Installation of squeegee
To get a good printing effect, before printing to check whether the scraper blade is straight, the inspection method can be used by visual inspection or a light hand across the sharp surface of the rubber scraping to verify whether the sharp surface is damaged.In case of serious damage, the tape should be reinstalled.In the installation process of the rubber scraping, the main thing is to choose the appropriate size of the scraper.Squeezer from the scraper handle out of the number of the amount depends on the hardness of the strip, ink viscosity and other printing conditions.General printing with a softer squeegees squeegees to install the part to be more, hard squeegees to install the part to be less, the exposed part should be more.The quality of scraper handle directly affects the use effect.
(I) Pay attention to key points when installing the scraper
(1) Choose one of the straight and non-defective strips. The end is the cutting edge, and the end with poor cutting edge is installed in the handle.
(2) Do not damage the blade during installation.
(3) Screen printing machine to install the scraper, screw do not screw too tight, so as not to damage the scraper, and to do the clamping flat, high and low level, and the screen contact flat.
The height of the scraper handle can be seen according to the screen printing requirements, if you need a little soft scraper can be more exposed (25~30mm).If the scraper needs to be hard, it can be exposed less (10~ 25mm).If using the graphics, pneumatic net printing PCB part article some glue scrape into scraper holder height, revealing strip height more than 25 mm, outside according to the thickness of the scraper strip, using 10 mm or 25 mm, so as not to because of the pressure in the printing on the hardness of the scraper lead to its contact with positive printing, the printing blurred, especially in printing PCB are easy to be eroded, while resistance welding plate printing ink layer thickening, influence the curing effect of solder resist ink, at the same time greatly reduce the service life of scraper.
The height of the unsupported part of the rubber strip (the part exposed outside the handle)
The height of the unsupported part of the strip is the height of the strip that is not inserted into the wooden handle.This is one of the most overlooked factors in making a scraper, and the height of the unsupported part of the strip during printing has a great impact on the hardness.The height of the strip exposed to the outer part of the handle is the principle that the unsupported part of the higher hardness (harder) scraper can be higher than the unsupported part of the lower hardness (softer) scraper.There is often a misconception in the industry that a hard squeegee-printed product is of better quality.In fact, the hardness of the scraper is relatively narrow adaptability, on the printing plane flatness, scraper pressure and speed adjustment requirements are higher.Generally speaking, the soft scraper is not supported part control in 2.5~3cm, such a scraper used to adapt to the wider surface.Scraper pressure is too large or uneven printing platform, will cause the rubber rolled up.The rubber strip with hardness between 50° and 55° and the uninlaid part around 1.5 cm has good printing adaptability, and its flexural performance is enough to buffer the error caused by operation or adjustment discomfort.
The length of the rubber strip
The ideal length of the scraper is 5cm longer than the entire image on the screen.This gives people a size that meets the minimum screen size required for printing (assuming the image is not too far from the frame).Strip to be cut into the appropriate length, because the scraper is too long will cause the mesh mesh maximum deformation.After the tape is cut, the sharp corners of each edge should be removed with a knife sharper and polished smooth with 100 mesh emery cloth.Reasonable choice suitable for the use of rubber scraping, at the same time, the more popular scraper “rotation system” (that is, rotation system), can also better improve the service life of the scraper.