A process for producing a rod, by a) extruding a plastics profile made of a first plastics moulding composition which forms the outermost layer and which is composed of at least 50% by weight of a semicrystalline thermoplastic, b) within the calibrator, a second plastics moulding composition is inserted into the freshly extruded profile and c) calibrating, drawing off and cooling the newly formed rod, wherein the first plastics moulding composition has the following properties: - crystallite melting point Tm in accordance with ISO 11357 of at least 170�C, - crystallization temperature Tk in accordance with ISO 11357 of at most 70 K below Tm and - enthalpy of fusion AH in accordance with ISO 11357 of at least 20 J/g, permits production of rods, in particular round rods, with high dimensional accuracy in terms of diameter and straightness. The rods are particularly suitable as semifinished product for producing finished parts by machining.
