What Does Milling Mean?
Milling is the process of mechanically removing excess material from the inside of a sewer pipe; it is performed remotely in trenchless operations, usually by a specialized hydraulic milling robot.
Milling forms a smooth surface on the interior of the pipe, necessary in pipe relining and continuous sliplining. The smooth surface provides foldable liners a smooth surface to which they may adhere. In continuous slip lining, the smooth interior surface of the host pipe ensures no obstruction to the insertion of the carrier pipes.