Systems and methods for applying a liquid coating material to a substrate

Abstract

Systems and methods for applying liquid coating materials to a substrate, such as an electronic component or circuit board. A control system ( 18, 24, 26 ) of a coating system ( 10 ) controls an applicator ( 16 ) and a robot ( 14 ) moving the applicator ( 16 ) to apply the liquid coating material to the substrate ( 12 ) in accordance with the information contained in a coating program. The control system ( 18, 24, 26 ) determines a volume of liquid coating material actually dispensed onto the substrate ( 12 ) during the coating program, and compares the dispensed volume to a desired dispensed volume of liquid coating material to produce an error signal representing the difference between the calculated and desired volume values. The control system ( 18, 24, 26 ) uses the error signal to change the dispensed volume of liquid coating material on a subsequent substrate by a future coating program.

1 . A system for applying a liquid coating material to a substrate as determined by a coating program, the system comprising:
 a reservoir containing the liquid coating material;   an applicator configured to receive the liquid coating material from the reservoir and configured to dispense the liquid coating material onto the components or areas of the substrate;   a meter configured to generate volume signals representing the volumes of liquid coating material flowing to the applicator;   a robot mechanically coupled with the applicator, the robot configured to move the applicator relative to the substrate; and   a control system configured to access the coating program, the control system configured to control the robot and the applicator to apply the liquid coating material to the substrate in accordance with information in the coating program, wherein at completion of the coating program, the control system configured to utilize one or more volume signals from the meter to determine a dispensed volume of the liquid coating material applied to the substrate during the coating program, the control system configured to compare the dispensed volume to a desired dispensed volume of the liquid coating material for the coating program and to produce an error signal representing a difference between the dispensed volume and the desired dispensed volume, and the control system configured to reduce the difference between the dispensed volume of the liquid coating material on a subsequent substrate and the desired dispensed volume based on the error signal.   
   
   
       2 . The system of  claim 1  wherein the control system is configured to implement an inner control window and an outer control window in response to the error signal. 
   
   
       3 . The system of  claim 2  wherein the control system is configured to take no action if the error signal is within the inner control window. 
   
   
       4 . The system of  claim 2  wherein the control system is configured to generate an alarm if the error signal is outside of the outer control window. 
   
   
       5 . The system of  claim 2  wherein the control system is configured to stop the system if the error signal is outside of the outer control window. 
   
   
       6 . The system of  claim 1  further comprising:
 a regulator configured to regulate a flow of the liquid coating material from the reservoir to the applicator, the regulator electrically coupled with the control system, and the control system is configured to manipulate the regulator to modify the flow for changing the dispensed volume of the liquid coating material on the subsequent substrate.   
   
   
       7 . The system of  claim 1  further comprising:
 a heater configured to regulate the temperature of the liquid coating material dispensed by the applicator, the heater electrically coupled with the control system, and the control system is configured to manipulate the heater to change the dispensed volume of the liquid coating material on the subsequent substrate.   
   
   
       8 . The system of  claim 1  wherein the control system is configured to adjust a velocity at which the robot moves the applicator relative to the substrate to change the dispensed volume of the liquid coating material on the subsequent substrate. 
   
   
       9 . A method of applying liquid coating material to a substrate as determined by a coating program, the method comprising:
 dispensing the liquid coating material from an applicator to the substrate as directed by the coating program;   moving the applicator relative to the substrate while the liquid coating material is dispensed;   determining a dispensed volume of the liquid coating material applied to the substrate;   comparing the dispensed volume to a desired dispensed volume of the liquid coating material for the coating program;   producing an error signal representing the difference between the dispensed volume and the desired dispensed volume; and   changing the dispensed volume of the liquid coating material applied to a subsequent substrate based upon the error signal.   
   
   
       10 . The method of  claim 9  wherein changing the dispensed volume of the liquid coating material further comprises:
 regulating the flow of the liquid coating material to the applicator with a regulator.   
   
   
       11 . The method of  claim 9  wherein determining the dispensed volume further comprises:
 generating volume signals representing volumes of liquid coating material flowing to the applicator; and   determining the dispensed volume based upon at least one of the volume signals.   
   
   
       12 . The method of  claim 9  further comprising:
 communicating the volume signals to a controller that determines the dispensed volume, compares the dispensed volume to the desired dispensed volume, and produces the error signal; and   communicating a control signal to a regulator for changing the dispensed volume of the liquid coating material on the subsequent substrate.   
   
   
       13 . The method of  claim 9  wherein changing the dispensed volume of the liquid coating material further comprises:
 implementing an inner control window for changing the dispensed volume; and   taking no action if the error signal is within the inner control window.   
   
   
       14 . The method of  claim 9  wherein changing the dispensed volume of the liquid coating material further comprises:
 implementing an outer control window for changing the dispensed volume; and   generating an alarm if the error signal is outside of the outer control window   
   
   
       15 . The method of  claim 9  wherein changing the dispensed volume of the liquid coating material further comprises:
 implementing an outer control window for changing the dispensed volume; and   stopping the flow of liquid material to the applicator if the error signal is outside of the outer control window.   
   
   
       16 . The method of  claim 9  wherein changing the dispensed volume of the liquid coating material further comprises:
 adjusting a temperature of the liquid coating material based upon the error signal when dispensing the liquid coating material onto another substrate.   
   
   
       17 . The method of  claim 9  wherein changing the dispensed volume of the liquid coating material further comprises:
 adjusting a velocity at which the applicator is moved relative to the substrate when dispensing the liquid coating material onto another substrate.