More typically the plastic preform used in compression molding does not contain reinforcing fibres. If desired the mold is first pre-loaded with a reinforcing fiber matrix or preform. The solder preform may include the solder flux needed for the soldering process. A resin is applied to the 3D preform to create the composite material. To manufacture a CMC material, the fiber preform is infiltrated with the chosen polymer. One method incorporates casting a forging preform from liquid metal. In compression molding, a "preform" or "charge", of SMC, BMC is placed into mould cavity. Many methods are used to manufacture the solder preform, stamping being the most common. Alternatively, polymer can be infiltrated into 1D, 2D, 3D preform creating high content polymer nanocomposites. Removal of the oxides from the solder preform is also troublesome. The aseptic filling lines comprise wet sterilisation technology and dry preform sterilisation using hydrogen peroxide. Typical communications fiber uses a circular preform. These thermosets can be in either preform or granule shapes. The preform is always stretched with a core rod as part of the process. In this way, kilometers of fiber can be produced from a single preform.