초록 ▼

A method of measuring and storing a center of rotation of a nozzle in a pick and place machine is provided. The method includes coupling an artifact to the nozzle. A substantially collimated laser beam is directed at the artifact, which is rotated while the collimated laser beam is energized. Edges

A method of measuring and storing a center of rotation of a nozzle in a pick and place machine is provided. The method includes coupling an artifact to the nozzle. A substantially collimated laser beam is directed at the artifact, which is rotated while the collimated laser beam is energized. Edges of a shadow cast by the rotating artifact are detected and used to calculate error of a coordinate of the center of rotation of the nozzle. A coordinate of the center of rotation of the nozzle is calculated based upon a previous coordinate of the center of rotation and the error. The calculated coordinate of the center of rotation is stored for subsequent measurements.

대표청구항 ▼

What is claimed is: 1. A method of measuring a center of rotation of a nozzle in a pick and place machine, the method comprising: coupling an artifact to the nozzle; directing a substantially collimated laser beam at the artifact; rotating the artifact while the collimated laser beam is energized;

What is claimed is: 1. A method of measuring a center of rotation of a nozzle in a pick and place machine, the method comprising: coupling an artifact to the nozzle; directing a substantially collimated laser beam at the artifact; rotating the artifact while the collimated laser beam is energized; detecting edges of a shadow cast by the rotating artifact; calculating error of a coordinate of the center of rotation of the nozzle using the detected edges; calculating a coordinate of the center of rotation of the nozzle based upon a previous coordinate of the center of rotation and the error; and storing the calculated coordinate of the center of rotation for subsequent measurements. 2. The method of claim 1, wherein the artifact is round. 3. The method of claim 2, wherein the dimension is the diameter of the artifact. 4. The method of claim 1, wherein the calculated coordinate is an x-axis coordinate, normal to a direction of the collimated laser beam. 5. The method of claim 4, wherein the method is performed iteratively until the calculated error is below a selected threshold. 6. The method of claim 5, wherein the selected threshold is 0.002 millimeters. 7. The method of claim 4, wherein the method is repeated. 8. The method of claim 1, wherein the calculated coordinate of the center of rotation is stored in a controller of a pick and place machine. 9. The method of claim 1, wherein the calculated coordinate of the center of rotation is stored in an alignment sensor. 10. The method of claim 1, wherein the previous coordinate is 0. 11. The method of claim 1, wherein the method is performed periodically. 12. The method of claim 1, wherein the method is performed when an alignment sensor is coupled to a placement head of the pick and place machine.