The needle-free highly oriented polypropylene fabric bulk bag of the type that can hold 500 to 5000 pounds (226.7 to 2268 kg) of bulk materials includes a highly oriented polypropylene fabric top, main body, and bottom, which has between the top and the main body Provides an airtightly connected heat fusion joint and another airtight heat fusion joint that connects the main body and the bottom. The filling opening and the discharge pipe may also be provided with an airtight heat fusion joint connecting the filling opening to the top and another airtight heat fusion joint connecting the discharge opening to the bottom. The heat-sealing machine includes a heat-sealing strip assembly that can be self-aligned during heat-sealing to apply uniform pressure to all heat-sealed areas. The heating element has a one-piece structure, and may include an end coupler portion as part of the one-piece structure. The carrier board used for heat-sealing assembly lines guides component placement, provides quality inspection of component placement, and machine tool assembly.