Method and system for operating a modular heater to improve layer bonding in a metal drop ejecting three-dimensional (3D) object printer

1. A method for operating a three-dimensional (3D) metal object manufacturing system comprising:

generating with a sensor a signal indicating a temperature of a surface of a metal object being formed by the 3D metal object manufacturing system prior to completion of the metal object;

comparing with a controller the temperature indicated by the signal from the sensor with a predetermined temperature;

operating with the controller at least one actuator to change an angular orientation of a frame mounted to an end of a reciprocating arm having a longitudinal axis with respect to the metal object, a plurality of independently controlled heating elements being arranged within the frame; and

providing electrical power selectively to the heating elements in the plurality of heating elements to heat the 3D metal object prior to formation of a next layer of the 3D metal object when the temperature indicated by the signal from the sensor is less than the predetermined temperature.

2. The method of claim 1 further comprising:

operating the at least one actuator with the controller to move the frame closer to the 3D metal object being formed when the temperature indicated by the signal from the sensor is less than the predetermined temperature.

3. The method of claim 2 further comprising:

operating the at least one actuator with the controller to chance the angular orientation of the frame with respect to the 3D metal object being formed when the temperature indicated by the signal from the sensor is greater than the predetermined temperature.

4. The method of claim 1 wherein the predetermined temperature is 400° C.

5. The method of claim 3 , the operation of the at least one actuator further comprises:

operating the at least one actuator with the controller to change the angular orientation of the frame in a yaw direction.

6. The method of claim 3 , the operation of the at least one actuator further comprises:

operating the at least one actuator with the controller to change the angular orientation of the frame in a pitch direction.

7. The method of claim 6 , the operation of the at least one actuator further comprises:

operating the at least one actuator with the controller to change the angular orientation of the frame in a yaw direction.

8. The method of claim 7 , the selective provision of electrical power to the heating elements further comprises:

operating with the controller an electrical resistance switching network to couple electrical power selectively to the heating elements in the plurality of heating elements selectively to heat the 3D metal object prior to formation of a next layer of the 3D metal object when the temperature indicated by the signal from the sensor is less than the predetermined temperature.

9. The method of claim 8 , the operation of the electrical resistance switching network further comprises:

operating the electrical resistance switching network with the controller to vary an electrical resistance coupled to at least one switch in the electrical resistance switching network to change an intensity of heat produced by at least one heating element with respect to an intensity of heat produced by at least one other heating element.

10. The method of claim 9 further comprising:

comparing with the controller the temperature indicated by the signal from the sensor with another predetermined temperature, the other predetermined temperature being greater than the predetermined temperature; and

changing with the controller the electrical resistances coupled to less than all of the switches in the electrical resistance switching network using three- dimensional model data to reduce the electrical power to the heating elements connected to the electrical resistances changed by the controller when the temperature indicated by the signal generated by the sensor is greater than the other predetermined temperature.

11. A modular heater for a three-dimensional (3D) metal object manufacturing system comprising:

a sensor configured to generate a signal indicative of a temperature of a surface of a metal object being formed by the 3D metal object manufacturing system prior to completion of the metal object;

a reciprocating arm having a longitudinal axis;

a plurality of heating elements configured for independent operation and arranged within a frame, the frame being mounted to one end of the reciprocating arm;

at least one actuator operatively connected to the reciprocating arm, the at least one actuator being configured to at least change the angular orientation of the plurality of heating elements within the frame with respect to the metal object being formed;

an electrical resistance switching network operatively connected to the heating elements in the modular heater; and

a controller operatively connected to the sensor, the at least one actuator, and the electrical resistance switching network, the controller being configured to:

compare the temperature indicated by the signal from the sensor with a predetermined temperature;

operate the at least one actuator to change the angular orientation of the plurality of heating elements within the frame with respect to the metal object being formed; and

operate the electrical resistance switching network to couple electrical power selectively to the heating elements in the plurality of heating elements to heat the 3D metal object prior to formation of a next layer of the 3D metal object when the temperature indicated by the signal from the sensor is less than the predetermined temperature.

12. The modular heater of claim 11 , the controller being further configured to:

operate the at least one actuator to move the frame closer to the 3D metal object being formed when the temperature indicated by the signal from the sensor is less than the predetermined temperature.

13. The modular heater of claim 12 , the controller being further configured to:

operate the at least one actuator to move the frame further from the 3D metal object being formed when the temperature indicated by the signal from the sensor is greater than the predetermined temperature.

14. The modular heater of claim 11 wherein the predetermined temperature is 400° C.

15. The modular heater of claim 13 , the controller being further configured to:

operate the at least one actuator to change the angular orientation of the frame in a yaw direction.

16. The modular heater of claim 13 , the controller being further configured to:

operate the at least one actuator to change the angular orientation of the frame in a pitch direction.

17. The modular heater of claim 16 , the controller being further configured to:

operate the at least one actuator to change the angular orientation of the frame in a yaw direction.

18. The modular heater of claim 17 , the controller being further configured to:

operate the electrical resistance switching network to vary an electrical resistance coupled to at least one switch in the electrical resistance switching network to change an intensity of heat produced by at least one heating element with respect to an intensity of heat produced by at least one other heating element.

19. The modular heater of claim 18 , the controller being further configured to:

compare the temperature indicated by the signal from the sensor with an other predetermined temperature, the other predetermined temperature being greater than the predetermined temperature; and

change the electrical resistances coupled to less than all of the switches in the electrical resistance switching network to reduce the electrical power to the heating elements connected to the electrical resistances changed by the controller when the temperature indicated by the signal generated by the sensor is greater than the other predetermined temperature.

20. The modular heater of claim 19 , the controller being further configured to:

use three-dimensional model data to operate the electrical resistance switching network.