During the advancement of the prepreg, the resin undergoes a cross-linking reaction due to heat, the viscosity is lowered, the viscous resistance is increased, and the gel starts to enter the gel region. 

Gradually harden, shrink and detach from the mold. The resin moves forward uniformly with the fibers at the same speed. The curing is continued in the curing zone and the specified degree of curing is achieved when the die is released. The curing temperature is usually greater than the peak of the exothermic peak of the glue, and the application temperature, gel time and traction speed are matched.The temperature in the preheating zone should be low, and the temperature distribution should be controlled so that the solidification exothermic peak appears at the back of the middle of the mold, and the breakaway point is controlled in the middle of the mold. The temperature difference of the three sections is controlled at 20 degrees Celsius to 30 degrees Celsius, and the temperature gradient should not be too large. The effect of the exothermic heat of the curing reaction should also be considered. Usually three zones are controlled by three pairs of heating systems.

Traction is the key to ensure the smooth release of the product. The traction depends on the cross-section shear stress between the product and the mold. The shear stress decreases as the traction speed increases, and three peaks appear at the entrance, middle, and exit of the mold. The peak at the entrance is caused by the viscous resistance of the resin there. Its size depends on the nature of the resin viscous fluid, the temperature at the inlet and the filler content. The viscosity of the resin in the mold decreases with increasing temperature, and the shear stress decreases. As the curing reaction proceeds, the viscosity and shear stress increase. The second peak corresponds to the point of detachment and decreases significantly as the traction speed increases. The third peak is at the exit, which is produced by friction between the product and the inner wall of the mold after curing. The value is small and the traction is important in process control. To make the surface of the product smooth, the shear stress (second peak) at the point of departure is required to be small and the mold is released as early as possible. The change in traction is dependent on the reaction state of the product in the mold and is related to fiber content, product shape and size, release agent, temperature and traction speed.