The modern paperboard machine coating method is diversified according to the devices, speed of the paperboard machine, as well as the types, raw materials, application of paperboard, and investment value, etc. Nowadays, the common coating method is pre-coating first and then surface coating. Pre-coating is usually accomplished by adjustable coating bar or film press device, even by scraper directly in some factories. After first coating and drying, the paperboard can be coated on surface by adjustable coating bar, air knife or combinational scrapers. It usually takes one or two coating for surface coating. According to the requirements on final quality of the product, the workman chooses proper machines to take certain times of surface coating.

As for a folding boxboard coating machine with three coating heads for printing with 100% renewable waste materials, JAGENBERG Company adopts adjustable coating bar for pre-coating to improve the smoothness and absorbing ability of the paperboard. With air knife for the first surface coating, this company aims to increase the coating weight and whiteness of the paperboard. Moreover, the second surface coating with soft scraper can realize ideal glossiness and printing property of the folding boxboard.

As to the instruction book, invitation card, postcard and other ivory boards in this series whose raw material are bleached craft pulp, both sides of the paperboard need coating one or two coating for they are required with high smoothness and glossiness. An ivory board coating machine is configured with 4 coating heads by JAGENBERG Company. The first two coating heads with combinational scrapers are used for pre-coating for both sides of the paperboard, as well as the scrapers can be replaced with adjustable coating bar. Yet the other two heads with combinational scrapers are used for surface coating on both sides of the paperboard. In addition, this coating machine is equipped with two dryers between the devices of pre-coating and surface coating.

Nowadays, more and more factories select the film press device for pre-coating, whose can satisfy the thick paperboard coating, as well as avoid the troubles effectively aroused by deckle edge on scraper. The film press device is usually used for coating on the production of the superior white paperboard and ivory board. After pre-coating and surface coating with combinational scrapers, the paperboard will show ideal physical characteristics.

On the coating technology, the distance between China and foreign countries has been shortened gradually. Many famous domestic coating machine manufacturers have been confirmed for the high quality and professional service. Moreover, a lot of domestic paperboard factories successfully adopt the three-coating technology with scrapers, which will get a great progress in future.