#Roller coater xce 121206 series#

#Roller coater xce 121206 series#

The particles can be trapped using filters similar to those used as air filters for automobiles and these may be in series with progressively finer filters. Alternatively, there are high surface area molecular filters that can do the same job. In some cases, it is possible to use a cold trap to condense vapors before they reach the pumps where the liquid or solid can be collected for periodic removal. This type of problem is found in some of the copper indium gallium diselenide photovoltaic deposition processes, where selenium vapor gets everywhere, and in atomic layer deposition processes where the process is designed to coat every surface uniformly. Low melting-point materials or compounds, that may have a high vapor pressure and low sticking coefficient, may get pumped as a vapor or, if the vapor is able to form particulates, the particles may be pumped directly. However, there are a number of processes where there is a significant amount of particles that can be generated during the deposition process, which means that the pumps need to be protected from large levels of particles that could abrade the close-fitting pumping surfaces or with oil-based pumps could clog up the oilways. The levels of dust or particles are kept low by vacuuming away any debris during the cleaning of the shields during the system downtime.

Many large roll-to- roll coating systems run without any filtering. Bishop, in Vacuum Deposition Onto Webs, Films and Foils (Third Edition), 2015 4.11 Filtering It operates on the same principle as the nip-fed coater but is more suited to low-viscosity materials.Д¬harles A. In such a case, a pan-fed coater is recommended. It is difficult to prevent leaks from the coating reservoir when a low-viscosity material has to be coated.

The coating thickness is dependent on the gap between the applicator roll and the metering roll, the rotational speed of the applicator roll and the amount of material transferred on the web, which in turn is dependent on the web pressure on the applicator roll adjusted by the backup roll. The coating material that does not get transferred from the applicator roll after contact with the web is manually removed, collected in a pan and recycled. In order to obtain a good coating, the applicator roll is in the opposite direction to the metering roll and to the web. This produces a high level of shearing action. The coating material is adhered to the applicator roll, which is then carried to the coating nip where the material is transferred to the web moving in the opposite direction. In this process, a layer of thin coating is metered between the applicator and the metering roll. Nip-fed reverse-roll coater: (1) applicator roll, (2) metering roll, (3) back-up rubber roll, (4) web, (5) coating pan, (6) doctor blades and (7) drip pan. To increase coating speed, one more roller вЂ“ a pick-up roller running at a reduced speed вЂ“ can be added, and this system is called a four-roll pan-fed coating system ( Greer, 1995 Grant, 1978, 1981).ДЇigure 10.25. 10.8(b)), a liquid film is formed on the applicator roller rotating through the coating liquid, metered by a metering roller, and deposited on the substrate fabric on a back-up roller. In three-roll pan feed or L-head coating ( Fig. It can be problematic when coating liquid has low viscosity. This configuration needs only a minimal amount of coating fluid, but a drawback is possible coating fluid leakage. Film formed on the applicator roller is deposited onto the substrate surface supported by a back-up roller. After coating liquid transfers from the metering roller to the applicator roller, any coating liquid remaining on the metering roller surface is cleaned by a doctor blade, otherwise it will result in coating defects, such as streaks or film roughness.

The applicator roller picks up the coating liquid from the nip and the amount of coating liquid delivered to the fabric substrate is metered by the metering roller rotating in a reverse direction to the applicator roller. 10.8(a)), the nip formed by a metering roller and an applicator roller is flooded with coating liquid and functions as a reservoir ( Greer, 1995 Grant, 1978). Common three-roll configurations are nip feed coating and L-head coating. Three-roll coating uses a metering roller, an applicator roller and a backup roller.