Plate, kit and method for calibrating an additive manufacturing apparatus

A portable calibration kit comprising:

• a removable calibration plate, able to be positioned in a field of a firing system for firing at least one power incident-radiation beam, which firing system belongs to an additive manufacturing apparatus,
• the removable calibration plate comprising a sheet,
• the sheet comprising an upper face intended to face toward the at least one power incident-radiation beam, the sheet bearing at least one reference marking and being intended to receive at least one test marking, and a lower face, which is distant from the upper face in a thickness direction of the sheet,
• wherein the removable calibration plate comprises at least one etching layer to be etched by the at least one power incident-radiation beam,
• wherein the at least one etching layer to be etched by the at least one power incident-radiation beam is secured to the upper face of the sheet and is opaque to visible light,
• wherein the at least one etching layer to be etched by the at least one power incident-radiation beam is able to be destroyed locally by the at least one power incident-radiation beam in order to form the at least one test marking,
• wherein the sheet is transparent to visible light, and
• wherein the lower face of the sheet is depolished;
• and
• at least one non-volatile memory in which there are recorded a unique identification of the removable calibration plate and absolute coordinates of the at least one reference marking, which absolute coordinates have been determined beforehand and are associated with the unique identification of the removable calibration plate.

A calibration method for calibrating a firing system for firing at least one power incident-radiation beam, which firing system belongs to an additive manufacturing apparatus, using at least a removable calibration plate,

• the removable calibration plate being able to be positioned in the firing system and comprising a sheet,
• the sheet comprising an upper face intended to face toward the at least one power incident-radiation beam, the sheet bearing at least one reference marking and being intended to receive at least one test marking, and a lower face, which is distant from the upper face in a thickness direction of the sheet,
• wherein the removable calibration plate comprises at least one etching layer to be etched by the at least one power incident-radiation beam,
• wherein the at least one etching layer to be etched by the at least one power incident-radiation beam is secured to the upper face of the sheet and is opaque to visible light,
• wherein the at least one etching layer to be etched by the at least one power incident-radiation beam is able to be destroyed locally by the at least one power incident-radiation beam in order to form the at least one test marking,
• wherein the sheet is transparent to visible light, and
• wherein the lower face of the sheet is depolished, and
• the calibration method comprising the following steps:
• positioning the removable calibration plate in the additive manufacturing apparatus, the at least one etching layer to be etched by the at least one power incident-radiation beam and that belongs to the removable calibration plate being oriented toward an emission side of the additive manufacturing apparatus from which the firing system emits the at least one power incident-radiation beam;
• commanding the firing system for firing the at least one power incident-radiation beam, which firing system belongs to the additive manufacturing apparatus, according to an aiming command for the aiming of the firing system, which is determined with respect to the at least one reference marking, to emit the at least one power incident-radiation beam from the emission side onto the at least one etching layer of the removable calibration plate in order thereon to form the at least one test marking by local destruction of the at least one etching layer;
• extracting the removable calibration plate from the additive manufacturing apparatus;
• moving the removable calibration plate to an image-capture apparatus for capturing at least one image, which apparatus is portable and separated from the firing system for firing the at least one power incident-radiation beam, which firing system belongs to the additive manufacturing apparatus,
• the image-capture apparatus comprising a casing comprising a surround delimiting an opening to accept the removable calibration plate, retainers for holding the removable calibration plate in the opening, at least one source of backlighting visible light situated beneath the opening, a sensor of at least one backlighting visible light image, a guiding and supporting device for positioning the sensor above the opening relative to the surround;
• positioning the removable calibration plate in the opening of the image-capture apparatus;
• commanding the at least one source of backlighting visible light of the image-capture apparatus so that the backlighting visible light passes from the lower face through the opening, the sheet, the at least one reference marking and the at least one test marking;
• acquiring, using the sensor, the at least one backlighting visible light image of a zone in which there are the at least one reference marking and the at least one test marking;
• analyzing, using a calculator belonging to the image-capture apparatus, the at least one backlighting visible light image acquired by the sensor and recognising the at least one reference marking and the at least one test marking in the at least one backlighting visible light image acquired, so as to calculate coordinates of the at least one test marking with respect to the at least one reference marking;
• and
• calculating and recording, in a first memory of the image-capture apparatus, using the calculator of the image-capture apparatus, aiming-command corrections for the aiming of the firing system for firing the at least one power incident-radiation beam, which firing system belongs to the additive manufacturing apparatus, as a function of at least the coordinates of the at least one test marking, that were calculated for the at least one reference marking.