CYLINDRICAL PLASTIC FILTER AND PRODUCTION OF THE SAME

PROBLEM TO BE SOLVED: To make tbe cylinder end part smooth to improve sealing property and prevent a particle from being parted from the cylinder end part by melting the surface of the cylinder end part, regarding a cylindrical plastic filter produced by sintering and molding a thermoplastic plastic material. SOLUTION: A cylindrical plastic filter 1 is produced by cutting a cylindrical body formed by sintering extrusion molding of an ultrahigh molecular weight polyethylene, which is a thermoplastic resin, in a prescribed length and the cylindrical body is subjected to melting treatment for the surface of both end parts 2. The melting treatment for both end parts 2 is carried out by pressing hot plates 3 heated at a proper temperature corresponding to the melting point of the material. That is, the respective end faces of both end parts 2 are heated and melted by the bottom faces 4b of the of heating grooves 4 formed in the hot plates 3 to become smooth faces with the excellent sealing property and at the same time the respective corner parts of both end parts 2 are heated and melted by the inclined faces 4a sloping toward the bottom faces 4b from the opening parts 4a in the same manner to chamfer the corner parts and to prevent a particle from being parted from the respective corner parts.