Machine and process capability coefficient of solder paste printers

For manufacturers of assembled boards seeking ISO 9000 certification, a number of requirements are placed on measurement instruments and tooling. This standard requires a system to document and maintain calibration and machine capabilities. One of these problems is the measurement of printing accuracies of solder paste printers. The paper presents: short theoretical overview of machine capabilities; methods of measurement of accuracies (x, y and rotation); recommendations for the calibration of printers; indications for the sources of inaccuracies; practical examples and results.