The application of UV in the printing industry is extremely fast. Forms, data, plastics, lotteries, magnetic cards, labels, and other products are commonly used UV materials, and almost all printing methods and printing models are applied, and these printers are required to be equipped with UV machine. Due to the complex type of presses, the types of curing machines are correspondingly varied. Producing an optional UV curing machine often makes print manufacturers scratching their heads.
The core components of the UV engine are UV lamps and transformers. How the curing effect is, the key is to select and match the UV lamp and transformer parameters, so that the lamp radiates 365nm UV light most effectively. The author has been engaged in this research for many years and has confirmed that the UV lamp transformer should be a well-matched system. When purchasing it, it cannot be separated. How to match and how to select its parameters? According to his own experience, the author talks about some opinions and discusses with peers.
I. Determination of UV lamp parameters UV lamp main parameters
The parameters of the UV lamp are: main wavelength (curing wavelength of the curing lamp in general printing and 365 nm); lamp arcing L (that is, the effective length of emitting UV light); and lamp rate density P. (Output power per cm, such as 80 watts/cm); lamp power P; lamp voltage U; lamp current I; lamp diameter;
2. UV lamp tube determination 1) lamp arc length L: the width of the cured material plus 2 cm;
2) Lamp power density P. : The power density is high and the UV efficiency of the lamp is high. Therefore, the power density should be selected according to the speed of the cured object and the characteristics of the cured material.
3) lamp current I: general lamp current is less than 10A, because the current is large, the transformer secondary heat loss is large, the secondary transformer winding coarse line caused transformer bulky. However, the current should not be too small, but generally it should be 5A. The lamp current can be adjusted by the leakage and gap of the electrical transformer. Generally, the output current of the high-speed leakage pin is not adjusted to the maximum, and then the current is reduced by the capacitor. The minimum value can be adjusted to 1-2A, but the capacitor cannot be used to adjust the lamp. Current.
4) The total lamp power P = L times P.
5) Lamp diameter: Experiments show that when the current density in the lamp is high, the output UV component is high. For example, the lamp tube of 160W/cm uses a 28mm wall, the UV intensity is 390W/cm2, and the tube is 22.5mm. The UV intensity is 620 W/cm2. When P. After the determination, the wall area energy load is large, the wall temperature is high, and the lamp life is low. The wall temperature can be lowered by water cooling or air cooling to increase the life.
6) Conduction in the lamp: UV lamps are commonly used in chemical lamps, and metal halide lamps are also used. Low power density generally uses mercury lamps. The mercury lamp output has a wide range of 365nm lines. Generally, the energy for curing is 18%-23% of the input energy, and both the visible and infrared light. The metal halide lamp, through the mixture of several halides, increases the output energy of the ultraviolet light, increases the solidification efficiency, and reduces the heat radiation, and is generally used for high power density lamps. Mercury lamps have a long life, typically 600-2000 hours, and halogen lamps have a short life, typically 200-1000 hours.
Second, the determination of the transformer parameters UV curing selected transformer, the following parameters are more important: including the input voltage, output voltage, input current, current. Since the internal conductivity of the lamp is that the cathode emits hot electrons to excite the mercury molecules to vaporize and conduct electricity, the ion conductivity in the lamp changes with the vaporization process of the mercury molecules. Therefore, the above parameters are also varied and generally reach stability after 3-5 minutes. The following describes the change process and selection method of several major parameters.
1) Input voltage: General 3KW or more transformer input power graves use 380V power.
2) Output voltage: The output open circuit voltage is 120%-125% of the lamp design voltage, so as to stimulate the lamp to turn on.
3) Output current and output voltage.
This is the basic process of lamp voltage and current from turning on the transformer to maintaining a smooth operation. Turning on the transformer lamp voltage is the open circuit voltage of the transformer, and the lamp current is zero at this time. As the thermal electron emission is conducted, the lamp voltage drops sharply, and the current rises. The electrons collide with the mercury molecules to cause them to excite. The movement of the electrons is hindered, the current drops slightly, and the voltage rises. When the supersaturated mercury is completely vaporized and conductive, The current rises to a steady state and the voltage drops to a stable value.
Third, the general method of using UV lamps and transformers The correct choice of UV lamps and transformers is the most effective way to radiate 365nm wavelength of ultraviolet light. The content of the following lecture is to briefly introduce some parameters theoretically. When choosing lamps and transformers, practical experience is very important. The following describes the general selection method.
1) Determine the lamp parameters and select the power density according to the curing requirements. For example, the curing speed of the rotary machine is fast, the power is 120-160W/cm, the printing speed of the screen machine is slow, and the lamp is low.
2) Select the lamp current. If the total power of the lamp is 3-12KW, then the current is 4.5-10A.
3) Select voltage, total power divided by current is voltage value. For example, the total power is 4KW, the current is 5.2A, and the voltage is 770V.
The transformer parameters must meet the requirements of the lamp, but the transformer has a large current greater than the current peak, which is usually 120% of the operating current. Voltage should take more than three groups of taps, because the lamp in the production process is more random, the parameter is not stable, use three sets of transformer taps to try, make the transformer output voltage close to the actual voltage of the lamp.
On-site handling of the fault of the paper cutting machine An example of the tension spring (material diameter 10mm, spring diameter 60mm, effective number of turns 35 circles) of the QZK program-controlled paper cutting machine in the paper lifter lifting mechanism was suddenly disconnected during one use. The length of the disconnection is 1/3 of the full length. This is because the paper cutter is used for a long time and the spring material is broken.
At that time, there were no spare parts in the factory. In order to restore the equipment to use as soon as possible, we decided to use it in due course, and then put two thirds of it back into use. The method was: to connect the springs with the inner circle to the high-speed screw Take a length so that the total length of the same length is equal to the length of the broken spring. After this treatment, it is used again. It is only a distance of 5mm shorter than the original distance (ie, the distance from the final point of rebound), but it does not affect the operation of the party and can meet the requirements for use. In this way, it took only two hours to restore the equipment to the land. After dealing with the urgent needs of the production, the borderland shipped the original specification from the Shanghai Post to the airport nearly a month later.
At an annual meeting of the Printing Technology Association in the region, I learned from my colleagues in another printing company that there was also a paper cutter with the same type of machine in our company. In one case, there were no spare parts at the time, and we handled it by using two different types of tension springs that were in stock at the time. (One parameter was: material diameter 8mm, spring diameter 45mm, effective number of turns 43 circles, another One is: The material diameter is 5mm, the medium diameter is 25mm, and the effective number of turns is 48. The spring with the middle diameter of 25mm is placed in the spring core with the median diameter of 45mm, and each of the two springs has its own thread pitch and is not adjustable. The screw connects the screw with the size of the screw (the outer thread of the screw is connected with the inner circle of the spring, the thread of the screw is connected with the thread of the adjustable screw), and this process also restores the operation of the party within a short time. This kind of thinking can be used by Jingdezhen for large loads and installation conditions. In the on-site processing, reference can be made to the relevant mechanical design data, and the reasonable design and use can be used to achieve better results. Management effect.
The core components of the UV engine are UV lamps and transformers. How the curing effect is, the key is to select and match the UV lamp and transformer parameters, so that the lamp radiates 365nm UV light most effectively. The author has been engaged in this research for many years and has confirmed that the UV lamp transformer should be a well-matched system. When purchasing it, it cannot be separated. How to match and how to select its parameters? According to his own experience, the author talks about some opinions and discusses with peers.
I. Determination of UV lamp parameters UV lamp main parameters
The parameters of the UV lamp are: main wavelength (curing wavelength of the curing lamp in general printing and 365 nm); lamp arcing L (that is, the effective length of emitting UV light); and lamp rate density P. (Output power per cm, such as 80 watts/cm); lamp power P; lamp voltage U; lamp current I; lamp diameter;
2. UV lamp tube determination 1) lamp arc length L: the width of the cured material plus 2 cm;
2) Lamp power density P. : The power density is high and the UV efficiency of the lamp is high. Therefore, the power density should be selected according to the speed of the cured object and the characteristics of the cured material.
3) lamp current I: general lamp current is less than 10A, because the current is large, the transformer secondary heat loss is large, the secondary transformer winding coarse line caused transformer bulky. However, the current should not be too small, but generally it should be 5A. The lamp current can be adjusted by the leakage and gap of the electrical transformer. Generally, the output current of the high-speed leakage pin is not adjusted to the maximum, and then the current is reduced by the capacitor. The minimum value can be adjusted to 1-2A, but the capacitor cannot be used to adjust the lamp. Current.
4) The total lamp power P = L times P.
5) Lamp diameter: Experiments show that when the current density in the lamp is high, the output UV component is high. For example, the lamp tube of 160W/cm uses a 28mm wall, the UV intensity is 390W/cm2, and the tube is 22.5mm. The UV intensity is 620 W/cm2. When P. After the determination, the wall area energy load is large, the wall temperature is high, and the lamp life is low. The wall temperature can be lowered by water cooling or air cooling to increase the life.
6) Conduction in the lamp: UV lamps are commonly used in chemical lamps, and metal halide lamps are also used. Low power density generally uses mercury lamps. The mercury lamp output has a wide range of 365nm lines. Generally, the energy for curing is 18%-23% of the input energy, and both the visible and infrared light. The metal halide lamp, through the mixture of several halides, increases the output energy of the ultraviolet light, increases the solidification efficiency, and reduces the heat radiation, and is generally used for high power density lamps. Mercury lamps have a long life, typically 600-2000 hours, and halogen lamps have a short life, typically 200-1000 hours.
Second, the determination of the transformer parameters UV curing selected transformer, the following parameters are more important: including the input voltage, output voltage, input current, current. Since the internal conductivity of the lamp is that the cathode emits hot electrons to excite the mercury molecules to vaporize and conduct electricity, the ion conductivity in the lamp changes with the vaporization process of the mercury molecules. Therefore, the above parameters are also varied and generally reach stability after 3-5 minutes. The following describes the change process and selection method of several major parameters.
1) Input voltage: General 3KW or more transformer input power graves use 380V power.
2) Output voltage: The output open circuit voltage is 120%-125% of the lamp design voltage, so as to stimulate the lamp to turn on.
3) Output current and output voltage.
This is the basic process of lamp voltage and current from turning on the transformer to maintaining a smooth operation. Turning on the transformer lamp voltage is the open circuit voltage of the transformer, and the lamp current is zero at this time. As the thermal electron emission is conducted, the lamp voltage drops sharply, and the current rises. The electrons collide with the mercury molecules to cause them to excite. The movement of the electrons is hindered, the current drops slightly, and the voltage rises. When the supersaturated mercury is completely vaporized and conductive, The current rises to a steady state and the voltage drops to a stable value.
Third, the general method of using UV lamps and transformers The correct choice of UV lamps and transformers is the most effective way to radiate 365nm wavelength of ultraviolet light. The content of the following lecture is to briefly introduce some parameters theoretically. When choosing lamps and transformers, practical experience is very important. The following describes the general selection method.
1) Determine the lamp parameters and select the power density according to the curing requirements. For example, the curing speed of the rotary machine is fast, the power is 120-160W/cm, the printing speed of the screen machine is slow, and the lamp is low.
2) Select the lamp current. If the total power of the lamp is 3-12KW, then the current is 4.5-10A.
3) Select voltage, total power divided by current is voltage value. For example, the total power is 4KW, the current is 5.2A, and the voltage is 770V.
The transformer parameters must meet the requirements of the lamp, but the transformer has a large current greater than the current peak, which is usually 120% of the operating current. Voltage should take more than three groups of taps, because the lamp in the production process is more random, the parameter is not stable, use three sets of transformer taps to try, make the transformer output voltage close to the actual voltage of the lamp.
On-site handling of the fault of the paper cutting machine An example of the tension spring (material diameter 10mm, spring diameter 60mm, effective number of turns 35 circles) of the QZK program-controlled paper cutting machine in the paper lifter lifting mechanism was suddenly disconnected during one use. The length of the disconnection is 1/3 of the full length. This is because the paper cutter is used for a long time and the spring material is broken.
At that time, there were no spare parts in the factory. In order to restore the equipment to use as soon as possible, we decided to use it in due course, and then put two thirds of it back into use. The method was: to connect the springs with the inner circle to the high-speed screw Take a length so that the total length of the same length is equal to the length of the broken spring. After this treatment, it is used again. It is only a distance of 5mm shorter than the original distance (ie, the distance from the final point of rebound), but it does not affect the operation of the party and can meet the requirements for use. In this way, it took only two hours to restore the equipment to the land. After dealing with the urgent needs of the production, the borderland shipped the original specification from the Shanghai Post to the airport nearly a month later.
At an annual meeting of the Printing Technology Association in the region, I learned from my colleagues in another printing company that there was also a paper cutter with the same type of machine in our company. In one case, there were no spare parts at the time, and we handled it by using two different types of tension springs that were in stock at the time. (One parameter was: material diameter 8mm, spring diameter 45mm, effective number of turns 43 circles, another One is: The material diameter is 5mm, the medium diameter is 25mm, and the effective number of turns is 48. The spring with the middle diameter of 25mm is placed in the spring core with the median diameter of 45mm, and each of the two springs has its own thread pitch and is not adjustable. The screw connects the screw with the size of the screw (the outer thread of the screw is connected with the inner circle of the spring, the thread of the screw is connected with the thread of the adjustable screw), and this process also restores the operation of the party within a short time. This kind of thinking can be used by Jingdezhen for large loads and installation conditions. In the on-site processing, reference can be made to the relevant mechanical design data, and the reasonable design and use can be used to achieve better results. Management effect.
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