Improving Press Bending Production Quality through Finite Element Simulation: Integration CAD and CAE Approach

E fficient operations and output of outstanding quality distinguish superior manufacturing sectors. The manufacturing process production of bending sheet metal is a form of fabrication in the industry of manufacture in which the plate is bent using punches and dies to the angle of the work design. Product quality is influenced by plate material selection, which includes thickness, type, dimensions, and material. Because no prior research has concentrated on this methodology, this research aims to determine V-bending capacity limits utilizing the press bending method. The inquiry employed finite element analysis (FEA), along with Solidworks was the tool of choice to develop drawings of design and simulations. The ASTM E290 standard guides this study. The software in this package may combine CAD (Computer-Aided Design) and CAE (Computer-Aided Engineering) without requiring extra design applications. This study tested SPCC and SPHC plate materials with five thickness variations. The findings embrace the number of failure risks associated with press bending exhibited on the von Mises stress diagram, which is directly proportional to showing the thickness limit of each material type throughout the bending process. The study's findings lay the groundwork for improving manufacturing quality by lowering the number of faulty goods produced by trial and error. Because the maximum allowable die width is 12 mm, the thickness limit of the press bending process is 2 mm. However, due to the greater intensity of the SPCC material, it has a reduced defect rate compared to SPHC material.


INTRODUCTION
Indonesia's manufacturing industry accounts for 4.6% of the global industrial sector (Budiyanti, 2016).Efficiency and high production quality are required to become a top manufacturing industry ( Omran, 2013; Hoe and Mansori, 2018).As a result, Indonesia's manufacturing sector has been steady since 1990 (Budiyanti, 2016).According to statistics from Badan Pusat Statistik Indonesia, the manufacturing industry, particularly the machinery sector, employs 0.16% of the total 14.17% of Indonesians in various industrial disciplines (Statistik, 2023).Based on this statistic, over 44 million people in Indonesia work in manufacturing, particularly machines.ATMI Duta Engineering Surakarta is a growing industrial enterprise specializing in equipment and sheet metal fabrication.Trudisk 3030,Trulaser 3030,Trubend V130,and Trumark equipment assist the production process at ATMI Duta Engineering.In addition to the automatic machinery, there are welding, finishing, and manual procedures machines.The firm manufactures souvenirs, replacement parts, and customized goods (ADE, 2018).Cutting, shaping, coating, heat treatment, and casting are some of the manufacturing methods used by the organization.Sheet metal bending is a sheet metal production method used in the firm.The plate is bent to produce an angle according to the work design requirements using a punch as a press tool and a die as a holding and shaping tool (Boljanovic, 2014; Jain and Sharma, 2016).Sheet metal bending is classified depending on the bending shape of the plate, which includes v-bending, r-bending, u-bending, and hemming (Abe et al., 2020;Hai et al., 2020).In a study by (Hai et al., 2020), the v-bending shape is the most often employed plate formation in bending.The plate is bent away from the straight axis at an angle of 1° until 179° in vbending (Chrissandhi, 2020).Press Bending is a common bending technique for v-bending sheet metal because it is easy and ideal for bending sheet metal.The plate gets pushed by the punch between the supporting dies during the press bending procedure, which involves bending it at three different spots (Boljanovic, 2014).Sheet thickness, sheet dimensions, kind of sheet material, sheet shape, compression force, and supporting equipment all influence the final product quality for the press bending process employing v-bending shapes on sheet metal (Armunanto et al., 2018).The compatibility of the parameters will impact the manufacturing quality because the product will be damaged A fracture or cracks in the bending results in damage to the workpiece plate (Chrissandhi, 2020).Product defects owing to poor manufacturing quality must be discarded, which increases the cost of the manufacturing process.ATMI Duta Engineering uses limit tests for material bending capabilities to minimize the effects of crack faults during manufacturing.The test is performed directly on the company's bending machine, utilizing the trial and error method to determine the parameters for manufacturing.This process generates faults in numerous early products, including cracks.Furthermore, the trial and error process has disadvantages, such as the requirement to raise the cost of test materials, machine utilization expenses, and uneven product quality.Simulation testing may be used to anticipate the limitations of the bending process that will result in fractures.Defects caused by cracks in the workpiece plate can be eliminated by modeling finite element analysis (FEA) for the bending process before being processed on the machine to enhance production quality on the factory floor (Karuppuswamy et al., 2022).Previous researchers have successfully carried out several prior studies connected to using CAE software using the notion of bending process simulation with CAE software This study focused on an innovation gap revealed in earlier research by applying optimization of design methods that relied on finite element analysis (FE) alongside Solidworks software under ASTM E290 standards to examine fractures in sheet metal to enhance the firm's production quality.Research conducted at ATMI Duta Engineering was carried out to overcome the limitation of press bending capabilities with limited equipment available in the company.Solidworks was chosen because it can be used as software for developing tools, testing materials, and doing FEA simulations, all inside the same package.Because it is simple to use in design and is widely utilized by educational institutions and businesses, Solidworks design software may be used to address these weaknesses.This software's design of 2-dimensional and 3-dimensional graphics may be immediately replicated with existing features.The ASTM E290 standard reference for bending tests for fracture analysis in sheet metal is used to design instruments, test materials, and simulation procedures.The simulation was performed at ATMI Duta Engineering and used changes in the material's kind and thickness based on the material's availability and the frequency of usage in the firm.The simulation's tools (punch and die) depend on the firm's availability.The FEA investigation determined the thickness limit of the material accessible at the firm.This material thickness restriction is intended to eliminate product failures during production, increase the quality of ATMI Duta Engineering production floors, and utilize the research as a global standard.

Materials and Tools for Bending
This bending modeling procedure uses Steel Plate Cold Rolled Coiled (SPCC) and Steel Plate Hot Rolled Coiled (SPHC).The materials utilized as test materials in this study were chosen based on the frequency with which ATMI Duta Engineering Surakarta uses this material.The thickness of the material used in the bending simulation process is tailored to the firm's availability.The cold rolling process produces SPCC or white plate to reach the desired thickness and width.SPCC is frequently used to make food cans, furniture, and electrical appliances.SPCC has the advantages of being formable, weldable and having a low surface roughness (Bui and Le, 2016; Krakatau Steel, 2023a).SPHC is a specific type of steel plate made by hot rolling.SPHC is known as a black plate because of the existing oil coating (HRC-PO or Hot Rolled Coil -Picked Oil).SPHC is frequently utilized in the automobile sector to build frame parts, brake components, wheels, clutch plates, tube frames, and compressors due to the material's excellent corrosion resistance ( Naipinij et al., 2022;Krakatau Steel, 2023b).According to a corporate study, the materials utilized came from PT. Krakatau Steel, a material provider.Table 1 presents data on the type, thickness, and material properties used in the bending simulation research, which was obtained from the vendor's specifications of the plate material used by the firm.SPCC material standards are based on the JIS G3141 standard (Japanese Standards Association, 2011), which is SPHC material specifications are based on JIS G3131 (Japanese Standards Association, 2010).The information in Table 1 will be utilized to create a design model in Computer-Aided Design (CAD) software.(1) The bottom dead point (Wo) is the gap between the die's surface and the bottom of the die basin.The angle between the slanted side and the straight line has been determined from the die width and angle measurements; thus, this number may be computed using the trigonometry formula by applying tan.The moment of inertia (I), as seen in Eq. ( 2), is calculated by multiplying the material's thickness (t) by its width (w) and then dividing the result by 12.The bent rod's moment of inertia is divided by the nominal 12.

Design of Materials and Tools
The original data in Table 1, Figures 1 and 2, and the size, shape, and kind of material are used to create materials and tools into a 3-dimensional data model.This is done to obtain a decent simulation model near the findings under real-world situations.Solidworks software is used in the image design process to turn 2-dimensional photos into 3-dimensional model images.According to AppliCAD Indonesia (AppliCAD Indonesia, 2014), the Solidworks software is CAD software manufactured by Dassault Systemes that industrial organizations and educational organizations extensively use due to the benefits of turning 2-dimensional designs into 3-dimensional ones.Solidworks features are easier to use than CAD applications for developing simple to complicated designs.Solidworks had three major menus when it first appeared: (1) Part is a menu for representing 3-dimensional things from 2 dimensions, and many characteristics in the part menu can be employed during the design process.
(2) Assembly is a menu that combines various 3-dimensional photos from the components menu to create a product assembly.This feature includes finite element simulation to calculate compressive force and stress area since the simulation procedure requires more than one portion.
(3) Drawing is a menu that converts three-dimensional pictures from the components and assembly menus into two-dimensional working drawings (Chrissandhi, 2020).

Finite Element Analysis Simulation
The

Bending Force
To calculate the bending force (F), as indicated in Eq. ( 1), parameters that include the modulus of elasticity (E) for every material type are required, as shown in Table 1.In addition, the die's width data may be observed in Fig. 1.To determine the bending force (F), parameters that include bottom dead point (Wo) and inertia (I) must be computed.Table 2 shows the results of the bending force (F) calculation for each material with changes in type and thickness.According to the findings of these calculations, the larger the bending force, the more dense the material.Based on the material, the SPCC material requires a stronger bending force (F) than the SPHC material, considering the SPCC material's elastic modulus (E) is greater than the SPHC, as shown in Table 1.

Drafting Material Design and Tools
Design planning is carried out for study data tools and materials to be simulated within CAE software applications.The Solidworks program is used to create research tools and materials.The tools employed in punches and dies are intended to match the size of the components in the machine shown in Figs. 1 and 2. The shapes and sizes from Figs. 1 and 2 are used to create a three-dimensional design in Solidworks software.As a research reference, the test material in the shape of a plate is given with parameters determined by ASTM E290 (ASTM International, 2009).Fig. 3 shows the outcomes of the materials and tools' three-dimensional design.The structure of the components made of materials and tools is also changed to the original information in Table 1, Figs. 1 and 2 by entering it into Solidworks.This is done to develop a credible simulation model that is near to the outcomes in real-world situations and can significantly enhance product quality.However, there are issues with entering material information for steel or plate materials throughout the design phase.The materials required for design are SPCC and SPHC, which are not accessible in the Solidworks program.The disparity in name standards with the variety of materials used by firms following ASTM and JIS naming standards causes this difficulty.Meanwhile, the word Solidworks is an abbreviation for the AISI standard.The answer to these variations is to determine the material based on the tensile strength and elastic modulus characteristics of the SPCC and SPHC materials stated in Table 1.

Finite Element Analysis Simulation
The simulation was performed using the same CAE program for developing tools and materials, Solidworks.This procedure uses Solidworks' simulation tool, with non-linear simulations picked from the sub-menu.In the simulation, contact set parameters for each side that will rub.The contact set was separated into two pieces for this investigation.The first section is the plate's top side, which will rub against the punch side, and the second is the plate's bottom side, which will rub against the die side.Fixed geometry parameters were used to establish which sections would not move throughout the simulation, and the punch's depth setting was reduced.In this test, the mesh density is at a fine level.The extremely fine mesh density has the maximum density enabled by the Solidworks program, which increases the accuracy of the simulation results.
Results from the finite element simulation will take the form of stress zones that develop during the bending process.The analysis of outcomes of simulations refers to the size of the stress region that happens through the simulation process as a whole.The green hue shows a normal stress region; the more red the color of the stressed area, the higher the chance of breakdown in the process of bending in the form of a fracture.Materials with stress sections with a broad red color spectrum at the bending angle are the sections that have the highest stress points during the bending procedure.The results of the red color spectrum in the material are still safe if no errors occur during the simulation.This error indicates that the material cannot be processed by press bending with the existing punch and dies so that cracks will continue to occur.The color dispersion will be aggregated into a unit amount that takes the shape of von Mises stress, representing the material's elastic limit through bending.
Bending FEA simulation results for each kind of material with thickness modifications are presented in Figs. 4 and 5.
Bending test findings revealed that the most important force in the press bending process occupies that region of the middle radius of the plate, which is pushed by the punch and die in the von Mises stress graph shown in Figs. 4 and 5.The existence of the highest value out of Figs. 4 and 5 indicates the region of the radius's center.The amount of load dispersion is shown by the color changes that occur.The error in the computer simulation outcomes with a material thickness of 2.5 mm reveals that if the pressure applied is too great, the remedy is to widen the die.Changing the usage of wider dies will affect the force needed owing to die width within the three-point formula utilizing bending as a divider (Armunanto et al., 2018).The greater the width of a die, the less force is required.3, the findings achieved for each plate material show that SPCC plates have more excellent resistance than SPHC plates.That result is indicated by the von Mises value produced by the SPCC material for each thickness being more significant than that produced by the SPHC material.The higher resistance of SPCC material compared to SPHC material in von Mises Stress results is due to the tensile strength and elastic modulus specifications of SPCC material, which are also higher than SPHC material, referring to Table 1.SPCC material has high resistance because SPCC material is used for the production of more durable goods (automotive, gas cylinders, etc.) compared to SPHC material (home furniture, electrical furniture, cans).Besides being constructed as a comparison table, the FE bending simulation results are compared with the curve lines in Fig. 6.The form of the comparison curve in Fig. 6 illustrates that the potential of failure for each material increases in precisely proportion to the thickness of the plate to be treated by press bending.Although at a material thickness of 2.5 mm, the lines for both materials have shrunk, and the simulation outputs are inaccurate.As illustrated in the graph for the fatigue limit, the reduction in the contour of the curve and the error suggest a fracture has developed.In numerous additional investigations, a descending slope indicates the presence of material flaws (Armunanto et al., 2018; Chrissandhi, 2020).As a result, for the company's high press bending production quality, a material thickness of 2.5 mm is the thickness limitation that may be produced for bending for dies with a width of 12 mm.

CONCLUSIONS
The press bending procedure is successful if there are no failures in the bending press outcomes, such as cracks.Several parameters, such as the punch radius and die width, can cause cracks in the material due to the sheet metal bending process.The small punch and die equipment employed in the study site, which was 12 mm wide, proved to be an impediment.
Based on the study of the press bending test performed in Solidworks using non-linear simulation, the capacity limit applicable to SPCC and SPHC materials is 2.5 mm according to the maximum capacity of press bending tools available at ATMI Duta Engineering Surakarta manufactures punches and dies with a width of 12 mm.The materials utilized in the test, SPCC and SPHC, are the most often used bending materials.
According to the study, the SPHC material is less likely to fail when bent than the SPCC.However, regarding the danger of process failure during press bending, the SPHC material outperforms the SPCC material.This is demonstrated by the von Mises value of the SPHC material for each thickness less than or equal to that of the SPCC material because the SPHC material must have excellent resistance to have qualities that are more difficult to form than the SPCC material.In the comparison calculation, if the risk value acquired by the SPHC is regarded to be zero, the average percentage of the five thicknesses against failure of the press bending process compared to the SPCC material is 6.23%.This percentage indicates that the press bending process failure in the form of a fracture on the 6.23% SPCC material has greater strength than the SPHC material.Using finite element simulation research in the current study can replace the trial and error procedure at ATMI Duta Engineering Surakarta.The replacement of this approach aids in the improvement of the firm's manufacturing quality, allowing it to become an excellent company.The simulation approach used will decrease product flaws caused by trial and error.Reduced crack faulty items can reduce production expenses in the firm, allowing production costs to be reduced as well.The results of this research only refer to the availability of materials often used in the company and the availability of bending equipment used in the bending press production process in the company.Further research to find the thickness limits of the press bending process with varying materials and bending equipment can be applied to obtain results from a different point of view.

(
Thuillier et al., 2010; Armunanto et al., 2018; Saravanan et al., 2018; Miranda et al., 2018; Cheng et al., 2019; Lu et al., 2020; Kumar et al., 2021; Karuppuswamy et al., 2022).(Thuillier et al., 2010; Armunanto et al., 2018) completed a research on FEA material tests concentrating related to the bending industry.However, this study was undertaken for the hemming procedure and did not include press bending testing for the vbending model.Although the outcome of this study is a search for spring back defects, numerous studies have also done material testing using FEA and focused on analyzing press bending for a v-bending model (Saravanan et al., 2018; Karuppuswamy et al., 2022).Kumar et al. conducted material testing using Finite Element Analysis (FEA) to examine press bending.The testing primarily targeted u-bending contours and aimed to analyze how differences in bending angles impacted the formation of cracks in the test material (Kumar et al., 2021).Other research related to FEA for bending press analysis has also been carried out, but the research focuses on solving the spring back problem by getting the correct numerical input (Miranda et al., 2018; Lu et al., 2020).Research using FEA has also been carried out focusing on spring back problems, and the test objects used are pipes and not plates (Cheng et al., 2019).
Plate Type Plate thickness(mm) Tensile Strength (N/mm 2 ) Elasticity Modulus (N/mm 2 and die are the instruments used in the press bending production process.Dimensions, component material kinds, and the bending ability of the punch employed on the TruBend machine are all required data tools.The TruBend machine is a bending machine used by PT.ATMI Duta Engineering in the manufacturing department.The collected data tools will be utilized as a reference in developing models in CAD software.At the company, there are two methods of bending work, specifically air bending and press bending, that are methods frequently utilized in the fabrication of sheet metal industry (Chrissandhi, 2020), and each of them has limited tools used considering the company is without all of the TRUMPF bending machine's tools.The instruments available at the firm for the press bending process are punches and dies with a width of 12 mm since the equipment available only reaches that width.The information data on the specifications of the tools utilized at PT. ATMI Duta Engineering is shown in Figs. 1 and 2 from the TRUMPF engine developer's catalogue (TRUMPF, 2018).

Figure 6 .
Figure 6.Graph of the Von Mises Stress Comparison Curve for SPCC and SPHC.

Table 1 .
Material Data for Bending Simulation Testing (

Jagota et al., 2013; Okereke and Keates, 2018; Liu et al., 2022). According
The simulation tools in Solidworks software make study connected to The FEA of an end product or processes simpler because testing does not need resources for developing and researching a product.Static, design studies, fatigue, thermal (hot), buckling, frequency, drop testing, sub-modeling, pressure, non-linear, and linear dynamic simulations are all possible in Solidworks.Non-linear simulations were employed for FEA on the press bending in this study.Nonlinear simulations are utilized in FEA simulations that concentrate on the material used, as are non-linear simulations in other investigations ( Liu et al., 2022)thod (FEM), commonly known as Finite Element analytical (FEA), is a technique for tackling different engineering issues using approximate solutions and numerical analytical tools ( Okereke and Keates, 2018;Liu et al., 2022).FEA may handle engineering issues such as strains, continuum mechanics, stresses, internal forces, and displacements of linear or non-linear structures.Because of the simplicity of its formulation, FEA is frequently employed (Jagota et al., 2013; Liu et al., 2022).The advancement of computerized technology has facilitated FEA, with beneficial computer software for conducting this approach.FEM software includes Abaqus, ANSYS, MSC, Catia, Solidworks, and others.The software's design tools for developing goods or workpieces to be studied make FEA implementation easier (to Arisma Data Setia, designs created in the Solidworks software program may be modeled without prior model construction (Arisma Data Setia, 2018).

Syed et al., 2016; Červinek et al., 2022; Zhang et al., 2022).
Non-linear simulations are also utilized to determine the fracturing limitation of the material when rubbed, as are static loads, since bending loads do not vary or remain constant.The FEA simulation technique also relates to the ASTM (American Society for Testing and Materials) standard, which is a global testing and materials standard developed by ASTM International.The ASTM E290 standard evaluates finite element flexural characteristics employed in the 3-point bending procedure (ASTM International, 2009).The testing specimen is in the shape of a rectangular plate.The specimen plate is 38 mm x 76 mm long and in breadth, with different thicknesses.The test specimen's bending angle was 90° (ASTM International, 2009).

Table 2 .
Bending Force (F) or Tonnage (N) Calculation Results

Table 3
is a comparison table based on the von Mises stress graphs in Figs.4 and 5to facilitate the findings of the FE bending simulation testing for each kind of material with thickness changes.

Table 3 .
Results of Von Mises Stress from SPCC and SPHC Materials.