PURPOSE: To expand the bone, cartilage, skin, tendon, diaphragm, etc. to desired size, by using a popping machine provided with a lid-catcher to clamp and fix the lid, and a means to properly restrict the opening of the lid-catcher.

CONSTITUTION: The drum is sealed with the lid 20, and heated under rotation. The rotation of the drum is stopped, and the swivelling lever 26 is inserted into the gap of the side plates at the top part P of the lid-catcher 15 by operating the handle 45 and the handle lever 35. The adjustment screw 29 is turned to form a desried gas (e) between the screw 29 and the top part P of the lid-catcher, and then, the clamping pin 19 is turned to release the seal of the lid 20. The opening of the lid 20 is restricted within the gap (e). The state of expansion can be adjusted freely according to the material to be popped by adjusting the gap (e).