Although this procedure describes CM-80 twin screw pipe extrusion start-up using pressure sizing, many of the same steps are also necessary for any extrusion process, regardless of end product or extruder type.

      RIGID PVC EXTRUSION HANDBOOK

                                           FOREWORD

PVC processing dates back to the industry’s beginning in the late 1930’s and early 1940’s, when oiled litharge, white lead, and the first metal-containing liquid stabilizers ( cadmium, tin) were some early additives used in the germinating vinyl industry. Over the next  twenty years PVC grew to become one of the “big three” of the United States plastics industry at the billion pound per year level of consumption---yet without rigid PVC extrusion applications, which remained essentially undeveloped up to the early 1960’s. Beginning in the mid 1960’s, the uses of rigid PVC extruded products grew at an increasing rate which even outpaced the total PVC industry growth rate, to the point that rigid vinyl extrusion now consumes a greater amount of PVC resin (almost 70%) than any other process. Primary extrusion products include pipe, conduit, siding, window profile, foam-core pipe, solid and foamed profile, and sheet, with fencing and docking among emerging newer applications.