Before welding the PPR pipe, the pipe must be clean and dry. That is to say, the surface of the PPR pipe should be free of oil stains, dust, impurities and other dirt, otherwise, during the hot melting process, the dirt and the welded pipe will be partially melted together, leaving a gap or flowing to the inner wall of the pipe, polluting the water quality. When welding PPR pipes, the pipe body should be kept dry. If there are water droplets on the outer wall of the PPR pipe, air bubbles may be left during welding, resulting in the hidden danger of false welding. The cut of the PPR pipe should be smooth, clean and free of burrs. If the cut of the pipe is inclined, the pipe and fittings will not be in a straight line during welding, and the welded PPR pipe will not be straight. Moreover, the overlapping lengths of the PPR pipes and pipe fittings at the joints are inconsistent, and when water flows through, it will have a certain impact on the thermally welded joints, shortening the service life of the joints.
