Roll grooving machine as a special tool is used to make a groove on the pipe end then use a mechanical joint to connect two pipes. The working principle of roll grooving machine is that the rotating down roller drove by motor makes the pipe rotate, and the upper roller moves down and presses the pipe by shaking the pump handle, then forms the groove.  For general pipes, we can use ordinary roll grooving machines; for some special pipes, we need to use special roll grooving machines, such as plastic-lined pipes.