| 摘要 |
PURPOSE:To enable machining with a specified dimensional accuracy by press fitting plate-like mandrels each having a gradually increased outside diameter and a squeeze-through blade on its side to be piled in a multiple stage, into the bore of a cylindrical material in its longitudinal axial direction. CONSTITUTION:In a multi-stage squeeze-through mandrel 1, plural squeeze- through blades 11 whose outside diameters are gradually varied bit by bit and which are piled in a multiple stage, are fitted over a through shaft 12 and fixed by a collar 13 and a nut 14. The mandrel 1 is installed on a press 3 via a guide 2, and pressed into the bore of a workpiece 5 placed on a receiving base 4 to carry out squeeze-through machining. As for the squeeze-through blade 11, the plate-like side face is formed in such a way that the angle of the guide part of the first-stage squeeze-through blade 11a is 5 deg.-10 deg. to the axis and that of the second-stage squeeze-through blade 11b is 3 deg.-7 deg.. Thereby, the cylindrical material can be machined into planishing, with a specified dimensional accuracy, without producing chips, and with less manhour, even if there is dispersion in its diameter in average. |
