Viscous material noncontact jetting system

Abstract

A viscous material noncontact jetting system has a jetting dispenser mounted for relative motion with respect to a surface. A control is operable to cause the jetting dispenser to jet a viscous material droplet that is applied to the surface as a viscous material dot. A device, such as a camera or weigh scale, is connected to the control and provides a feedback signal representing a size-related physical characteristic of the dot applied to the surface. The size-related physical characteristics of subsequently applied dots is controlled by heating and cooling, or adjusting a piston stroke in the jetting dispenser, in response to the size-related physical characteristic feedback. Dispensed material volume control and velocity offset compensation are also provided.

1 . A viscous material noncontact jetting system for applying a dot of viscous material onto a surface comprising: 
 a jetting dispenser having a nozzle adapted to be connected to a source of viscous material, the jetting dispenser being mounted for relative motion with respect to the surface;    a control operatively connected to the jetting dispenser and having a memory for storing a desired size-related physical characteristic of a dot of viscous material to be applied to the surface, the control being operable to command the jetting dispenser to apply dots of viscous material onto the surface;    a device connected to the control and providing a feedback signal to the control representing a detected size-related physical characteristic of the dots applied to the surface;    a temperature controller comprising a first device for increasing the temperature of the nozzle and a second device for decreasing the temperature of the nozzle, the control being operable to cause the temperature controller to change a temperature of the nozzle in response to a difference between the detected size-related physical characteristic and the desired size-related physical characteristic.    
   
   
       2 . The noncontact jetting system of  claim 1  wherein the size-related physical characteristic is determinative of a diameter of the dots applied to the surface.  
   
   
       3 . The noncontact jetting system of  claim 1  wherein the size-related physical characteristic is determinative of a volume of the dots applied to the surface.  
   
   
       4 . The noncontact jetting system of  claim 1  wherein the size-related physical characteristic is determinative of a weight of the dots applied to the surface.  
   
   
       5 . The noncontact jetting system of  claim 1  wherein the device is a camera.  
   
   
       6 . The noncontact jetting system of  claim 1  wherein the device is a weigh scale.  
   
   
       7 . The noncontact jetting system of  claim 1  wherein the temperature controller comprises: 
 a heater connected to the control, the control being operable to cause the heater to heat the nozzle in response to the detected size-related physical characteristic being less than the desired size-related physical characteristic; and    a cooler connected to the control, the control being operable to cause the cooler to cool the nozzle in response to the detected size-related physical characteristic being greater than the desired size-related physical characteristic.    
   
   
       8 . A method of dispensing a viscous material onto a surface with a jetting dispenser having a nozzle, the method comprising: 
 operating the jetting dispenser to apply dots of viscous material onto the surface;    determining a size-related physical characteristic of the dots applied to the surface;    operating one of a first device that increases the temperature of the nozzle or a second device that decreases the temperature of the nozzle in response to the size-related physical characteristic of the dots applied to the surface deviating from a desired value.    
   
   
       9 . The method of  claim 8  wherein the size-related physical characteristic is determinative of a weight of the dot applied to the surface.  
   
   
       10 . The method of  claim 8  wherein the size-related physical characteristic is determinative of a volume of the dot applied to the surface.  
   
   
       11 . The method of  claim 8  further comprising 
 increasing the temperature of the nozzle of the jetting dispenser with a first device in response to the size-related physical characteristic of the dots applied to the surface being less than the desired value; and    decreasing the temperature the nozzle of the jetting dispenser with a second device in response to the size-related physical characteristic of the dots applied to the surface being greater than the desired value.    
   
   
       12 . A method of dispensing a viscous material onto a surface comprising: 
 providing a desired size-related physical characteristic of a dot of viscous material to be applied to the surface;    causing relative motion between a dispenser and the surface;    operating the dispenser to apply dots of viscous material onto the surface;    generating feedback signals representing detected size-related physical characteristics of the dots on the surface;    operating one of a first device that increases the temperature of the nozzle or a second device that decreases the temperature of the nozzle in response to the detected size-related physical characteristics being different from the desired size-related physical characteristic.    
   
   
       13 . The method of  claim 12  wherein the size-related physical characteristics are determinative of respective diameters of the dots on the surface.  
   
   
       14 . The method of  claim 12  wherein the size-related physical characteristics are determinative of a volume of the dots on the surface.  
   
   
       15 . The method of  claim 12  wherein the size-related physical characteristics are determinative of a weight of the dots on the surface.  
   
   
       16 . A viscous material noncontact jetting system for applying dots of viscous material onto a surface comprising: 
 a jetting dispenser having a nozzle adapted to be connected to a source of viscous material, the jetting dispenser being mounted for relative motion with respect to the surface;    a control operatively connected to the jetting dispenser and being operable to command the jetting dispenser to apply dots of viscous material to the surface;    a device connected to the control and providing a feedback signal to the control representing a detected weight of dots applied to the surface;    a temperature controller operable to increase or decrease a temperature of the nozzle, the control being operable to cause the temperature controller to change the temperature of the nozzle in response to the detected weight of the dots applied to the surface being different from a desired value.    
   
   
       17 . A method of dispensing dots of viscous material onto a surface with a dispenser having a nozzle, the method comprising: 
 operating the dispenser to apply dots of viscous material onto the surface;    determining a weight of the dots applied to the surface;    changing the temperature of the nozzle in response to the weight of the dots applied to the surface deviating from a desired value.    
   
   
       18 . A viscous material noncontact jetting system for applying a dot of viscous material onto a surface comprising: 
 a jetting dispenser having a nozzle and a piston being reciprocable with respect to a seat, the jetting dispenser adapted to be connected to a source of viscous material and mounted for relative motion with respect to the surface;    a control operatively connected to the jetting dispenser and having a memory for storing a desired dot size value representing a desired size of a dot of viscous material to be applied to the surface, the control being operable to command the piston to move through a stroke away from a seat and the piston being movable through the stroke toward the seat to jet a droplet of viscous material through the nozzle, which is applied to the surface as a dot of viscous material;    a device connected to the control and providing a feedback signal to the control representing a size-related physical characteristic of the dot applied to the surface;    the control being operable to change the stroke of the piston in response to the feedback signal representing a size-related physical characteristic of the dot applied to the surface being different from the desired dot size value.    
   
   
       19 . The noncontact jetting system of  claim 18  wherein the size-related physical characteristic is determinative of a diameter of the dot applied to the surface.  
   
   
       20 . The noncontact jetting system of  claim 18  wherein the size-related physical characteristic is determinative of a volume of the dot applied to the surface.  
   
   
       21 . The noncontact jetting system of  claim 18  wherein the size-related physical characteristic is determinative of a weight of the dot applied to the surface.  
   
   
       22 . The noncontact jetting system of  claim 18  wherein the device is a camera.  
   
   
       23 . The noncontact jetting system of  claim 18  wherein the device is a weigh scale.  
   
   
       24 . A method of dispensing a viscous material onto a surface with a jetting dispenser having a piston reciprocable with respect to a seat, the method comprising: 
 withdrawing the piston through a stroke away from the seat;    moving the piston through the stroke toward the seat to jet a droplet of viscous material through the nozzle, which is applied to the surface as a dot of viscous material;    determining a physical characteristic of the dot applied to the surface;    increasing or decreasing the stroke of the piston in response to the physical characteristic being respectively, less than, or greater than, a desired value; and    iterating the steps of withdrawing, moving, determining and increasing or decreasing the stroke of the piston to apply a plurality of dots to the surface and maintain the physical characteristic of the plurality of dots close to the desired value.    
   
   
       25 . A method of dispensing a viscous material onto a surface with a jetting dispenser having a piston reciprocable with respect to a seat, the method comprising: 
 providing a desired size-related physical characteristic value representing a desired size-related physical characteristic of a dot of viscous material to be applied to the surface;    causing relative motion between the jetting dispenser and the surface;    applying dots of viscous material to the surface by iteratively withdrawing the piston through a stroke away from the seat and then moving the piston through the stroke toward the seat to jet a droplet of viscous material through the nozzle;    generating feedback signals to the control representing size-related physical characteristics of the dots applied to the surface;    changing the stroke of the piston in response to the feedback signals representing an average size-related physical characteristic different from the desired size-related physical characteristic value.    
   
   
       26 . The method of  claim 25  wherein the size-related physical characteristics are determinative of a diameter of the dots applied to the surface.  
   
   
       27 . The method of  claim 25  wherein the size-related physical characteristics are determinative of a weight of the dots applied to the surface.  
   
   
       28 . The method of  claim 25  wherein the size-related physical characteristics are determinative of a volume of the dots applied to the surface.  
   
   
       29 . A viscous material noncontact jetting system for applying dots of viscous material onto a surface comprising: 
 a jetting dispenser having a nozzle and a piston being reciprocable with respect to a seat, the jetting dispenser adapted to be connected to a source of viscous material and mounted for relative motion with respect to the surface; and    a control operatively connected to the jetting dispenser and having a memory for storing a table with values relating dot sizes to respective operating parameters, each operating parameter causing the jetting dispenser to dispense a respective dot size of viscous material on the surface, the control being operable to command the piston to move through a stroke away from a seat and the piston being movable through the stroke toward the seat to jet a droplet of viscous material through the nozzle, which is applied to the surface as a dot of viscous material, the control being further operable to select from the table a first operating parameter causing the jetting dispenser to dispense a number of first dots of a first dot size on the surface and thereafter, to select from the table a second operating parameter causing the jetting dispenser to dispense a number of second dots of a second dot size on the surface.    
   
   
       30 . The noncontact jetting system of  claim 29  wherein each operating parameter is one of temperature, stroke of the piston or operating pulse on-time.  
   
   
       31 . A method of dispensing a viscous material onto a surface with a jetting dispenser having a piston reciprocable with respect to a seat, the method comprising: 
 providing a table of values relating dot sizes to respective operating parameters, each operating parameter causing a dispensing of a respective dot size of viscous material on the surface;    utilizing a first operating parameter from the table corresponding to a first dot size;    applying a first number of viscous material dots of the first dot size to the surface by iteratively withdrawing the piston through a stroke away from the seat and then moving the piston through the stroke toward the seat to jet a droplet of viscous material through the nozzle;    utilizing a second operating parameter from the table corresponding to a second dot size; and    applying a second number of viscous material dots of the second dot size to the surface by iteratively withdrawing the piston through a stroke away from the seat and then moving the piston through the stroke toward the seat to jet a droplet of viscous material through the nozzle.    
   
   
       32 . The method of  claim 31  wherein each operating parameter is one of temperature, stroke of the piston or operating pulse on-time.  
   
   
       33 . The method of  claim 31  wherein the surface is a substrate and the method further comprises applying the first number of viscous material dots to one portion of the substrate and applying the second number of viscous material dots to the one portion of the substrate.  
   
   
       34 . The method of  claim 31  wherein the surface is a substrate and the method further comprises applying the first number of viscous material dots to one portion of the substrate and applying the second number of viscous material dots to a second, different portion of the substrate.  
   
   
       35 . A viscous material noncontact jetting system for applying dots of viscous material onto a surface, the jetting system comprising: 
 a jetting dispenser having a nozzle and adapted to be connected to a source of viscous material, the jetting dispenser being mounted for relative motion with respect to the surface;    a control operatively connected to the jetting dispenser and having a memory for storing a total volume value representing a total volume of the viscous material to be dispensed and a length value representing a length overwhich the total volume of viscous material is to be dispensed, the control being operable to execute a calibration cycle by commanding the jetting dispenser to apply a number of dots of viscous material to the surface;    a device connected to the control and providing a feedback signal to the control representing an amount of the viscous material contained in the dots applied to the surface, the control being responsive to the feedback signal, the volume value and the length value to determine a maximum velocity value for the relative motion between the jetting dispenser and the surface resulting in the total volume of material being dispensed over the length.    
   
   
       36 . The noncontact jetting system of  claim 35  wherein the device is a weigh scale.  
   
   
       37 . A method of dispensing a viscous material onto a surface with a dispenser operatively connected to a control, the method comprising: 
 providing a total volume value representing a total volume of the viscous material to be dispensed and a length value representing a length over which the total volume of viscous material is to be dispensed;    operating the dispenser to apply a number of viscous material dots to the surface;    generating a feedback signal to the control representing an amount of the viscous material contained in the number of viscous material dots applied to the surface;    determining a maximum velocity of relative motion between the dispenser and the surface resulting in the total volume of viscous material being dispensed over the length.    
   
   
       38 . The method of  claim 37  wherein determining a maximum velocity further comprises: 
 determining a volume of viscous material dispensed in each of the number of viscous material dots;    determining a total number of dots required to substantially equal the total volume of viscous material represented by the total volume value;    determining a distance between each of the total number of dots required to substantially uniformly distribute viscous material dots over the length represented by the length value; and    determining a maximum relative velocity between the dispenser and the surface resulting in the total number of viscous material dots being substantially uniformly dispensed over the length.    
   
   
       39 . The method of  claim 37  wherein determining a maximum velocity further comprises: 
 determining a volume of viscous material dispensed in each of the number of viscous material dots;    determining a total number of dots required to substantially uniformly dispense the total volume of viscous material represented by the total volume value;    determining a distance between each of the total number of dots required to substantially uniformly distribute the viscous material dots over the length represented by the length value; and    determining a dot rate value representing a rate at which the viscous material dots are to be dispensed from the dispenser to dispense the total volume of viscous material over the length at the maximum relative velocity.    
   
   
       40 . A viscous material noncontact jetting system for applying a dot of viscous material onto a surface comprising: 
 a jetting dispenser having a nozzle and adapted to be connected to a source of viscous material, the jetting dispenser being mounted for relative motion with respect to the surface;    a control operatively connected to the jetting dispenser and having a memory for storing an offset value, the control operating the jetting dispenser at a first location to apply a dot of viscous material onto the surface;    a camera connected to the control and providing a feedback signal to the control representing a location of a physical characteristic of the dot on the surface;    the control being operable to determine a location of the dot on the surface and then, to determine an offset value representing a difference between the first location and the location of the dot on the surface.    
   
   
       41 . A method of dispensing a viscous material onto a surface with a jetting dispenser operatively connected to a control, the method comprising: 
 providing first coordinate values representing a position of the jetting dispenser at which the jetting dispenser is operable to apply a dot of viscous material onto the surface;    moving the jetting dispenser at a relative velocity with respect to the surface;    operating the dispenser to apply a viscous material dot onto the surface;    detecting the viscous material dot with a camera;    generating a feedback signal representing a location of a physical characteristic of the viscous material dot on the surface;    determining second coordinate values representing a position of the viscous material dot on the surface; and    determining an offset value representing a difference between the first coordinate values and the second coordinate values, the offset value being used to modify the first coordinate values during a subsequent application of a viscous material dot onto the surface.    
   
   
       42 . A method of dispensing a viscous material onto a surface with a jetting dispenser operatively connected to a control, the method comprising: 
 moving the jetting dispenser at a relative velocity with respect to the surface;    operating the jetting dispenser to dispense a viscous material dot onto the surface;    storing first coordinate values representing a position of the jetting dispenser upon operating the jetting dispenser;    storing second coordinate values representing a position of the viscous material dot on the surface;    determining an offset value representing a difference between the first coordinate values and the second coordinate values, the offset value being used to modify the first coordinate values during a subsequent operation of the jetting dispenser.    
   
   
       43 . A method of dispensing a viscous material onto a surface with a jetting dispenser operatively connected to a control, the method comprising: 
 (a) moving the jetting dispenser at a first velocity in a first direction with respect to the surface;    (b) operating the jetting dispenser at a first position with respect to the surface to apply a first viscous material dot onto the surface;    (c) moving the jetting dispenser at a second velocity in a second direction with respect to the surface;    (d) operating the jetting dispenser at a second position with respect to the surface to apply a second viscous material dot to the surface;    (e) determining a distance between the first viscous material dot and the second viscous material dot;    (f) determining an offset value for the first relative position.    
   
   
       44 . The method of  claim 43  wherein the second direction is opposite the first direction.  
   
   
       45 . The method of  claim 44  wherein the first relative velocity is equal to the second relative velocity.  
   
   
       46 . The method of  claim 43  further comprising 
 (a) moving the jetting dispenser at a first velocity in a first direction with respect to the surface;    (b) operating the jetting dispenser at the first position as modified by the offset value to apply another viscous material dot to the surface;    (c) moving the jetting dispenser at a second velocity in a second direction with respect to the surface;    (d) operating the jetting dispenser at the second position to apply a further viscous material dot to the surface;    (e) determining a distance between the other viscous material dot and the further viscous material dot;    (f) determining an offset value for the first relative position such that the distance between the other viscous material dot and the further viscous material dot is reduced during subsequent iteration of steps (a) through (d); and    iterating steps (a)-(f) until the distance between the other viscous material dot and the further viscous material dot is equal to a desired value.