thermoplastic welding apparatus and related methods are disclosed . an example method includes providing a smart susceptor between composite parts that are to be joined via thermoplastic welding . the example method includes positioning the composite parts and the smart susceptor on a tooling surface within a cavity of a tooling apparatus and applying a seal to the composite parts and the tooling surface to form a vacuum chamber between the composite parts and the tooling surface at a welding joint of the composite parts ; producing a magnetic field at the welding joint . the example method includes providing a vacuum in the vacuum chamber during a welding operation .