Technical characteristics of the scraper
DATE：2019/11/21 9:04:39 / READ： / SOURCE：This station
Technical characteristics of the scraper
In the first blade coater, the blade was attached to the lower lip of the cell and pressurized using the entire cell device pressed against the back roll. Because the blade is at an angle to the radius of the roller, it is skewed and forms a force on the top. The load was found to control the amount of coating, but it was not constant. Because the scraper wears quickly, it changes from a square edge to a beveled edge, which reduces the pressure per unit area on the top and reduces the skewness of the scraper. It is acceptable for low-quantity papers such as the 5th paper, but further investigation is still needed. When inverted scrapers become common, it is urgent to strengthen research.
This is a matter of course, the blade must be absolutely flat and absolutely straight in the width direction of the coater. The two sides must be parallel and the thickness must be uniform.
It is known from experience that a diagonal doctor blade is preferably used for a lower coating amount, and a curved or straight blade is used for a higher coating amount. A little explanation is needed, that is, the oblique knife should be pre-ground, not ground on the coater. Experience also tells us which paper grades and coatings need to be angled and when new scrapers are needed. The new scraper should be polished with a grindstone one by one and inspect the brush and crack. They are treated to prevent rust and then carefully packed.
The coater has many different configurations and correspondingly requires doctor blades of different widths and thicknesses. The thickness is from 2.5 to 7.6 mm. There are two cases of width variation. A part of the scraper is in the fixture, and a part of the sub-blade is scraped. Generally, the clamping part is 25mm, and the following 75mm is reserved to continue the operating distance by means of a pressurized tube or rod. The part of the really redundant scraper is generally 6~25mm.
The lift of the scraper will be adjusted by the hydraulic force of the paint, the speed of the machine and the load on the scraper. On a curved scraper or straight scraper surface, the pressure per unit area (kPa) is much lower than that of the inclined scraper, so wear is expected to be slower.
In the first blade coater, the blade was attached to the lower lip of the cell and pressurized using the entire cell device pressed against the back roll. Because the blade is at an angle to the radius of the roller, it is skewed and forms a force on the top. The load was found to control the amount of coating, but it was not constant. Because the scraper wears quickly, it changes from a square edge to a beveled edge, which reduces the pressure per unit area on the top and reduces the skewness of the scraper. It is acceptable for low-quantity papers such as the 5th paper, but further investigation is still needed. When inverted scrapers become common, it is urgent to strengthen research.
This is a matter of course, the blade must be absolutely flat and absolutely straight in the width direction of the coater. The two sides must be parallel and the thickness must be uniform.
It is known from experience that a diagonal doctor blade is preferably used for a lower coating amount, and a curved or straight blade is used for a higher coating amount. A little explanation is needed, that is, the oblique knife should be pre-ground, not ground on the coater. Experience also tells us which paper grades and coatings need to be angled and when new scrapers are needed. The new scraper should be polished with a grindstone one by one and inspect the brush and crack. They are treated to prevent rust and then carefully packed.
The coater has many different configurations and correspondingly requires doctor blades of different widths and thicknesses. The thickness is from 2.5 to 7.6 mm. There are two cases of width variation. A part of the scraper is in the fixture, and a part of the sub-blade is scraped. Generally, the clamping part is 25mm, and the following 75mm is reserved to continue the operating distance by means of a pressurized tube or rod. The part of the really redundant scraper is generally 6~25mm.
The lift of the scraper will be adjusted by the hydraulic force of the paint, the speed of the machine and the load on the scraper. On a curved scraper or straight scraper surface, the pressure per unit area (kPa) is much lower than that of the inclined scraper, so wear is expected to be slower.
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