Fine Blanking Process Research Articles

Energy efficiency improvement of heavy-load hydraulic fine blanking press for sustainable manufacturing assisted by multi-stages pressure source system

The fine blanking process has the highest forming accuracy in the field of metal forming and its production volume has increased sharply. However, hydraulic fine blanking presses (HFBP) – the core equipment of the fine blanking process, have suffered from significant energy loss due to the inefficient hydraulic system. To enhance the energy efficiency of the hydraulic system, this study introduced a novel approach – a multi-stage pressure source system comprised of distinct pump-accumulator groups, each operating at varied supplied pressures to narrow the mismatch of the installed and demanded power. This adaptive system is capable of automatic adjustments to align with the required pressure, thereby mitigating energy losses while concurrently preserving superior dynamic working performance. First, this study commenced with a theoretical analysis of the system configuration and energy characteristics of HFBP. Subsequently, a comprehensive exploration into the inherent inefficiencies of the hydraulic system is undertaken by formulating a precise energy consumption model. Finally, a novel energy-saving optimization design was carried out on the fast-approaching subsystem. The results demonstrated that the implementation of the proposed system led to a notable reduction of 76.87% in energy loss within the flow-regulating module, and an overall diminution of 13.53% in energy dissipation compared to the conventional system. This study will significantly advance sustainable manufacturing practices within the metal-forming domain by reducing electricity consumption and production cost.

Energy consumption analysis for the fine blanking process

Energy consumption analysis for the fine blanking process

Study on material-data-driven process parameterization in fine blanking

In industrial sheet-metal processing, processes are parameterized based on the material specifications. However, the manufacturing process of sheet-metal coils determines the material properties and as every manufacturing process is subject to variations, variations in material properties occur in the semi-finished product influencing the subsequent sheet-metal processing. The production of high-quality parts requires considering these varying material properties to adapt the processes accordingly. This paper shows that material data from non-destructive eddy current measurements and process data of the coil production enable decision support for the parameterization of fine blanking processes. A material-data-driven approach using material data recorded in an industrial setting is employed to investigate the influence of parameter settings in the fine blanking process on specific quality characteristics of fine blanked workpieces.

Prediction of Tool Wear in Fine Blanking Punch with PVD Coating with TiCN for JIS.SKH51 High Speed Tool Steel Using Archard Wear Model

The aim of this study is predict tool wear in the fine-blanking process using a tribometer tester with ASTM G99-17 standard. Then, the result of wear volume and tool life were confirmed with finite element simulation and experiment. The punch material used in fine blanking process was selected to be hight speed steel JIS.SKH51 with surface coating thickness 4 µm of TiCN, the work piece material was used as hot-rolled steel JIS.SPHD P/O, with a thickness of 8 mm. The experimented and simulated results were found that the pressure, and sliding velocity were increase in term of linear curve with slope K = 2.09x10-6 and K = 2.07x10-6 ,respectively, and the hardness of material was increase in term of power at 1.983 and slope of K = 2.14 x10-6. These three factors were effect to the wear volume and tool life, simultaneously, the summation of three factors will average as K = 2.10 x10-6. From comparison of the applied wear equation model with tribology tester the simulated and experimented results were similarly equal with 0.05 by significance at 95% reliability confident. The resulted were precisely confirmed according to the previous research.

Fine Blanking of Austenitic Stainless Steel Gears Using Carbon-Supersaturated High-Speed Steel Tools

Austenitic stainless steel gears were fabricated via the fine blanking process that can be used for mass production. A carbon-supersaturated (CS)-matrix high-speed steel punch was prepared to minimize the adhesive and abrasive wear damage. Its edge profile was tailored and finished to control the local metal flow around the punch edges and edge corners. This CS punch was utilized in fine blanking the AISI304 austenitic stainless steel gears. Ball-on-disc (BOD) testing was first employed to describe the frictional behavior of the CS tool steel disc against the AISI304 stainless steel balls. SEM-EDX analysis on the wear track revealed that a free-carbon tribofilm was formed in situ in the wear track to prevent adhesive wear via galling on the tool steel disc. No significant adhesive or abrasive wear was detected on the punch edges and punch edge corners after continuously fine blanking with 50 strokes. AISI304 gears were produced to have fully burnished surfaces. Their pitches, widths and circles were measured to evaluate their gear-grade balancing during the fine blanking process. The stabilized gear-grade balancing in JIS-9 to JIS-10 grades was attained for these as-blanked AISI304 gears without finishing processes.

Advantages in the production of power transmitting gears by fineblanking

Fineblanking of gears has an enormous time and cost saving potential as well as the potential to significantly reduce CO2 emissions compared to conventional manufacturing of gears. Conventional manufacturing of gears consists of at least three steps such as milling, case hardening, and grinding. With fineblanking, only one manufacturing step is necessary. However, the load-carrying capacity regarding different gear fatigue failure modes, such as pitting or tooth root breakage, is stated significantly lower for the commonly used shear-cutting steels compared to the conventional case-hardened gears made out of high-strength hardened steels. This work shows the possibility of utilizing compressive residual stresses that are induced by the fineblanking process to increase the load-carrying capacity regarding tooth root breakage up to the level of case-carburized gears. Pinions and wheels made of S355MC (1.0976) and S500MC (1.0984) are fineblanked using parameters determined in previous works with a focus on the induction of high compressive residual stresses into the finished products. The variants are investigated regarding, e.g., cut surface characteristics, hardness, and residual stresses. For the two steels, as well as a stress relived variant, the tooth root bending strength is also determined in pulsator tests with the fineblanked pinions.

Data-driven indirect punch wear monitoring in sheet-metal stamping processes

The wear state of the punch in sheet-metal stamping processes cannot be directly observed, necessitating the use of indirect methods to infer its condition. Past research approaches utilized a plethora of machine learning models to infer the punch wear state from suitable process signals, but have been limited by the lack of industrial-grade process setups and sample sizes as well as their insufficient interpretability. This work seeks to address these limitations by proposing the sheared surface of the scrap web as a proxy for the punch wear and modeling its quality from acoustic emission signals. The experimental work was carried out in an industrial-grade fine blanking process setting. Evaluation of the model performances suggests that the utilized regression models are capable of modeling the relationship between acoustic emission signal features and sheared surface quality of the scrap webs. Subsequent model inference suggests adhesive wear on the punch as a root cause for the sheared surface impairment of the scrap webs. This work represents the most extensive modeling effort on indirect punch wear monitoring in sheet-metal stamping both from a model prediction and model inference perspective known to the authors.

Optimization of Hydraulic Fine Blanking Press Control System Based on System Identification

Fine-blanking is a molding process based on the common blanking process, which obtains hydrostatic stress through blank holder reverse jacking, in order to increase material plasticity. It requires special equipment, namely a fine-blanking press, to complete the fine-blanking process. In this paper, the problem of the speed of the slide block fluctuation found in the actual use of a 12,000 kN hydraulic fine-blanking press after multi-stage pressure source optimization is studied. Firstly, the mathematical model of the motion of the slide block in the blanking stage of the hydraulic fine blanking press is established, and the accurate mathematical model in the blanking stage of the hydraulic fine-blanking press is obtained through the least square method system identification experiment. Aiming at the complex working situation of the fine-blanking press, a phased PID control strategy is creatively proposed. The optimal PID control parameters are obtained by a genetic algorithm, and established a fuzzy PID controller for the blanking stage to accurately control the movement speed of the slide block. The results show that the new control strategy is very effective in improving the movement accuracy of the slide block, effectively improving the machining accuracy and reducing the impact vibration of the hydraulic system.

Comparative study of v-ring indenter configurations in fineblanking in order to derive tool design guidelines

The v-ring indenters and their configurations play a major role in the fineblanking process, directly influencing component quality and characteristics. While past studies regarding residual stresses of blanked components focused mainly on the use of a pair of v-rings, so far no efforts were undertaken to compare different v-ring setups, deducing tool design guidelines and enabling possible cost savings. Therefore, a comparative study of different v-ring indenter setups and their influence on cut surface parameters, surface hardness and induced residual stresses of the produced components was performed. The obtained results indicate a minor influence of blank holder-sided v-rings on the observed component characteristics in comparison to indenters situated on the die leading to recommendations with regard to cost-efficient tool design.

Numerical Simulation of Fine Blanking Die Wear and Die Performance Analysis

In order to study the die wear law of rotary fine blanking helical cylindrical gear, a three-dimensional rigid plastic finite element model of rotary fine blanking helical cylindrical gear is established on the Deform-3D software platform. Based on the Archard wear model, this paper analyzes the die wear in the fine blanking process, obtains the wear distribution of each point on the working surface of the die, determines the maximum wear area, and makes a comparative analysis with the fine blanking die wear of spur gear. Through the single factor variable method, this paper studies the effects of reverse jacking force, blank holder force, blanking speed, punch and die clearance, die fillet radius, and die initial hardness on die wear. The test results show that when the punch reduction is the same, the wear of the female die of fine blanking helical cylindrical gear is greater than that of fine blanking spur cylindrical gear. When the counter jacking force increases from 100 kN to 200 kN, the maximum wear of the die gradually increases from 6.91 × 10–6 mm to 9.38 × 10–6 mm; when the blank holder force increases to 3/4 of the blanking force, the die wear decreases with the increase of blank holder force; it is ideal when the blanking clearance is 0.5% t (0.02 mm). Conclusion. The wear model can accurately predict the relationship between main process parameters and wear in the process of rotary fine blanking, and the measures to reduce die wear are put forward from the aspect of process design.

A Novel Force Variation Fine-Blanking Process for the High-Strength and Low-Plasticity Material

High forming force is often needed when high-strength and low-plasticity materials are processed by fine blanking. Too high forming force increases the load of the die and greatly increases the risk of die failure. If the forming force is reduced, the material will fracture prematurely, which will lead to poor quality parts. Aiming at this problem, a new force variation load fine-blanking technology is proposed in this paper. During the loading process, the forming force does not remain constant but changes with the blanking stroke. A 2D finite element fine-blanking model was established for the TC4 material. The mechanism of force variation fine blanking is also revealed. This paper proposes a method to design the loading route of the forming force with variable load. This method combines finite element simulation with neural network and a multi-objective genetic algorithm. Finally, the application of variable load fine blanking production and the application of traditional fine blanking production parts are verified by the experimental method. The same results are obtained from both simulation and experiment. It is found that the variable load fine blanking process can greatly reduce the load of the die on the premise of ensuring the quality of fine-blanking parts.

Numerical simulation and optimization of fine-blanking process for copper alloy sheet

When the fine-blanking process is used, secondary grinding or processing can be omitted because the shear surface of fine-blanking parts can achieve almost zero fracture zone requirements. The primary objective of the fine-blanking process is to reduce the fracture zone depth and die roll zone width. This study used a 2.5-mm-thick central processing unit (CPU) thermal heat spreader as an example. Finite element analysis software was employed to simulate and optimize the main eight process parameters that affect the fracture zone depth and die roll zone width after fine-blanking: the V-ring shape angle, V-ring height of the blank holder, V-ring height of the cavity, V-ring position, blank holder force, counter punch force, die clearance, and blanking velocity. Simulation analysis was conducted using the L18 (21 × 37) Taguchi orthogonal array experimental combination. The simulation results of the fracture zone depth and die roll zone width were optimized and analyzed as quality objectives using Taguchi’s smaller-the-better design. The analysis results revealed that with fracture zone depth as the quality objective, 0.164 mm was the optimal value, and counter punch force made the largest contribution of 25.89%. In addition, with die roll zone width as the quality objective, the optimal value was 1.274 mm, and V-ring height of the cavity made the largest contribution of 29.45%. Subsequently, this study selected fracture zone depth and die roll zone width as multicriteria quality objectives and used the robust multicriteria optimal approach and Pareto-optimal solutions to perform multicriteria optimization analysis. The results met the industry’s fraction zone depth standard (below 12% of blank thickness) and achieved a smaller die roll zone width.

Active Vibration Control of a Mechanical Servo High-speed Fine-Blanking Press

The fine-blanking process as an advanced sheet metal forming process has been widely applied in industry. However, specially designed equipment is required for this process. In this paper, a novel mechanical servo high-speed fine-blanking press with the capacity of 3200 kN is proposed, and the vibration control for this machine is researched to achieve the requirement of fine-blanked parts of high dimensional accuracy, since the vibration of the fine-blanking machine will cause the machining displacement error and reduce the machining accuracy. Self-adaptive feed-forward control is used to simulate the active vibration control of the mechanical fine-blanking machine. The vibration control principle of the fine-blanking machine is described, and the control algorithm is established. At the same time, the mechanical vibration model of the fine-blanking machine as the controlled object is established, and the parameters of the excitation input and the mechanical model are obtained by the fine-blanking finite element simulation and the experiments of the vibration measurement of the press. Finally, the numerical simulation and analysis of active vibration control based on MATLAB are carried out. The results show that the control effect is good, and the vibration response is effectively reduced, thus greatly increasing the processing accuracy, saving a significant amount of energy, and reducing the energy consumption and defective rate.

Investigation of the Micro Hardness at the Cut Surface of Fine Blanked Parts with Variation of Sheet Material and Cutting Temperature

Fine blanking is a production technology of high importance especially for the automotive industry. As a procedure of sheet metal separation, it is possible to produce complex parts in a single stroke. As a difference to conventional punching, the cutting surface of fine blanked parts can often be used as a functional surface without further process steps. However, fine blanking as a forming process changes the microstructure of the metal sheet to a higher extend than cutting or machining processes. Due to this, it is of utmost importance to investigate the cause-effect-relations between the fine blanking process parameters and the resulting properties of the fine blanked part. Especially the condition of the cut surface as an important quality criterion has to be investigated. The quality characteristics of the cut surface of fine blanked parts are often subject of investigations. In addition, it would be of importance to investigate how the material properties in the shear zone are changed by the fine blanking process. This on one hand in turn can enable conclusions to be drawn about possible punch wear. If, on the other hand, hardening of the cut surface takes place as a result of fine blanking, then this could have a positive influence on the application properties of fine blanked components. Thus, an experimental fine blanking investigation of the micro hardness of the cutting surface has been made with variation of steel material and cutting temperature. It could be demonstrated that the micro hardness increases in direction towards the burr. This is independent on material and cutting temperature.

Effects of fine blanking process on cutting surfaces of high-strength DP600 and DP800 sheets

ABSTRACT In this study, both blanking and fine blanking processes were performed using 1mm thick DP600 and DP800 sheet materials. The cutting surfaces of the materials were examined using scanning electron microscopy (SEM). The SEM examinations showed that the extent of the fracture zone in the blanking method was much greater than in the fine blanking method, whereas the extent of the shear zone in the fine blanking method was much greater than in the blanking method. In addition, in the fine blanking experiment, it was observed that the crescent and star pieces were nearly all sheared and detached from the test material, whereas with the blanking method, the crescent and star pieces were broken off from the test material. In the blanking, more than half of the cutting surface (0.6t) formed a fracture zone, while in the fine blanking no fracture zone and a shear zone of 0.9t was seen.

Experimental Investigation of Process Forces and Part Quality for Fine Blanking of Stainless Steel with Inductive Heating

Fine blanking is a highly productive process of industrial mass production with which high quality components in particular but not exclusively for the automotive industry are produced. The manufacturing process faces its limits at elevated tensile strengths of the materials to be processed. Consequently, high-strength steels can currently only be fine blanked to a limited extent. This can be overcome by lowering the flow stress of high-strength steels by means of inductive heating. A steel of high importance especially for industries with high hygiene standards such as medical and nutrition production is the stainless steel X5CrNi18-10 (1.4301). As a metastable austenitic steel which can initiate cutting impact on the press through martensitization, fine blanking of stainless steel is a challenge. X5CrNi18-10 is not a high-strength steel per se but becomes difficult to process due to the high hardness of the martensite phase, known as transformation-induced plasticity (TRIP) effect. Thus, in order to combine the possible advantages of the fine blanking process with inductive heating and the important properties of stainless steel, fine blanking of this steel was investigated with inductive heating prior to the fine blanking. The process forces and product quality properties such as die roll were investigated and found to be advantageous in comparison to non-heated fine blanking specimens of the same steel. The process forces and the die roll height decreased due to the heating.

Mechanical characteristic analysis of a separable stator fabricated by fine-blanking process with numerical and experimental methods

Ultrasonic motor acts as a significant equipment which has been widely used in automobile, aerospace, and medical industry. As the core part of the ultrasonic motor, a novel separable stator fabricated by the fine-blanking process is proposed, and the validity and rationality as well as the operation performance of the novel stator are investigated. A finite element model is used to check the feasibility of the stator. The model of the stator contains teeth body, piezoelectric ceramic ring, inner and outer gaskets, and adhesive and welding layer. Based on the model, simulations are carried out to obtain mechanical characteristics. The inner, outer gasket and teeth body of the stator are welded together. This manufacturing process cost can be significantly reduced compared to the machining process for the conventional stator. The stator prototype is also fabricated and assembled. The maximum rotary speed and stalling torque are tested by torque speed sensor. The experimental results show that maximum rotary speed can reach to 150 r/min, and maximum stalling torque is 1.42 Nm, which shows the fine-working performance and the rationality of the stator structure. The research confirms that the separable stator fabricated by fine-blanking process has promising future in the ultrasonic motor application area.

A Review of Fine Blanking: Influence of Die Design and Process Parameters on Edge Quality

Conventional blanking is the single-stroke shearing of closed contour profiles. However, the blanked pieces have inherent errors like fractured cut surface and blank dishing necessitating further sizing and/or finishing operations. Fine blanking is a more precise version of the blanking operation with lesser errors such that post-forming steps required will be minimal. Thus, it is an ideal candidate for manufacturing precision machine components. This review paper starts with the introduction to the process. Then, studies aimed at the analysis of fine blanking tooling and process parameters and their effect on fine-blanked part characteristics are presented. Inferences from studies on the design of equipment for fine blanking, deformation mechanics involved and the fine blanking performance of different materials are also discussed. The use of finite element simulation studies to understand the process better has also been determined. Various reported strain measurement techniques are then discussed. The recent improvement in techniques like in situ digital image correlation enables accurate experimental measurement of strain in the shear zone which can be used to validate the findings from FE simulations. Fine blanking process modifications that aimed at cost reduction or improvement in product quality are summarized as well.

Finite element simulation and experimental investigation of the effect of clearance on the forming quality in the fine blanking process

The general concept of blanking seems a simple one but governing parameters are many and have a complex relation-ship, which directly affect the quality of the produced parts. These parameters are assessed using three main criterions: the burr amount, the appearance of the cut edge and dimensional accuracy. However, the optimization of these parts produced depends on full understanding of the fine blanking process. The aim of our work is to develop the numerical computations in order to investigated the influence of selected parameter of the cutting process on the stress state of cold-rolled steel sheets being cut. The material testing and the characterization are carried out in order to fit the constitutive model parameters to the experimental data and to establish the sheet metal constitutive law. The identified model is, then, used for numerical simulations which are performed using LsDyna/Explicit software of various blanking tests. During of numerical simulations of the fine blanking process was observed elongation in shear surface and simultaneous reduction in fracture zone versus clearance punch/die and also that punch is be considered deformable or not. The numerical results of the validation simulations were in agreement with the experimental data.

Analysis of fine blanking process through finite element simulations

ABSTRACT Fine blanking is a widely used process in the automotive industry to produce different parts in mass production. In blanking, the quality of the final product mainly depends on process parameters. The present paper is focused on developing the finite element model for the blanking process to study the effect of process parameters on the quality of the blanked part. The finite element model has axisymmetric quadrilateral elements with an automatic mesh adaptivity feature. The effect of clearance, punch/die corner radius, and binder type on plastic flow, punch forces, and die rollover has been studied through FE simulations. The FE results reveal that die rollover height and die rollover depth is increasing with the increase in clearance. The V-ring binder is decreasing the die rollover over the flat binder. The punch force is not effecting much with the clearance between die and punch. The developed FE models can be used to improve the robustness of the process and process optimisation to enhance the quality of the blanked parts.