| abstract |
A syringe or other suitable dispensing device is coupled to conventional controls for dispensing viscous material such as adhesives or solder paste through a tip thereof. The syringe is supported on a motor driven carriage for movement along a Z axis in response to height control signals. A camera also mounted on the carriage generates output signals representative of an image of the surface of a workpiece such as a PC board. Circuity processes the output signals from the camera to determine when the image is maximally in focus and generates the height control signals necessary to maintain the tip of the syringe a predetermined constant height above the surface of PC board. This ensures the dispensing of uniform balls of solder paste or adhesive at various locations on the PC board despite warpage in the board. |