Abstract-There are many process variables, which more or less influence quality of a manufacturing process, and there are many parameters of a product, which constitute its quality. The control of variables of a manufacturing process for achievement of requested quality of a final product is a multi-parametric task. It is paid great effort to find such the way, which might lead to the most rapid solution. The use of full factorial experiments, fractional factorial experiments and Taguchi approach were compared from the point of view of number of experiments requested. It was found that the Taguchi orthogonal arrays are the most efficient method for higher number of process factors and that the full factorial experiments request the highest number of experiments from all methods under test.

Process of lead-free soldering is deeply monitored starting from July 2006, when RoHS directive was activated. The goal of the work was to analyze influence of 4 control parameters of a process of lead-free soldering on bridging and filling of through holes on a test board.Following control parameters (factors) were taken into account: the solder temperature, the time of a contact between the soldered area and solder, the preheating temperature and flux wettability. Every factor was used in 3 levels. Taguchi orthogonal array of the type L9 was used for process analysis. The analysis showed that bridging is influenced with the preheating temperature and with the time of a contact between solder and a pad dominantly, influence of the solder temperature is minimal. The filling of the through hole depends above all on the preheating temperature; influence of other control parameters is low. It has been also confirmed effectiveness of the use of Taguchi orthogonal array in comparison with full factorial experiments.

Quality of electrically conductive adhesives is a main component in electronic packaging. It highly influences the total quality of a product containing such a component. With time and usage, adhesives lose some of the qualities. In some cases, changes in the molecule structure for example, can be responsible for this influence on material characteristics. This process is known as aging. It can badly affect the total electrical conductivity of adhesives and non-linearity, even mechanical properties of adhesive joints can be affected. In research field, aging is applied to test the expected reactions of the most important material parameters of electrically conductive adhesives. It also helps identifying the total operating life of the tested components. This work focuses primarily on analyzing the effect of thermal aging on the resistance of three types of adhesives, one of these adhesives is a two-component type, and the other two are onecomponent type.

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