Spinning Force Research Articles

Finite element simulation and experimental investigation on the forming forces of 3D non-axisymmetrical tubes spinning

3D non-axisymmetrical tube (NAT) spinning is a kind of new spinning technology, which breaks through the restriction that only axisymmetrical hollow parts could be produced by traditional spinning technology. The research on the spinning force aims to optimize the machine design and the processing parameters selection. The neck-spinning process of the 3D NAT is simulated by 3D elastic–plastic finite element software, MARC. The characteristics of the neck-spinning force of 3D NAT are compared with that of the axisymmetrical tube (AT) spinning. The effect of the main forming parameters, such as offset amount, oblique angle, nominal reduction of blank radius, feed rate and path direction, on the spinning forces have been studied theoretically and experimentally. It shows that during 3D NAT spinning, the spinning forces varies periodically with the revolution angle of the roller around the blank; the spinning force during backward path spinning is greater than that of forward path spinning. The simulation results conform well to the experimental ones.

Mechanism research for 3D non-axisymmetric thin-wall tube offset spinning

Difference of offset spinning with conventional symmetric spinning is analyzed. A 3D FEM model for offset tube neck-spinning is established and the spinning process is simulated by means of ANSYS software. Dynamic boundary and contact problems in simulation are solved. Transient stress distribution of contact area, transient strain distribution of nodes in typical section and strain distribution of the workpiece at last are attained, the place and the cause of crack are analyzed. Strain variation curves with time of offset spinning and conventional spinning are compared. It shows the mechanism difference between offset spinning and conventional spinning. In addition, simulation results show how strain distribution of typical section, thickness of some typical nodes, axial extension in left section and force of three rollers change with time. According to the study of the variation curve, material flow law along radial, tangential and axial direction is attained and the whole spinning process is studied. The simulation results discover that offset distance is the key to manufacture offset non-symmetric tube, and process parameters change with spinning angle. Experiment data really reflect different process parameters' influence on conventional symmetric and offset spinning force. Experiments accord well with simulation.

An analysis of force distribution in shear spinning of cone

An analytic model for calculation of shear spinning force incorporate factor of over-roll (press down) of the blank is derived. The effects of blank thickness, roller nose radius, mandrel revolution and roller feed on the spinning force are discussed. Results obtained from calculation were compared with the experiment and other theoretical predictions. It is found that the present findings yield optimum results.

A study of the one-path deep drawing spinning of cups

This paper deals with an investigation into the characteristics of the one-path deep drawing spinning of cups. On newly studied forming cups by spinning process, steel and aluminum sheets are formed to circular cups of various sizes by one-path in order to reduce the working procedures and increase the productivity of the manufacture. Forming conditions studied in this paper are the material property, the feed rate of the roller per revolution f, the nominal deep drawing ratio m, and the relative clearance between the roller and mandrel δ. It is thereby shown that the axial components of the spinning force P a is larger than the radial components of the spinning force P r in the initial stage of the forming, and reverse is true in the later stage. The variations of the nominal thickness strains ε are similar to those in the ordinary deep drawing except the area near the cup opening. Wrinkle, necking and fracture occur depending on the material property, forming process parameters and radius of the mandrel roundness. Fractures occur at the blank near the workpiece bottom. The forming limit diagrams and the ranges of the successful spinning for various process parameters are thus obtained.

Analysis on the spinning forces in flexible spinning of cones

Analysis on the spinning forces in flexible spinning of cones

Effects of indented feed of roller tool on parallel spinning of circular aluminum tube

Spinning is a very effective and flexible manufacturing technology for short production runs in a variety of sizes and shapes. Spinning is widely applied in the tube forming corresponding to the increased usage of the tubular parts. Authors have built a prototype computer numerically controlled spinning machine which uses the numerical control technology to spin a tube instead of dies in order to improve the tube processing. The indented feed of a roller tool is one of the important spinning conditions. The effects on the spinning force, spinning accuracy and thickness strain are experimentally examined in this study as a function of indented feed of the roller tool on parallel spinning of a circular aluminum tube. The spun tube properties are also made clarified. Results show that with the increment of indented feed of roller tool, the wall-thickness strain and the axial strain becomes steady, the spinning force increases, the diameter accuracy becomes worse, and the surface hardness as well as surface roughness increase.

An experimental study on paraxial spinning of one tube end

Spinning technology is widely applied in the production of the axisymmetric industrial parts. The application of spinning technology in tube forming is increasing recently corresponding to the increased usage of the tubular parts. In this study, an experiment of paraxial spinning on one end of circular aluminum tube is performed with the parameters of diametral reduction and spinning pitch. The experimental results show that the thickness strain, the spinning force, the twisting angle and the surface roughness increase as the tube diameter reduces and the spinning pitch increases. The axial strain increases as the tube diameter reduces and the spinning pitch decreases. The diametral accuracy becomes better as tube diameter reduces and the spinning pitch decreases. The forming characteristics of paraxial spinning on one tube end are made clarified in this study.

Forecast of shear spinning force and surface roughness of spun cones by employing regression analysis

A series of shear spinning experiments has been performed to produce axi-symmetric cones from blank sheet. The experiments investigated influences of roller nose radius, mandrel revolution and roller feed on the spinning force and the inside/outside surface roughness of spun cone. Statistical analysis was adopted to construct the regression equations governing these parameters. Independent experiments verified the findings. It was discovered that the established regression equations possess a significant degree of reliability.

Optimal angle of attack in tube spinning

The angle of attack of the roller used in tube spinning has an essential effect on the build-up and bulge ahead of the roller, the variation of the inner diameter of the spun part, and the forces applied to the roller. Recognizing the importance of determining a proper angle of attack in practice, an analytical method of defining the optimal angle of attack in tube spinning is proposed on the basis of minimizing the resultant spinning force. The optimal angle of attack in forward and backward tube spinning in the form of a transcendental function of the relevant variables such as feed rate, reduction of wall thickness and friction factor, can be solved numerically by the Newton-Raphson method. The optimal angle of attack calculated according to the method proposed is in agreement with the data on desired angle of attack reported in the literature.

The three-dimensional structure of periodic vorticity layers under non-symmetric conditions

Numerical simulations of a three-dimensional temporally growing shear layer are obtained at high Reynolds number and zero Froude number using a vortex scheme modified for a variable-density flow. Attention is focused on the effect of initial vorticity and density distributions on the interaction between instability modes which lead to the generation and intensification of streamwise vorticity. Results show that the three-dimensional instabilities evolve following the formation of concentrated span wise vorticity cores. The deformation of each core along its span resembles the amplification of the translative instability. The generation of vortex rods, which wrap around individual cores while stretching between neighbouring cores, suggest a mode similar to the Corcos instability. The instability modes leading to the formation of both structures, energized by the extensional strain generated by the cores, grow simultaneously. A similar series of events occurs in variable-density shear layers and in shear layers which start with an asymmetric vorticity distribution. Baroclinic vorticity generation in the variable-density layer leads to the formation of asymmetric cores whose volumetric composition is biased towards the lighter fluid. The structures are propelled, by their asymmetric vorticity distribution, in the direction of the heavier stream while their eccentric spinning forces an uneven stretching of the vortex rods. The origin of the asymmetry is established by comparing these with the results of a shear layer with an initially asymmetric vorticity distribution in a uniform-density flow. The strong late-stage asymmetry exhibited by the former is not observed in the latter. Thus, baroclinic vorticity generation is responsible for the observed symmetry. We also find that initially asymmetric vorticity distribution does not, as suggested before, lead to asymmetric spacing between the streamwise rods, it is concluded that the experimentally observed asymmetric spacing must arise after pairing.

An unusual prediction utilising FENE-P rheological models in the fibre-spinning problem

Predictions of the draw ratio versus spinning force for two spring types are presented. An idealized fibre-spinning experiment is considered for ascertaining the influence of model parameters; this is found to be independent of spring type. The unusual prediction is that the graph of draw ratio against spinning force may be S-shaped, so that in some circumstances three different values of the spinning force are possible for one draw ratio. This arises from when the competing effects of solvent viscosity, polymer elasticity and finite extensibility are of comparable magnitudes. This can have important implications for the interpretation of fibre-spinning experiments and the deduction of elongational flow properties.

On the conventional simple spinning of cylindrical aluminium cups

In this work, a study into the conventional simple spinning of cylindrical aluminium cups was carried out. The effects of roller face angle, feed rate and roller nose radius on each of wall thickness variation, cup inner diameter uniformity, spinning ratio, roundness uniformity, surface roughness, and spinning forces during simple spinning under dry conditions were investigated. Theoretical relationships for axial and radial components of the spinning force are determined and their validity is experimentally examined. The results show that decreasing both roller angle and feed rate, and increasing roller nose radius improve most of the spinning characteristics of the spun cup for the range of parameters considered. The results could be interpreted in terms of temperature rise in the deformation zone, over-rolling and spring-back phenomena, spinning forces, and the variations of contact area between the roller and the spun metal.

A Theory of Shear Spinning of Cones

The theoretical deformation mechanism of shear spinning of cones was re-evalued. It was found that the predicted tangential or power spinning forces for commercially pure aluminum and lead for several spinning conditions agreed well with the experimental data. In addition, the normal force and axial force components were also evaluated and fair agreement between theory and experiment was achieved.