Stamping Process Research Articles

Deep Learning Approach for automatic detection of split defects on sheet metal stamping parts

Sheet metal stamping processes are used primarily for high-volume products produced for a range of sectors, from white goods manufacturing to the automotive and aerospace sectors. However, the process is susceptible to defects. Due to the numerous potential defects that may arise in the stamping product, human inspectors are often deployed for their detection. However, they are unreliable and expensive, especially when operating at production speeds equivalent to the stamping rate. This study investigate CNN-based automatic inspection for stamping defects. The study carried out two sets of experiments. All the Experiments yielded high classification accuracy, recall and precision demonstrating the viability of the CNN method for defect detection in the sheet metal stamping process. Additionally, this study revealed that in limited data confounding factors can be a challenge. The second experiment further explored the impact of small neck defects, harsh lighting and reflections on defect detection. The observations indicated that the model struggled to identify defects occluded by reflections, particularly small neck defects.

Influence and improvement of stamping process parameters on V-shaped clamp forming quality

Aiming at the problems that a V-shaped clamp is easy to crack, wrinkle, and springback in the stamping process, a method to improve forming quality by setting the best stamping process parameters is put forward in this paper. The stamping process of the V-shaped clamp was simulated by using the software of ABAQUS, which showed that the stamping process parameters, such as friction coefficient, stamping speed, and mold gap, can affect the forming quality. The optimal combination of stamping process parameters was obtained through an orthogonal experiment. Simulation, profile dimensional measurement, and Fuji paper test were conducted to evaluate and examine the quality of V-shaped clamps before and after optimization. According to the findings of the study, the stamping speed is the main factor affecting the simulation results. The comprehensive effect of the maximum thinning rate, maximum thickening rate, and maximum springback is the best with the stamping speed of 10.00 mm·s−1. The ideal specifications for the stamping process are a 0.16 friction coefficient, a 10.00mm·s−1 stamping speed, and a 2.20 mm mold gap. Process parameter modification can greatly increase the dimensional accuracy and mechanical properties of molded parts.

Spring-In Prediction of CFRP Part Using Coupled Analysis of Forming and Cooling Processes in Stamping.

The spring-in phenomenon of the composite parts can affect the assembly process. This study aims to predict the spring-in phenomenon of a carbon fiber reinforced plastic (CFRP) part. Here, we predict the spring-in of the CFRP part using a coupled analysis of the forming and cooling processes during the stamping process. First, a simulation of the entire forming process, such as the transfer of the composite laminate, gravity analysis, and forming was performed to obtain the temperature distribution of the CFRP part. Subsequently, a finite-element (FE) simulation of the cooling process was conducted to predict the spring-in phenomenon of the shaped CFRP part using the temperature data obtained in the forming simulation. Finally, a CFRP part was manufactured and compared with the results of the FE simulation.

Comparative Study of Anti-Corrosion Properties of Different Types of Press-Hardened Steels.

Hot stamping (or press hardening) is a new technology that is widely used in the production of advanced high-strength steel parts for automotive applications. Electrochemical measurements, including potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), and accelerated corrosion tests (the neutral salt spray test and periodic immersion test) were conducted on press-hardened samples produced from uncoated (cold-rolled and cold strip production (CSP) hot-rolled) and Al-Si-coated press-hardened steels to elucidate their distinct anti-corrosion mechanisms. The cross-sectional micromorphology and element distribution of three types of press-hardened steels after a neutral salt spray test were observed using scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDAX). The corrosion resistance of Al-Si-coated press-hardened steel was found to be significantly diminished following the hot stamping process due to the presence of microcracks and elevated iron content in the coating subsequent to austenitizing heat treatment. On the other hand, the corrosion resistance of uncoated press-hardened sheets produced from cold-rolled and CSP hot-rolled press-hardened steel was found to be proximal due to their nearly identical composition and microstructure (fully martensite) after the hot stamping process. Considering the high efficiency and energy-saving properties of hot-rolled press-hardened steel, it holds the potential to replace cold-rolled and even aluminum-silicon-coated press-hardened steel in automobile manufacturing.

Development of Hot Stamping Process Technology with 60% Improved Energy Efficiency by Applying Joule Heating Technology

Development of Hot Stamping Process Technology with 60% Improved Energy Efficiency by Applying Joule Heating Technology

Damage failure prediction study of carbon fiber metal laminates in hot stamping process

In addressing the difficulty of forming Fiber Metal Laminates (FMLs), a laminate composed of a 0.1 mm-thick 304 Stainless Steel Foil (SSF) and Carbon Fiber Reinforced Plastics (CFRP) as the base material is prepared using a specific process. Subsequently, forming limit diagrams are obtained through hemispherical bulge forming experiments to investigate the forming performance of FMLs laminates. The damage phenomena of various forming specimens during the thermal stamping process are analyzed. Based on different damage forms, corresponding theoretical models are established to simulate and predict the forming damage modes of FMLs through simulation. The research results indicate that the stamping formability of FMLs is influenced by the damage tolerance of the thin stainless steel foil. During the thermal stamping process, FMLs may experience delamination, fracture/crack of the thin stainless steel foil, and rupture/tearing/wrinkling of the prepreg. To address these issues, cohesive elements, GTN-M-K damage, and Hashin damage models are established, providing a reasonable simulation prediction of the stamping damage phenomena of FMLs.

SAVING THE USE OF ELPIGI GAS IN THE OVEN MACHINE (CALCINATION) USING THE ENERGY SAVING MODE METHOD AT PT. ABC

Energy has become a basic need and as one of the main components in the industry, one of which is the ABC factory, one of the efforts to reduce production costs without affecting the results or quality of production is by means of safe energy modes PT. ABC is a manufacturing company engaged in the machinery industry which produces catalyst products for two-wheeled vehicles and four-wheeled vehicles. Broadly speaking, there are several stages of the catalyst manufacturing process, namely the Slury material preparation stage, the process of inserting material into the catalyst on the Cyzec machine, the material gluing process on the Calcination Oven machine, the OK product stamp process, the Final Inspection process. This research was conducted on the Drying oven machine, the line that uses elpigi gas. Based on the period January - June there has been an increase in the amount of gas bills used, After using the Energy Safe Method the amount of gas used decreased by 1 cubic every day and saved expenses in the period January - April.

Enhanced Yield Strength and Total Elongation of an Ultrahigh Strength Hot‐Stamped Steel via Tempering Treatment

A 2460 MPa ultimate tensile strength (UTS) has been achieved in this experimental steel, which was processed by a conventional hot stamping process with water quenching to room temperature. Additionally, comparing the microstructure evolution and strengthening mechanism before and after tempering, the microstructure has changed from fresh martensite transformed into tempered martensite with acicular carbides, and the fracture mode has also changed from brittle fracture transformed into ductile fracture mainly. Meanwhile, the main strengthening mechanism has changed from dislocation strengthening to precipitation and dislocation strengthening. Overall, the tempering process reduces dislocation density and produces acicular carbides, which decrease UTS. However, the tempering process reduces the quenching residual stress and changes the morphology of twin martensite, resulting in an increase in ductility. Meanwhile, it enhances the effect of carbide pinning dislocations, significantly enhances precipitation strengthening, and improves yield strength.

LOWERING CUSTOMER CLAIM &; NG RATIO ON JACK BRACKET PART USING LEAN SIX SIGMA-DMAIC METHOD AT PT. XYZ

PT. XYZ is a manufacturing company that produces Sub Assembly products for two-wheeled and four-wheeled vehicles. Broadly speaking, the stages of the Jack Bracket production process consist of five processes, namely the sharing stage in the Raw Material Line, the Stamping process in the Small Press Line, the Spot Welding Stage in the Welding Assy Line and the Checking Stage in the Final Inspection Line. This research was conducted at Line Assy Welding where the Line produces Jack Bracket parts and Line Final Inspection. Based on NG Outflow &; NG Ratio data in the period July to December 2023, 57 pcs of spot defects were obtained and the number of internal process defects was 32,325 PPM which is equivalent to sigma level 3.3. After applying the six sigma method, the number of NG Customer Claims is nil (0 pcs) and the level of product defects can be reduced to 7,500 PPM which is equivalent to sigma level 4.

FEM model optimization study of mechanical properties and material selection in stamping process

Abstract This paper establishes a finite element model of stamping and forming and proposes solution algorithms for static and dynamic forces. The finite element simulation of the hot stamping process is carried out to analyze the thermophysical parameters of BR1500HS ultra-high-strength steel sheet material and H13 steel mold material. Set the temperatures of austenitic material in the transfer process and molding process, obtain the rheological stress data of BR1500HS ultra-high-strength steel plate during plastic deformation at high temperature, and determine the basic mechanical properties of the material at high temperature. A geometric finite element model of thermal-force-phase coupling of the hot stamping and forming process is established to simulate the temperature field change of the steel plate during the hot stamping and forming process by combining the process conditions and process parameters. At the same time, the ultra-high-strength boron steel 22MnB5 is selected to simulate the hot forming and tempering process of U-shaped parts made of high-strength steel sheet material, and the feasibility of the finite element model is verified. Different hot stamping process parameters are set to analyze the forming quality of both BR1500HS ultra-high strength steel and ultra-high-strength boron steel 22MnB5. When the stamping speed is increased from 50mm/s to 100mm/s, the maximum equivalent force of BR1500HS ultra-high strength steel decreases, and thus, when the stamping speed is 100mm/s and the holding time is 5s, the part forming performance is better, which meets the requirements of the gradient performance hot stamping process.

A stamped aluminium gas chromatographic column disk employing directly grown anodic aluminium oxide stationary phase for the separation of aromatic and chlorinated compounds.

In this study, mesoporous anodic aluminium oxide (AAO) with moderate polarity was used as a GC stationary phase to demonstrate the applicability to various compound species. The fluidic channel measured 6 meters in length and had a cross-section area of 0.127 mm2. The column disk measured 6.2 cm in diameter and was fabricated through a stamping process on an aluminium substrate. The AAO stationary phase was directly grown on the aluminium substrate through an anodization process using oxalic acid as the electrolyte. The pore size of the AAO stationary phase was approximately 50-70 nm, with film thicknesses ranging from 6-20 μm. AAO based on oxalic acid exhibited significantly reduced surface polarity, making it suitable for separating polarizable and slightly polar compounds. The theoretical plate number for benzene had reached 1800 plates per meter, and for n-butane, it had reached 2500 plates per meter. A complex mixture of 16 compounds spanning alkanes, olefins, aromatics, and chlorinated hydrocarbons was effectively separated in 8 minutes with the temperature programmed to 200 °C.

A comparative analysis of predictive models for estimating the formability of stamped titanium bipolar plates for proton exchange membrane fuel cells

The microchannels on the bipolar plates (BPPs) of a proton exchange membrane fuel cell (PEMFC) have various functions. Increasing the microchannel depth leads to an increase in the efficiency of the fuel cell. In this paper, metallic BPPs of the PEMFC made of commercial pure titanium (CP-Ti) with an initial thickness of 0.1 mm are manufactured using the stamping process. First, after performing the process using experimental tests and finite elements (FE) simulation, the accuracy of the numerical results is confirmed. In the following, using the FE model and considering process parameters including die clearance, forming speed, and sheet/die friction coefficient, a set of experiments is implemented using the response surface method (RSM). The results of the filling rate are obtained from the experiments and a regression model is established to predict the filling rate of the microchannel. Then, four meta-heuristics methods including artificial bee colony optimization (ABCO), genetic algorithm (GA), artificial neural network (ANN), and adaptive neuro-fuzzy inference system (ANFIS) are used to estimate the formability of the CP-Ti BPPs. According to the results, the ANFIS model with an error of 0.0062 × 10−3 % compared to experiments is more reliable to predict the filling rate in the stamping of the CP-Ti BPPs.

Artificial Intelligence Enabled Energy-Saving Drive Unit With Speed and Displacement Variable Pumps for Electro-Hydraulic Systems

In this paper, an artificial intelligence enabled energy-saving strategy (AIESS) is proposed to achieve high energy efficiency of hydraulic systems with a speed and displacement variable pump (SDVP). The AIESS, which integrates extreme gradient boosting (XGBoost) and genetic algorithm (GA), can generate the optimum combination of motor speed and pump displacement of SDVP in real time under actual working conditions. The XGBoost-based power model is used to accurately predict the input power of the SDVP considering environmental factors, e.g., oil temperature, then followed by GA for optimization, in which the XGBoost-based power model is the objective function. A test rig with a 16t hydraulic press and a stamping process is applied to validate the effectiveness of the proposed strategy. Compared to four other algorithm models, the XGBoost-based power model has the highest accuracy. The optimum combination can be obtained quickly by GA. The results show that the AIESS can reduce energy consumption by 28.6% during pressure-maintaining operation and by 11.2% during one stamping cycle compared to the previously proposed segmented control energy-saving strategy. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —Energy-saving hydraulic system is a topic in the automation industry. The low energy efficiency of electro-hydraulic systems is mainly caused by poor flow rate matching. A speed and displacement variable pump (SDVP) is used to address this problem, but it is difficult to find the matched speed and displacement for the highest energy conversion efficiency of the SDVP due to the inaccuracy energy model and the challenge of coupling variables. This paper presents an energy-saving strategy integrated with machine learning and a genetic algorithm to handle this challenge. Relative variables of the machine learning model are picked through analysis of the mathematical energy model, and the usage of machine learning can fit the high-nonlinear energy model caused by uncertainties in both components and environmental factors. The trained model is then used as an objective function for a GA-based optimization process to generate the optimum motor speed and pump displacement combination. Considering the processing time of GA, this combination can be optimized before the operation for known working conditions. Finally, we have established a 16t hydraulic press to validate this energy-saving strategy and pre-optimized five combinations for a stamping process. The proposed strategy can reduce energy consumption by 11.2% compared with the previous strategy. This energy-saving strategy can also be applied to other automated hydraulic equipment, such as injection machines.

Development and study using digital simulation in QFORM program of hot stamping process of double-layer parts

A scheme is proposed and the hot stamping process of two-layer parts (such as mandrels for piercing mills) is studied. Digital modeling in the QForm program determined the effect of technological parameters on the power parameters of the process, the stress-strain state and temperature fields of the forging and the tool along the transitions. A die equipment scheme is proposed.

Novel Heat Stamping of Ti6Al4V panels with high drawability and low springback

Conventional commonly used titanium stamping techniques like hot forming and superplastic forming each have distinct disadvantages. Hot forming usually leads to limited formability and significant springback, whilst superplastic forming often results in long cycle times, high energy use, and costly tooling. A novel, energy-efficient, and cost-effective Heat Stamping process emerges as a promising solution. Two types of Ti6Al4V components, cup-shaped and U-shaped, were produced using the novel Heat Stamping process, and their properties were examined. A defect-free cup-shaped component achieving a considerably high draw ratio of up to 1.8, was successfully fabricated. A moderate enhancement in the hardness of the component indicated a superior post-form strength achieved by Heat Stamping. Further analysis of the U-shaped components shows that the one produced using the novel method demonstrated a notable reduction in springback angle, from 4.8° to 0.7°, highlighting the potential of H eat Stamping in achieving high shape accuracy for near-net-shape forming.

Experimental investigation and kinetic analysis of Al–Zn–Mg alloy coating

The hot-dip 55 wt%Al–Zn-1.6 wt%Si-(0–3)wt.%Mg alloy coatings were experimentally investigated, and the solidification behaviors and hot cracking susceptibility were simulated by means of CALPHAD (CALculation of PHAse Diagrams) method. The scanning electron microscopy (SEM), electron probe micro-analyzer (EPMA) and glow discharge spectrometer method (GDS) were utilized to determine the microstructures and the distribution of elements of the Al–Zn–Mg alloy coatings with different Mg contents. It is discovered that with the increase of Mg content, the percentage of the eutectic microstructure scales up, and the surface quality of the alloy coating is improved. Meanwhile, the bending properties of Al–Zn–Mg coatings with different Mg contents still requires further improvement according to the present bending test. Subsequently, the equilibrium solidification processes of the coatings were calculated using thermodynamic approach. In general, the calculated results reflect the solidified phases and the precipitated temperatures according to theory of equilibrium solidification. However, there still exist discrepancies between the thermodynamic calculation results and the observed experimental results during the practical galvanizing process, because the cooling rates were not taken fully into consideration. Consequently, the kinetic analysis was carried out to obtain the secondary dendrite arm spacing under different cooling rates. The cracking susceptibility index (CSI) was also calculated to predict the hot workability of the Al–Zn–Mg alloy coating. In summary, the appropriate increase of the cooling rate turns out be the effective approach to benefit the microstructure and the corrosion resistance of the Al–Zn–Mg coatings in the practical galvanizing process, and the coating is not suitable for the hot stamping process.

Numerical Modelling for Efficient Analysis of Large Size Multi-Stage Incremental Sheet Forming

Incremental sheet forming (ISF) is an advanced flexible manufacturing process to produce complex 3D products. Unlike the conventional stamping process, ISF does not require any high cost dedicated dies. However, numerical computation for large-size ISF processes is time-consuming, and its accuracy for spring back due to unclamping tools after ISF cannot satisfy industrial demand. In this paper, an advanced numerical model considering complicated forming tool paths, trimming, and spring back was developed to efficiently simulate the multi-stage deformation phenomena of incremental sheet forming processes. Numerical modeling accuracy and efficiency are investigated considering the influence of tool path, material properties of the blank, mesh size, and boundary conditions. Through a series of case studies and comparisons with experimental results, it is observed that the numerical model with kinematics material properties and a moderate element size (5 mm) may reproduce the deformation characteristics of ISF with good accuracy and can obtain practical efficiency for a large-size ISF part.

Application of the double crank mechanism in designing complex-stroke press

Although having a development history of over 200 years, researches and developments about press machines are still draw interest of modern mechanical engineering. This paper introduces a new press structure that utilizes a double crank mechanism to enhance productivity and efficiency for the stamping process. By adjusting the positions between the component links, the dynamic characteristic of the ram can be modified, optimizing the performance and improving operations of the system. The proposed design also allows for easy adjustments to adapt with different production requirements, such as changing forging and stamping speeds (fast and slow) to avoid the impact of springback properties in sheet metal. The kinematics of the structure have also been determined by mathematic equations, demonstrating significant improvements in the operation of the ram. Results from the research offers a promising solution to enhance production efficiency and enable the creation of simple yet capable mechanisms to perform complex operation.

Deformation Mechanisms and surface/interface Characteristics of Titanium-based Thermoplastic FMLs under Ultrasonic Impact Loading

Some typical defects like delamination, fiber fracture, non-uniform resin distribution and springback are inevitable as titanium-based thermoplastic FMLs are formed by general stamping process at elevated temperature due to the significant differences of various constituent materials in mechanical and thermal properties as well as deformation mechanism. Thus, a novel ultrasonic impact sizing/shaping process method was proposed in the present work, in which a stepped horn and impact tools with a cylindrical tip end was designed by means of vibration modal and harmonic response analysis, and the corresponding experiment setup was established to verify the process mentioned above. Moreover, ultrasonic impact tests were carried out for titanium-based FMLs stacked by titanium sheet, thermoplastic resin film and carbon fiber reinforced fabric to reveal their sizing/shaping mechanism and the effect of key process parameters such as ultrasonic amplitude, scanning speed of impact tool and its tip end diameter on the surface and interface characteristics of titanium-based FMLs. The research results show that the ultrasonic impact scheme with the ultrasonic amplitude of 12 μm, the scanning speed of impact tool within 2 mm/s ∼ 3 mm/s, the tip end diameter of impact tool within Ø4mm∼Ø6mm are proper for the ultrasonic impact sizing/shaping process of titanium-based FMLs.

Design and optimization of cooling channels in hot stamping dies applying additive manufacturing design concept

The stamping process is a process that represents a key manufacturing process in the automotive industry. With the implementation of the stamping process, mechanical elements obtain mechanical resistance, in addition to a very low ratio in quantity/cost. Within the design premises that govern the automotive industry, it is worth highlighting the requirement for mechanical resistance, passenger safety, and the lightness of materials. All of this contributes to the current use of alloyed materials with high mechanical resistance. These materials in addition to keeping the mechanical requirements of the different components subjected to load, must satisfy the geometric requirements established by the designers. In the last few years, the use of the Ultra High Strength steels has grown in the automotive industry. This type of alloyed steel contributes to car safety and clean mobility. Given the mechanical nature of these ultra-high-strength alloys, they require the use of hot stamping. This makes the deformability of the different steels easier and allows that, using a conventional stamping method, would not be able to deform according to the geometric requirements of the different mechanical components.