※Control process ※ Behind the light The UV lamp on the exposure machine will age and the total amount of energy emitted will vary. Therefore, it is better to use the amount of exposed light instead of time. Monitoring the output energy of the lamp allows the plate-making personnel to adjust the exposure time correctly so as not to fail due to aging of the lamp. Using the UV-A photometer to test the UVA is more accurate. It is necessary to select UV wavelength lamps and photometers. Most machine/plate suppliers should recommend it. Also, it is a good idea to test the exposed backside, because the sensitivity of each batch of materials sent by the supplier will also be different. ※ Mainly exposed (negative film exposure) Figure 4 shows this typical problem, requiring a lot of exposure time to create a solid foundation to show the fine details of the highlights. At present, the UV light will also affect other parts of the plate after it has been disconnected. The energy affects the area. For example, the photopolymerization reaction is started below the micro-introduction, but the part that should not have effect has also become available." Fill in the effect of the ripples. Kitchen Sofa,Corner Sofa,Sleeper Sofa,Sofa Club CAMOSA HOME , https://www.camosafurniture.com
This section will discuss how the plate maker can effectively use the time and space controls in photopolymerization. A typical platemaking step involves the exposure of light to determine the thickness of the plate, giving the image its primary exposure, and the film passing UV light. Polymerization or interlacing reaction of the resin plate, there is also a washing process, which can be washed with organic solvents, aqueous solutions or hot water, and UV-C <wavelength 254nm> or VU-A exposed to de-tack treatment and make the plate in the Completely stable after the plate making process.
The exposed light allows the plate-making staff to determine the thickness of the bottom of the plate. In the end, how to control the thickness of the bottom plate/wash plate depth? Plate makers usually rely on experience, "from the results of previous processing platemaking" to determine the exposure time needed to create a certain thickness of the plate. In this way, relying on past experience, there will still be some degree of risk. The correct approach is to use a periodic back exposure test to obtain the desired bottom thickness. This requires a series of different time exposures on one plate to wash the plate. "It is not necessary to expose the film on the front." By measuring the thickness of the publication at different times, it is possible to estimate the time required for the correct backside exposure of the required bottom thickness. At this point, the producers are using different times to control photopolymerization. 
<Plastic Printing Plates with UV Exposure Before Washing in Figure 3>
In this UV-A exposure process, the plate material is exposed through the film or masking. The exposure time of the film is set to obtain high-quality printing plates based on previous experience. Some technologies can reliably set the total amount of exposed light. The technical discussion in this chapter must return to the aforementioned photopolymerization.
Why is it that the time for exposing the full-size area can be less than 2% of the high-brightness dots? To answer this question, we must understand that photopolymerization is controlled by space. Part of the dots were exposed by UV light through only 2% of the holes, because only about one-fifth of the UV rays in 2% of the area were projected onto the surface of the plate. Therefore, it is necessary to have a longer exposure time than the full plate area to illuminate the 2% dot area to avoid being washed away during the plate cleaning process. As a result, controlling the amount of UV light in the second-degree space <in the image portion on the negative film> also affects the three-dimensional space <infiltrate to the bottom of the plate material or not? Why do we need more exposure time in the fine details? When will the fine anti-white part fill up? This has a great relationship with the latitude of the plate. However, in a high-quality printing plate, it is common to contain both very fine dots and very slight anti-white portions, which are the same under the underline of detecting photopolymerization.
<Figure 4 Exposure Latitude Test Challenge>
(to be continued)
The principle of application of flexo printing photosensitive resin plate II
As long as the UV light source continues to irradiate the plate, the sensitization initiator (monomeric resin) continues to exist and the propagation effect will continue. If the UV light is no longer irradiated, the termination reaction will stop. This opening or closing of the UV light source also provides a temporary control of the start or stop of polymerization of the photosensitive resin. Platemakers also use this to apply negative or negative film to control or block the entrance of UV light. The photopolymerization described in FIG. 2 completely depends on the amount of ultraviolet light input into the plate. The interlaced network forming the image area (full plate, dot or line) is shown in orange in FIG. Photopolymerization changes the physical properties of the photosensitive resin. This is the key to forming the desired image on the plate. The polymerized or interlaced portion is not dissolved by the solvent during the plate-washing process. This change in solubility is utilized for the plate-washing operation. At the same time, there is a big relationship between the washing of the syrup, and some can also use hot water to wash the plate. If this is not properly controlled by the plate making operation, good results will not be obtained.