UV curing machine is a kind of mechanical equipment capable of emitting usable strong ultraviolet rays. It has been widely used in printing,
electronics, building materials, machinery and other industries. The types and styles of UV curing machines vary depending on the products they
are light curing, but their ultimate purpose is the same, which is to cure UV paint or UV ink. The UV curing device consists of five parts: light source
system, ventilation system, control system, transmission system and cabinet.
First. Light source system
It consists of UV lamp, lampshade, transformer (ballast), capacitor (trigger). At present, there are two types of UV lamps on the market: high-pressure
mercury lamps and metal halogen lamps. Domestic equipment generally uses high-pressure mercury lamps, and some imported equipment uses metal
halogen lamps.
⒈The choice of UV lamp power.
(1)The power of UV lamp is the radiant energy of UV lamp, also called penetrating power. First, it must meet the spectral wavelength and power density
requirements of UV ink (varnish) absorption. If the power of the UV lamp is not enough, even if the illumination time is longer, the UV curing device
will pass more times, and the product will not be fully cured. On the contrary, it will also make the surface layer of UV ink (varnish) aging, sealing,
embrittlement, etc. At the same time, the adhesion of the ink (varnish) is also not good, which will make the interlayer adhesion of overprinting poor.
Because the low-power UV light cannot penetrate the bottom of the ink layer, the bottom is not cured or the curing is insufficient.
(2)The power of UV lamp should generally meet the requirements of 80～120W/cm², but the greater the power, the greater the heat. Therefore, the power
should be selected according to the curing material and curing speed.
(3)The maximum life of UV lamps is generally 800 to 1000 hours, and should be replaced after the time is reached, because the intensity of the UV light
emitted by the UV lamps at this time becomes weaker, which will affect the curing effect. At the same time, it is recommended to use anhydrous ethanol
to clean the reflector surface of the lamp tube surface and the reflector surface at an appropriate time during the use period according to the different
production environment (air dust content), and then turn the UV lamp tube 90°, which is beneficial to UV All rays are effectively radiated to UV ink or
varnish to ensure a certain penetration.
⒉ Reflector, the types of reflector are focusing type, non-focusing type and multi-facet reflection type. The focus type is generally used. The structural feature
of this reflector is that the energy of the reflected UV light is concentrated, and the efficiency of light curing is high, which is conducive to the curing of the
ink of the thick ink layer and the deep layer of the ink can be completely cured. It should be noted in this regard that the material and shape of the reflector.
(1)The material selection must be aluminum, not iron or stainless steel for cost saving, because the stainless steel plate will become black at high temperature,
not only will it not reflect the light, but also absorb light. The best reflective effect is the mirror alumina plate, whose reflectivity can reach more than 80%,
thereby greatly improving the utilization rate of ultraviolet rays.
(2)Shape The shape of the reflector is to ensure that the UV light can be gathered together, so the shape of the semi-circular arc is the best. Also pay attention
to the erection position of the UV lamp to ensure that it is in focus. In addition, the reflection cover is an important channel for heat dissipation of the UV
lamp, so the outside of the aluminum cover should be processed into a heat sink to increase the heat dissipation area. The reflector plays a very important
role in the UV curing device. Some manufacturers often neglect its role, and use some alternatives to act as reflectors, or even do not install reflectors, so
that 40%-50% of UV energy of UV lamps is wasted. Some manufacturers' countermeasures are to blindly increase the power of UV lamps. This will not only
solve the problem fundamentally, but also cause greater waste of electrical energy.
⒊Transformer, the choice of transformer must match the power of the UV lamp. That is, the transformer must have enough output voltage to ensure that the
UV lamp can work at full power. If the output voltage is too high, the lamp tube will be burnt out; and if the output voltage is too low, the lamp tube cannot
work at full power, which makes the ultraviolet output intensity insufficient.
⒋The choice of capacitor and capacitor should be matched with the lamp tube and transformer. Choose the withstand voltage of the capacitor used according
to the output voltage of the transformer. If not selected properly, the capacitor will break down, affecting the normal operation of the UV curing device.
Second. Ventilation system
It is composed of fan, air duct and wind collecting hood. What should be noted here is the choice of fan and the control of air volume and the way of exhaust.
1.The choice of fan should be determined according to the power of the UV lamp and the actual situation of the box space. Generally, two fans, wind and
induced wind, have to be distributed, but some are equipped with only one induced draft fan. Insufficient fan power and insufficient air flow will cause
the temperature in the chassis to be too high, the lamp life will be shortened, or even melt, which also makes it difficult to ensure the quality of the cured
product; if the fan power is too large, the air volume will be too large and the temperature in the chassis will be too low. The UV lamp cannot work at full
power, and the cured product is not easy to dry.
2.Air volume control means that the air volume of the UV curing device should be adjustable. This is because considering the large temperature difference
between winter and summer, many factories do not have a constant temperature workshop, so if the UV curing device works with the same air volume in
winter and summer, it will definitely affect the quality of the product. Generally, two fans are controlled by a temperature control method. When a certain
temperature is reached, one fan is automatically started, and when a certain temperature is reached, another fan is started, and a live valve is provided on
the exhaust and inlet to control the inlet. The volume of wind and exhaust.
3. The method of exhausting air refers to adopting the methods of upward-drafting and downward-drafting or upward-drafting and downward-drafting. But
no matter what way, do not blow the wind directly on the UV lamp tube, because the consequence of this is that the UV lamp cannot work at full power
due to excessive heat loss (the light changes from white to non-glaring blue), So that the ink can not be dried at all.
Third, the control system
It is a system used to control the work of the entire light curing machine. It is worth noting here:
1. The control of the fan is best controlled by the temperature automatically, because the human control may have omissions and is not accurate enough.
⒉Turn on the light when starting the machine, and then turn on the fan after 2-3 minutes (when the fan is not temperature controlled).
⒊After shutting down, the fan should continue to run until the lamp and the cabinet cool down.
⒋The second start should wait until the lamp tube is completely cooled before starting.
Fourth, the transmission system
It is composed of speed-regulating motor (or frequency conversion speed-regulating), conveying mesh belt, chain (or conveying roller).
What should be noted here is the speed adjustment problem. The curing speed should be considered from two aspects, one is full curing, and the other is
curing at the best speed. The best speed selection method is: first pass the product through a UV curing device at a certain speed, if it is cured, then speed up
the speed until the ink layer of the product coming out of the UV curing device cannot be cured. The speed at this time multiplied by 0.8 is the optimal speed.
In addition, you should pay attention to the use time of the lamp, because as the energy of the Uv lamp decay, the speed should also be slowed down.
Fiveth. Cabinet
The size of the box is determined according to the different products applied by the UV curing device.
It should be noted in this regard: to make the surface of the cabinet flat, the interior light can be exposed to the interlayer as much as possible to avoid
excessive temperature outside the cabinet and scalding. There should be no light leakage outside. In short, in order to enable the UV curing device to operate
safely and normally, and to achieve the best results of light curing, the above several components should be noted, and no one link can be ignored.
UVLED light curing technology is a new technology developed in recent years. At present, some manufacturers have replaced the UV lamp on the UV curing
machine with a UVLED light source. The UVLED light source is composed of high-intensity UVLED lamp beads. Compared with the UV light source, It has the
advantages of long life, ready to use, green and environmental protection. With the development of UVLED light curing technology, it is believed that UVLED
light source will replace UV lamps.
