High-speed Stamping Research Articles

Trajectory optimization of the redundant manipulator with local variable period under multi-machine coordination

AbstractThe coordinated motion between the press and the feeding mechanism directly determines the production efficiency of the high-speed stamping line. In order to generate the high-performance trajectory of the feeding mechanism, this paper investigates the optimization of the trajectory with the local variable period. Based on the quintic B-spline curve and normal distribution, the smooth interpolation method of variable-time interval is proposed to generate the collision-free and energy-jerk-minimal trajectory with variable-time intervals. The advantage of the proposed method is that it can make the feeding mechanism transition smoothly between districts of variable-time and fixed-time intervals. It is beneficial to avoid re-performing the entire process of trajectory planning. ADAMS and actual experiments are used to validate the effectiveness of the proposed method. Results show that the proposed method can maintain the high performance of the initial trajectory, and there is no sharp point in the displacement-time and velocity-time curves. The investigation provides a new direction for the direct generation of local variable-period trajectories in the multi-machine coordination of the stamping line.

Utilization of CFRP in High-Speed Stamping Presses and its Gigacycle Fatigue Testing at Resonance Frequency

Carbon fiber reinforced polymer (CFRP) utilization meets the requirements of stiffness, damping, and light weight for enhanced performance of machine tools. Stamping presses are expected to function for billions of cycles, resulting in the fatigue of the employed materials and parts. High-speed stamping presses, such as the Bruderer BSTA-200, should fulfil the increasing customer requirement of enhancing both quality and quantity of the delivered parts. Among the quickest presses currently available in the market, these BSTA presses can reach speeds up to 2000 strokes per minute (spm) with a stroke of 8 mm and still continue operating for many decades. For this project, new requirements were defined: a 25% increase of the stamping speed reaching up to 2500 spm, while maintaining the same stroke of 8 mm. The ram was redesigned by making use of CFRP, and because of its high stiffness and strength, it enabled a weight reduction of 65%. Owing to the stamping force of 200 kN and the impact of the stamping process, the material of the ram is highly strained. A major concern in utilizing CFRP in machine tools is the fatigue and change in material properties with increasing stress cycles. Therefore, the fatigue behavior of CFRP had to be validated in the very high cycle fatigue (VHCF) range. This was performed using a newly developed fatigue test bench. To complete 109cycles within a few weeks, the testing occurred at the specimen’s resonance frequency with a constant and controlled strain of 0.1%. Aspects such as resonance frequency testing, heating of the specimen, and an accurate measuring system were considered. The specimens had to be designed and optimized for this type of testing, thus resulting in a cylindrical tube shape with a unidimensional (UD) arrangement of the fibers in longitudinal and transverse direction.

RESOURCE-SAVING TECHNOLOGY FOR HIGH-SPEED HOT EXTRUSION OF BIMETALLIC ROD PARTS

Processes of high-speed shaping changes and especially high-speed hot extrusion create efficient conditions for treatment of weakly plastic and poorly deformable materials which are widely used in tool making facilities. Due to the fact that high-speed stamping provides accurate billets with increased mechanical properties, it can be used as a technological process for manufacturing rod parts of die tooling operating under conditions of increased loads and wear. The purpose of the given paper is to carry out experimental investigations on the possibility to obtain a bimetallic rod tool where structural steel is considered as a basis of the tool and a working cavity is made of high-alloyed tool steel with its saving up to 90 %. A scheme of loading and geometry of conjugated surfaces of the composite billet have been developed in the paper. Technology for obtaining bimetallic rod parts of die tooling with deformation at speed of v д = 70–80 m/s and composite billet temperature of Т = (1150±20) o С has been experimentally tested with formation of a compound due to plastic flow of two billet parts on contact surface with removal of surface oxide films. Microstructures of the bimetallic compounds obtained with the help of high-speed hot extrusion method for compositions of structural and high-alloy steels have been investigated and their high quality has been proved during the investigations. Dependences of micro-hardness distribution have been established outbound two steel contact plane in the zone of connection that are characterized by a minimum micro-hardness value in the connection joint. Availability of more plastic zone in the contact plane contributes to reduction of residual stresses due to their relaxation in this zone and higher joint strength.

The Quality Improvement in Manufacturing “Screw”-Parts Using the DEFORM-3D Software

The check of developed inventory for high-speed stamping "Screw"-part forging fabricated from aluminum alloy by using DEFORM is performed. The high efficiency of the program is shown. The characteristic of metal flow and stress-strain state during the processing is opened.

Production of new isotropic electrical steels at OAO NLMK

Specialists at OAO NLMK, in close collaboration with research institutes, have developed new grades of isotropic electrical steels and practical principles for their mass production, especially for use in high-efficiency magnetic cores. These include steels with low magnetic losses, high magnetic induction, and high magnetic permeability (high-permeability steel); semiprocessed rolled products from several alloying groups; and steel for high-speed stamping. The proposed technologies have no counterparts anywhere in the world and permit complete import substitution.

Dynamic tensile behaviour and deformational mechanism of C5191 phosphor bronze under high strain rates deformation

High speed stamping process is used to high strength and high electrical conductivity phosphor bronze with extremely high strain rates more than 103s−1. This study on the dynamic tensile behaviour and deformational mechanism is to optimise the high speed stamping processes and improve geometrical precision in finished products. Thus, the tensile properties and deformation behaviour of C5191 phosphor bronze under quasi-static tensile condition at a strain rate of 0.001s−1 by electronic universal testing machine, and dynamic tensile condition at strain rate of 500, 1000 and 1500s−1 by split Hopkinson tensile bar (SHTB) apparatus were studied. The effects of strain rate and the deformation mechanism were investigated by means of SEM and TEM. The results showed that the yield strength and tensile strength of C5191 phosphor bronze under high strain rates deformation increased by 32.77% and 11.07% respectively compared with quasi-static condition, the strain hardening index increases from 0.075 to 0.251, and the strength of the material strain rates sensitivity index change from 0.005 to 0.022, which presented a clear sensitive to strain rates. Therefore, it is claimed that the dominant deformation mechanism was changed by the dislocation motion under different strain rates, and the ability of plastic deformation of C5191 phosphor bronze increased due to the number of movable dislocations increased significantly, started multi-line slip, and the soft effect of adiabatic temperature rise at the strain rate ranging from 500 to 1500s−1.

ANALYTICAL MODELING OF THE MICROSTRUCTURE EVOLUTION OF TITANIUM ALLOYS DURING HIGH-SPEED STAMPING OF THE BLADES OF GAS-TURBINE ENGINES

The analysis procedure of the microstructure evolution during intense deforming is developed and approved by an example of high-speed stamping (HSS) of GTE blades made of VT9 titanium alloy based on the analytical model of dynamic recrystallization. Model coefficients were calculated by the results of the measurement of grain sizes during the preliminary experiments on high-speed upsetting of cylindrical samples made of VT9 alloy. The microstructure was investigated experimentally after HSS of the blades made of VT9 alloy using a VSM4 hammer with the motion velocity of falling parts in deformation beginning of 30 m/s. The microstructure evolution of the deformed medium is modeled analytically (by the sizes of the α phase) allowing for the variation in texture along main deformation directions with an error up to 10 %.

Analytical modeling of the microstructure evolution of titanium alloys during high-speed stamping of the blades of gas-turbine engines

The analysis procedure of the microstructure evolution during intense deformation is developed and approved by the example of high-speed stamping (HSS) of GTE blades made of VT9 titanium alloy based on an analytical model of dynamic recrystallization. Model coefficients were calculated by the results of a measurement of grain sizes during preliminary experiments on the high-speed upsetting of cylindrical samples made of VT9 alloy. The microstructure was investigated experimentally after the HSS of blades made of VT9 alloy using a VSM4 hammer with the motion velocity of falling parts in the beginning of deformation at 30 m/s. The microstructure evolution of the deformed medium is modeled analytically (by the sizes of the α phase), allowing for the variation in texture along main deformation directions with an error reaching 10%.

High-Speed Stamping of Powder Workpieces for Objects of High Density and Strength

Development of high-speed workpiece stamping technology for objects of domestic designation from iron-based powders is analyzed. Results of experiments performed by the authors are discussed for cold high-speed stamping of objects such as bushes with a conical section made from iron powder grades PZhV3 and PZhV4 followed by sintering, and also by high-speed stamping of these objects. A die construction and methods for preparing workpieces of the bush type with a conical end section proposed by the authors are protected by patents.

Invited: Coatings for Robust Metal Bipolar Plates

Metal bipolar plates have advantages of lighter weight and smaller volume over graphite based bipolar plates for automobile fuel cell stacks. Stainless steel has been identified as the primary candidate of the substrate. It has reasonable corrosion resistant, high electrical and thermal conductivity, suitable mechanical properties and formability to form the proper flow field by conventional high speed stamping process. The most important, SS foil is widely commercially available and used in various markets, which result in its low cost comparing with other corrosion resistant alloys. Additional treatment on stainless steel is necessary for three reasons. First is to reduce the surface electrical contact resistance with gas diffusion layer. The second is to further improve the corrosion resistance of stainless steel in PEM fuel cell stack operation conditions, especially under the transient high voltage conditions. The third is to minimize the absorption of leached ions on the electrode catalyst that may poison electrodes.Two types of coatings have been investigated. One is the coating using precious metal, the other is precious metal free coating technologies. The advantages and progresses of each coating will be reviewed. TreadStone has been involved in corrosion resistant metal plate development for several years. A unique design of metal plate coating and its low cost fabrication technology have been developed. It has demonstrated stable long term (2,000 hours) operation for automobile fuel cell stacks under dynamic operation conditions. More development activites are on-going to further reduce the cost with the supports from US Department of Energy.

The Static and Modal Analysis of 12000KN Fine Blanking Press Frame

The fine blanking press supports huge impact load and high-speed stamping frequency in the work process, and the deformation of the molds and the precision of components are significantly influenced by the deformation and vibration of the press. The frame under impact load and stamping frequency, thus the frame structure is the key factor to ensure the reliable work. To make the virtual prototype of the 12000KN fine blanking press frame meet requirements in the best way, the concept design of the frame was built. And optimal interval of the frame stiffness and first order natural frequency were find according to finite element analysis, which can lay the foundation for the design of an ideal frame.

Research on Online Visual Inspection System for Multi-Feature Trademark Defect

Modern printing industry detective techniques, which have transferred from traditional single discrete manual operation into line detection based on machine vision. The line detection research under the highly automated process requirements, which is based on color graphics, gravure text, high-speed stamping and laser hologram hot stamping technology, is the multi-feature defect detection and recognition. By CDD study linear measurement techniques and computer vision technology, the research built the visual inspection platform, and design detection scheme combined with the specific requirements of the printing process in database technology and image processing technology. Research obtained the online testing solutions and system information flow characteristics, which achieved requirement of multi-feature detection, high precision and high speed continuous production technologies.

Analysis of the influence of high-frequency current and annealing modes on the complex of mechanical properties of titanium alloy GTE compressor blades produced by high-speed stamping

The paper presents a pilot study and analysis of the influence of high-frequency current heating and annealing modes on the macro and microstructure, the complex of mechanical properties, the amount of buckling and thermal stability of blades produced by high-speed stamping. The possibility of straightening combined with thermal processing to obtain satisfactory geometry of blades without essential decrease in the complex of mechanical properties is investigated.

The influence of high-frequency current heating temperature on the structure and properties of VT9 alloy blanks for high-speed stamping

The paper is devoted to the influence of technological parameters and methods of high-frequency current heating on the structure of VT9 alloy blanks for high-speed stamping. The influence of the blank structure on the strain stress state, the complex of mechanical properties, the energy of deformation and stability of stamping equipment are analyzed. Comparative estimation of high-frequency current heating and oven heating is given. The procedure of carrying out the experiments is presented and the analysis of their results is given.

Multi-Objective Optimization of Inertia Equilibrium in Ultra High Speed Stamping Machine

With the development of manufacturing industry, the stroke speed of stamping machine is higher and higher. In accordance with the development, researchers and engineers have paid more and more attention to developing various types of ultra high speed stamping machines. The key to develop ultra high speed stamping machine is to solve the problem of inertia equilibrium. This paper presents an optimization approach for multi-objective inertia equilibrium design for ultra high speed stamping machine. Simulation results demonstrate the effectiveness of the proposed approach.

Light Metal in High-Speed Stamping Tools

The required number of punched and blanked parts in the electronic industry, such as leadframes, contact pins or plugs often reach several million pieces. According to this, the production process has been sped up to frequencies up to 2000 parts per minute. At this production rate parts of thin steel or copper sheets are produced with high-speed stamping presses and blanking tools. Because of the high gating velocities in the blanking tool there is a recurring acceleration at the moment, when the blank holder contacts the sheet metal. A second shock in the blanking tool arises, when the sheet cracks. This is also known as the impact shock during the blanking process. Trough these two impulses and through the cycle of the plunger movement a periodic oscillation arises in the tool. Horizontal vibrations can lead to an undefined position between punches and die-plate, while vertical movement leads to increased wear because of friction forces between the blanked surface and the lateral area of the punches. The goal of this project was to minimize these oscillations in cutting tools by the usage of lightweight materials in the flux of forces. An experimental cutting tool was designed with alternative top and bottom plates for the comparison of the oscillation status in the cutting process when using plates of steel, aluminium or magnesium. The centre plate of the tool remains constant. Experiments were accomplished for several velocities and tool setups with different plate materials. To determine the influence of the materials with different density and elasticity acceleration, force and acoustic emission sensors were integrated in the tool. The set of problems was investigated by analyzing the measured data and by determining the wear in practical tests.

Study of Solutions and Causes for Scrap Jumping up in High-Speed Stamping

High-speed sheet metal stamping is popular because it is economical and quick means of producing intricate, accurate and durable components in large quantities. Scrap jumping up is one problem which usually occurs in high-speed stamping manufacturing processes. In this paper, the relevant factors are analyzed and studied such as the press tool, the shape and size of the stamping pieces, the structure and rigidity of pressing die, the clearance between punch and die, material properties of the blank, etc. Then ten cases are summarized that lead to scrap jumping up. For each case, corresponding solution is presented to avoid the scrap jumping up.

Research on Intelligent Control System of Pressure Forming Equipment for Stator and Rotor

An intelligent control system of pressure forming equipment for stator and rotor is presented. The architecture of the high-speed stamping product line is introduced first. Then the function of the control system is analyzed and the control system is designed. Finally, the stamping process is studied and the intelligent stamping process optimizing system is developed.

Analysis and Simulations of Inertia Force in Ultra High Speed Stamping Machine

Based on analysis and simulations, it is found that extremely high inertia forces will be generated in stamping machine when stroke speed falls in range for ultra high speed stamping machine if a regular crank-slider mechanism is used. This paper presents a design method to lower the inertia forces by using balancing structure. The effectiveness of the proposed structure is validated through simulations. An analytical method to evaluate performance of balancing structure is also presented. This work paves the way to develop ultra high speed stamping machine.

Adjustment of two-cell temper rolling mill and tinplating unit 2 after modernization

New equipment at AO ArcelorMittal Temirtau considerably improves the appearance and corrosion resistance of tinplate by eliminating longitudinal bands from the surface and also reduces customer complaints regarding the nonplanarity of tinplate in modern high-speed stamping lines.