1. Use gaskets: Add some suitable gaskets or washers inside the mold to increase the clamping force. The gasket can be made of rubber, plastic, etc. And the appropriate thickness and hardness can be selected according to the needs.

2. Adopt elastic sleeve: install elastic sleeve or rubber pad inside the mold to adapt to the size difference between two cylinders through its own elasticity and deformation characteristics, so as to realize clamping. The elastic sleeve can be made of natural rubber or synthetic rubber.

3. Adjust the die aperture: If the diameters of two cylinders are quite different, the die aperture can be adjusted again to adapt to different cylinder diameters and achieve stable fixation.

4. Use spare dies: If the above method cannot achieve effective fixing effect, multiple dies can be used, and the corresponding dies can be selected according to the diameter of the cylinder to be adapted, or specially designed clamps and fasteners can be used for fixing and clamping.