Extruded tube mfr with continuous ultrasonic monitoring - of wall thickness and automatic correction of floating die

摘要

Immediately after leaving the die the wall-thickness of the tube is measured continuously and without contact in at least two places and, when a difference in thickness occurs, the die is moved in the direction of the greatest thickness w.r.t. the mandrel or the container holding the tube blank. The wall-thickness is pref. measured at four opposite points, the values obtd. from each pair being compared and the compared value used to move the die. Ultrasonics are pref. used to measure the thickness at four cooled locations at 90 degrees w.r.t. each other. Tubes with uniform wall thickness can be mfd.