Patent DE-102012010477-A1 (DE)
Title: Coating a substrate using laser, comprises melting the substrate using a laser beam produced along gauge to be melted, promoting powder to substrate, and partially introducing powder for producing coating into melted substrate
Inventor: KIRSTE THOMAS DIPL ING
IPC: B23K26/34
Filed: 2012-05-26
Abstract: The method comprises melting a substrate using a laser beam produced by a laser along a gauge to be melted, promoting a powder to the substrate, partially introducing the powder for producing a coating into the melted substrate, varying a powder mass flow and a laser power (PL) along a given function in an area of an initial coating and/or a final coating, and calculating a target slope of the function of the powder mass flow so that a relative ratio between the powder mass flow and the laser power over an area of 80% of a variation of the powder mass flow is larger than 0.5. The method comprises melting a substrate using a laser beam produced by a laser along a gauge to be melted, promoting a powder to the substrate, partially introducing the powder for producing a coating into the melted substrate, varying a powder mass flow and a laser power (PL) along a given function in an area of an initial coating and/or a final coating, and calculating a target slope of the function of the powder mass flow so that a relative ratio between the powder mass flow and the laser power over an area of 80% of a variation of the powder mass flow is larger than 0.5 with a maximum displacement (S). The variation of the powder mass flow and/or the laser power takes place with the slope, which is provided for starting and/or ending the variation smaller or equal to the calculated target slope and is provided by an entire area of the initial coating and/or a final coating equal to the calculated target slope. The function of the powder mass flow is predetermined as a linear function with the target slope for the variation of the powder mass flow. The maximum displacement takes place by: determining a maximum distance between the function of powder mass flow and the function of the laser power, where the maximum distance corresponds to the maximum displacement; measuring a time interval, which requires the powder of a powder conveyer system to the melted substrate, where a standard deviation of the time interval is determined and converted in dependence of a process speed into the distance and the distance corresponds to the maximum displacement; adjusting a target powder function at the powder conveyer system, where an actual function of the powder mass flow is measured shortly at the melted substrate or in direction of the powder mass flow before the target powder function and a determined maximum target actual deviation corresponds to the maximum displacement; and/or determining a molten bath size and their maximum deviation of a diameter of the laser beam in a direction opposite to the process direction, where the maximum deviation corresponds to the maximum displacement. The slope is smaller than the target slope, increases by a gauge route (LS, LS1) in such a way that an average slope of a gauge inlet corresponds to the target slope, and decreases by a gauge route in such a way that an average slope of a gauge outlet corresponds to the target slope.