The article presents the results of research on the influence of limit stress of the densification process on sublimation of dry ice during the forming process in piston technology. The research concerns the process of agglomeration of waste material in fragmented form, obtained as a result of the crystallization process of liquid carbon dioxide. The material is characterized by low temperature and sublimation under ambient conditions. During the research, the focus was on determining the influence of the limit value of densification stress on the value of the material efficiency factor of the process. In previous studies, it was observed that the weight of the product in the form of pellets is significantly smaller than the fragmented dry ice dispensed to the densification chamber. In order to improve the efficiency of the process, tests were carried out to determine the characteristics describing its change in function of the limit value of the densification stress.