Applicator of coating product, multiaxis robot comprising such an applicator and application method of a coating product

Abstract

An applicator making it possible to apply a coating product on a surface to be coated, including at least one row of nozzles, among which at least the first nozzle in the row includes a valve, the applicator further including at least one distance sensor, to measure an application distance of the first nozzle from a point in front of the latter on a path of the applicator, and an electronic control unit of the valve, which is programmed to collect the distance measured by the distance sensor and, based on the collected distance value, to open or close the valve.

1 . An applicator of a coating product on a surface to be coated, including at least one row of nozzles, among which at least a first nozzle in the row includes a valve, wherein the applicator further comprises:
 at least one distance sensor, to measure an application distance of the first nozzle from a point in front of the first nozzle on a path of the applicator, and   an electronic control unit of the valve, which is programmed to carry out the following steps:
 i) collect a distance measured by the distance sensor, and 
 ii) based on the distance collected in step i), open or close the valve. 
   
     
     
         2 . The applicator according to  claim 1 , wherein each nozzle in the row comprises a valve, and wherein the distance sensor is able to measure the application distance of at least certain nozzles in the row at respective points in front of the latter on the path of the applicator. 
     
     
         3 . The applicator according to  claim 2 , wherein the distance sensor is a laser sensor, comprising a cell emitting a laser beam and a cell receiving a reflected laser beam, and wherein the distance sensor is able to scan, with its beam, a line perpendicular to a movement direction of the applicator, so as to measure the application distance of at least certain nozzles in the row, at points in front of the latter on the path of the applicator. 
     
     
         4 . The applicator according to  claim 1 , wherein each valve is a piezoelectric valve, a flow rate of which depends on an excitation frequency of the valve. 
     
     
         5 . The applicator according to  claim 1 , wherein the electronic control unit is programmed to close the valve of the first nozzle when the distance measured by the distance sensor is greater than a reference value. 
     
     
         6 . The applicator according to  claim 1 , wherein it further comprises at least one thickness measuring sensor, configured to respectively measure the thickness of a film of coating product applied by the nozzles at points withdrawn relative to those on the path of the applicator. 
     
     
         7 . The applicator according to  claim 6 , wherein the applicator comprises another row of nozzles, positioned on a delay relative to each thickness measuring sensor on the path of the applicator. 
     
     
         8 . A multiaxis robot, comprising a moving arm on which an applicator according to  claim 1  is mounted. 
     
     
         9 . A method of applying a coating product on a surface of a part, this method being carried out using an applicator comprising at least one row of nozzles, among which at least the first nozzle in the row includes a valve, the method comprising the following steps:
 a) moving the applicator in a first direction to apply a first layer of coating product, and   b) moving the applicator in a second direction substantially parallel to the first direction to apply a second layer of coating product adjacent to the first layer, comprising sub-steps consisting of:
 b1) measuring at least one application distance of the first nozzle from a point in front of the first nozzle on a path of the applicator, and 
 b2) based on the measured application distance, opening or closing the valve. 
   
     
     
         10 . The method according to  claim 9 , wherein sub-step b1) consists of collecting application distances of at least certain nozzles in the row at points respectively in front of the latter on a journey of the applicator, in order to determine a surface profile to be coated over all or part of the application width of the applicator, while sub-step b2) consists of analyzing the surface profile to detect the position of an edge of the first layer of coating product along the surface profile, and opening all of the valves of the nozzles that are positioned on one side of the edge and closing the valves positioned on the other side of the edge along the surface profile. 
     
     
         11 . The method according to  claim 10 , wherein the valves are proportional valves and in that step b) comprises other sub-steps consisting of:
 i. establishing a thickness profile of the layer of coating product along the axis, and   ii. monitoring the flow rate of the valves based on the thickness of the layer at each of the forward points.   
     
     
         12 . The method according to  claim 9 , further comprising a step consisting of repositioning the applicator when the surface is vertical or inclined and wherein this repositioning step consists of moving the applicator with a certain amplitude and in a direction parallel to an axis of the row of nozzles to offset the deviation of the coating product due to gravity. 
     
     
         13 . The method according to  claim 12 , wherein a movement amplitude of the applicator during the repositioning step is computed dynamically based on the incline of the applicator relative to the ground, the application distance of the nozzles, an ejection speed of the product through the nozzles and on a size of the nozzles, or is extracted from a prerecorded chart. 
     
     
         14 . The method according to  claim 9 , further comprising a step consisting of closing the valve of the nozzle(s) that may, due to gravity, spray coating product on a zone of the surface covered by the first layer of coating product. 
     
     
         15 . The method according to  claim 9 , wherein the valves are proportional valves and in that step b) further comprises the following sub-steps:
 i. evaluating an incline of a surface portion intended to be covered by each nozzle relative to a plane perpendicular to a spray axis of the nozzles, and   ii. monitoring a flow rate of coating product applied by each nozzle based on the incline of the surface portion intended to be covered by the corresponding nozzle.