FIELD: machining of plastic materials. SUBSTANCE: method involves forming a blank by means of adjustable-capacity extruder, expansion mandrel, and controllable-speed drawing means. Positioned in the zone of mandrel receiving end is a bath for tempering pipe to drawing temperature. Cooling bath is positioned in the zone of drawing portion. Raman spectrometer positioned after cooling bath operates on laser waves whose frequency is coordinated with particular synthetic material in hand. Energy of laser waves is coordinated with thickness of pipe wall so that, apart from the wave dissipated or reflected by synthetic material, the pipe returns at least one wave corresponding to Raman spectral line. Degree of axial orienting of molecules of synthetic material is determined on the basis of properties of the wave dissipated on the pipe, reflected and/or emitted back. EFFECT: higher efficiency. 9 cl, 2 dwg
