Screen printing operators all know that a clean and tidy environment is very important for plate making, and a neat environment can avoid many quality problems. Because the dust and grease in the environment adhere to the surface of the photosensitive layer, pinholes may be formed on the screen, which may affect the quality of the printing plate, thereby resulting in a decrease in product quality.
Relatively speaking, the clean and clean oven is also very important, but this point is often overlooked. Some small and medium-sized enterprises in the expansion of production scale, the drying equipment changed from the hair dryer to the oven, but due to the lack of effective management, will be handy to put the warm cloth and some debris into the drying oven with the screen, and sparse In the oven's hygiene and clean, unconsciously buried the hidden dangers of quality.
Secondly, when the screen plate coated with photosensitive emulsion is placed in an oven and dried, the temperature cannot be too high and the drying time cannot be too long. Because the temperature is too high, the sensitized adhesive undergoes a thermal adhesive reaction; drying for a long time will affect the normal operation of the exposure, resulting in a screen plate that is not transparent to the development of the stencil and causes the screen to be rejected. Therefore, under normal circumstances, the oven temperature is controlled between 30 ~ 45 °C is appropriate, in order to shorten the drying time can also put some desiccant in the oven. In addition, the drying temperature of the screen also affects the moisture content of the screen, which has great influence on the screen printing strength, especially when the air is dry. However, for special printing requirements, the photoresist is thicker. In the screen, the screen drying time should be appropriately extended.
In addition, some screen plates may undergo degumming after oven drying or during printing operations. This is because the residual moisture between the stretched tape and the frame causes the screen plate to dry unevenly and incompletely. A new stretch of screen printing plates retains the work of tape sticking during the revision work.
In short, only care at all times, be careful everywhere, in order to produce a qualified screen printing plate, in order to produce a good screen printing products!
Reprinted from: Bureau of Indian Network: Han Tao
A blackboard (also known as a Chalkboard) is a reusable writing surface on which text or drawings are made with sticks of calcium sulphate or calcium carbonate, known, when used for this purpose, as chalk. Blackboards were originally made of smooth, thin sheets of black or dark grey slate stone.
A blackboard can simply be a board painted with a dark matte paint (usually black, occasionally dark green).Matte black plastic sign material (known as closed-cell PVC foamboard) is also used to create custom chalkboard art.Blackboards on an A-frame are used by restaurants and bars to advertise daily specials.
A more modern variation consists of a coiled sheet of plastic drawn across two parallel rollers, which can be scrolled to create additional writing space while saving what has been written. The highest grade blackboards are made of a rougher version porcelain enamelled steel (black, green, blue or sometimes other colours). Porcelain is very hard wearing, and blackboards made of porcelain usually last 10–20 years in intensive use.
Lecture theatres may contain a number of blackboards in a grid arrangement.The lecturer then moves boards into reach for writing and then moves them out of reach, allowing a large amount of material to be shown simultaneously.
The chalk marks can be easily wiped off with a damp cloth, a sponge or a special blackboard eraser usually consisting of a block of wood covered by a felt pad. However, chalk marks made on some types of wet blackboard can be difficult to remove. Blackboard manufacturers often advise that a new or newly resurfaced blackboard be completely covered using the side of a stick of chalk and then that chalk brushed off as normal to prepare it for use.
Wooden Chalkboard,Wooden Blackboard,Wooden Sandwich Board,Chalkboard Sign
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