1. Check whether the soft ball is installed correctly: make sure that the soft ball is installed in the correct position without looseness or inclination.
2. Use sticky substances: Apply some glue or double-sided tape on the surface of the soft ball to increase its friction with the surrounding environment, thus reducing sliding.
3. Increase the weight: Add some heavy objects, such as small steel balls or metal pieces, on the surface of the soft ball to increase its weight, thus reducing the sliding.
4. Replace the proper soft ball: If the above method fails to solve the problem, you may need to replace a more suitable soft ball. You can ask the manufacturer or distributor for more information about soft balls suitable for your application.