| 摘要 |
A tube cutting machine comprises a tube secured in a chuck tightened against an outer tube wall and by a mandrel expanded within the tube against the tube inner wall opposite the chuck. A blade with a conical body side on the tube body side advances into the tube at the body side angle, eliminating longitudinal force against the tube body and accumulation of tube material on the blade body side. In alternative embodiments, either the tube or the blade can rotate. As the blade edge enters the tube wall, the blade end side, opposite the body side is also conical and pushes the tube cut portion longitudinally away from the tube body, causing the tube before the blade to neck under the longitudinal force imposed by the blade end side. The blade is reversed when the neck weakens and is unable support the tube cut portion but has not yet broken, referred to as the failure point. The blade is then withdrawn and the neck is snapped off. The failure point is detected by a rod urged transversely against the tube end. When the tube end begins to move indicating pending tube wall failure, the blade is immediately withdrawn from the tube. The rod continues to move the tube cut portion, snapping it from the tube body. The resulting cut does not have any burrs radially inward or outward of the tube wall, though there is a small burr extending longitudinally from the tube wall.
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