The product passes through the portion of the coater known as the application chamber at a constant speed of up to 500' per minute (15m/min). As it enters the chamber, it passes through a template which has the same shape hole, or profile, in itself to the shape of the product passing through. As it exits the chamber, it passes through another template called the exit template that also has a similar matching profile.
Paint is drawn from a reservoir by a diaphragm pump, filtered for large particles, and delivered through a hole into the bottom of the coater head. The fluid delivery diaphragm pump is by definition low shear and under low pressure. The level of the coating then rises within the head until the part passing through is completely surrounded or immersed.
A vacuum is applied to the reservoir and the application chamber. The reservoir is a sealed environment attached to the coating head. The coating head contains the only area for air to inrush and that is the space between the product and the template profile. It is this inrush of air that is used to strip excess coating from the product and this removal of excess coating is what determines the wet film thickness applied. The amount removed is subject to the vacuum relief valve, the size of the templates, the linear speed of the product, and the viscosity of the coating. This application and removal method stratifies the coating on removal and then it is drawn up and over a baffle and drains to the reservoir.
Tungsten Heater used in vacuum coating, please contact sales@chinatungsten.com.
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