System for Aligning Laser System to a Carrier Plate

1 . A three-dimensional printing system for manufacturing a three-dimensional article comprising:

a build chamber;

a carrier plate defining:

a receptacle for receiving and aligning a prefabricated body; and

an alignment target formed into the carrier plate;

a vertical positioning apparatus;

a laser system;

a sensor;

a powder dispenser; and

a controller configured to:

operate the laser system to generate and scan a radiation beam over an upper surface of the carrier plate;

concurrent with scanning the radiation beam, receive a signal from the sensor;

analyze the signal to align the radiation beam to the prefabricated body; and

operate the vertical positioning apparatus, the laser system, and the powder dispenser to selectively fuse layers of powder over the prefabricated body to complete manufacture of the three-dimensional article.

2 . The three-dimensional printing system of claim 1 wherein the receptacle is a recess formed into the upper surface of the carrier plate.

3 . The three-dimensional printing system of claim 1 wherein the receptacle includes a plurality of datum surfaces for engaging and aligning outer surfaces of the pre-fabricated body.

4 . The three-dimensional printing system according to claim 1 wherein the alignment target includes a plurality of openings that pass through the carrier plate.

5 . The three-dimensional printing system according to claim 1 wherein the alignment target is a recess formed into the carrier plate, the recess including a bottom surface having a radiation absorbing coating.

6 . The three-dimensional printing system according to claim 1 wherein the sensor is above the carrier plate.

7 . The three-dimensional printing system according to claim 1 wherein, during receiving the signal, the laser system is operated at a low power level that is generally less than a high power level used for fusing powder.

8 . The three-dimensional printing system according to claim 1 wherein analyzing the signal includes finding points along an edge of a target and then computing a center location of the target.

9 . A method of manufacturing a three-dimensional article comprising:

loading a prefabricated body into a receptacle formed into an upper surface of a carrier plate;

loading the carrier plate into a build chamber;

operating a laser system to initially scan a radiation beam over the upper surface of the carrier plate;

concurrent with initially scanning the radiation beam, receiving a signal from a sensor indicative of a reflected intensity of radiation from the upper surface;

analyzing the signal to find locations of targets formed into the carrier plate and to align the laser system to the receptacle; and

operating a powder dispenser, the laser system, and a vertical positioning apparatus to selectively fuse layers of material over the pre-fabricated body and to complete manufacture of the three-dimensional article.

10 . The method of claim 9 wherein the prefabricated body is loaded into the receptacle before the carrier plate is loaded into the chamber.

11 . The method of claim 9 wherein loading the prefabricated body into the receptacle includes engaging outer surfaces of the prefabricated body with receptacle datum surfaces.

12 . The method according to claim 9 wherein the initially scanned radiation beam includes generating the radiation beam at a low power level, operating the radiation beam to selectively form layers includes generating the radiation at a high power level that is greater than the lower power level.

13 . The method according to claim 9 wherein finding locations of targets individually includes identifying locations along an edge of an opening having a geometry shape and then computing a particular location of the opening based upon the identified locations.

14 . The method of claim 13 wherein the opening is circular and the particular location is a center of the opening.

15 . The method according to claim 9 wherein finding locations of targets include finding locations of at least three separate openings formed into the carrier plate.

16 . The three-dimensional printing system of claim 1 wherein the receptacle includes a plurality of receptacles arranged across the upper surface of the carrier plate.

17 . The three dimensional printing system of claim 4 wherein the openings are preferably circular.

18 . The three dimensional printing system of claim 1 wherein the sensor includes a plurality of sensors, analysis includes combining the signals from the plurality of sensors to improve accuracy.

19 . The method of claim 9 wherein loading the prefabricated body includes loading a plurality of the prefabricated bodies into a corresponding plurality of receptacles across the upper surface of the carrier plate.

20 . A three-dimensional printing system for manufacturing a three-dimensional article comprising:

a build chamber;

a carrier plate defining:

a receptacle formed into an upper surface of the carrier plate for receiving and aligning a prefabricated body; and

an alignment target including a plurality of openings formed into the carrier plate and in precise alignment with the receptacle;

a vertical positioning apparatus;

a laser system;

a sensor configured to received radiation reflected from the upper surface;

a powder dispenser; and

a controller configured to:

operate the laser system at an initial low power to generate and scan a radiation beam over an upper surface of the carrier plate;

concurrent with scanning the radiation beam, receive a signal from the sensor;

analyze the signal to align the radiation beam to the pre-fabricated body, analyzing includes identifying points along edges of the openings and computing locations of the openings from the identified points; and

operate the vertical positioning apparatus, the laser system, and the powder dispenser to selectively fuse layers of powder over the prefabricated body to complete manufacture of the three-dimensional article, the laser system is operated at a high power level that is greater than the low power level during the selective formation.