Pinball, Sphere and gravity, hitting sphere off the table

Hi there.

To get me started in Unity I have created a simple pinball game, with two paddles using a hinge joint and the in-built physics engine.

They work, the can hit the sphere around the table, however sometimes the sphere will fly off the table once struck with the paddles.

Here is what I have tried, adjusting mass of sphere, gravity on the X,Y axis (both currently set to -12), mass of the paddles. Usually changing one of these adversely effects another such as the speed of the sphere, or the power of the paddles to hit the sphere.

Any suggestions on how I can resolve this would be excellent.

Thanks.

Could you just put a plane on top of the machine facing down so that you can still see in but the ball can't fly out.

OR

Could you freeze the position of the rigidbody on the y axis under it's inspector properties? Not sure how your tables laid out.