The tennis ball machine is an automatic machine that serves balls during tennis practice. The most common type of tennis ball machine works by squeezing the ball with the relative rotation of two wheels to propel it forward.

1.The most mainstream tennis ball machine currently in use works by squeezing tennis balls through the relative rotation of two wheels, which then launch the balls. You can observe a ball outlet at the front, through which you can see the two wheels. These motor-driven wheels rapidly rotate to compress and shoot the balls. By adjusting the rotational speeds of the upper and lower wheels, the machine can generate adjustable topspin or backspin when launching the balls.

2. Tennis balls won't be crushed, but the instruction manual for the ball machine recommends using training balls, which have thicker cores, are less prone to losing air, and are more durable