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This review presents a survey of most literature published on tube spinning in English language. This paper aims to provide insight into mechanics of the process and act as a guide for researchers working on tube spinning and other flexible forming processes. The review has revealed several gaps in knowledge of tube spinning mechanics. Evolution of stress and strain state in the tube is not well understood, mainly due to long computational times required to model the process accurately. Failure mechanisms of spinning are not understood. Toolpath design has been explored, but no attempt has been made to automate it. Studies on novel process configurations have demonstrated the potential of the process for further flexibility and production of a wider range of complex geometries. [ABSTRACT FROM AUTHOR]

Tube spinning is a continuous bulk forming technique used to produce seamless tubes. In the last six decades, tube spinning process has been applied to a wide range of engineering products; especially in automotive, aerospace and nuclear industry. However, understanding of the process mechanics is limited. Key references were published about 60 years ago. This paper investigates tube spinning mechanics using physical trials and a numerical model. Mechanisms of material accumulation, wave, bell-mouth and diametral growth in tube spinning are investigated and their mechanisms explained. Numerical model results show that both equivalent plastic strain and plastic strain rate are localised in the region immediately under and ahead of the roller producing highly non-uniform strain distributions and that the process reaches steady-state at an early stage. The stress state is dominated by compressive normal stresses in all three directions. [ABSTRACT FROM AUTHOR]

In this study, an artificial neural network (ANN) model was constructed to investigate the relationship between the roller path parameters to form a cylindrical cup in multi-pass conventional spinning and the thickness distribution throughout the height of a workpiece. Furthermore, the path parameters that simultaneously realize multiple target values of the workpiece dimensions were calculated instantly by the iterative solution based on the constructed model. A systematic design of the path parameters for a constant thickness distribution was established as follows. First, the roller path was expressed using 12 parameters. Second, the workpieces were spun under various experimental conditions, which were determined by partial randomization of the orthogonal array based on the Taguchi method. Third, an ANN model was trained by considering seven path parameters as inputs and five forming result values as outputs (cup height, wall thickness at 25%, 50%, and 75% of the cup height, and residual path length). Finally, the path parameters required for realizing a constant thickness were determined using an ANN model with an iterative solution. Although several samples of the training dataset exhibited non-uniform thickness distributions, the workpieces that were spun under the parameters obtained via iteration exhibited a constant thickness distribution. The parameters responsible for stretching the material in the radial direction significantly affected the thickness distribution. The most influential parameter was the increment in the axial start position for each curved pass. [ABSTRACT FROM AUTHOR]

This study clarified the strain state evolution of a cylindrical cup spun from a rolled aluminum sheet in 13 passes. Measurements of radial (ɛr), circumferential (ɛθ), and thickness (ɛt) directional strains as well as forming forces revealed that the strain state evolved as follows: the cup-wall exhibits ɛr < 0 and small |ɛθ| and |ɛt| in early passes and ɛr > 0, ɛθ < 0, and ɛt < 0 in later passes; meanwhile, the cup-edge exhibits ɛr > 0 and small |ɛθ| and |ɛt| in early passes and ɛr > 0, ɛθ < 0, and ɛt > 0 in later passes. The relationship between the strain states and the forming force is interpreted as follows. The normal direction forming force, which pushes into the workpiece in the thickness direction, primarily deforms the workpieces. The radial direction forming force, toward the edge along the workpiece configuration, facilitates elongation in the radial direction of the cup-wall and results in ɛr > 0 during spinning. By contrast, a small radial direction forming force or a forming force whose direction is inverse against the roller movement direction restrains to elongate the material in the radial direction and facilitates shrinkage, thereby resulting in ɛr < 0 in the cup-edge in early passes. Furthermore, the small or inverse directional force facilitates the accumulation of the material to the edge and results in ɛt > 0 in latter passes. [ABSTRACT FROM AUTHOR]

With the development of metal spinning, the limitation of producing axisymmetric shapes has been broken through by many researchers using the synchronous spinning method in which the motion of the roller is synchronized with the rotation of the mandrel. The thickness distribution on the product formed in synchronous spinning is usually non-uniform due to the irregular motion of the roller. A method of pass design for thickness control in synchronous multi-pass spinning is proposed in this study. The effects of different parameters on the circumferential distribution of the wall thickness on cylindrical cups in synchronous multi-pass spinning are investigated. The rotational direction of the mandrel is reversed under several schemes. The cross sections of the product during forming are adjusted to control the thickness distribution by changing the concavity of the pass λ and the roller-mandrel clearance δ at different circumferential positions. The thicknesses and strains were measured during the experiment to understand the material flow. Experiments are also conducted in conventional spinning for comparison. The results showed that the torsion in synchronous spinning with oblique shapes can be reduced by reversing the rotational direction of the mandrel; the circumferential distribution of the thickness can be controlled by changing the geometry of the roller pass circumferentially. [ABSTRACT FROM AUTHOR]

Various approaches to produce non-axisymmetric parts in metal spinning have been developed by researchers. In asymmetric multi-pass spinning, the motion of the roller is synchronized with the mandrel's rotation by CNC codes to achieve oblique or non-circular shapes. In this study, cylindrical cups are formed using two kinds of oblique pass sets to investigate the effects of different parameters on thickness distribution and forming limit. In the translational pass set, the inclination angle is determined by the difference of the wall depths on two sides of the product and it is determined by the difference of half cone angles in the rotational pass set. The difference of wall thickness distribution in the translational pass is greater than that in the rotational pass and it increases as the inclination angle increases. The difference between the axial distributions on two sides of the wall decreases as the pass pitch increases near the top of the product, and it increases near the edge of the wall. A greater incremental angle does not affect the difference but reduces the uniformity of the wall thickness in the rotational pass set. All the failures are wrinkles in the experiments. Wrinkles occur when the pass pitch or the roller feed ratio is too large. A greater inclination angle reduces the forming limit in the translational pass set and does not affect the forming limit in the rotational pass set. [ABSTRACT FROM AUTHOR]

Various approaches have been attempted by researchers to break through the limitation of axisymmetric shape in metal spinning. In this study, a synchronous multipass spinning method for offset blanks is proposed. The motion of the roller and the rotation of the mandrel are synchronized to achieve asymmetric shapes. The roller trajectory is represented by a set of scattered data which contains the axial position of the roller, the radial position of the roller, and the rotational angle of the mandrel. Conventional spinning for offset blanks is also conducted in comparison with synchronous spinning. The geometries of the products with different offset values λ are examined. The axial distribution of wall thickness varies at different circumferential positions of the product due to the oblique shape. The thickness increases from the short side to the long side of the product. A larger offset value λ results in a larger product diameter due to the springback of the material. Forming limits in terms of roller feed ratio f, offset value λ, blank thickness t0, blank diameter D, and the number of passes are investigated. Both fracture and wrinkling occur in the experiments. Due to the oblique shape, wrinkling tends to occur during the first several passes on the long side of the flange, and fracture tends to occur during the last several passes on the long side of the product. The experiments are more likely to succeed when a small offset ratio λ, a small blank diameter D, a small feed ratio f, or a large blank thickness t0 is used. Compared with synchronous spinning, the difference between the axial thickness distributions on both sides of the product is smaller in conventional spinning due to the uniform feed ratio. In terms of forming limits, conventional spinning has a slightly better performance. [ABSTRACT FROM AUTHOR]

Methods of rotary forming of products from sheets include: burring of a sheet edge with rolls, cutting on rotary cutters, grooving, roll forming and spinning. The Łukasiewicz Research Network -- Metal Forming Institute has been engaged in studies on spinning for many years. In recent years, as part of its statutory work, the Institute designed and built the unique, numerically controlled MWS-200 spinning machine for forming products with complicated shapes. The MWS-200 machine makes it possible to form products with elliptical, square and triangular cross-sections but also axially symmetrical products. This article presents the results of research concerning reverse engineering of forming of a cone-type product with the application of spinning technology. Laboratory tests were conducted on the MWS-200 machine. Simufact Forming software was applied for numerical simulations. The method of designing the technological process for spun drawpieces is being developed based on experience and empirical tests, which poses large problems and is time-consuming in the case of products with a complicated shape. This article contains the results of spinning tests in which a sheet disk was formed in one and three movements of the spinning roll. Test results illustrating differences between laboratory tests and numerical simulations in the shape of the produced conical product are presented. The numerical process that made it possible to obtain convergence of results is presented. Planned studies applying the reverse engineering method are intended to reduce the time of development of the technological process for axially symmetrical drawpieces based on numerical simulations. [ABSTRACT FROM AUTHOR]

In the paper the results of experimental research of the process of flow forming of cylindrical drawpieces were presented. The drawpieces were made of the 3.1 mm thick AMS 5596 sheet by drawing process. Tests were performed on two-roller metal spinning machine of a vertical axis Leifeld SFC 800 V500. The main purpose of this research was to determine the relationship between relative thickness reduction and the mechanical properties of tested material. Knowledge of these dependencies is especially useful in designing machines' components manufactured by flow forming, in the selection of parameters of realization of this technological process as well. Mechanical properties were determined on the basis of uniaxial tensile of the micro samples obtained from the drawpieces: (I) after cold flow forming, (II) after cold flow forming and in-process heat treatment. Obtained results were shown graphically in the diagrams and their analysis was carried out. In addition, the microstructure of the sheet material tested after drawing and flow forming is presented. [ABSTRACT FROM AUTHOR]

Recently, various methods for the metal spinning of noncircular shapes have been proposed to overcome the limitation of its application range. In this study, a metal spinning method for noncircular shapes with oblique bottoms is proposed. This method is a combination of synchronous spinning and multipass spinning, in which the roller is synchronized with the mandrel rotation to track a noncircular cross section while the workpiece is gradually deformed without much thinning through some paths of the roller. The roller trajectory is calculated by linear interpolation in the radial direction and axial direction between the inclined blank shape and the inclined cross section of the product. A circular cup and square cup with an oblique bottom and vertical side walls are successfully spun using this method. As the wall thickness locally increases at the side edges of the square cup, the thickness distribution is equalized by using an intermediate circular shape. This method interpolates the roller trajectory between the blank shape and intermediate shape and between the intermediate shape and the product. The difference in the wall thickness is reduced since the square shape is formed via a cylindrical shape. In addition, the effect of the process parameters on the forming results is experimentally investigated. [ABSTRACT FROM AUTHOR]

Metal spinning is one of a number of flexible sheet forming processes which is a cost effective option for the production of parts with a very high strength to weight ratio. Although the wall thickness of the formed part in conventional spinning is generally considered to be nearly constant, a non uniform distribution of wall thickness is in fact observed. In this study, the wall thickness variation of a formed part made of Cr-Mn austenitic stainless steel was analysed. The thickness variation was measured using an optical 3D scanning method and the influence of mandrel speed, feed ratio and tool path profile (convex, concave and linear) on wall thickness variation was studied. A three-level full factorial design of the experiment and ANOVA (Analysis of Variance) were used. The results show that the maximal variation in wall thickness is observed in approximately half of the part wall height (thinning) and on the open end of the part (thickening). Feed ratio and roller path profile are statistically significant factors governing wall thickness variation. There was no obvious effect from the variation in mandrel speed on the thickness distribution. [ABSTRACT FROM AUTHOR]

This study is an investigation into the effect of the different parameters of the pass set on the formability in synchronous multipass spinning. Synchronous multipass spinning is a metal spinning method that can produce a noncircular cylindrical shape with a noncircular bottom and vertical walls from a metal sheet. The radial position of the roller tool is synchronized with the spindle rotation while the work piece is formed from a flat disk into the shape of the mandrel step by step along varying trajectories. The tool trajectory is calculated by linear interpolation between the mandrel shape and the blank disk shape along a pass set. Here, a pass is the tool trajectory in the normalized two-dimensional space defined by the radial and axial directions of the mandrel. The aim of this study is to examine the effect of different parameters of the pass set on the formability of two sample shapes, a circular cup and a rectangular box. The formability was experimentally examined using a rotational pass set and a translational pass set as simple tool trajectories. The rotational pass set consists of curved passes with the same start point and a constantly increasing angle inclination. The translational pass set consists of passes with the same inclination and a start point that is moved by a constant amount. The angle of growth of the rotational pass set, the incremental movement of the translational pass set, and the nominal product height are varied for comparison in the experiments. [ABSTRACT FROM AUTHOR]

A new laser integration into a spinning machine was developed offering the flexibility to apply completely new processing strategies for laser-assisted multi-pass metal spinning. In this process the formability of challenging materials is improved by selective heating of the forming zone by means of laser. In order to decrease the strength and increase the formability of titanium (grade 2) experimental investigations have been performed to generate a suitable temperature field in the workpiece. [ABSTRACT FROM AUTHOR]

Flexible spinning with three internal support rollers can allow the economic production of very low-volume or one-off prototypes by removing the need for a mandrel. However, to produce a range of shallow products accurately, it is necessary to position the internal support rollers correctly and to compensate for springback. This paper demonstrates the use of a laser scanner to monitor the current workpiece, position the internal rollers correctly, and compensate for springback. The approach is demonstrated by producing a 316 mm cup with a 50 mm corner radius with a geometric error of just 1.5 mm. [ABSTRACT FROM AUTHOR]

Abstract: This review presents a thorough survey of academic work on the analysis and application of the mechanics of spinning. It surveys most literature published in English and the most important publications in German and Japanese languages. The review aims to provide insight into the mechanics of the process and act as a guide for researchers working on both metal spinning and other modern flexible forming processes. The review of existing work has revealed several gaps in current knowledge of spinning mechanics: the evolution of the stress state and the strain history of the workpiece in both conventional and shear spinning is not well understood, mainly due to the very long solution times that would occur in modelling the process throughout its duration with a sufficiently fine mesh to capture detailed behaviour through the workpiece thickness; the evolution of microstructure, residual stress and hence springback, has not been examined—either numerically or by experiment; the failure mechanisms of spinning – fracture and wrinkling – are only partially understood, through analogy with other processes, and as yet models of the process have not made use of contemporary damage mechanics; the design of toolpaths required to make particular parts without failure remains an art, and cannot currently be performed automatically with confidence. Studies on novel process configurations in spinning have shown that great potential for innovation in spinning exists. The process has the potential to be more flexible, to produce a wider range of shapes, and to form more challenging materials. [Copyright &y& Elsevier]

Abstract: The distribution of equivalent plastic strain through the thickness of several AISI 1020 steel plates formed under different conditions over a smooth cylindrical mandrel using a single-roller forward flow forming operation was studied by measuring the local micro-indentation hardness of the deformed material. The equivalent plastic strain was higher at the inner and outer surfaces and lowest at the center of the workpiece. Empirical expressions are presented which describe the contribution of the roller and mandrel to the total local equivalent plastic strain within the flow formed part. The dependence of these expressions upon the thickness reduction during flow forming is discussed. [Copyright &y& Elsevier]

The selection of forming lubricants in metal spinning process is often observed to be a multi-criteria decision-making problem with conflicting and diverse objectives. This contribution presents a current state of the development of a computer application for optimal selection of lubricants in the stage of metal spinning process design with regard to minimization of health and environmental risks. The system requirements and the principal structure of the developed software tool are described. The proposed tool automates the forming lubricants selection. As a part of existing CAPP software it will serve as an aid in lubrication decision-making for machine shop engineers in metal spinning process planning. [ABSTRACT FROM AUTHOR]

This paper reports the results of modelling of the spinning of thin sheet aluminium with the MSC MARC finite element (FE) package and its domain decomposition facility using Patent MPI software. The use of networked computers, both single and dual processor machines, is compared. The network used consists of over twenty computers and a 3COM switch with a nominal capacity of 100 Mbit/s. The effect of reduced network capacity is noted. The effect of increasing the number of computers involved is investigated in terms of resulting solution times. The results show the potential for large reductions in solution times. The impact of the background support of a network solution on the conventional computer user is examined.Partitioning of the model into ‘super-elements’ or separate domains is reviewed. Various partitions of the meshed geometry are compared, giving some indication of where pitfalls may lie in this critical aspect of multi-domain FE models.The results of the modelling are compared with experimental measurements of a conventional spinning operation using a CNC lathe. A flat disk is formed by a spinning operation into a dished shape. The material used is commercially pure aluminium. [Copyright &y& Elsevier]

Spinning sheet metal parts successfully requires the design of a complex toolpath to avoid workpiece failure. Notwithstanding decades of research, industrial CNC spinning of new parts today still relies on trial and error, which results in considerable time waste and does not guarantee optimisation of the toolpath. Yet, hand spinning artisans in non-industrial settings can successfully spin new parts first time thanks to the skill accumulated in years of practice. So this paper asks: is there a way to capture and parameterise human skill to drive research into automation? What rules do hand spinners follow? A haptic spinning system is implemented to capture and parameterise the skill of six spinning artisans. Their speech and actions are recorded in a set of over 70 experimental trials and a database of toolpaths is created including information on the trajectory of the roller, applied forces and shape of the workpiece, alongside their speech. The database is analysed, and seven principles for toolpath design are formulated: 1. Take small bites, 2. Stay on the mandrel, 3. Use forward and backward passes, 4. Push in the right place, 5. Go at the right speed, 6. Keep the flange at the right angle, 7. Use a draft. Quantitative toolpath parameters are developed to parameterise the first six principles: the average plastic strain in each toolpass, the fraction of workpiece shape on the mandrel, the fraction of backward passes, the position of the force peak, the feed ratio and the concavity of the toolpass. In trials on thinner and larger blanks than previously investigated in the literature, these parameters appear to be a good predictor of success. This suggests that displacement control alone is not sufficient to automate toolpath design, and that new parameters relating to force and shape control must be employed. [ABSTRACT FROM AUTHOR]

This study clarified the evolution of texture in the thickness direction of the cylindrical cup which was spun from a rolled aluminum sheet in 13 passes, using electron backscatter diffraction pattern analysis. The study also obtained the relationship between the strain and layer structure, characterized by the textures. The spun workpiece had three layers in the thickness direction. The layer structure was composed of four types of textures: the Cu texture, "texture-I", which rotated 20° around <111> from the Cu texture; "texture-II", which rotated 5° around its <110> from the Cu texture; and "texture-III", which rotated 10° around its <001> from texture-I. When a blank disk had the sandwich-type layer structure Cu-I-Cu in its thickness direction, the structure changed to the Cu-II-II and Cu-III-III layer structures for the negative and positive thickness directional strains, respectively. A complex-type structure was found in the transition from Cu-I-Cu to Cu-II-II and Cu-III-III. [ABSTRACT FROM AUTHOR]

In this paper, we propose a method of forming a tube into an oblique/curved shape by synchronous multipass spinning, in which the forming roller reciprocates in the radial direction in synchrony with the rotation angle of the spindle while the roller moves back and forth along the workpiece in the axial direction to gradually deform a blank tube into a target shape. The target oblique/curved shape is expressed as a series of inclined circular cross sections. The contact position of the roller and the workpiece is calculated from the inclination angle, center coordinates, and diameter of the cross sections, considering the geometrical shape of the roller. The blank shape and the target shape are interpolated along normalized tool paths to generate the numerical control command of the roller. By this method, we experimentally formed aluminum tubes into curved shapes with various radii of curvature, and the forming accuracy, thickness distribution, and strain distribution are examined. We verified that the curved shapes with the target radii of curvature can be accurately realized. [ABSTRACT FROM AUTHOR]

In spinning process of large thin-walled aluminum alloy parts, the wrinkling phenomenon easily tends to appear on the blank flange. By applying a constraint condition to the flange, such as a backup roller, the flange stiffness can be increased, and the wrinkling tendency is delayed. In order to understand the deformation mechanics under the flange-constrained conditions, the effects of two kind of flange-constrained methods on the spinnability of an aluminum alloy hemispherical part are studied in this paper, and the effects of the flange-constrained conditions and process parameters on the wrinkling initiation at the flange are analyzed. At the same time, multi-pass flange-constrained spinning processes are completed. The spinnability test results show that the forming defect of the single-side flange-constrained(SSFC) spinning is wrinkling, and that of the double-side flange-constrained (DSFC) spinning is cracking; the two flange-constrained methods can both increase the spinnability of the hemispherical spun part. And the analysis of process parameter shows that with the increase of the feed rate and the operating angle, and with the decrease of the roller nose radius, the flange wrinkling initiation in the SSFC spinning occurs in advance. Besides, in the multi-pass forming of the hemispherical part, compared with the conventional spinning, the two flange-constrained spinning processes can not only make forming passes fewer, but also improve the wall thickness uniformity. [ABSTRACT FROM AUTHOR]

Metal spinning is an incremental forming technique commonly employed in the production of hollow axisymmetric components. In recent years, asymmetric spinning processes have been developed to expand the range of component geometries achievable by the technique. However, most of these processes have employed a solid mandrel to set the target shape and provide internal support to the workpiece, thus requiring new tooling to be manufactured for every new part. Moreover, no studies have been performed on the link between the geometry of the target part and the achievable forming height. In this paper, the range of curvature in the target part's planform is used to quantify its degree of asymmetry, and the influence of this parameter on the formability of spun parts is investigated in a series of experimental trials. The hypothesis that the range of planform curvature predicts the likelihood of workpiece failure is tested. Methods to design the multi-pass toolpaths and the blanks required to spin both axisymmetric and asymmetric components without a mandrel are developed. The results show that increasing the degree of asymmetry of the target part only weakly influences the achievable forming height. This finding points to the potential of the technique to produce multiple geometries flexibly and to reduce the costs of prototyping and testing new sheet metal parts considerably. [ABSTRACT FROM AUTHOR]