Dynamic analysis of impact pinning AL203 ceramic substrates

Impact pinning is used to stake pins into a ceramic substrate by striking cylindrical pins with a ballistic piston to cold-form a head and a bulge on opposite sides of the substrate. The dynamics and controlling mechanisms of this process are elucidated. The deformation of the pins is the result of the competing mechanisms of simple axial compression and dynamic buckling induced by the applied force. Sinusoidal buckling wave modes are set up initially in each pin, but are relatively unimportant until after the pins fill the holding die cavities. The pins next impinge the substrate through-holes' walls, and head formation commences. Continued pin buckling causes impingement to become more severe, and the pins capture the substrate. The substrate abruptly accelerates, causing the bulge to form. The development of the bulge stops the motion of the substrate. Head formation is completed. The entire sequence of events takes less than 100 mu s (in the case of interest). Quantitative analysis and modeling reveal the details of process evolution. Theoretical calculations were verified experimentally.<>