A stitchless highly oriented polypropylene fabric bulk bag of the type that can hold 500 to 5000 pounds (226.7 to 2268 kilograms) of bulk material includes a highly oriented polypropylene fabric top, body and bottom, with a heat fused joint providing an air tight connection between the top and body, and another air tight heat fused joint connecting the body and bottom. A fill spout and discharge tube may also be provided with an air tight heat fused joint connecting the fill spout to the top and another air tight heat fused joint connecting the discharge spout to the bottom. Heat sealing machinery include heat seal bar assemblies that can self-align during heat-sealing to apply even pressure to all areas being heat sealed. A heating element is of single piece construction and can include end coupler portions as part of the single piece construction. Carrier plates used in a heat-sealing assembly line guide parts placement, provide quality checks for parts placement, and tooling set-up for machinery.