Screen printing principles are expressed in many ways, but the core idea is the same.

Screen printing is the silk fabric, synthetic fiber fabric or wire mesh stretch on the wooden frame or metal frame, the use of manual paint film or photochemical platemaking method to make screen printing plate.And modern screen printing technology, is the use of photosensitive materials through photographic plate making method to make screen printing plate, so that the screen on the screen printing plate part of the picture and text hole is through hole, non-text part of the screen hole is blocked.Printing through the squeegee extrusion, so that the ink through the picture and text part of the mesh transfer to the substrate, forming the same as the original text.

Screen printing must have five elements are screen, screen frame, photosensitive adhesive, scraper and screen printing ink.

The whole statement above is very vivid and rigorous, here we will understand some of the concepts.

Hand-carved paint film: hand-carved paint film is a more traditional way, the text line print screen can choose engraving paint film paper plate making.

(1) paint film paper production

1, wax paint film paper production

Stick tracing paper or cellophane on flat board or glass, mix rubber water and gasoline evenly according to 1:1, use shading brush to brush on paper for isolation layer, to be dry after painting, spraying spray gun from the paper surface about six or seven inches is appropriate;Spray seven or eight times.Thickness by their own control, the general wax paper can be prepared thick, medium, thin three.

Spray the first layer to dry and then spray the second layer, the third layer…, if the amount of production is small, can be brushed with shading brush.Soft clear spray paint for colorless transparent body, in the production of wax paper, must be spray paint dyeing, that is, in the spray paint with a little magenta or magenta, magenta green pigment, easy to distinguish when engraving, color palette should be light, not too thick, or affect the line of sight when engraving, dye should be dissolved with alcohol first.Castor oil should be added according to the paint performance, weather changes and sincere weighing.Dibutyl ester can replace castor oil, but not as good as castor oil.

2. Gelatin film paper production

Place the gelatin in clear water in a container, boil and dissolve. Add glycerin and a little magenta dye. Stir well with a glass rod.Will be attached to the polyester film film substrate in a very flat board or glass plate, with a shading brush will be vinyl chloride slurry and cycloethyl ketone solvent coated brush on paper as an isolation layer, after drying spray or brush with shading brush.Let it dry naturally and store in a dry and ventilated place.When the temperature exceeds 180°C, 1 g sodium sulfate can be added.

(2) engraving paint film paper

Will be painted ink paper under the paper, and transparent tape paste, with a carving knife to the printing part of the film from the lining paper to remove.Many sets of color engraving, to carefully examine the painting, distinguish the sequence of overlapping colors.In order to prevent the version, engraving the range of the first – set of color is slightly larger than the original, the range of the second set of color and the size of the original, after printing is exactly the same.First printing to be a little wider, after the printing of the engraving to be large.In addition, when engraving the contour line, by the contour line pressure that color should be placed in half of the outside line, the contour line is to be engraved and the original manuscript.

(3) stretch the net

Wire mesh and wire mesh selection should be based on substrates, printing method, flexible printed material properties to choose, fine printing graphic, can choose 130-150 mesh screen, printing graphic with coarse can choose 100-120 mesh, gelatin film version on paper for use temperature, can choose silk screen, lacquer film paper version with potions, the version without the temperature, so choose nylon network as well.With stretch machine or manual stretch net method, will stretch the screen in the frame network, stretch the screen should be flat, elastic moderate, and screen front and back with acetic acid wipe clean oil and dirty.

(4) previous edition

Draw on the rules line on the manuscript, many sets of color version as the rules of the rules.The engraved version together with the manuscript, put in the appropriate position of the screen board, according to the rules of the line of the original binding rules of the rule sheet with milky glue on the screen board, and paper stick firmly.There are a few sets of color with a few screen table set out a unified rule.Put the manuscript together with the engraved version, put on the good rule of the board, put down the screen frame, on the screen with an iron aimed at the four corners of the edge of the engraved scallop fixed iron, let the scallop stick hot on the screen after the original sample.Put some thick cardboard on the board, put down the screen frame to make the gelatin paper pad flat, and then cover a piece of mylar film film on the screen for spacing, iron back and forth several times, so that the film iron on the screen.After a good plate let it dry naturally, and then remove the lining paper and ring ketone on the back of the plate and the lining paper interval coated with vinyl chloride clean.If the version has fallen off the place can be fixed with glacial acetic acid, such as the knife blade contact and small strokes of the fall off, the brush can be dipped in gelatin solution repair.

(5) block the Internet

Screen screen is about to screen with colloidal sticky up, so that the printing plate in printing ink.Wax film version of the screen can be sealed with nitrocellulose varnish, gelatin solution can seal gelatin film version and nitrocellulose varnish modified film version.The sealed plate can be printed when dry.

Photochemical platemaking

Photochemical etching, also known as photochemical processing, is the combination of photolithography and photolithography (chemical etching)

Dense and fine processing technology.The main difference between it and chemical etching processing is that the former does not need the template manual engraving, marking, but

Through photographic photosensitive to determine the surface of the workpiece to be etched graphics, lines, thus can be processed into very fine text patterns.

photoengraving

Photographic plate making is a common method in modern plate making process.

Photosensitive material refers to the photochemical reaction, (show, definite) processing can form an image of the material.

Plate making method

Direct platemaking

Methods: direct plate-making’s method is in the plate making the coated with light-sensitive materials wrist sheet base photosensitive film face flat on the work surface, will stretch good wrist net frame on a flat on the base, then in net box in the photosensitive slurry and soft squeegee pressure coating, peel off after dry fully plastic base, attached to the wrist of photosensitive film screen can be used for plate burning, after enhancement, dry will make printing screen.

Process flow: stretch the net – degrease – dry – strip – base – exposure – development – drying – repair – a net

Indirect platemaking

Method: indirect plate making way is indirect exposure film in the first place, with 1.2% H2O2 sclerosis with warm water after enhancement, drying is made after stripping graphics plate, plate when the graphic film film with good screen tiejin, tense by squeeze film and moist screen paste, jie the lower base, made screen printing screen the wind blow dry it.

Process flow:

1) have stretched the net to degrease and dry

2) indirect film exposure, hardening and development

1and2- fit – blow dry one repair and one seal

3) direct mixing plate making method

First the photosensitive adhesive layer with water, alcohol or photosensitive adhesive adhesive on the wire mesh frame, after hot air drying, remove the film base, and then print, after development processing is made into screen.

In fact, there are many principles and matters needing attention in making plates with photosensitive materials commonly used in modern times, and we will talk about them later.