Analysis Of The Section Deformation Of The Tube's Coupling In The Turning Process

As the demand of the oil tubes'coupling raises sharply, the supply cannot meet the demand now, the oil tubes'coupling is used to joint the oil tube, insuring the gas tightness of oil transport process. As tubes'coupling is a thin-walled workpiece, clamping force affects a lot in the process of turning the inner wall, large force always causes the roundness error out of the tolerance. And the Bao Steel has suffered a lot from this problem, to solve this problem, this paper has made researches around the key issue as follows:1. The principle to determine the clamping force. Suitable size of clamping force has been discussed. The clamping force should be large enough for the security of the processing; however, the size of the force had an upper limit value as considering the roundness tolerance.2. The clamping force and the cutting force model. The relation between the clamping force and the cutting force has been analyzed. Experiments of measuring the main cutting force had been done, and a Back-Propagation Neural Network for forecasting the main cutting force has also been built.3. Roundness model. The relation between roundness and the clamping force has been analyzed; a theory model of the roundness has been built. Experiments and finite element model are made to demonstrate the validity of the model. Three-point symmetry clamp and four-point symmetry clamp has been compared based on the roundness.4. Error separation method for roundness measurement. Some error separation methods for roundness measurement was discussed. Symmetry multipoint error separation method separated the eccentric error and the main axis jerking error from the roundness excellently, and based on this method many experiments for demonstrating the roundness model has been done.