The absolute size of large-format screen is making big sides version of a major step - mesh preparation, coating, exposure and recovery - also is the main challenge.But now, we use multiple solutions to simplify the process of making network edition.For example: hand-made silk screen has been replaced by automated equipment in many factories, silk screen coating also replaced by the automatic coating machine.Let's discuss the every step, and introduces some can be used to simplify the production technology and tools used in the large screen plate.
Screen preparation: polyester mesh is a kind of design precision of synthetic fiber.This material has excellent barrier properties and the flood characteristics, that is why it used in soda bottles and packaging film.Accurately, it is a difficult to glue the inert plastic products.
Emulsion type of coating is a bit like water-based coatings, the emulsion is not easy to adhesion in the plastic, and have very poor adhesion properties.To produce the high quality with a relatively long life screen, must be properly prepare silk screen, the emulsion will stick well on the screen.Good viscosity in the use of grinding or water-based ink is very important, such as glass or textile printing.This in some areas in an image are covered with adhesive tape or blocked, and opened the case again when the next phase of the printing is also very important, it can avoid damage to the screen.
Screen must be cleaned, remove grease or pollutants, so that we can prevent emulsion wetting the surface of the screen plate, fiber also need wetting agent processing.Doing this can improve the level of surface tension, or on the surface of the polyester net energy, make it reach an acceptable level, such emulsion can attach to it.The principle of printing on the low energy plastic printing factory is very familiar with, such as printing is such in polyethylene.These substrates need to be surface treatment make the surface tension reaches a certain level, achieve the best printing ink adhesion effect.A after good degreasing operation and pretreatment of silk screen will form uniform complete after rinse water film.After the network version of the improved tackiness, exposure latitude and resolution can reach high.
Glue, high solid content emulsion should be used.So that we can avoid in the process of drying shrinkage, and help you use simple coating technology to produce high quality template.Now the coating machine also has a built-in drying device, can be used in the high number of mesh large-format screen when the performance is very outstanding.Has to a small number of mesh screen will be used in the wet emulsion, so that the dry coating machine more quickly and effectively.
Non-polluting drying: dry silk screen is usually in the isolation zone under the environment of dry, and where there is lamp irradiation.Warm and dry around 100 ° F (40 ° C) of the hot air in can in dry area, free circulation, in order to remove moisture.
In the process of drying and storage, the photopolymer emulsion is affected by the residual moisture and high temperature.They can be smoothly in the case of not completely dry.But the diazo and dual curing emulsion must be dry thoroughly before exposure, exposure under water content below 4%.You can use a contact type gauge precisely measuring residual water content in the emulsion.
Exposure: template technology progress in the field of production has been in terms of cost and efficiency of the traditional large-format phototypesetter poses challenges, and other similar methods.Computer screen imaging system directly bring efficiency for silk screen printing blocks of digital process, the film has been cancelled, exposure and silk screen processing process is simplified, the original essential large-format vacuum plate burning machine is no longer needed, finally spent on fixing plate pinhole also greatly shorten the time, because no longer have to attract dust on the surface of the film or glass.
Although large-format inkjet printer and the computer screen system directly, but their output quality for other companies often have to wait the film printing has much better, a lot of silk screen printing using large-format inkjet printer in the plant in the production of large size film.
Projection unit greatly cut the cost of film.For a used to make large screen version of the image, if in 10 x magnification, so the size of the film is only 1% of the final product.A special type of emulsion makes the control of exposure time in a minute, because they don't need the vacuum plate burning machine, so again by simplifying the silk screen processing.
Don't have to consider how you are on your plate exposure, the most important thing to make the exposure time is long enough, in order to ensure the emulsion fully cured, and generate a can resist chemical corrosion and abrasion, good adhesion of the durability of the plate.Using a color conversion exposure calculator to determine the diazo, double emulsion curing the correct exposure time.This method finally, as one of the color conversion processing show that the correct exposure time.For example: yellow heavy nitrogen content in the process of exposure was bleached, it can change the exposure is the color of the template.Usually color change from green to blue or from brown to purple.
Judge exposure of a tool is to use the grey wedge exposure level 21 calculator, it can be used to and diazo photosensitive polymer emulsion and dual curable emulsion.Ideal exposure depends on the wire mesh is made after curing 7 grey level need time.
Exposure in large format template, exposure is a major problem.In order to maximize during exposure large-format screen exposure latitude, the most important thing is to choose a support high resolution emulsion, perfect the coating process, reduce the uneven thickness of coating layer and through the screen appropriately pretreatment to improve network version of the adhesive property.
Development: in order to achieve the best resolution, must in the screen on both sides with high pressure spraying, uniform distribution of solution of development.On the small screen plate is easy to do this, but in large screen plate is difficult.Because it is the process and space has certain requirements.Effective solution is to use automatic can also developing the cleaning equipment.So less demand for space and don't need to carry on the design, development tower is the nozzle.The best artificial selection is to use a minimum speed to 1000 psi with a flow rate of 3-5 gallons per minute, fan-shaped spray nozzle cleaning pressure.
Recycling: artificial cleaning large-format screen requirement workers' attention focused particularly, tool use is to correctly, so as to ensure the efficiency and security.Tools include the brush with a long handle, it can stretch to the screen in the corner, and protective clothing, glasses, gloves, boots and so on.Cleaning every step of the way you need to use a separate brush to avoid cross contamination between the chemical containers.Please don't underestimate the importance of a good pressure water gun.They can afford to buy a you biggest and best cleaner, it won't let you down.
Automatic screen recycling equipment can do a lot of hard work, and can reduce the possibility of the workers affected by chemical damage.Modular and on line equipment system to get rid of the greasy dirt on the screen, removal of ghosting is still a problem, because this machine also can't do it.So even if you are using an automated system, you still have many opportunities to need to clean themselves.
In the large screen printing machine
The emergence of large silk net edition is printed on different substrates more closely related to the pursuit of a better image.Only on the material and technology to innovate unceasingly, is likely to ensure business prosperity, to ensure that screen printing is always in the large central position in the field of imaging.