Abstract:In order to solve the issues such as beating, rebound, shaping force inequality existing in bamboo turning round and turning straight process by using bamboo shaping machine, based on noncircular and nonstraight bamboo structural characteristics, through researching bamboo shaping mechanism, the bamboo plastic stress model was established, a kind of shaping method was proposed in which pressure was applied inside and outside the bamboo simultaneously to realize turning round and turning straight of the bamboo. Then a closed type hydraulic controlled expansion shaft was designed, including the structure and hydraulic control system. The prototype trial was completed. This expansion axis applies to thin bamboo veneer and bamboo preprocessing field, it has positive meaning to improve the comprehensive utilization of bamboo.