Calibrating a focused beam of energy in a solid freeform fabrication apparatus by measuring the propagation characteristics of the beam

A method of calibrating a focused beam of energy in a solid freeform fabrication apparatus by detecting and eliminating a non-optimal condition present in propagation characteristics of the focused beam, the propagation characteristics established by beam conditioning optics, the method comprising:

• directing the focused beam of energy to a profiling stage on the apparatus, the profiling stage receiving the focused beam of energy having substantially the same propagation characteristics used by the apparatus when forming a three-dimensional object;
• taking a first set of at least two measurements indicative of a beam width of the focused beam of energy at the profiling stage, the first set of measurements associated with a first planar position orthogonal to a propagation axis of the focused beam of energy;
• shifting the propagation characteristics of the focused beam of energy respectively with the profiling stage along the propagation axis of the focused beam by a first relative distance;
• taking a second set of at least two measurements indicative of the beam width of the focused beam of energy at the profiling stage, the second set of measurements associated with a second planar position orthogonal to the propagation axis of the focused beam of energy;
• shifting the propagation characteristics of the focused beam of energy respectively with the profiling stage along the propagation axis of the focused beam by a second relative distance;
• taking a third set of at least two measurements indicative of the beam width of the focused beam of energy at the profiling stage, the third set of measurements associated with a third planar position orthogonal to the propagation axis of the focused beam of energy;
• producing beam propagation data from the sets of measurements taken in each of the planar positions and the first and second relative distances;
• analyzing the beam propagation data to detect a non-optimal condition of the beam;
• producing at least one response when a non-optimal condition is detected;
• delivering the response to the beam conditioning optics;
• and
• adjusting the beam conditioning optics upon the delivery of the response to substantially eliminate the non-optimal condition.

A solid freeform fabrication apparatus adapted to measure the propagation characteristics of a focused beam of energy utilized by the apparatus when forming three-dimensional objects from a build material, the apparatus comprising:

• an apparatus structure;
• a platform in communication with the apparatus structure for supporting the build material of the three-dimensional object when the three-dimensional object is formed by the apparatus;
• a laser beam generator in communication with the apparatus structure for producing the energy that is transmitted in the focused beam of energy;
• beam conditioning optics in communication with the apparatus structure, the beam conditioning optics receiving the energy transmitted from the laser beam generator and projecting the focused beam of energy about a propagation axis;
• scanning optics in communication with the apparatus structure receiving the focused beam of energy and directing the focused beam of energy towards the platform;
• a profiling stage in communication with the apparatus structure and adapted for receiving the focused beam of energy from the scanning optics;
• at least one sensor in communication with the profiling stage to take at least two measurements indicative of the beam width of the focused beam of energy at the profiling stage;
• a controller in communication with at least the beam conditioning optics, the scanning optics, the sensor, the platform;
• and
• wherein the controller
• (a) produces beam propagation data from sets of at least two measurements indicative of the beam width, the first set taken in a first planar position, the second set taken in a second planar position, and the third set taken in a third planar position;
• (b) analyzes the beam propagation data to detect a non-optimal condition of the focused beam;
• and
• (c) produces at least one response when the non-optimal condition of the focused beam is detected.

A solid freeform fabrication apparatus adapted to calibrate a focused beam of energy utilized by the apparatus when forming three-dimensional objects from a build material, the apparatus comprising:

• an apparatus structure;
• a platform in communication with the apparatus structure for supporting the build material of the threedimensional object when the three-dimensional object is formed by the apparatus;
• a laser beam generator in communication with the apparatus structure for producing the energy that is transmitted in the focused beam of energy;
• beam conditioning optics in communication with the apparatus structure, the beam conditioning optics receiving the energy transmitted from the laser beam generator and projecting the focused beam of energy about a propagation axis;
• scanning optics in communication with the apparatus structure receiving the focused beam of energy and directing the focused beam of energy towards the platform;
• a profiling stage in communication with the apparatus structure and adapted for receiving the focused beam of energy from the scanning optics;
• at least one sensor in communication with the profiling stage to take at least two measurements indicative of the beam width of the focused beam of energy at the profiling stage;
• a controller in communication with at least the beam conditioning optics, the scanning optics, the sensor, the platform;
• and
• wherein the controller
• (a) produces beam propagation data from sets of at least two measurements indicative of the beam width, the first set taken in a first planar position, the second set taken in a second planar position, and the third set taken in a third planar position;
• (b) analyzes the beam propagation data to detect a non-optimal condition of the focused beam;
• and
• (c) produces at least one response when the non-optimal condition of the focused beam is detected and delivers the response to the beam conditioning optics to substantially eliminate the non-optimal condition.