Continuous machining of millimetric rod sheathed in plastic - to form axially parallel or spirally running accurate grooves

摘要

A cylindrical length of dielectrical material having a diameter less than some centimetres is machined continuously to produce a profile of spiral grooves around the diameter, according to the following steps: 1) feeding the rod from a supply reel turning on a horizontal axis at right angles to the line of motion of the rod; 2) guiding the rod so that its axis remains parallel to the direction selected; 3) machining the rod machine by passage through the rotating tool of a die head from which the cuttings are ejected as chips and a heated die head with a die aligned to the selected axis; 4) guiding the machined rod along the selected axis; 5) drawing the rod forward at a controlled speed with a drafting mechanism, and 6) winding the rod on a reel. The method is for prodn. of a number of accurately profiled grooves along the circumference of a thin rod. The grooves may be either parallel to the axis of the rod or run spirally round it at uniform or alternating pitch. The rod may be a complex structure on which a smooth insulating coating is extruded. Its diameter may range from a few mms to cms. and it may form part of a cable the conductors of which are optical filaments. The die head is arranged in tandem with the extruder and the system has the advantages that the run can be interrupted without causing irregularities in the grooves as would be the case if the profile were extruded.