Research Progress of Vacuum Winding Coating Technology

This article summarizes the research progress of vacuum web coating technology from system structure, parameter control and coating method. According to the structure, it can be divided into single-chamber, double-chamber and multi-chamber vacuum winding systems. The latter two can solve the problem of unwinding and venting and control the respective vacuum degrees of the winding and coating chambers. Winding tension control is divided into taper, indirect and direct control models. The taper control model can solve the problems of film wrinkles and uneven radial force distribution; indirect tension control does not require sensors and can be replaced by a vector inverter with built-in tension control module; direct tension control The tension value is accurately measured by the tension sensor, but a variety of parameters such as moment of inertia and angular velocity are required. Vacuum winding coating mainly includes vacuum evaporation, magnetron sputtering, etc., which can be used to prepare new high-refractive-index films, graphene and other nanomaterials, and flexible solar cells and other semiconductor devices. In view of the current research status of vacuum coil coating technology and the problems in the transition to industrialization, a brief analysis and outlook are finally made.

Vacuum winding coating (roll-to-roll) is a technology that uses different methods to achieve continuous coating on a flexible substrate under vacuum. It covers many aspects such as vacuum acquisition, electromechanical control, high-precision transmission and surface analysis. The key point is to increase the winding rate, control the stability of the coating and implement online monitoring while ensuring the quality of the coating. Roll-to-roll technology has the advantages of low cost, easy operation, compatibility with flexible substrates, high productivity, and continuous multi-layer coating. The first vacuum evaporation coil coating machine was made in 1935, and the coating width is now from 500 to 2500mm. The application of roll-to-roll technology has gradually expanded from packaging and decorative films to functional films such as laser anti-counterfeiting films and conductive films. It is one of the mainstream technologies in the future flexible electronics industries.

vacuum coating machine,pvd coating machine,pvd vacuum machine,vacuum ion coating machine,multi-arc ion coating machine

At present, the international frontier is to study the properties of functional films under different preparation processes and improve the preparation of composite films. The winding coating machine has two trends towards large-scale industrialization and small-scale scientific research. Domestic companies such as Lanzhou Vacuum Equipment and Guangdong Zhonghuan Vacuum Equipment produce large-scale industrial winding equipment. Foreign companies such as TW Graphics and Intellivation are mainly for scientific research. The agency provides small or micro roll coating machine.

vacuum coating machine,pvd coating machine,pvd vacuum machine,vacuum ion coating machine,multi-arc ion coating machine

The vacuum roll-to-roll equipment consists of vacuum, winding, coating and electrical control systems. According to whether the vacuum chamber has baffle or not, it can be divided into single-chamber, double-chamber and multi-chamber structures. The single-chamber rewinding and unwinding roller and the coating roller are in the same chamber, and the structure is simple, but when unwinding, air venting will pollute the vacuum environment. The double-chamber structure divides the system with baffles into winding and coating chambers, and the gap between the roll and the baffle is about 1.5mm, which avoids the problem of unwinding and venting. Multi-chambers are often used to prepare composite films. On a dual-chamber basis, adjacent coating areas are separated by baffles to avoid interference. For example, Krebs and others fixed the Capeton baffle of Skultuna Flexibles AB between two magnetron sputtering targets, and the two sides of the plate were coated with a copper layer of 50 μm.

The smaller the gap between the partition baffle and the vacuum chamber wall, the better. According to the function of the roller during coating, it is divided into single main roller and multi-main roller winding coating machine. According to the number of motors, it can be divided into two-motor, three-motor and four-motor drive systems.

vacuum coating machine,pvd coating machine,pvd vacuum machine,vacuum ion coating machine,multi-arc ion coating machine

Because of its large area, low cost, continuity, etc., vacuum coil coating has great advantages over intermittent coating, and has attracted wide attention from domestic and foreign researchers and enterprises. The current winding coating technology has progressed rapidly, solving the problems of hollow lines, white stripes, and wrinkles, and has begun to be used to prepare new functional media and devices such as graphene, organic solar cells, and transparent conductive films. Therefore, higher requirements are put forward for the film forming process and film quality. The main pump of the vacuum unit has been developed from a large pumping speed diffusion pump to an oil-free ultra-high vacuum molecular pump and a cryogenic pump, and a large wrap angle double cooling roll coating machine has been developed. To reduce the stretching deformation of the film. Tension control mostly uses the winding model considering the clamp induced tension and the unwinding model with single-span nonlinear dynamics.

vacuum coating machine,pvd coating machine,pvd vacuum machine,vacuum ion coating machine,multi-arc ion coating machine

At present, the precise control of the coil coating needs to be improved. For example, when transferring graphene, it is difficult to completely remove the pyrolytic glue between the substrate and the graphene, and the shear stress caused by the excessively fast winding speed or the hard substrate will cause the graphene layer to form Cracks or holes. For another example, the organic thin film prepared by vacuum winding has many surface defects and low carrier mobility, which seriously affects the photoelectric characteristics of the device. In the future, measurement and control units such as film stress should be added to integrate film forming technologies such as CVD, ion plating, high-voltage electrostatic spinning, vacuum jetting and in-situ polymerization to provide guarantee for the development of new organic and inorganic composite functional films and devices.

Founded in 2015,Zunhua Baorui Titanium Equipment Co.,Ltd. is a manufacturer specializing in pvd vacuum ion coating equipment. The company’s products mainly include large plate coating machine, large tube collating machine, tool coating machine and LOW-E glass production line. Mr.Wang baijiang ,general manager of the company ,has been engaged in vacuum coating industry for more than 30 years. He continuously improve production technology, improve product performance and devote himself to provide customers with better product experience and higher production efficiency.