Rotary screen printing process principle

- Aug 02, 2017 -

Rotary screen printing has been developing rapidly since its introduction in the 60s of last century. It has nearly 60% of the total amount of fabric printing and accounts for more than 90% in Western europe. Rotary screen printing has the advantages of high printing speed and high automation. In the past, screen printing machine was mostly used for printing cotton and polyester cotton products, and the demand for printing fabric was enlarged with the market. With the development of textile types, the scope of application of rotary screen printing machine is greatly expanded, which is suitable for printing of knitted fabrics, silk fabrics and various kinds of simulation fabrics. Therefore, PML301 rotary screen printing machine can be widely used in printing and dyeing, knitting, silk, wool spinning and other industries, and has broad prospects for promotion.

Rotary screen printing machine was invented by Storck company of Holland in 1963. Although its history is not long, it has developed rapidly. The rotary screen printing machine is composed of cloth feeding, printing, drying and cloth laying. The mechanical part of the printing part can be divided into a printing adhesive tape, a round net driving device, a round net and a printing scraper frame, a flower device, a rubber band washing and scraping device, and a printing fabric sticking and feeding slurry pump system.

Rotary screen printing machine has the following advantages: nickel mesh light, loading and unloading round nets, flowers, syrup and so on, easy to operate, low labor intensity, high yield, temple color limit. Because the processing is carried out without tension, it is suitable to print fabric with easy deformation and wide fabric without lining cloth.

A cylindrical nickel net was made, and the moulds were made first.  With a diameter of 194 mm, 12 mm thick, seamless steel tube length is 1600 mm, by turning to the diameter of 190~191 mm, after cleaning before plating a layer of 0.01~0.03 mm thickness thin nickel layer, and then make the outer copper tubular thick copper layer. Then grinding into the lathe. In order to facilitate the demoulding of the nickel screen, both ends are slightly tapered, and the surface of the die is not allowed to have any concave and convex unevenness, so as to be bright as a mirror. In the steel core machine with steel core mold in mould pressing cylinder surface net pit. The pit is shaped like an equilateral hexagon and arranged like a hive. The commonly used screen mesh with 26 per cm, 34 and 40, the level of the circular net mesh size is determined by the net hole steel core molded the mesh yang. When the copper mould is pressed by the steel core, the surface finish is worse, and it must be polished again.

The mold must be plated with chromium before nickel plating. The purpose of chromium plating is two, one is to improve the surface hardness of the die; two is the chromium layer and nickel layer bonding force is poor, first coating a layer of chromium, then nickel plating, easy to nickel net demoulding. After chrome plating, before the nickel plating, paint or photoresist will be used to fill the die surface of the dot dent filled, so that the pit site into insulators.  Thus, the pits on the die surface are non conductors; the gaps between the pits and the adjacent pits are metal conductors.

Circular screen photosensitive plate making. A stencil process similar to that of a drum. Photosensitive ingredients have also added novel polyvinyl alcohol, epoxy resin and dicyandiamide as curing agent. First, the photosensitive glue is coated on the shaped round net, and then the film is exposed to the circular net for carrying out exposure, developing and rinsing by means of the color separation and positive film. Photosensitive adhesive printed pattern area is not sensitive, after developing the transparent mesh; photogelatin non blank area pattern by exposure of photoreceptor hardening, hardening of the mesh was sensitive glue blocked. In order to make the photosensitive glue layer is completely cured, increasing the rotary screen plates, it will be placed in the round net baking oven, in 180~200 constant temperature under 2 hours of baking, the photosensitive adhesive layer further dehydrated reticulated water soluble polymer, completely lost. The baking time and temperature should be yellow brown in the adhesive layer. If the color is too dark and dark brown, then the temperature is too high or too long, should be appropriate to reduce the temperature or reduce baking time.

Round screen plate making is the main process of rotary screen printing. At present, a universal emulsion emulsion printing plate is adopted. This is the first water-soluble photoresist evenly coated nickel round online, then sensitive. Where no pattern was sensitive, water soluble photosensitive glue of insoluble resin into the mesh blocked, the paste can't permeate through; and the pattern of the place was not sensitive, can wash, water slurry from the meshes through to the fabric, realize printing.


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