Methods and systems for quality inference and control for additive manufacturing processes
This disclosure describes an additive manufacturing method that includes monitoring a temperature of a portion of a build plane during an additive manufacturing operation using a temperature sensor as a heat source passes through the portion of the build plane; detecting a peak temperature associated with one or more passes of the heat source through the portion of the build plane; determining a threshold temperature by reducing the peak temperature by a predetermined amount; identifying a time interval during which the monitored temperature exceeds the threshold temperature; identifying, using the time interval, a change in manufacturing conditions likely to result in a manufacturing defect; and changing a process parameter of the heat source in response to the change in manufacturing conditions.
1. An additive manufacturing method comprising:
monitoring a temperature of a portion of a build plane during an additive manufacturing operation using a temperature sensor as a heat source passes through the portion of the build plane;
detecting a peak temperature associated with one or more passes of the heat source through the portion of the build plane;
determining a threshold temperature by reducing the peak temperature by a predetermined amount;
identifying a time interval during which the monitored temperature exceeds the threshold temperature;
identifying, using the time interval, a change in manufacturing conditions likely to result in a manufacturing defect; and
changing a process parameter of the heat source in response to the change in manufacturing conditions.
2. The additive manufacturing method of claim 1 wherein determining the threshold temperature incudes adjusting the threshold temperature based on a requirement of a specific additive manufacturing operation.
3. The additive manufacturing method of claim 1 wherein changing the process parameter in response to the change in manufacturing conditions further comprises changing a second process parameter.
4. The additive manufacturing method of claim 1 wherein the process parameter comprises at least one of beam power, beam travel speed, and hatch spacing.
5. The additive manufacturing method of claim 1 wherein the temperature sensor comprises a pyrometer.
6. The additive manufacturing method of claim 1 further comprising:
determining a plurality of time intervals, wherein each time interval of the plurality of time intervals is associated with a region the portion of the build plane associated with the temperature exceeding the threshold temperature; and
determining an average time interval associated with the plurality of time intervals.
7. The additive manufacturing method of claim 1 further comprising:
determining a plurality of time intervals, wherein each time interval of the plurality of time intervals is associated with a region of the portion of the build plane associated with the temperature exceeding the threshold temperature; and
determining a hatch spacing parameter associated with the plurality of time intervals.
8. The additive manufacturing method of claim 1 wherein the temperature is an observed temperature.
9. The additive manufacturing method of claim 1 wherein the temperature is a true temperature.
10. An additive manufacturing system, comprising:
a heat source;
a non-imaging optical sensor configured to measure temperatures across a surface of a material during an additive manufacturing operation in which the material is heated by the heat source; and
at least one processor configured to collect temperature data from the optical sensor, the at least one processor being further configured to:
monitor a temperature of a portion of a build plane during an additive manufacturing operation using the non-imaging sensor as a heat source passes through the portion of the build plane;
detect a peak temperature associated with one or more passes of the heat source through the portion of the build plane;
determine a threshold temperature by reducing the peak temperature by a predetermined amount;
identify a time interval during which the monitored temperature exceeds the threshold temperature;
identify, using the time interval, a change in manufacturing conditions likely to result in a manufacturing defect; and
change a process parameter of the heat source in response to the change in manufacturing conditions.
11. The additive manufacturing method of claim 10 , wherein determining the threshold temperature incudes adjusting the threshold temperature based on a requirement of a specific additive manufacturing operation.
12. The additive manufacturing method of claim 10 , wherein changing the process parameter in response to the change in manufacturing conditions further comprises changing a second process parameter.
13. The additive manufacturing method of claim 10 , wherein the process parameter comprises at least one of beam power, beam travel speed, and hatch spacing.