1. More effective pipeline cleaning * An on-line heating system can not only be used to control the temperature of the UV varnish, but also heat the water used to rinse the water-based varnish system. This cleaning method is very effective because pumping hot water through the system can remove even the most stubborn residues. * A blender module in the varnish line makes UV varnish work better, which is why blenders are standard components on Rapida presses with UV processing capabilities. * It is recommended to use special varnish lines for special high-viscosity varnishes. Although this optional device is not very common in the United States, it has already become standard in other places. * When removing the viscous foaming varnish with a viscosity of 100s or more (DIN viscosity flow cup) from the anilox roller, the automatic cleaning system is usually more effective than manual cleaning. Even so, it may be necessary to end the cleaning of the rollers manually, which is why-like all special applications-the rollers should be carefully cleaned and inspected. 2. Selection and setting of varnish oil pump * Low viscosity varnish is pumped by H & B system (for example) at 1 stroke per second (about 9 liters per minute). According to the size of the printing press, the absorption of the varnish is between 1.6 liters / min (Rapida 105) and 3.5 liters / min (Rapida 205), that is, the pumped volume and the returned volume are higher than the absorption a lot of. If the delivery volume is too high, it may cause excessive pressure in the Blade cavity and squeeze out some varnish. * If you regularly use high-viscosity varnishes, it is best to consult with you on which varnish pump to buy. Varnishes with a viscosity of around 200s bring the pumps to the limit of their mechanical capabilities and cause excessive wear. Varnish viscosity of 150s or more may cause changes to the pump, but even so diaphragm pumps have proven to be less suitable. * Backflow pumping is possible when the residual volume does not exceed 1.5 liters. Since air is also pumped back at the same time, it is fatal to pump expensive metal varnishes back, because metallic pigments can oxidize quickly. 3. Adverse effects on the blade The varnish delivery system manufactured by Harris & Bruno and Tresu differs in the design of the integrated scraper system. Tresu's doctor blade cavity pivots above the upper doctor blade so it can be raised and lowered. So the angle at which it is closed is determined equally by the pressure of the two scraper blades. Therefore, the blade pressure caused by the relatively heavy cavity is always the same, and is not affected by blade wear. The opposite is true when using H & B chambers, the closing / leaving movement is linear. Therefore, the cavity is always placed on the anilox roller at the same angle. The pressure of the blade is controlled by hydropneumatic method, or the standard 2 bar (2000 hPa) or another predetermined value, and the blade is automatically adjusted to prepare for wear. However, the operation of the cavity is not completely without problems. In order to avoid or eliminate the adverse effects, the following content must be checked. * There may be three basic reasons for the leakage of the spatula cavity: -Insufficient closing pressure may leave a slight gap between the doctor blade and the anilox roller, which causes excessive varnish to remain on the roller, and therefore is applied to the printing plate, and when the printing press is stationary Varnish will leak out. -One or two doctor blades, possibly seals or blade clamps, have been worn and / or contaminated. These parts should be checked once a week and cleaned as needed. If you do not apply varnish for any period of time, you should tilt the cavity and lubricate the seal. If the blade wear is excessive, it may be necessary to use different types of blades such as synthetic, long-life or ceramic, or use non-segmented blades if quality standards permit. The causes of abrasion that should be avoided are abrasive pigments (such as titanium oxide in water-based opaque white paint; UV opaque white paint can be used as a substitute) and anilox rollers with incorrect surface finishing or with abrasive engraving patterns. -The speed of the printing press may be too high, causing turbulence and cavitation of the varnish (the formation and collapse of low-pressure areas in the flowing liquid), which pushes the doctor blade backward instantly. * Oil scraping is a phenomenon that can occur on both the upper and lower blades, even when the seal is tight and the blade has sufficient pressure. The leak is not its cause. -If the pressure of the blade is too high, the two scraper blades will bend in their lengthwise direction, so that the side of the blade instead of the blade is in contact with the roller. Attempting to repair this loosening of the contact line by increasing the compression pressure will only make the problem worse. -The open engraved part of the anilox roller (ART, ART-TIF) has no mesh wall, so it cannot form a tight seal with the doctor blade. Therefore, even when the printing press is stationary, the low-viscosity varnish may leak out. -Excessive pressure (filling pressure) in the spatula cavity may push the varnish out of the cavity. * Centrifugal drift may occur on the shadow roller, especially when the anilox resolution is less than 50 lines? Inches and when using low viscosity varnish. The centrifugal force drives the varnish along the endless grooves, causing the varnish to gather at one end. It is recommended to use different engraved parts and varnishes with higher viscosity. * If the varnish does not properly wet the ink, or if there is not enough varnish, or if the level of the varnish in the squeegee cavity is uneven, ghosting may occur even if the squeegee is in the correct position These problems will also cause uneven application of varnish. Blade Brush Cutter Blade,Grass Cutter Blade,Brush Blade,Brush Cutter Blade For String Trimmer Shaoxing Haotuo Machinery CO., LTD. , https://www.haotuochinatools.com