technology is divided into two types: visual inspection and automatic process inspection.
A. Visual inspection
After a large number of steps in the PCB assembly process, visual inspection can be used, and the visual inspection equipment is selected according to the position of the inspection target. The effectiveness of the visual inspection depends on the competence of the inspectors, the consistency and applicability of the inspection standards.
Inspectors must be fully aware of the technical requirements for each type of solder joint, as each type of solder joint may contain up to 8 defect criteria, and there may be more than 6 solder joints on different assembly equipment. Therefore, visual inspection is not suitable for quantitative measurement of effective structural process control.
B. Structural Process Test System (SPTS)
Digitization and analysis systems for real-time and automatic video capture can significantly improve the tolerance and repeatability of visual inspection. Therefore, structural process test systems rely on certain forms of emitted light, such as visible light, laser beams, and X-rays. All of these systems process images to obtain information to identify and measure defects related to solder joint quality.
C. Automatic / Automatic Optical Inspection (AOI)
The AOI system relies on multiple light sources, a programmable LED library, and some cameras to illuminate the solder joints and shoot. Under reflected light, the leads and solder joints reflect, reflecting most of the light, while PCB and SMD reflect very little light. The light reflected from the solder joint does not provide actual height data, while the pattern and intensity of the reflected light provides information about the curvature of the solder joint. A professional analysis is then performed to determine if the solder joints are complete, whether the solder is sufficient, and if wetting has not occurred.
D. Automatic laser test (ALT) measurement
ALT is a more direct technique for testing height and shape solder joints or paste deposits. When the image of the laser beam is focused on one or more position-sensitive detectors at an angle to the laser beam, the system is used to measure the height and reflectance of some surface parts.
During the ALT measurement, the surface height is determined by the position of the light reflected by the position-sensitive detector, and the surface reflectance is calculated from the power of the reflected beam. Due to the secondary reflection, the beam may illuminate a position-sensitive detector at multiple locations, which requires a solution to distinguish the correct measurement.
In addition, when traveling along the light of the position sensitive detector, the reflected light beam may be shielded or interfered by interfering materials. To eliminate multiple reflections and prevent shielding, the system should test the reflected laser beam along an adjusted independent optical path.
How to determine the PCB assembly inspection method?
Despite the variety of detection methods, there is a big difference between AOI inspection and X-ray inspection. The three factors to consider when determining the inspection method are defect type, cost, and inspection speed. When it comes to defect types AOI and X-ray coverage, AOI is usually used for inner layer testing before lamination. Defect items include solder paste amount, component location, missing and polarity, and solder joint defects.
The above is a detailed introduction to the common methods of testing printed circuit boards. If you have any questions about our answer, you can contact us.