We introduce the development of screen printing materials through the development of ink, the development of substrate, the development of photosensitive materials three dimensions.Today we will look at another dimension: the classification and development of screen making technology.
1.Hand patterning
Manual plate making method is generally refers to the traditional screen printing plate making method with manual operation.This method of platemaking quality is poor, but more economical, can be used for the quality requirements are not high, the number of printing plate.There are two methods commonly used: drawing plate method and cutting plate method.
Description of plate making method: description of plate making method is a method of painting directly on the screen, Yin and Yang painting method.
Cut paper making method: on a thin, firm, fat-free paper, draw the outline of the figure with a pencil, then use a sharp knife to carefully carve out the figure, become a piece of paper film.
Shellac cutting and plate-making method: a piece of tracing paper is coated with a layer of gelatin, and then the gelatin is coated with a layer of mixture of shellac and wax to form a piece of shellac paper.The paper is translucent, can be covered on the original cut, get insect film.
Printing method: printing method is the use of typewriters and special printing paper to make a plate film, and then paste on the screen.This kind of screen printing plate to use the thinner ink printing, but also can get a thicker print, print resistance up to 1000 ~ 3000.Hand – cut film making method: this is in the film with hand – cut graphics, and then paste on a screen on a plate making method.It is composed of film, connecting film and film base.Film is a film for engraving;Connection film is to make film and film base temporarily connected together, once the plate is finished, film is stripped from the base;Film base is fixed by film, including the separation of graphic elements, most of the film base material is polyester, but also coated paper or other plastic film.
2.Photosensitive platemaking methods and techniques
Photosensitive plate making method also known as photographic plate making method, it is the use of photosensitive materials see light physical or chemical changes in the characteristics of the plate film made by printing, that is, screen printing plate.This is the common silk screen photosensitive plate making method, ultraviolet light through the film irradiated to the photosensitive film, the photosensitive film part of the light hardening, did not see the light part does not harden, and then with the appropriate solvent erosion of the film, then the hardening of the corrosion resistance, the non-hardening of the corrosion resistance and dissolved, so as to make a plate film.Plate film and screen bonding together into a screen printing plate.With other printing methods of printing plate method, generally through the record of the processed text of the original text information negative, that is, the bottom plate to print.
3.Projection magnification process
This is a special method for making large format screen printing plates.It USES the photographic equipment, will be small bottom plate through the optical system, magnifying projection to coated with photosensitive adhesive on the screen plate, its photographic light source is ultraviolet light, through the exposure of the screen plate development, so as to make a screen printing plate.It USES the equipment for projection magnifying plate making machine, both photographic and printing two kinds of functions, so it is more than the ordinary printing machine an optical lens, mainly by the host and photosensitive plate (screen) frame two parts.Screen plate is fixed in a photosensitive plate frame, plate frame and the host parallel and perpendicular to the ground, can be moved back and forth;The main machine can also be moved back and forth, which is mainly composed of a frame, a lens frame, a manuscript frame, a printing light source, a darkroom, a driving mechanism and an automatic control system.As the photosensitive material of plate making is much lower than silver salt photosensitive material, so the quality requirements of the projection magnifying plate making machine are higher, in addition to the need for a good light source and lens, also need to have reliable mechanical stability, in order to adapt to the low sensitivity of the material exposure time long requirements.Projection magnifying plate making method can save silver salt photographic film, reduce darkroom photographic equipment and space, shorten the plate making time, for large format screen printing plate making, is a better method.
4.Printing scanning exposure direct platemaking method
This is a kind of screen printing direct plate making method, not only does not need the base plate, but also can be made by photosensitive plate making method screen printing.It is with the computer color separation system of inkjet scanning equipment, you can directly on the original text text information processing, processed information by the way of inkjet output recorded in the coated with photosensitive adhesive screen, and then screen for exposure, ink (development) developed, that is, screen printing.Direct plate-making method without silver salt photosensitive film, the original text and text information processing by the computer directly recorded on the screen, save a text and text information transmission link, can improve the accuracy of printing, and speed, so is the direction of the development of plate-making.5.Infrared patterning
Infrared plate making method, is the use of a thermal shrinkage of a special performance of synthetic resin film, as a screen printing plate photosensitive material to make plates.When making the plate, the first coating on the screen, and then the black and white manuscript on the screen, under the infrared exposure, because the original text and text part of the heat absorption, so that the resin coated film shrinkage, so that the text and text part of the mesh is transparent, that is made of screen printing.This method is fast in making plates, but the printing precision is not high.
6.Metal plate making process
For high precision integrated circuit screen printing, high precision step screen printing and screen printing, in order to ensure the quality of printing, generally use metal plate printing.Metal plate is screen for metal, plate film can be photosensitive film, can also be metal or only metal plate film (excluding screen).As a result of printing plate variety, so there are many ways to make a plate, the following several main methods are introduced.Circular screen plate making: circular screen refers to the screen for the cylinder, printing plate for continuous rotary movement, mainly used in the printing and dyeing industry.The screen is generally made of a closed electrocast nickel screen cylinder, the appearance is hexagonal mesh (also have square).Nickel mesh is made by means of copper plating, pressing dot, polishing, chrome plating on the die of seamless steel tube.
Photographic etching process
Photographic etching process is on the thin metal sheet with photographic (photosensitive) method of imaging, and then use the corrosion method to make plate film (no screen film), or plate film and screen film at the same time (screen film).The plate-making process is as follows: preparation of metal sheet a surface treatment a coated photosensitive adhesive a printing a development a corrosion – film – plate film on the frame
When using the corrosion method for circular screen printing plate, the metal roll should be degreased, and then on the roll electroplating, electroplating as a metal plate base, and then in accordance with the process of making flat screen plate to establish a photosensitive film and complete printing, development, and finally out of the metal roll, corrosion screen metal screen.
8. Plating process
This is the combination of photography and electroplating a method of plate making, that is, photographic imaging, electroplating plate film, its plate making process is: metal plate base surface treatment a photosensitive adhesive a print a plate a plate development a plate film electroplating a net plating a screen plate film frame produced on the screen plate film frame and the same as the corrosion method.
Compared with photosensitive template, the metal template obtained by corrosion method and electroplating method has the characteristics of resistance to printing, sharp lines and uniform film thickness.
Corrosion method and electroplating method, the former film is thicker, but the line quality is a little poor;The thin layer of membrane, line is of good quality, therefore also has the combination of mix method, the plate making process is: the version of the base metal (copper) a two sides coated photosensitive glue a graphic and silk screen printing on both sides of the two sides developed a two electroplating a strip coating a metal version of the base corrosion on the web version of the film frame 9. Copper (zinc) version of the photographic plate
Copper (zinc) plate photosensitive plate making method is the use of copper (zinc) and other metal plate made of text part of the convex printing plate, and then on the metal plate filled with nitrocelluvial paint, after the paint dry, with fine sandpaper on the metal plate of the paint and exposed metal, only the concave part filled with nitrocelluvial varnish.Then the metal plate and screen paste, concave nitro paint that is soluble paste on the screen, become ink resistance part (non – text part).Finally take down the metal plate, the original metal printing plate raised part, the paint is rubbed off, then on the screen is transparent mesh (that is, the image text), that is made of screen printing plate.Its plate-making process is as follows: metal plate polishing a coated with photosensitive adhesive a print a development a baking a corrosion a coated with rubber water – paint a lacquer – sticky plate
10.Electronic engraving
Electronic engraving method is through the special screen printing electronic engraving machine.It is coated on the screen with a special film, with light scanning the surface of the manuscript, the reflected light into electricity, the re-use of electricity in the screen film perforation, so as to make screen printing.This method has been applied to printing and dyeing industry in foreign countries. There are still some problems in precision and color separation, but it represents the development direction of silk-screen printing.
11.Laser production of metal plate film plate making method: this method is the use of CAD(computer-aided design) for precision pattern design, using laser CAM(computer-aided production) processing metal plate film to make screen printing plate.It can quickly lithography a high precision metal plate film, and avoid the errors due to single corrosion process and double corrosion displacement problems;Excellent performance of the metal plate film can be produced.
12.Composite screen plate making method: metal screen and metal film in printing can not be flexible flexible printing, therefore, the metal plate composite in a better elastic polyester screen, can be improved, made of a composite screen plate.When compound, the wire mesh and metal film stretch on the aluminum frame, in the wire mesh and metal film around the remaining white, remaining white part of the adhesive bonding polyester screen and stretch on the box.Polyester screen parts are very soft, with strong solvent – resistant resin to fill the hole, this bonding process is called composite processing, in high density and high precision printing plays an important role.If the width of the polyester screen around the plate film is not enough, it will affect the tension and printing flexibility, so it must be given an appropriate width.In addition, in the case of high position accuracy requirements, it is necessary to judge whether only in the scraper start moving side, the wire mesh and metal film directly glued on the frame fixed, or with thin metal plate aluminum frame, improve the strength.The image formed by the wire mesh, compared with the image formed by the resin photosensitive film, the image formed by the nickel foil and the metal wire wire fixed with nickel plated stainless steel wire mesh intersection strength is very good, especially after mixing processing, the net is fixed on the box, its cumulative size of the precision is very high.
With the continuous penetration of computer technology in the printing field, screen printing is experiencing the traditional technology to the digital direction of development, the computer appeared in the 1990s without film direct platemaking method.
The whole plate-making process is also developing towards the direction of more intelligent, faster, more convenient and more environmentally friendly. Meanwhile, the development of plate-making process is also affecting the profound changes in the screen printing industry.