Seam stress release and protrusion elimination process

A process comprising

• providing a support having an elongated surface with an arcuate convex substantially semicircular cross section and having a predetermined radius of curvature,
• providing a flexible belt having parallel edges and a welded seam extending from one edge to the other edge, the belt seam comprising a seam region comprising an overlap and two adjacent splashings, polymer material having a glass transition temperature, an inner surface and an outer surface,
• supporting the inner surface of the seam on the elongated surface with the belt conforming to the predetermined convex radius of curvature,
• progressively elevating the temperature of localized sites on and along the seam from one edge of the belt to the other with heat energy to at least the glass transition temperature of the polymer material by directing a beam of heat energy at the localized sites,
• applying line compression pressure against the seam region by pressing a rotatable wheel having a peripheral surface with an arcuate concave cross section having a radius of curvature which matches or is slightly larger than the predetermined curvature of the arcuate convex substantially semicircular cross section of the elongated surface,
• simultaneously rolling and pressing a part of the peripheral surface of the wheel against the outer surface of the seam, to continuously generate lines of compressive contact over the seam region, from one edge of the belt to the other while the temperature of the localized sites pressed by the wheel is at least the glass transition temperature of the polymer material, the line of compressive contact at the peripheral surface of the wheel pressing against the outer surface of the seam being
• substantially parallel to the predetermined curvature of the elongated surface having an arcuate convex substantially semicircular cross section and
• in substantially line contact with the outer surface of the seam, and
• rapidly cooling the seam to a temperature below the glass transition temperature of the thermoplastic material while maintaining the belt in conformance with the predetermined arc of the elongated surface.