The production process of bronze medals depends on the size of the first, the smaller the available pour, printing, baking yellow process, the process of high precision, difficulty, can be done as fine patterns. The screen printing process can also be used, and the method of screen printing can be used for mass production with high yield, but it is not suitable for very fine products. Large bronze medals can be printed using a printing process. This method can be used to create products of unlimited size. The advantages are: standard Song, imitation song, isoline, English letters, etc. are applicable, the disadvantage is that the product with high precision requirements is not suitable for the application of the process. These methods have their own differences, and they need to avoid weaknesses in production, select the production process depending on the product size and fineness, and can also mix applications so that they can make good products. The larger bronze medals are mostly signs hanging on the market. The fonts are concave and raised are rare, especially the medals issued by government agencies. There are several types of specifications, 40 6ocm, 50 7ocm, 60 socrn, etc. There are long brands, 200 50cm, in addition to special specifications depending on the needs. The raised bronze medals are not easy to deal with, but they also lost the beauty and luxury of copper's own material. There are also copper-word raised logos, which are sculpted in 3mm thick copper plates. After trimming, polishing, and protecting the light, the entire copper plate is polished and protected, and then the holes are set on the reverse side. The entire brand is Golden, very beautiful and luxurious. Smaller bronze medals are generally required to be relatively high. They can be poured, glued, dried, and dried in yellow. The method is as follows. First of all, do a good job of preparatory work, choose a good bronze material, according to the required size of the material, the edges should be neat, flat edges and spare. Fix the black and white contrast film (high gamma value) for the printing plate. Cut the square to the right, slightly larger than the size of the copper plate. There is a side of the film on the glass, the font should not be flipped over, the glass should be flat and not corrugated. , bubbles, black spots, blemishes, etc. The higher the transparency, the better. Four sides are affixed with tape and then sealed with a black stick. The glass is larger than the film. The affixed space is the same size as the copper plate. It is best to wipe it with toilet paper, alcohol, and then dry it again. Before affixing to the glass, check whether there is any unclear writing on the film. The excess part is removed with a small knife. The transparent and bright trachoma is sealed with thick ink. The missing place is filled with ink and then affixed to the glass. The glass should be worn on all four sides so as not to scratch the skin. If there is no problem, put it back. Then check the wheel used for the squeezing glue, if the suction head is leaking, and if the electric furnace is tried first, whether it is electrified or not, and the sensitized glue used is not adjusted. Light box, hard liquid for printing, dyeing methyl violet, alcohol, ground carbon, clips, black flannel, boiling water, cold water, large and small plastic basins, and a small red light bulb in the darkroom. These are ready to start printing. Production. Before the production, the quality of the black and white transparency film is very important and should be taken seriously. If the edge of the word or pattern is found to have blue smoke, like smoke, such a low film cannot be used. There are many methods for the production of film, there are photo-making method, the product with high precision requirements should use this process plate, but the price is more expensive, it is best to use full-color film. As long as it is not a very small pattern or small print, the larger ones can be made by the following methods. The price is cheap, and it does not affect the plate making effect. It is practical and feasible. The method is as follows: Choose smooth, high-transparency glass, wash the water with detergent powder, brush the glass on both sides with a shoe brush, lightly brush it with light water, and dry it for use. Then squeeze a single black propaganda color a little, put a little detergent and water on the grinding platform into a thicker ink paste. At this time, the drawn artwork paper can be placed under the glass plate, and the brush ink can be used to trace the shape of the figure. Do not move the pen too fast, the ink should be uniform, the strokes should be neat, and have a certain thickness. The drafts to be painted should be carefully inspected, clear and dark enough to be refilled and dried for future use. The homemade glass plate should not be touched by hand to avoid the ink on the pattern, especially in the summer. If you use it for a long period of time, you can thinly apply the varnish once more, brush it again, and do not repeat it. The disadvantage is that the exposure is sticky. We must pay attention to a problem. We must choose a thin plate for glass, because it is a positive image, and it is an anti-word. Thick ghosts affect the accuracy. This method is more suitable for making positive pictures, making it more difficult to make negative pictures. But there are ways to solve it, the process is as follows: To make a negative image, use a piece of glass of the same size as the positive figure, brush on both sides, wash the edges with a detergent, rinse off with water, and dry them for later use. However, it must not be dried. It must have a certain degree of hydrophilicity, otherwise it will not be glued. Dry the water, do not rub it, use the suction head on the wheel to hold the glass in the middle, and gently bake and bake it on the hotplate. While turning, turn it while changing positions. Do not overheat or the glass will burst. After the micro-heating, use the teapot to pour the sensible glue, shake the wheel backwards and shake it down, and use the effect of centrifugal force to throw the glue out and dry it. Do not overheat, so as not to wash away the undesired part when the water is developed, ie, it is roasted. Combine the dried glass with adhesive film and the glass draft with positive pictures. The adhesive surface is close to the ink draft, clamped with a clip, and a black velveteen cloth is placed on it to open the lamp for exposure. Exposure time 3 to 5 minutes, remove the glass with adhesive film, put it in 30 degrees warm water, develop, use a new cotton dipped in water and gently rub the glass surface with glue, rinse with warm water, by the way check whether the pattern or handwriting are clear , Well, then put the developed glass into boiled blue, boiled green or vulcanized blue or green, used for dyeing cotton cloth. The entire bath went to the water and stopped for a while, flushing the water with water, drying it, or throwing it dry. A piece of glass was painted out. The dried version of the glass film is put in water for fixing, and it is also to remove the extra pattern or writing film to expose a vivid image. The version called “glass version†by this method, also known as the “Management Editionâ€, is an ideal method for making negative images. The price is about one-tenth that of photo films, which is both economical and practical. After the dried glass plate is dried, it is wrapped in paper, and it should not be exposed to sunlight, so as not to reduce the black color. There is also a method of directly making overcast images, using white advertising color according to the manuscript painted on the frosted glass, spray a good ink, dry, put it into the cold water and gently swing, the advertising color is water-soluble, put a clean advertising After the color is dried, it is filled with ink. This method is suitable for the not-so-fine version. The general product version can still be used. Some bronzes are larger and can be traced with cellophane or sulfuric acid paper. Put the manuscript under the cellophane and stick it with tape. Don't move and start tracing. Based on many years of experience, the inks of the drafts are available for reference. 1. Use good soot and ink sticks, add 1 to 2 drops of glycerol when grinding, and study to thick ink. 2. Take 150 ml black ink, add about 8 to 10 ml of formaldehyde, 3 ml of glycerol to adjust the average, let it natural concentration, if it is too strong can add appropriate amount of original ink and mix thoroughly. 3. Use two bottles of Tianjin-made drawing ink, add a tablespoon of white sugar and a small spoonful of borax. Pour it in a beaker and put it on a simmered glass until you can reduce the ink in the cup to about half. 4. Use Yideuge ink plus the right amount of detergent to grind to a thick ink and use it. This method can write a certificate, easy to stick ink. Painting strokes should be drafted according to the intention of the manuscript. Do not behave rashly. Take it seriously. Put the painted manuscript on a flat glass and seal it with transparent tape. It is best to brush it off before applying it. After the vote, make sure to brush it once and do not repeat it. You can also brush kerosene for the purpose of increasing its transparency. In addition, there is a polyester film with high transparency, which is specially used for printing. It is especially suitable for large-sized manuscripts such as drawings, etc. The effect of positive drawing is excellent. The film is frosted on one side and is like frosted glass. There is also an imported red tear film, with the knife gently engrave the film surface above, according to the contents of the pattern to remove the film can be. This red-removal film does the best for negative images. It can be used directly with screen-printed versions, especially for large-format screens, and can also be used as a screen-printing version for films. This material is imported and it is more expensive. There is also a kind of paint paper, green, the same usage and red tear film, low price, simple process, very practical. The disadvantage is that you can't use banana water brush screen version, nor can it be used as a soft film print. Can also use red instant paste plate, the method is simple and quick. First stick the sticky note to the top of the glass and press it flat, no bubbles. The manuscript was printed on blue paper, but it must be a back draft. Red sticks are close to the screen plate during the printing process, without ghosting. Using a knife to make a negative or positive drawing according to the requirements of the manuscript, the effect is very good and the cost is cheap. Some medium and small bronze medals can use laser imagesetters to produce the required manuscript content. The positive figure can be typed directly, and the negative figure can be written in white on a black background, also called Lu Bai. The finished manuscript is printed on a copying machine and printed with a transparent polyester film film. This method is simple and quick, shortens the construction period, and the copied polyester manuscript can be used with ink. The above materials and manuscript preparation methods are simple and easy to implement, and the process requirements are not high and they are very practical. The exquisite products should adopt positive or negative photographs. Although they are more expensive, they are precise and have excellent results. After the process of making the film is completed, the photosensitive adhesive is formulated. Its formula is as follows: Polyvinyl alcohol (low degree of polymerization) 80g Dichromate 12g Ethanol .20 ml Water 500 ml First, put the prepared polyvinyl alcohol into a medical glucose bottle, add 250 ml, cover with a plastic cover, and insert the waste plastic tube with a ball-point refill into the center of the cover, which is 5 cm long. Then stew it in the pot and it takes about 12 hours to cook. Can also be cooked and ready, 20-C can be stored for more than one year, does not affect the quality. The hot filter 200-280 mesh filter into a red-brown large-mouth bottle, about 30 °C is appropriate. Dilute the dichromic acid with 100 ml of water, heat a little, and stir it clockwise in a dark room with a glass rod. Dissolve and filter it all. Pour the polyvinyl alcohol into the bottle. Stir and stand still until the bubbles in the bottle disappear. Pour in 20 ml of ethanol (alcohol) and stir. At this time, the material in the bottle reacts. A cotton-like object is wrapped around a glass rod, and it is returned to the bottle with another glass rod. After standing still for 24 hours, it is filtered into another red-brown bottle for use. Add 250 ml of water to the bottle of boiled polyvinyl alcohol. The rest of the water will be brushed on the bottle, but it must be poured into the emulsion, otherwise it will be too thick to use. It is thick in the summer and thin in the winter. With a good sensitized rubber wrapped with a black cloth, put it in a cool dry place, generally can save more than 3 months, except in summer. Can also be placed in a thermos bottle, cover the lid, does not affect the quality. But it must be done in a dark room. Over-thickening can warm the water and add waves and alcohol.
Source: International Screen Printing
Copper Plate Selection in Screen Printing and Its Production Process