Based on the traditional Chinese stonemill, pan mill type equipment designed for polymer stress reactions in the solid state has been developed. Experimental results show that this equipment is much more efficient than the traditional vibromill at pulverising brittle polymer materials and is also very efficient at pulverising ductile polymers. A theoretical analysis of the structure and milling process of the novel equipment is given, which demonstrates that during pan milling the pan mill type equipment could exert reasonably strong pressure and shear forces on the materials owing to its particular structure. The materials were shown to move in a spiral manner. A mathematical model was derived to describe the particle trajectory during milling, which was verified experimentally.