A camera assembly is employed in additive manufacturing to improve the fidelity of a printed object. The camera may scan the surface of a build plate of a 3D printer and an object as it is being printed to generate image data. The image data is processed to detect errors in the build plate or printed object. The printer compensates for the detected errors, which can including modifying the printer configuration and/or modifying the instructions for printing a given object. Using the updated configuration, subsequent objects may then be printed, under a corrected process, to produce an object with fidelity to an original object model.

A build platform of an additive manufacturing apparatus is disclosed. The build platform includes a surface formed of a material having a first emissivity; and a plurality of reference markers disposed on the surface. The reference markers have a second emissivity that is different from the first emissivity. A thermal imaging unit calibration method and additive manufacturing apparatus are also disclosed.

A build platform of an additive manufacturing apparatus is disclosed. The build platform includes a surface formed of a material having a first emissivity; and a plurality of reference markers disposed on the surface. The reference markers have a second emissivity that is different from the first emissivity. A thermal imaging unit calibration method and additive manufacturing apparatus are also disclosed.

We describe a calibration method for calibrating one or more optical elements of an additive layer manufacturing apparatus useable for producing a three-dimensional workpiece, the method comprising: projecting, using the one or more optical elements, an optical pattern onto a material in order to prepare, from said material, solidified material layers using an additive layer manufacturing technique to form a test sample; determining a geometry of the test sample; comparing the determined geometry with a nominal geometry to generate calibration data; and calibrating the one or more optical elements using said calibration data.

We describe a calibration method for calibrating one or more optical elements of an additive layer manufacturing apparatus useable for producing a three-dimensional workpiece, the method comprising: projecting, using the one or more optical elements, an optical pattern onto a material in order to prepare, from said material, solidified material layers using an additive layer manufacturing technique to form a test sample; determining a geometry of the test sample; comparing the determined geometry with a nominal geometry to generate calibration data; and calibrating the one or more optical elements using said calibration data.

We describe a calibration method for calibrating one or more optical elements of an additive layer manufacturing apparatus useable for producing a three-dimensional workpiece, the method comprising: projecting, using the one or more optical elements, an optical pattern onto a material in order to prepare, from said material, solidified material layers using an additive layer manufacturing technique to form a test sample; determining a geometry of the test sample; comparing the determined geometry with a nominal geometry to generate calibration data; and calibrating the one or more optical elements using said calibration data.

We describe a device for calibrating an irradiation system of an apparatus for producing a three-dimensional workpiece, the irradiation system comprising an irradiation unit for selectively irradiating an irradiation beam onto an irradiation plane, wherein the device comprises: a control unit configured to control the irradiation system to irradiate the irradiation beam onto the irradiation plane, and an optical detection unit coupled to the control unit, wherein the optical detection unit comprises an optical detector and an objective lens for optically detecting a portion of the irradiation plane, wherein the optical detection unit is configured to detect a position of a spot of the irradiation beam on the irradiation plane, wherein the objective lens is adapted to be arranged, with respect to an irradiation beam path of the irradiation beam, between the optical detector and an irradiation beam scanner of the irradiation system, wherein the optical detection unit is configured to detect the position of the spot of the irradiation beam in multiple focal planes based on a focal length of the optical detection unit being adjustable, wherein the optical detection unit is configured to output a signal to the control unit in response to the optical detection unit detecting the position of the spot of the irradiation beam on the irradiation plane, and wherein the control unit is configured to control the irradiation system based on the signal output from the optical detection unit to the control unit.

We describe a device for calibrating an irradiation system of an apparatus for producing a three-dimensional workpiece, the irradiation system comprising an irradiation unit for selectively irradiating an irradiation beam onto an irradiation plane, wherein the device comprises: a control unit configured to control the irradiation system to irradiate the irradiation beam onto the irradiation plane, and an optical detection unit coupled to the control unit, wherein the optical detection unit comprises an optical detector and an objective lens for optically detecting a portion of the irradiation plane, wherein the optical detection unit is configured to detect a position of a spot of the irradiation beam on the irradiation plane, wherein the objective lens is adapted to be arranged, with respect to an irradiation beam path of the irradiation beam, between the optical detector and an irradiation beam scanner of the irradiation system, wherein the optical detection unit is configured to detect the position of the spot of the irradiation beam in multiple focal planes based on a focal length of the optical detection unit being adjustable, wherein the optical detection unit is configured to output a signal to the control unit in response to the optical detection unit detecting the position of the spot of the irradiation beam on the irradiation plane, and wherein the control unit is configured to control the irradiation system based on the signal output from the optical detection unit to the control unit.

A printing unit comprises a movable carriage being movable along a path and having a plurality of energy emitters arranged in an array, a controller to control a supplied energy level of the emitters, and a sensor unit to measure an emitted energy level of each emitter, wherein the controller is to compare the measured energy level with a target energy level associated with the supplied energy level to obtain and to generate a matrix indicating a compensation value for each emitter based on the comparison result so as to calibrate the energy level of comparison result.

A z-lift and leveling assembly for leveling a platen in a heated chamber of a 3D printer includes first, second, third, and fourth z-actuators in a rectangular configuration. Each z-actuator includes a linear drive configured to supply motion in the z-direction and a mounting bracket secured to the linear drive and configured to move with the linear drive in the z-direction. The assembly includes a set of four pin couplings each associated with one of the first, second, third and fourth z-actuators. Each pin coupling includes a pivot block secured to the mounting bracket with a first pivot pin forming a first pin joint between the mounting bracket and the pivot block, where the pivot block is configured to move relative to the mounting bracket about a first pivot axis of the first pivot pin. The pivot block is secured to the platen or an arm of the platen with a second pivot pin forming a second pin joint such that the pivot block and the platen move relative to each other about a second pivot axis. As the mounting bracket is moved, the pivot block moves relative to the mounting bracket about the first pivot axis and the pivot block moves relative to the platen about the second pivot axis such that a z-position of the platen can be manipulated to and maintained in a substantially level configuration in the z-direction though the independent manipulation of the first, second, third and fourth z-actuators and wherein the substantially level configuration can be maintained when the platen is incremented in the z-direction during printing of a part.