Patent ID: 12214377

DETAILED DESCRIPTION

A detailed description of the hereinafter described embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. Although certain embodiments are shown and described in detail, it should be understood that various changes and modifications may be made without departing from the scope of the appended claims. The scope of the present disclosure will in no way be limited to the number of constituting components, the materials thereof, the shapes thereof, the relative arrangement thereof, etc., and are disclosed simply as an example of embodiments of the present disclosure.

As a preface to the detailed description, it should be noted that, as used in this specification and the appended claims, the singular forms “a”, “an” and “the” include plural referents, unless the context clearly dictates otherwise.

In brief overview, embodiments of the present invention relate to a coating machine that leverages sensor data to automatically adjust a coating process if an error is detected. The sensor measures a characteristic of the applied coating, such as a thickness of the applied coating, and sends the sensor data to a controller/computer for processing. The sensor data is processed to determine whether the applied coating is within an acceptable tolerance of a desired specification (e.g. desired thickness). If the controller/computer determines that the thickness of the applied coating exceeds the acceptable tolerance, the controller adjusts one or more parameters of the coating machine to reduce or increase an amount of coating material to be applied, thereby brining the thickness of the applied coating within the acceptable tolerance of the desired specification. The coating machine is configured to coat a sequence of substrates, and by leveraging the sensor data to automatically adjust the coating process, a number of substrates exposed to errors in the coating process are substantially reduced. In many cases, the error is detected, and associated adjustments are made prior to coating a subsequent substrate.

Advantageously, the sensor is disposed proximate to a dispensing device for more immediate error detection and corrective action. Instead of ejecting the substrate from the dispensing component of the coating machine for remote inspection of the applied coating material, the sensor located in the same vicinity as the dispensing device inspects the applied coating and sends the data for processing prior to the substrate leaving the vicinity of the dispensing device. In this way, any error can be detected much sooner than if the substrate was passed to another assembly line or remote component for inspection while another substrate is loaded in the coating machine. Quicker error detection means that the necessary adjustments to the coating machine are completed earlier in the coating process, which reduces delays in coating subsequent substrates and reduces the number of subsequent substrates being coated in error prior to the adjustment. Moreover, the proximal location of the sensor to the dispensing device allows for touch-ups or additional dispensing to the current substrate, eliminating the need to discard the substrate.

Referring now to the drawings,FIG.1depicts a coating machine100, in accordance with embodiments of the present invention. The coating machine100is a machine configured to dispense, apply, or otherwise coat a substrate5with a coating material. In an exemplary embodiment, the coating machine100is a conformal coating machine configured to apply a conformal coating to a substrate5, such as a printed circuit board. The coating machine100is defined by a housing6made up of a plurality of frame members, panels, and access points. The panels attached to the frame may be a combination of both solid panels and see-through panels, such as Plexiglas®, glass, plastic, and the like, to allow operational viewing. Moreover, coating machine100is a discrete unit but other discrete units having other functions (e.g. curing) can be coupled to the coating machine100to complete the conformal coating process.

The housing6has in internal region containing both a dispensing device10and an inspection device20and is suited for receiving a sequence of substrates5as part of a coating process; there could be a single substrate within the housing6or more than one discrete substrates located within the housing6for receiving a coating material. Optionally, the coating machine100includes a display unit12for displaying operational data, such as flow pattern characteristics, sequences, status updates, output volume, component data, and the like.

The dispensing device10located within the housing6of the coating machine100is configured to dispense the coating material onto a surface of the substrate5or a sequence of substrates moved through the coating machine100; the entire surface of the substrate5can be coated or one or more target areas of the substrate5can be coated. The coating material may be a fluid, a liquid, or other viscous material suitable for coating electronics or other components needing proper coating. The dispensing device10includes a dispenser17to dispense the coating material onto the substrate5. The dispenser17is operably attached to an end effector14located within the coating machine100. The end effector14can be used with an X-axis actuator, a Y-axis actuator, and/or a Z-axis actuator for achieving movement in one or more axes. The machine housing or other component element(s) receiving the end effector may utilize a robotic platform to perform automated tasks with accuracy, precision, and repeatability. For example, the machine may be a Gantry robot having a plurality of principal axes (Cartesian coordinates) controlling linear motion, wherein the horizontal member(s) may be supported at both ends. The machine may also be any robotic manipulator such as a selective compliant assembly robot arm (SCARA) system, linear robot, multi-axis robot arm system, and the like. However, an embodiment of the machine will be described as utilizing a Gantry robot for exemplary purposes. The end effector14may refer to any device(s) attached to a X, Y, Z or other axis of movement to perform a variety of tasks, such as dispensing, picking and placing, routing, coating, and the like. For instance, end effector14is capable of rotation about the Z axis, and may move left and right along the Y axis by sliding along the Y axis actuator, and move back and forth along the X axis by sliding with the Y axis actuator as it slides along the X axis actuator. Additionally, the end effector14may move up and down on the Z-axis by sliding along the Z-axis actuator. The X-axis actuator, the Y-axis actuator, and the Z-axis actuator may be a ball screw slide, linear motion slide, a linear actuator, and the like. In some embodiments, the end effector14may also allow for a tilting of the dispenser17to dispense the coating material at various angles with respect to the substrate5.

The dispenser17may be referred to as a valve or more particularly a dispensing valve and may be a device, an apparatus, valve, mixing valve, two-part spray head, dual-component spray valve, or any component or system that is configured to deliver a fluid on a surface, edge, and/or perimeter of a substrate. The dispenser17is operably connected to a regulator and a fluid supply. In an exemplary embodiment, the regulator12and the fluid supply (not shown) are in fluid communication with the dispenser17. The regulator12and other components of the dispenser17are mechanically connected in a manner that facilitates the dispensing and regulating of a fluid from the dispenser17. The regulator12controls, adjusts, regulates, etc. a pressure of the coating material being dispensed from the dispenser17. Embodiments of the regulator12may be a pneumatically controlled regulator or an electropneumatical regulator. Further, a pump is associated with the fluid supply and is operated to effectuate a change in pump output. For instance, a pump, such as a gear pump, may be used to increase or decrease a pump speed through the dispenser17.

In one embodiment, progressive pumps with an integrated spray cap for selective application of reactive materials can also be used with the dispenser17. For instance, the dispenser17may selectively coat a circuit board (e.g. coat some areas of the circuit board and not others) by spraying a reactive material, mixed by a mixing element of the dispenser, onto the target substrate, wherein the reactive material is atomized prior to exiting the nozzle. An integrated air cap allows for a control of the atomized reactant material for selective applications.

With continued reference toFIG.1, the inspection device20is integrated with the dispensing device10. The inspection device20being integrated with the dispensing device10means that the inspection device20is disposed close enough to the dispensing device20so that an inspection of the applied coating by the dispensing device10can be performed by the inspection device20without requiring a movement of the substrate5. For example, the inspecting occurs while the substate5is in a same position within the coating machine100, after the dispensing. While movement of the substrate5is not required for inspection by the inspection device20, the substrate5can be moved, repositioned, or otherwise manipulated within the housing6after dispensing of the coating material and prior to the inspecting. The substrate5may also be moved during the inspection by the inspection device5. In this way, the inspecting occurs prior to the substrate5exiting the coating machine100for more immediate error detection and corrective action, as described supra.

Various configurations of the coating machine100exist to integrate the inspection device20to the dispensing device17within the coating machine100. As shown inFIG.1, the inspection device20is coupled to the dispensing device10within the housing6so that each component is located within the housing6of the coating machine100. The inspection device20is physically attached to the end effector14, which is a part of the dispensing device10. Movement of the end effector14results in movement of both the inspection device20and the dispenser17. In another embodiment, the inspection device20can be attached to the end effector14via a bridge or linking element, such as a bar or plate attached to the end effector14on one end and the inspection device20on the other end. In another embodiment, the coating machine100includes a second end effector within the housing6to which the inspection device20is attached; the second effector can be controlled similar to end effector14and can be used to movably position the inspection device20with respect to the substrate5and/or the dispensing device10. In another embodiment, the inspection device20can be mounted the frame of the coating machine100at a location within the housing6to inspect the applied coating dispensed by the dispensing system10. Other configurations may be used to dispose the inspection device20proximate the dispensing device10. Each configuration integrates the inspection device20with the dispensing device10so that the applied coating material can be inspected by the inspection device20without requiring an ejection of the substrate5.

The inspection device20is one or more sensors configured to perform an inspection of the coating material applied to at least one substrate of the sequence of substrates. For example, the inspection device20measures a thickness of the coating material applied to the substrate5and/or detects a placement of the coating material in one or more target areas of the substrate5. The data captured by the inspection device20is transmitted to a controller coupled to the coating machine100, the dispensing device10, and the inspection device20, which is used to make adjustments to the coating machine100, as described in greater detail infra. In an exemplary embodiment, the inspection device20is a spectral interference laser sensor capable of providing accurate measurements of the thickness of the applied coating material in one or more target areas of the substrate5, or the entire surface of the substrate. Other embodiments of the inspection device20include confocal laser, a displacement laser, 3D scanner, and the like.

Referring now toFIG.2, the coating machine100includes a controller30. The controller30is configured to adjust at least one parameter of the coating machine100based on the inspection by the inspection device20. Sensor data is transmitted to the controller30from the inspection device20to be analyzed for taking corrective actions impacting a dispensing operation of the dispenser17. The controller30generates and sends control signals to one or more components of the coating machine100that impact or otherwise modify the dispensing operation of the dispenser17, based on the received sensor data from the inspection device. The control signals issued by the controller30adjust at least one parameter of the dispensing device10and/or the coating machine100. The at least one parameter of the dispensing device10and/or coating machine100includes a pump speed, a fluid pressure, an orifice opening, a valve stroke, a travel speed, and a coating position. A single parameter can be adjusted or a combination of parameters can be adjusted by the controller. As example, the controller30can increase the pump speed of the dispensing device10to deliver a volume of coating material to the dispensing device10at faster intervals, increase the pump speed of the dispensing device10to deliver a volume of coating material to the dispensing device10at slower intervals, reduce the orifice opening of a nozzle of the dispensing device10to reduce a flow rate of the coating material to be dispensed from the dispenser17, increase the orifice opening of the nozzle of the dispensing device10to increase the flow rate of the coating material to be dispensed from the dispenser17, decrease a travel speed of the end effector14so that a larger amount of coating material is applied per pass of a target area of the substrate, and/or increase the travel speed of the end effector14so that a smaller amount of coating material is applied per pass of the target area of the substrate. Other adjustments can be made to the dispensing device10, end effector14, the dispenser17, components associated with the dispenser17, and the coating machine100that will impact the thickness of the coating material applied to the substrate.

The controller30includes an error detection module31and an adjustment module32. A “module” refers to a hardware based module, software based module or a combination of hardware and software. Embodiments of hardware based modules include self-contained components such as chipsets, specialized circuitry and one or more memory devices, while a software-based module is part of a program code or linked to the program code containing specific programmed instructions, which are loaded in the memory device of a computer system associated with the coating machine100. A module (whether hardware, software, or a combination thereof) is designed to implement or execute one or more particular functions or routines. The error detection module31includes one or more components of hardware and/or software program code for detecting an error between a desired coating property (e.g. desired thickness) and an actual coating property (e.g. measured thickness). In an exemplary embodiment, the error detection module31compares the thickness measured by the inspection device20to a preset tolerance. The preset tolerance is a ±range that is an acceptable deviation from the desired thickness, or other coating property being measured. The error detection module31determine whether the thickness measured by the inspection device20exceeds the preset tolerance surrounding a desired thickness. If the error detection module31determines that the measured coating property does not exceed the preset tolerance, then no adjustments to the coating machine100are required. If the error detection module31determines that the measured coating property exceeds the preset tolerance, then the adjustment module32calculates the necessary adjustments to the coating machine100required to reduce the deviation from the desired coating property. Once the necessary adjustments are calculated (e.g. orifice opening of the nozzle needs to be reduced, travel speed of the end effector needs to be increased, etc.), the adjustment module32generates command signals and sends the command signals to the components of the coating machine100to effectuate the physical changes to the mechanical components of the coating machine100.

The controller30is coupled to the components of the coating machine100via a data bus line, as shown inFIG.2. However, the controller30can also be connected to the coating machine100and components thereof over a network2, as depicted inFIG.3. The network2refers to a group of two or more computer systems linked together. Network2may be any type of computer network known by individuals skilled in the art. Examples of computer network2include a LAN, WAN, campus area networks (CAN), home area networks (HAN), metropolitan area networks (MAN), an enterprise network, cloud computing network (either physical or virtual) e.g. the Internet, a cellular communication network such as GSM or CDMA network or a mobile communications data network. The architecture of the computer network2may be a peer-to-peer network in some embodiments, wherein in other embodiments, the network2may be organized as a client/server architecture.

A method200for controlling the coating machine100, or a dispensing system, will now be described with reference toFIG.4. At step201, the dispensing device10dispenses a coating material onto a first substrate in a sequence of substrates to be moved through the coating machine, according to a first dispensing operation. The first dispensing operation is a programmed dispensing of coating material onto the substrate5to achieve a desired coating thickness with initial coating machine/dispensing device parameters set accordingly; a combination of pump speed, orifice opening, robot travel speed, and flow rate can be used to achieve a specific coating thickness. For example, the first dispensing operation sets a pump speed value, an orifice opening value, a robot travel speed value, and a flow rate value to achieve a coating thickness of 125 microns (˜0.005″) on a substrate. The coating material is dispensed onto the substrate according to the first dispensing operation. At step202, the inspection device20inspects the coating material applied to the substrate5by measuring the coating thickness of the applied coating material. A spectral interference laser sensor measures the thickness of the applied coating material and transmits the sensor data to the controller. The inspecting step occurs prior to the first substrate exiting the dispensing system; the first substrate as used herein does not necessarily mean the first substrate in the sequence of substrates but the first substrate to be inspected. At step203, the first dispensing operation is altered based on the inspecting so that the coating material is dispensed onto a subsequent substrate according to a second dispensing operation. The controller processes the sensor data to determine if there is an error in the first dispensing operation. For example, the controller determines whether the measured coating thickness deviates from the desired coating thickness beyond a preset tolerance. In the event of an error detection, one or more parameters of the coating machine are adjusted to create a second dispensing operation. The second dispensing operation is a programmed dispensing of coating material onto the substrate5to achieve the desired coating thickness with updated and/or modified coating machine/dispensing device parameters; a combination of pump speed, orifice opening, robot travel speed, and flow rate can be used to achieve a specific, modified coating thickness. For example, the second dispensing operation sets a pump speed value, an orifice opening value, a robot travel speed value, a flow rate value, in which one or more of these values varies from the first dispensing operation, to achieve a coating thickness of approximately 75 microns (˜0.003″) on the substrate. At step204, the first substrate is either ejected from the coating machine and a subsequent substrate is coated according to the second dispensing operation, or the first substrate is touched up to achieve the desired thickness and then ejected from the coating machine.

FIG.5depicts a flow chart of a method300for controlling a coating machine. At step301, a coating material is dispensed onto a substrate received by the coating machine. At step302, a thickness of the coating material applied to the substrate is measured with a sensor disposed proximate a dispensing device within the coating machine. At step303, an error in the thickness of the coating material is determined. At step304, at least one parameter of the dispensing system is adjusted to correct the error. At step305, a corrective action is performed in response to the adjusting. In one embodiment, the corrective action is dispensing additional coating material onto the substrate and obtaining a subsequent thickness measurement according to the previous steps. In another embodiment, the corrective action includes ejecting the substrate from the dispensing system and dispensing the coating material onto a subsequent substrate entering the dispensing system.

FIG.6depicts a more detailed flow chart of a method400of a closed loop thickness control. At step401, the coating process is started. At step402, an uncoated substrate enters the coating machine. At step403, a coating process is performed to coat the uncoated substrate. At step404, coating thickness measurements are performed. At step405, the coating thickness measurement is compared with a preset tolerance. Step406determines whether the difference between the measured thickness and the desired thickness is outside a tolerance range. If no, step407determines whether the substrate is the last substrate in the sequence of substrates of the coating process. If the measured substrate is the last substrate in the sequence, the coating process is ended. If the measured substrate is not the last substrate in the sequence, the method400returns to step401. If yes to step406, step408adjusts one or more parameter of the coating machine. Step409determines whether the measured substrate should be touched-up (e.g. add additional coating material to one or more target areas). If yes, then the coating process returns to step403. If no, the coating process proceeds to step407. The coating process ends at step410.

While this disclosure has been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the present disclosure as set forth above are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention, as required by the following claims. The claims provide the scope of the coverage of the invention and should not be limited to the specific examples provided herein.