Controlled thermal coating

Abstract

The combined measurement of particle speed, particle temperature, particle intensity, burner current and the control thereof within a tolerance range allow the coating structure, coating thickness and the coating weight to be maintained despite wear-associated fluctuations in the coating process.

1 . A method for thermal coating by means of a material flow ( 42 ) by means of a nozzle ( 30 ), in particular by means of a powder flow,
 in which a material (M xy ) of the material flow ( 42 ) is heated, partially melted and/or melted, in particular by means of a plasma or a flame, in which at least one of the target variables (Z 1 , Z 2 , Z 3 , . . . ) material flow velocity (v P ) of the material flow ( 42 ) and/or   brightness distributions (H(x,y); ∫H(x y)dxdy) or   temperature distribution (T(x,y); ∫T(x,y)dxdy) of the material flow ( 42 )   
       and/or
 voltage (U B ) between an electrode ( 36 ) and the nozzle ( 30 ) and/or 
 the power (P) of the nozzle ( 30 ) 
 are measured or determined and controlled. 
 
     
     
         2 . The method as claimed in  claim 1 ,
 in which a brightness distribution (H(x,y);) ∫H(x,y)dxdy) of the material flow ( 42 ) or the voltage (U B ) between the nozzle ( 30 ) and the electrode ( 36 ) or the power (P) at the nozzle ( 30 ) are controlled as at least one target variable (Z 1 , Z 2 , Z 3 , . . . ).   
     
     
         3 . The method as claimed in  claim 1 ,
 in which, as target variables (Z 1 , Zd 2 ),   
       either
 the material flow velocity (v P ) and 
 the voltage (U B ) between the nozzle ( 30 ) and 
 the electrode ( 36 ) 
 
       or
 the material flow velocity (v P ) and 
 the power (P) at the nozzle ( 30 ) 
 are controlled. 
 
     
     
         4 . The method as claimed in  claim 1 ,
 in which, as target variables (Z 1 , Z 2 ),   a brightness distribution (H(x,y); ∫H(x y)dxdy) of the material flow ( 42 ) and   the material flow velocity (v P )   are controlled.   
     
     
         5 . The method as claimed in  claim 1 ,
 in which, as target variables (Z 1 , Z 2 ),   a temperature distribution (T(x,y); ∫′T(x,y)dxdy) of the material flow ( 42 ) and   the material flow velocity (v P )   are controlled.   
     
     
         6 . The method as claimed in  claim 1 ,
 in which, as target variables (Z 1 , Z 2 , Z 3 ),   
       either
 a temperature distribution (T(x,y); ∫T(x,y)dxdy) of the material flow ( 42 ), 
 the material flow velocity (v P ) and 
 the voltage (U B ) between the nozzle ( 30 ) and the electrode ( 36 ) 
 
       or
 a temperature distribution (T(x,y); ∫T(x,y)dxdy) of the material flow ( 42 ), 
 the material flow velocity (v P ) and 
 the power of the nozzle ( 30 ) 
 are controlled. 
 
     
     
         7 . The method as claimed in  claim 1 ,
 in which, as target variables (Z 1 , Z 2 , Z 3 ),   
       either
 the brightness distribution (H(x,y); ∫H(x,y)dxdy) of the material flow ( 42 ), 
 the material flow velocity (v P ) and 
 the voltage (U B ) between the nozzle ( 30 ) and the electrode ( 36 ) 
 
       or
 the brightness distribution (H(x,y); ∫H(x,y)dxdy) of the material flow ( 42 ), 
 the material flow velocity (v P ) and 
 the power (P) at the nozzle ( 30 ) 
 are controlled. 
 
     
     
         8 . The method as claimed in one or more of  claim 1 ,  2 ,  3 ,  4 ,  5 ,  6  or  7 ,
 in which the current intensity (I B ) between the nozzle ( 30 ) and the electrode ( 36 ) 
 
       and/or
 the gas flow rates ({dot over (m)} H2 , {dot over (m)} Ar ) of the nozzle ( 30 ) are varied as control variables (R 1 , R 2 , R 3 ), 
 in order to keep the target variables (Z 1 , Z 2 , Z 3 ) such as the brightness distribution (H(x,y); ∫H(x,y)dxdy) of the material flow ( 42 ) or the temperature distribution (T(x,y); ∫T(x,y)dxdy, of the 
 material flow ( 42 ) or 
 the voltage (U B ) at the nozzle ( 30 ) or 
 the power (P) at the nozzle ( 30 ) and/or the material flow velocity (v P ) 
 in a specific tolerance range or constant. 
 
     
     
         9 . The method as claimed in one or more of  claims 1  to  8 , in which the current intensity (I B ) is increased or lowered as a control variable (R 1 , R 2 , R 3 ). 
     
     
         10 . The method as claimed in one or more of  claims 1  to  9 , in which the gas flow rate ({dot over (m)} Ar , {dot over (m)} H2 ) of the primary gases (argon, helium)
 and/or of the secondary gases (hydrogen, . . . ) of the nozzle ( 30 ) are increased or lowered as at least one control variable (R 1 , R 2 , R 3 ). 
 
     
     
         11 . The method as claimed in one or more of  claims 1  to  10 , in which the material flow rate ({dot over (m)} m ) is not varied during the coating. 
     
     
         12 . The method as claimed in one or more of  claims 1  to  11 , in which the temperature distribution (T(x,y)) of the material flow ( 42 ) is used as the temperature. 
     
     
         13 . The method as claimed in one or more of  claims 1  to  11 , in which an integral value (∫T(x,y)dxdy) of the material flow ( 42 ) is used as the temperature of the material flow ( 42 ). 
     
     
         14 . The method as claimed in one or more of  claims 1  to  11 , in which an integral value (∫H(x,y)dxdy) of the material flow ( 42 ) is used as the brightness value. 
     
     
         15 . The method as claimed in one or more of  claims 1  to  11 , in which the brightness distribution (∫H(x,y)dxdy) of the material flow ( 42 ) is used as the brightness value. 
     
     
         16 . The method as claimed in one or more of  claim 1  to  11 ,  14  or  15 ,
 in which the light intensity or radiation power of the material flow ( 42 ) is used as the brightness value (H). 
 
     
     
         17 . The method as claimed in one or more of  claims 1  to  16 ,
 in which an HVOF method is used. 
 
     
     
         18 . The method as claimed in one or more of  claims 1  to  16 , in which a plasma spraying method is used. 
     
     
         19 . The method as claimed in one or more of  claims 1  to  18 , in which, before the coating,
 proceeding from one and/or more initial values of the control variables (R 1 , R 2 , R 3 ) 
 at which the desired target variables (Z 1 , Z 2 , Z 3 ) are achieved and/or maintained, 
 sets of parameters for various constellations, such as higher, lower and constant, of the control variables (R 1 , R 2 , R 3 ) are set, and 
 the variations in the target variables (Z 1 , Z 2 , Z 3 ) are determined, 
 these then being used later for control.