This blue plastic fitting piece is located in the grid mechanism and is designed to wear over time, by doing so this prevents wear on other more expensive parts of the grid frame mechanism.
The blue plastic fitting piece helps drive the grid frame mechanism and once it has worn down to much can lead to movement in the frames and lead to uneven cutting.
The material the blue plastic fitting piece is made from PAS-LX which requires no lubrication and creates no friction which in turn prevents heat build up.
