Wireless variable gap coater apparatus

Abstract

Systems and methods for coating thin films with viscous materials such as liquids, pastes, or adhesives to a desired thickness are disclosed. In such a system (100), two thin films (112, 114) are moved adjacent to each other in opposite directions along the top of two rollers (102, 104) separated by a known gap (20) that defines the coating thickness, with the material being transferred from one film to the other. The rollers can be held in their relative positions by springs (116, 118) and / or linear actuators (124a, 124b) and positioned using linear encoders (120). In an alternative arrangement, the material to be coated can be a low viscosity material such as a polymer solution. Air knives (602a, 602b) can be provided near the gap to create an air flow that helps prevent the low viscosity material from freely flowing beyond the boundaries of the film during coating.

Description

[0001] Related applications

[0002] This application claims priority to U.S. Provisional Application No. 62 / 704,213, filed April 28, 2020. Technical Field

[0003] The present invention relates to the formation of thin film coatings using flowable materials, and more specifically, to a facility for obtaining thin films or coatings having controlled variable gaps. Background Technology

[0004] Various types of wet film applicators are known from the prior art. To accurately determine certain specific properties of the coating, it is necessary to ensure that the applied coating will have a predetermined thickness. Furthermore, it is desirable that the applicator device be adjustable to obtain films of desired thicknesses from various materials with different physical properties.

[0005] A wet film applicator known from the prior art includes a pair of wedge-shaped elements parallel to each other and carrying transverse planar blades for forming a coating. The gap between the bottom edge of the blade and the base plane (substrate) determines the thickness of the coating being applied. This gap thickness changes as the blade moves along the wedge-shaped elements. Once the desired gap thickness is set, the relative arrangement of the parts in the apparatus is fixed. The blade is oriented perpendicular to the coating direction and forms a film of the desired thickness as the applicator moves relative to the substrate surface. This apparatus is very versatile and provides a level of precision sufficient for forming conventional paints, varnishes, and other wet film coatings. A problem with this technology is that during clamping of the mechanism, the tightening screw presses directly against the blade, giving the blade torsional motion, which in turn reduces the accuracy and quality of the film.

[0006] Various known methods exist for forming high-quality films, and therefore various apparatuses exist for implementing these methods. For example, a scraper or scraper (rubber brush) can be used to apply a wet solution, which can be a blade (sheet) or a cylinder. However, these apparatuses do not guarantee the formation of highly anisotropic films with reproducible properties, and such film formation methods require lengthy preparation work to determine the optimal coating conditions for each batch of initial raw materials.

[0007] Attempts to solve such problems have resulted in rather complex devices, and existing applicators also include devices of the slot extrusion coating system type.

[0008] Patents describing various prior art devices include U.S. Patent Nos. 4,869,200, 6,174,394 and 8,028,647.

[0009] Despite the existing solutions, problems are still encountered which are related to the need to combine in one device the necessary characteristics, including high precision, simple regulation, control over the film parameters, in particular thickness, and the possibility of improving the quality of the applied coating by compensating for substrate non-uniformity. SUMMARY

[0010] Embodiments of the invention relate to forming a layer of material in a gap between two films. The presence of two films that can be moved relative to each other enables the creation of a uniform layer of material between the films, while maintaining the possibility of easy cleaning by simply rolling up each of the films when they are detached, thus creating a completely new gap between the films. The device according to embodiments of the invention enables the creation of a coating at high application rates, with low raw material consumption and high precision control over the film thickness at very low cost.

[0011] Systems configured according to embodiments of the invention are particularly suitable for cases where film quality is of great importance. One important example of such an application is the series of laser-enhanced jetting applications (see, for example, U.S. Patent No. 10,144,034 and U.S. Patent No. 10,099,422). In such applications, a highly uniform layer of material is required in order to produce stable and reproducible jets. To this end, Zenou et al. in U.S. Patent No. 10,603,684 introduce a new method using two films, which use a pair of films between which there is a wire to control the gap width and thereby the material layer thickness. The present invention introduces another method in which the gap is maintained in the absence of a wire.

[0012] Thus, embodiments of the invention provide for coating a thin film with a desired material at a desired thickness. The material can be a viscous material in the form of a liquid or paste, or a low viscosity material. It can be an adhesive or a metal or ceramic slurry or any polymer solution.

[0013] In some embodiments, the coating occurs in a gap between two rollers, but it can also be produced with a flat (planar) substrate at one side of the gap. In either case, the rollers used to create / maintain the gap can be metal, ceramic or rubber rollers, such as polyurethane rubber rollers or other rollers that will create a soft contact. The rollers can be free rollers or fixed rollers. The width of the gap between the rollers or between the roller and the planar substrate determines, directly or through some correlation, the thickness of the material layer. The gap can also be controlled by pressure control using the same mechanical structure.

[0014] In one embodiment, the film to be coated is passed over one roll, and a second film is passed over a second roll opposite the first roll. This second film can be advanced along with the first film to remove any residue from a previous coating operation, or to recycle unused material, or for other purposes. Using such a second film enables coating of multiple materials one after the other without any contamination, creating a very powerful tool for printing different materials in a sequential order. An air knife can be placed near the gap to create an air flow that helps prevent low viscosity materials from freely flowing outside the boundaries of the film during coating.

[0015] As the first film is advanced through the gap between its roll and the second film covering roll, material forms a layer on the film with a thickness equal to the distance across the gap between the two films. The roll opposite the roll of the film to be coated / being coated can be held in place by one, two, or more springs or other biasing elements. Two linear actuators parallel to the springs can be used to move the second roll away from the first roll through two arms, thereby widening the gap. When the linear actuators begin to pull the second roll away from the first roll, a second (or other number) of springs arranged in parallel force the arms away from the second roll to avoid backlash.

[0016] Linear encoders can be installed on each side of the system to measure the position of each arm. When the linear actuators move the second roll, the zero position of the system can be set to the position at which the linear encoders first detect motion. If the zero position corresponds to the rolls touching (or nearly touching) each other, then the width of the gap is determined by the amount of motion measured by the linear encoders after that point. A pressure actuator can also be used to determine the start of motion point by force. In addition, the system can be equipped with optical, mechanical, or electrical limit switches to identify when the arms have reached their starting position, which can correspond to a zero gap width, a fully open gap width, or some other gap width in between.

[0017] These and other embodiments of the present invention are described below. BRIEF DESCRIPTION OF DRAWINGS

[0018] The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which:

[0019] Figures 1A-1C One embodiment of a wireless variable gap width system configured in accordance with the present invention is shown in perspective view Figure 1A ), front view Figure 1B ), and rear view Figure 1C .

[0020] Figure 2 A cross-sectional view of the system shown in Figure 1 is shown.

[0021] Figure 3A detailed view showing the gap region between the rollers of the system of Figure 1 during coating of material onto the film.

[0022] Figure 4 A detailed view showing one region of the system of Figure 1, specifically showing the connection between the arm and its rollers.

[0023] Figures 5A-5C Use of the well-defined gap of a wireless variable gap width system configured according to embodiments of the present application for mixing multiple materials when coating a film or other substrate.

[0024] Figures 6A-6D Another embodiment of a wireless variable gap width system configured according to the present application, including an air knife for removing material.

[0025] Figure 7 Further showing the provision of an air knife near the gap between the rollers of a wireless variable gap width system configured according to embodiments of the present application.

[0026] Figure 8 A cross-sectional view showing a pair of air knives near the gap between the rollers of a wireless variable gap width system configured according to embodiments of the present application. DETAILED DESCRIPTION

[0027] Before describing the present application in detail, it is helpful to present an overview. Reference is made to Figures 1A-1C and Figure 2 A wireless variable gap width system 100 configured according to embodiments of the present application includes a frame 10 supporting a spool 12 and a take-up shaft 14 between sides 16a, 16b of the frame. A film 114 carried on the spool 12 is passed over one of a pair of rollers 102, 104 supported longitudinally adjacent to each other at one end of the frame 10 and is collected on the take-up shaft 14. Motors or other actuators connected to the take-up shaft 14 and the spool 12, not shown in the figures, can advance the take-up shaft 14 and the spool 12 to dispense the film 114 before, during and / or after material deposition operations discussed further below. The rollers 102 and 104 can be supported by pins about which the rollers are free to rotate within the frame 10. Alternatively, the rollers 102 and 104 can be fixed about such pins, with the films 112, 114 sliding over the rollers but the rollers themselves not moving.

[0028] A film 112 to be coated with material is passed around the roller 102, between the rollers 102, 104, adjacent to the film 114 along the lateral dimension of the frame 10, closest to the rollers 102 and 104 at this point. Coating of the film 112 occurs in a gap 20 between the rollers 102 and 104 (or more accurately, between the films 112 and 114 disposed around the outer surfaces of the two rollers).

[0029] like Figure 3 As shown, material 110 to be coated onto membrane 112 is deposited at a point above gap 20 (or more precisely, upstream of membrane 112 in the direction of travel from gap 20), and the movement of membrane 112 around roller 102 pulls a layer 18 of material 110 onto the outer surface of membrane 112, wherein the width of gap 20 determines the thickness of material layer 18. As membrane 112 advances around roller 102, membrane 114 may advance around roller 104 to remove any residual material 110 from the area of ​​gap 20 (e.g., residues due to previous coating operations), to recover unused portions of material 110, or for other purposes (e.g., in relation to replacement of material 110). Material 110 to be coated onto membrane 112 may be a viscous material such as a liquid, paste, or adhesive, or it may be a low-viscosity material such as a polymer solution. In various embodiments, material 110 may be replaced between two consecutive coating processes, wherein gap 20 widens during the coating of a second material so as not to displace the previously coated layer of material on membrane 112. The various rollers and reels described herein may be made of metal, ceramic, plastic, rubber, or combinations of such materials and may be coated to allow the films 112, 114 to be freely passed over them.

[0030] In some embodiments, material 110 may be deposited from a syringe or other reservoir in which material 110 is held near gap 20. Such a syringe or other reservoir may be maintained in a controlled environment, where pressure, temperature, and / or other environmental conditions are maintained as needed for material 110. From the syringe or reservoir, material 110 is deposited upstream of gap 20 to coat film 112 (or another substrate), and then the film passes through gap 20 formed by a pair of cylindrical rollers 102, 104. After passing through gap 20, a uniform layer 18 of material 110 will be present on film 112, and the coated film may be provided to another station for material deposition / dispensing or for other purposes. In some cases, after the uniform layer 18 of material 110 has been coated, the coated portion of film 112 may be returned to a position upstream of gap 20 (e.g., around a point or by linear translation) to be recoated with a uniform layer of a second material, or to fill any spaces in layer 18 resulting from the first coating. For example, in various embodiments, the membrane 112 can be bidirectionally translated in a controlled manner, such that the membrane can be repositioned when the gap 20 between rollers 102, 104 is opened, thereby allowing the same area of ​​the membrane 112 to be recoated with material 110 (or another material) without contaminating the rollers and reducing or eliminating the amount of membrane 112 consumed during the coating process. The membrane 112 can be a transparent membrane or other substrate, with or without a metal (or other) backing.

[0031] A more detailed inspection of system 100 is required. Figures 1A-1C and Figure 2Arms 106a, 106b are shown inside the inside sides 16a, 16b of frame 10. While two parallel arms 106a, 106b are preferred, in some embodiments there can be only a single arm or alternatively more than two arms. In the following description, reference is made to a single arm 106 and its associated components, however, it is understood that the same description applies equally to them in the event there is a second arm and / or additional arms and their associated components.

[0032] With reference to Figure 4 , arm 106 is biased along its length by springs and associated bearings, as discussed below, to maintain uniformity of width across the lateral dimension of gap 20. At one end of arm 106 is a guide assembly 130 through which a tapered portion 132 of arm 106 passes. Tapered portion 132 of arm 106 terminates in a notched end 134 having two parallel outer edges 136 and an internal spring anchor 138 in the form of a detent that does not extend the entire length of a groove 140 formed by the two parallel outer edges 136 in notched end 134.

[0033] H-shaped bracket 108 receives notched end 134 of arm 106 within a groove 142 formed on one side of the bracket. The opposite side of bracket 108 abuts a bearing 144 that acts as a joint between bracket 108 and roller 104. Bearing 108 can be made of metal, ceramic, plastic, rubber, or a combination of such materials and can be coated so as to allow roller 104 to freely rotate about its axis.

[0034] Spring 118 is helically coiled around the outer periphery of tapered portion 132 of arm 106 within groove 142 and guide assembly 130 and is compressed between detent 148 of guide assembly 130 and transverse member 146 of H-shaped bracket 108. As arm 106 is moved (under the control of a linear actuator, as described below), the position of H-shaped bracket 108, and thus the position of roller 104, changes, thereby changing the width of gap 20 between roller 104 and roller 102. Second spring 116 is positioned within groove 140 in notched end 134 of arm 106 and is helically coiled around internal spring anchor 138. Spring 116 biases arm 106 against H-shaped bracket 108 and in turn against roller 104 and is compressed between the inner surface of groove 140 in notched end 134 and transverse member 146 of H-shaped bracket 108. Thus, when the linear actuator begins to move arm 106, spring 116 forces arm 106 away from roller 104 to avoid backlash. Springs 116 and 118 have corresponding pieces of the arms on opposite sides of frame 10.

[0035] Returning to Figures 1A-1C and Figure 2Linear actuators 124a, 124b (one for each arm 106a, 106b) are arranged to move the respective arms 106a, 106b longitudinally within the frame 10. Moving the arms 106a, 106b in this manner will cause the rollers 104 to translate within the frame 10, thereby adjusting the width of the gap 20 between the rollers 102, 104. In one embodiment, a processor-based controller (not shown) is used to implement operation of the linear actuators 124a, 124b. One example of a processor-based controller upon which the methods of the present invention can be based or used in the practice of the present invention will typically include a processor which is communicatively coupled to a bus or other communication mechanism for communicating information, a main memory, such as a RAM or other dynamic storage device, coupled to the bus for storing information and instructions to be executed by the processor and for storing temporary variables or other intermediate information during execution of instructions to be executed by the processor, and a ROM or other static storage device coupled to the bus for storing static information and instructions to be executed by the processor. A storage device, such as a magnetic disk or solid state drive, can also be coupled to the bus for storing information and instructions. In some cases, the body controller can include a display coupled to the bus for displaying information to a user. In such cases, an input device, including alphanumeric and other keys, can also be coupled to the bus for communicating information and command selections to the processor. Other types of user input devices, such as a cursor control device, can also be coupled to the bus for communicating direction information and command selections to the processor and for controlling cursor movement on the display. The controller can further include a communication interface coupled to the processor for providing a two-way data communication to / from the controller via a local area network (LAN). The communication interface sends and receives electrical, electromagnetic or optical signals that carry digital data streams representing various types of information. For example, the controller can be networked with remote units (not shown) to provide data communication to a host or other device operated by a user. Thus, the controller can exchange messages and data, including diagnostic information, with the remote units to assist in fault detection if needed.

[0036] Such a controller can be programmed to operate the linear actuators 124a, 124b to move the arms 106a, 106b to achieve a desired gap width 20 for coating the film 114 with a film 18 of material 110 having a desired thickness. The controller can also be programmed to advance the film 112 and / or the film 114 as needed for such a coating process. To achieve a desired level of precision in the gap width 20, the linear actuators 124a, 124b can employ piezoelectric transducers that include piezoelectric ceramics that expand in a defined direction when an electric current is applied (e.g., under the control of the controller). The ceramic can be oriented so that when it expands (with an electric current applied under the control of the controller), the arm connected to the actuator shifts along a single axis (e.g., the longitudinal dimension) in the direction in which the crystal expands. In general, each actuator can use multiple piezoelectric transducers, and the various piezoelectric transducers can be energized simultaneously (or nearly simultaneously) so that their actions are coordinated with one another. Thus, the piezoelectric transducers can be arranged so that they impart longitudinal motion to the arm in the same direction, and the distance of translation can be proportional to the magnitude of the electric current applied to the piezoelectric transducers. The piezoelectric transducers employed in embodiments of the present application can be any of the following: a longitudinal piezoelectric actuator, in which the electric field in the ceramic is applied parallel to the ceramic polarization direction; a piezoelectric shear actuator, in which the electric field in the ceramic is applied orthogonal to the ceramic polarization direction; or a tube actuator, which is radially polarized and has electrodes applied to the outer surface of the ceramic so that the field parallel to the ceramic polarization also extends in the radial direction. Alternatively, the linear actuators 124a, 124b can employ lead screws that advance or retract according to control signals from the controller to move the arms 106a, 106b in the longitudinal dimension. Or, the linear actuators 124a, 124b can employ worm drives that activate according to control signals from the controller to move the arms 106a, 106b in the longitudinal dimension. The term "actuator" as used herein is intended to encompass various alternative devices for shifting the arms along the longitudinal dimension.

[0037] As mentioned, springs 118 are used to bias the rollers 104 toward the rollers 102, so as to maintain a constant gap width across the rollers' longitudinal dimension. When the associated linear actuators 124a, 124b begin to pull the rollers 104 away from the rollers 102, the respective springs 116 are used to bias the arms 106a, 106b away from the rollers 104 to avoid kickback, so as to widen the gap 20. Linear encoders 120 are mounted on the frame 10 to measure the position of each respective arm 106a, 106b. When the linear actuators 124a, 124b move the rollers 104, the system's "zero" position can be set to the position at which the linear encoders 120 first detect such motion. The width of the gap 20 is then determined by the amount of motion measured by the linear encoders 120 after that point. The system 100 is also equipped with two optical or other limit switches 122a, 122b. The limit switches 122a, 122b are used to identify the time at which each respective arm 106a, 106b has reached its starting position. The starting position can define a minimum, maximum, or other gap width between the rollers 102, 104.

[0038] As noted above, the coating of the layer 18 of material 110 on the film 112 occurs in the gap 20 between the rollers 102 and 104. The width of this gap 20 determines the thickness of the layer 18 of material, and is set by positioning the rollers 104 to a desired distance from the rollers 102 using the linear actuators 124a, 124b. The linear actuators 124a, 124b adjust the position of the arms 106a, 106b, which in turn set the position of the rollers 104 (e.g., relative to the rollers 102) through the biasing of the respective springs 118 (one spring per arm and parallel to one another). As an amount of material 110 is deposited upstream and adjacent to the gap 20, the film 112 is passed over the rollers 102 and the film 114 is passed over the rollers 104 opposite the film 112 (e.g., to remove any material residue from a previous coating, to recycle unused material 110, or for other purposes). As the film 112 is advanced through the gap 20 between the rollers 102, 104, the material 110 forms a layer 18 on the film 112 having a thickness equal to the gap width.

[0039] In some embodiments, the layer of material coated on the film 112 can be a mixture of two or more separate materials. Figures 5A-5CThis illustration shows one use of a well-defined gap 520 between rollers 502, 504 of a wireless variable gap width system 500 configured according to an embodiment of the invention for mixing multiple materials 510a, 510b during coating of a film 512 or other substrate. The ability to use gaps in such systems to mix two or more materials prior to printing can be particularly important when various materials react with each other and being dispensed together onto the film from a common dispenser (e.g., a syringe) could eventually clog or otherwise impair the dispenser's operation. By using the gap as a mixing point, each material is dispensed onto the film from its own dispenser, and any reactions between the materials occur on the film only prior to printing. In practice, this technique can be employed in other gap-based coating systems that do not utilize other aspects of the wireless variable gap width system described above; therefore, the provision of gap-based mixing arrangements should not be construed as limiting to such systems.

[0040] like Figure 5A As shown, system 500 includes two films 512, 514, each film rolling over a corresponding roller of a pair of rollers 502, 504 to create a known gap 520 between the rollers. The films and rollers of the system can be made of any material used in articles of this kind described herein. The film 512, on which a layer of material is coated, is distributed by an arrangement structure 550, in this example having a pair of feed rollers, but this is for illustrative purposes only and the details of the arrangement structure are not important to the present invention.

[0041] like Figure 5B As shown, upstream of gap 520 (viewed from the direction of travel of membrane 512), a certain amount of materials 510a and 510b are dispensed onto membrane 512. Materials 510a and 510b to be coated onto membrane 512 can be dispensed separately, for example, to avoid reaction within the co-dispenser, and refer to... Figure 5C The movement of the membrane 512 around the roller 502 draws the two materials together to form a single mixture 510c, which then forms a layer 518 on the outer surface of the membrane 512, wherein the width of the gap 520 determines the thickness of the layer 518. As the membrane 512 advances around the roller 502, the membrane 514 may advance around the roller 504 to remove any residual amount of mixture 510c from the area of ​​the gap 520, for example, to prevent gap blockage. The materials 510a, 510b used to form the mixture 510c can be any of those materials discussed above, and one or more materials may be replenished and / or replaced between successive coating processes, during which the gap 520 is widened so as not to displace the previously coated material layer 518 on the membrane 512.

[0042] Further, while maintaining a fixed gap width, the direction of travel of the coated film can be controlled such that the coated film with layer 518 thereon is pulled back through gap 520 and then the coated film is passed through gap 520 in the original direction in order to ensure that the material making up layer 518 is thoroughly mixed. Such a process can be repeated multiple times to achieve optimal levels of such mixing and to ensure uniform layer thickness on film 512. Alternatively, such bidirectional translation of film 512 through gap 520 can be performed while reducing the width of gap 520, e.g., using a biasing arm controlled by a linear actuator to position roller 504 relative to roller 502 as discussed above in order to produce layer 518 of a desired thickness.

[0043] This ability to mix materials in the gap and ensure a robust and reproducible printing process that provides a high quality layer of material coated on a film or other substrate is a direct result of the method for the printing process. Other printing techniques, such as inkjet or screen printing, cannot provide such assurances. Further, the present process also ensures that materials such as two components of an epoxy paste do not react with each other in the dispenser prior to printing, thereby extending the shelf life of the component materials. Mixing the components at the gap as in the present system is also less prone to clogging than other techniques because the gap can simply be made fresh by moving an uncoated film through the gap to remove any contaminants.

[0044] Reference is now made to Figures 6A-6D , Figure 7 and Figure 8 , showing another embodiment of a wireless variable gap width system 600 configured in accordance with yet another embodiment of the present application. In these illustrations, components that are the same as those discussed above with respect to wireless variable gap width system 100 are given similar reference numerals and will not be further described, except for components associated with air knives 602a, 602b included in wireless variable gap width system 600 for removing material. As mentioned above, gap 20 can become contaminated with unused material 110 when coating film 112. Some of the contaminants can be removed using second film 114, and this technique works well with relatively sticky materials. However, low viscosity materials can tend to flow freely when deposited upstream of gap 20, particularly when film 112 pulls such materials through gap 20, and thus to stop low viscosity materials from spilling over the film (e.g., in a direction orthogonal to the direction of travel of the film as it passes through the gap), air knives 602a, 602b can be used. That is, air pushed by air knives 602a, 602b can act as a physical barrier to low viscosity material flow beyond the boundaries of film 112, where the material can contaminate rollers 102, 104, e.g., on their sides opposite gap 20.

[0045] Figure 7It is further shown that air knives 602a, 602b are provided near the gap 20 between the rollers 102, 104 of a wireless variable gap width system configured in accordance with embodiments of the application, and Figure 8 A cross-sectional view of a pair of air knives 602a, 602b is shown near such a gap 20. Each air knife 602a, 602b produces an air flow at an angle of 0-180 degrees from the respective side of the propagating material film 112, and preferably at an angle of 70-110 degrees from that side. That is, the angle of the air flow can be directed from the respective side of the film from 0 degrees to 180 degrees by rotating the air knives relative to the frame 10 and / or by the design of the air flow channels within the air knives, but it is clear that an angle of 70-90 degrees will be most effective at preventing free flow of low viscosity materials.

[0046] The air knives 602a, 602b each include a threaded coupling 604 to which an air hose can be attached. For example, the threaded couplings 604 can be check valves that allow air flow in only one direction. In some embodiments, the threaded couplings 604 can be Schrader valves or Presta valves, either of which can have an associated valve stem 606 to direct air from an air hose or other air supply to an outlet 608 that is directed toward the area of the edge of the film 112 that will be passing near the gap 20. The air knives can be used in conjunction with any of the embodiments described herein.

[0047] Thus, the present application provides, in various embodiments, systems and methods that enable thin film coating of viscous materials or other materials at a desired thickness at low cost and high quality.

Claims

1. A coating system (100, 500, 600) comprising two films (112, 114, 512, 514) arranged to move adjacent to each other on outer surfaces of respective rollers (102, 104, 502, 504) positioned relative to each other to define a gap (20, 520) between the films (112, 114, 512, 514) which in turn defines a thickness of a layer (18, 518) of material to be coated onto one of the films (112, 114, 512, 514), wherein a first one (104, 504) of the rollers is positioned relative to a second one (102, 502) of the rollers by a bearing (144) biased by a first pair of parallel springs (118) and is adjustable in position relative to the second one (102, 502) of the rollers by a pair of linear actuators (124a, 124b) configured to translate respective arms (106a, 106b) supporting the first pair of parallel springs (118).

2. The coating system (100, 500, 600) of claim 1, further comprising: a second pair of parallel springs (116) arranged to bias the arms (106a, 106b) away from the first one (104, 504) of the rollers.

3. The coating system (100, 500, 600) of claim 1, further comprising: a pair of linear encoders (120) mounted to measure a position of each respective arm (106a, 106b), wherein an initial position of the system (100, 500, 600) is set to a position at which motion is first detected by the pair of linear encoders (120) as the pair of linear actuators (124a, 124b) move to adjust the position of the first one (104, 504) of the rollers by the arms (106a, 106b).

4. The coating system (100, 500, 600) of claim 3, wherein a width of the gap (20, 520) is determined as a distance measured by the pair of linear encoders (120) by movement of the arms (106a, 106b).

5. The coating system (100, 500, 600) of claim 3, further comprising: limit switches (122a, 122b) configured to identify a starting position of the arms (106a, 106b), wherein the limit switches (122a, 122b) are optical, electrical or mechanical limit switches.

6. The coating system (100, 500, 600) of any of the preceding claims 1-5, wherein the material is one of a paste, an adhesive or a polymer solution.

7. The coating system (100, 500, 600) of any of the preceding claims 1-5, wherein the material is a viscous material.

8. The coating system (100, 500, 600) of any of the preceding claims 1-5, wherein the material is a liquid.

9. The coating system (100, 500, 600) of any of the preceding claims 1-5, wherein the material is a low viscosity material.

10. The coating system (100, 500, 600) of any of the preceding claims 1-5, wherein the rollers (102, 104, 502, 504) are metal, ceramic, plastic, or rubber.

11. A coating method, comprising coating a first film (114, 514) with a layer of material (18, 518), moving the first film (114, 514) and a second film (112, 512) adjacent to each other over respective rollers (102, 104, 502, 504) through a gap (20, 520) between the rollers (102, 104, 502, 504), the gap (20, 520) defining a thickness of the layer of material (18, 518) on the first film (114, 514), such that an amount of the material deposited upstream from a direction of movement of the first and second films (112, 114, 512, 514) from the gap (20, 520) is drawn through the gap (20, 520), positioning a first roller (104, 504) of the respective rollers opposite a second roller (102, 502) of the respective rollers by biasing a bearing (144) supporting the first roller (104, 504) of the respective rollers by a first pair of parallel springs (118), and widening the gap (20, 520) between the rollers (102, 104, 502, 504) by moving the first roller (104, 504) of the respective rollers relative to the second roller (102, 502) of the respective rollers using a pair of linear actuators (124a, 124b) coupled to translate respective arms (106a, 106b) supporting the first pair of parallel springs (118), wherein the first film (114, 514) is conveyed over the first roller (104, 504) of the respective rollers and the second film (112, 512) is conveyed over the second roller (102, 502) of the respective rollers opposite the first film (114, 514).

12. The coating method of claim 11, wherein the second film (112, 512) is advanced with the first film (114, 514) to remove any residue from a previous coating or to recycle unused amounts of the material.

13. The coating method of claim 11 or 12, further comprising: Biasing the arms (106a, 106b) away from the first roller (104, 504) of the respective rollers by a second pair of springs (116) to avoid recoil when the pair of linear actuators (124a, 124b) translate the arms (106a, 106b).

14. The coating method of claim 13, further comprising: The position of the respective arm (106a, 106b) is measured during movement of the arm (106a, 106b) using a pair of linear encoders (120), a zero position is defined as the position at which the pair of linear encoders (120) first detect movement as the pair of linear actuators (124a, 124b) move the arm (106a, 106b), and a limit switch (122a, 122b) is used to identify when the arm (106a, 106b) has reached a start position.

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