Thermal spraying instrument
AssigneeSnecma Services
InventorsMichel Vardelle, Thierry Renault, Cédric Bossoutrot, Frédéric Braillard, Hakim Hoffmann
Life of this patent
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Abstract
The invention relates to a device and method for controlling the operation of a thermal spray torch (12). The inventive device and method are characterized in that an on-board camera (54) and pyrometer (70) are used to measure the properties of the jet (16) and the temperature of the deposit (24) on the part (22) and in that the correction to be made to supply parameters of the torch (12) is deduced. Furthermore, the invention is characterized in that the corrected parameters are sent to the cabinet (30) that controls the torch (12).
Claims21
A thermal spray instrument (10) having a thermal spray torch (12), the torch (12) having a geometrical axis (14), the torch (12) being capable of spraying a jet (16) along its geometrical axis (14), the jet (16) consisting of a gas flow at elevated temperature loaded with molten particles of the material to be sprayed, the instrument (10) having a control unit (30) supplying the torch (12) with ingredients by applying supply parameters (122) which are communicated to said control unit, the instrument (10) having a computer (100) communicating the supply parameters (122) to the control unit (30) by means of a unit-computer connection (120), the instrument (10) having sensors (52) capable of monitoring the movements of the torch (12), the sensors (52) being capable of transmitting information (112, 114) about the operation of the torch (12) to the computer (100), this transmission being carried out by means of a sensors-computer connection (110), characterized in that:
- a. the computer (100) has software for realtime analysis of the information (112, 114), in order to repetitively deduce therefrom the measurement of at least one spray parameter to determine when the measurement has stabilized, in order to calculate a new supply parameter value (122) and transmit the new supply parameter to the control unit (30) when the measured value of the spray parameter is outside a preestablished acceptable range of values specific to the spray parameter being processed, this new value of the supply parameter being suitable for returning the spray parameter to an acceptable range,
- b. the sensors (52) have a camera (54) capable of periodically providing the computer (100) with the information (112, 114) in the form of digital images (112) of the jet (16) as seen in profile over a part of its length, and
- c. the spray parameter measured from the images (112) is the width L of the jet (16), the camera (54) being capable of observing the jet (16) with a resolution at least equal to 0.5 mm, L being proportional to the standard deviation of the distribution of the luminance of the jet (16) along a geometrical line (154) transverse to the jet (16), in order to regulate the hardness of the coating (22).
A method for controlling a thermal spray torch adapted to spray a jet consisting of gas flow at elevated temperatures with molten particles entrained therein, the jet being sprayed along a geometric axis of the torch and the torch being controlled by a control unit which supplies ingredients to the torch in accordance with supply parameters communicated to the control unit by a computer, said method comprising:
- periodically generating digital images of a profile of the jet;
- communicating the digital images to the computer;
- calculating, with the computer and based on the digital images, at least one spray parameter value of the jet for each digital image to generate a plurality of values for the spray parameter, the spray parameter comprising the width L of the jet;
- comparing the calculated spray parameter value for each image and the next consecutive image to determine the difference between the spray parameter values for the consecutive images;
- determining that the spray parameter value has reached a stable state when the difference between the spray parameter values for consecutive images is less than a stability threshold;
- determining if the stable state spray parameter value is within a predefined acceptable range for the spray parameter;
- if the stable state spray parameter value is outside the predefined acceptable range for the spray parameter, calculating with the computer a new supply parameter value for returning the spray parameter value back to the acceptable range for the spray parameter;
- and
- transmitting the new supply parameter value to the control unit, which, in turn, varies the ingredients supplied to the torch in accordance with the new supply parameter value to return the spray parameter value of the jet back to the predefined acceptable range for the spray parameter.
Dependencies are inferred from the claim text.