Specific Installation and Adjustment of Doctor Blades
Scraper Angle:
Optimal printing results require the correct adjustment of the scraper angle. For gravure printing, the scraper angle should be 55-65 degrees. A flatter angle creates a larger contact area, resulting in smearing and smearing. A steeper angle can easily produce blade wire.
Scraper Installation:
Hard blade mounting: When X = 3mm, this effectively resolves the problem of poor scraping.
Neutral blade mounting: When X = 4mm, this is standard mounting.
Soft blade mounting: When X = 5mm, this facilitates dot transfer and printing with coarse ink particles (e.g., white ink).
The scraper must be installed straight and free of undulations.
Scraper Pressure:
The scraper pressure should be as light as possible. The thinner the blade edge, the less pressure required. The scraper needs to have a certain degree of toughness to compensate for radial runout or diameter deviation of the roller. Excessive pressure increases the contact area and friction between the scraper and the plate roller, causing the scraper to bend. In severe cases, the cutting edge may break, resulting in “wire” (a phenomenon known as “steel wire”).