Masters Abstracts (1993)

GLEASER, COLETTE MARIE
(August 1993), Allen Bradley, AB

Email: glaeser@niia.net

Accuracy Evaluation Methodology in Fine Pitch Surface Mount Placement Equipment

A significant number of flaws and defects occurring in solder joints originate from the component placement process. These are often the result of placement equipment errors, the mechanical characteristics of the substrate, the components placed, or a combination of these three. With higher lead count devices, more precise and accurate placement is necessary. The differences between the actual placement locations and the nominal placement locations with respect to the X Y, and Z axes of motion are suitable measurable output characteristics from the placement process which allow the process capability of the placement equipment to be determined. By employing a process capability assessment technology of the placement equipment, the contribution to misalignment due to component placement inaccuracies can be estimated as a function of machine type, component pitch and/or size, and placement head rotation. These estimates provide information with which to select the best placement technique thus enhancing the probability of an accurate placement of the desired component type. System sell-off (i.e.., customer acceptance testing of equipment performance) and periodic calibration of the placement equipment (i.e., comparison of system performance against a higher-order standard of greater accuracy) are two applications which will benefit from this method of determining placement accuracy and repeatability for a particular placement machine.