Frequently Asked Questions
What are the factors to consider when selecting a doctor blade for a roller printing machine?
Source：Best printing machinery Time：2016-08-16 Click：391 Times
Factors to consider when selecting the doctor blade for a roller press:
1, flower structure and area: flower-type structure is divided into block surface, lines, moiré, snow, spray and so on. And often a pattern includes several flower-type structure. In considering the pattern structure should also take into account the pattern area, generally can be divided into Montreal, large, medium and small flowers four. Flowers for the floor, wide flowers wide horizontal, it is necessary to use thicker, less hardness of the blue steel blades such as 20 good, 21 and so on. To prevent the blade hardness is too large, too high elasticity, causing the blade flashing, the large area of ??the paste in the pattern scraping out, resulting in a horizontal knife-edge splash or bottom. The thin lines in the flowers, moire, snow and other should use thin blade, stainless steel and white steel can be used to improve flexibility, to clean the scraping paste, without damage to fine and shallow patterns.
2, flower tube carving peak when the level of the peak: in order to make the pattern part of the slurry can be carried in uniform, in the concave pattern made of textured or oblique lines, when the line peak and the same pattern as usual flower tube depression, the choice of thin blade effect: Peak lower than the flower tube, the thicker blade should be used to avoid the blade is too flexible, the pattern caused by scraping out the paste at the end.
3, the depth of carambola carving: When the tassel on the pattern deep, in order to prevent the overflow of pulp and take color defects, often double thin blade. The use of large elastic characteristics, try to scrape the pattern at the color paste, thereby reducing the amount of carrying pulp, when the tassel on the shallow pattern, the use of thick blade, so that more color paste at the pattern to increase the amount of slurry contained.
4, the nature of the paste: the use of acid paste printing, the choice of stainless steel or white steel blade. Scraper knife is the direction of the installation of the cylinder, scraper knife and flower tube angle is small, scraping paste effect is not good, but the knife wear less, long service life. On the contrary, prone to damage and the emergence of a knife. Generally the angle between the doctor blade and the fountain is between 19 and 35 degrees. In addition to yarn scraper (knife) is made of brass or phosphor bronze. In order to eradicate the surface of velvet and removal of flower tube surface residual pulp, to prevent the transfer color. In addition to yarn scraper installed in the reverse direction of operation behind the flower tube printing. And the angle of the flower tube can not be too large, otherwise it will shovel bad flower tube.
5, broach device: in order to protect the fountain and scraper from damage, better play scraping slurry effect, so that the scraper axis along the cylinder for reciprocating motion device broach device.