Patent Application
20220242672
The present invention provides a solution for coating substrates which are moved on a carrier that can move from painting, coating or treatment modules in a continuous inline production facility having a system which allows to easily switch between a back and forth limited rotational movement, called rocking mode, for critical processes such as physical vapor deposition (PVD) coating, UV hardening and IR flashing, and a continuous rotational movement of the substrates when the substrates are in a painting or drying process module.
Processes to paint, coat and treat substrates in complex processing lines are well described by Ribero et al. (U.S. Pat. No. 10,016,774 B2), Spangler et al. (US 2009/0277384 A1) and Keckes et al. (U.S. Pat. No. 9,476,116 B2, U.S. Pat. No. 9,529,450 B2). The economic advantage of using a modular inline approach to allow a serial processing instead of using large different treatment chambers in batch processes is evident.
However, the major challenge is that each module make use of different processes, such as cleaning of the substrate by etching, ultrasound or plasma process; the coating of single or multilayer systems by physical vapor deposition (PVD) either by magnetron sputtering or arc discharge, using at least one sputter target per PVD module; the painting process to spray a coating dispersion, UV-hardening lacquer; the treatment of the lacquer by backing the substrate through an heat source, such as IR source, curing and/or hardening the lacquer by UV emission sources. All these processes require specific positions and movements of the substrates. The rate of each process is quite fast within a few minutes or faster. It is therefore critical to be able to switch from one type of movement of the substrate to another without interrupting the continuous process.
The transport and movement of the substrates between each modules is usually done by means of a carrier which is moved through a transport belt. The carrier is supporting one or several rotating spindles, usually of cylindrical form on which small sized substrates are mounted. The cylinder is rotating through the spindle at different rotation speed and can be synchronized with the movement of the transport belt within a processing module.
One of the challenge is to provide a simple and economic solution to transport the substrates between each of the modules and at the same time provide optimized movements of the substrates adapted to the different processes in the modules without increasing the complexity of the system.
For example, in PVD processes, it is very important to accurately position the substrates with respect to the target, where the material is evaporated. If parts are not moved during the deposition process, the produced layer will most likely not be homogenous, due to the inhomogeneity of the evaporation and diffusion of the material from the surface of the target. This is why the substrates are moved in front of the target through a rotating cylinder. The exposure time in front of the target determines the coating thickness and coating thickness distribution.
On the other hand, spraying of UV-hardening lacquer, for example, will require a different movement of the substrate as the painting of suspension particles onto the substrate will still remain in a fluid phase before the hardening process occurs and could run out if the part is not moved in a certain way. Heat treatment by IR or UV curing of the lacquer will require a more homogenous movement of the substrate in order to spread the heat or the light in a more homogenous way onto the substrate.
The simplest solution in this case is to use the same rotational movement for each process allowing some adjustment on the rotation speed for each process. This would be acceptable in most of the cases when the substrates to be coated or painted are rather small and can be placed on the cylindrical support.
This specific state of the art case is illustrated in
However, this type of movement is quite limiting when considering larger substrates, where a simple rotation would not be sufficient to produce the desired coating quality. This situation is illustrated in
The objective of the invention is to provide a carrier that can move from one painting, coating or treatment module in a continuous inline production facility having a system that allows to easily switch between a back and forth limited rotational movement, called rocking mode and a rotational movement of the substrates. The inventive system, as well as the preferred and additional embodiments are described more in detail in the following paragraphs.
The inventive solution and the different possible enabled movements of the substrates are illustrated in
The coupling rod length and the location of the attachment of the rod on the spindle clamp and coupling gear is set so that when the coupling gear is rotating completely, the spindle makes a back and forth movement of preferably +30° to −30° measured with respect to the horizontal plane of the carrier. The frequency of the back and forth movement or rocking movement of the spindle can be set by setting the speed of the chain through the servo motor. The movement of the rocking movement can be either continuous or discontinuous (indexed) at certain given angles and given time during the process.
The rocking movement of the spindle can be complemented by a horizontal back and forth movement of the carrier through the transport belt. Depending on the dimension of the module, this distance can be of about −300 mm to 300 mm in the PVD coating chamber.
The frequency of the rocking movement between the two maximum angles, preferably +30° and −30° can be varied between 0.1 and 10 Hz.
The inventive apparatus allows to switch from the rocking mode, where the coupling gear and the spindle clamps are coupled together to the classical rotational mode (
A second spindle or more can be positioned on the carrier. In case of two spindles, the coupling gear is located between the two spindles. The configuration of the coupling rod and spindle clamp being symmetrical on the second spindle.
This type of gear system allows to quickly switch between a continuous rotation mode and a rocking mode when the carrier is moving from one module to the other.
The positions shown in the
Another advantage of the inventive apparatus is the possibility to additionally combine mechanical movements of the substrates over the targets during PVD coating and change the power of the sputtering source on the target according to the specific position of the substrates in the coating chamber. In particular, the back and forth movement can be synchronized with the power source of the magnetron sputtering of the targets to allow a smooth transition between a low power and high power while the substrate is close or away from the target. This way a control of the coating thickness is possible while having a limited back and forth movement of the carrier inside the coating module.
The specific positioning of the mechanical link and radius where the spindle clamp is attached is designed in such a way that the complete rotation of the small gear only allows the movement of spindle gear between −30° and 30° from the horizontal plane. These limitations of the angles are critical in some processes because the distances between the targets, IR lamps or UV sources and substrates in the process modules are very narrow and critical. It is also a way to have a mechanical limitation so that the expensive UV emission sources cannot be damaged during processing by mistakenly producing a complete rotation of the larger substrate in the UV processing module.
Another advantage of the inventive apparatus is to be able to combine the rocking movement of the larger substrates when located in one module, for example, during PVD coating or UV curing, and change the rocking mode into a fully rotational mode when the larger substrates are located in another module, for example, during the painting process. In this specific case a rocking movement or static positioning of the larger substrate would not be optimum as the painting of the paint or UV-hardening lacquer in form of suspensions would still remain in a fluid phase before the hardening process has started and could run off if the parts are not constantly moved. The heat treatment by heat source or IR source also require rotational movement of the substrates in order to spread the heat of the IR source in a more homogenous way over the complete area of the substrate.
With the different embodiments shown as illustration and not limiting to the invention, it is shown that the inventive apparatus allows the coating and treatment of larger substrates, keep a simple transport and movement system limited to at least two servo motors, two chains and a few gears that can be quickly adjusted between the different modules and at the same time keep the standard process of coating smaller samples using spindles.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/000049 | 2/20/2020 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62807965 | Feb 2019 | US |
