Investigating the movement of chip components during reflow soldering

The self-alignment of chip resistors has been investigated by experiments and by simulations as well. By evaluating the results it can be said, that the self-alignment of chip resistors occurred even in the case of 500 mum x direction (lateral) misplacement. Another observation can be stated on the base of the experiment, that the SM (surface mounted) chip resistors moved less distance in y direction than in x direction. The average distance which is traveled by the component in x direction is 249 mum, while the average distance in y direction is 75 mum. It was proposed on the base of our physical model that if metallization presents on the sidewalls of the component then the y direction self-alignment of components can be improved. The proposal was confirmed by simulations and by real experiments as well. Surface mounted chip resistors and chip capacitors were compared from the viewpoint of y direction self-alignment. The chip capacitor has a shape of metallization nearly the same as the proposed one. On the base of the results it can be stated that the y direction self-alignment of chip capacitors is significantly better.