Papers by Keyword: SPIF

Abstract: The reshaping approach is widely considered a virtuous strategy in line with the pillars of the Circular Economy. According to this approach, End-of-Life (EoL) components are subjected to a second forming process to achieve a new functional geometry. However, EoL parts often exhibit a non-uniform thickness distribution and work-hardened zones resulting from the primary manufacturing step, which makes the design of the reshaping step not trivial. Beyond the standard objectives like avoiding fracture and minimizing springback during the reshaping operations, one of the most concerning aspects is the complete removal of the geometrical features coming from the initial forming process. Flexibility and versatility of the forming process are unavoidable requirements to make the reshaping successful. Therefore, three different reshaping routes are numerically investigated in the present work: (i) reshaping by hydroforming (RH) at room temperature; (ii) reshaping by gas forming (RGF) at hot temperature; (iii) a hybrid approach, based on the combination of an intermediate deformation step via Single Point Incremental Forming followed by sheet hydroforming (RHA). The three routes share the same EoL, characterized by the presence of a deep-drawn square feature. Comparing the three routes, in terms of final shape and thinning distribution, with a reference case study (represented by the sole hydroforming process carried out on an undeformed flat blank) allowed to conclude that the feature removal and a non-severe thinning could not be achieved simultaneously: in fact, while RGF and RHA ensure a more evident suppression of the pre-existing feature, they simultaneously induce a more pronounced and localized thinning compared to the RH route.

Abstract: Traditional sheet metal forming processes necessitate specialized tooling and costly dies to manufacture sheet metal components, leading to time-consuming and uneconomical procedures that are particularly unsuitable for batch production. However, Single Point Incremental Forming (SPIF) has emerged as a cost-effective solution for rapid prototyping, customization, and batch production. To achieve this, precise estimation of the incremental sheet forming force is essential, necessitating the design of dedicated equipment and the adaptation of machinery. This study explores the impact of several process parameters on the forces involved in SPIF to investigate their effects. Specifically, the focus is on analyzing the influence of step size, forming angle, and spindle speed on axial peak forces for Cp-Ti grade sheets. The results reveal that the maximum forming force increases with larger step downs, while a decrease in forming force is observed for smaller step sizes. Additionally, higher forming angles result in increased friction between the tool and the blank, leading to elevated forming temperatures. The evolution of forming force, which varies under different bending conditions, could serve as an indicator to prevent sheet failure. The current provides valuable insights into optimizing SPIF processes by understanding the relationship between process parameters and forming forces, facilitating more efficient and reliable production of sheet metal components.

Abstract: The paper focuses on the simulation process of Incremental Sheet forming (ISF) technology of the stainless steel SUS304 by the Multi-Stage Single Point Incremental Forming (MSPIF) with Abaqus software. Although being a popular stainless material with high mechanical and corrosion-resistant properties, widely used in various industries, forming of SUS304 steel by MSPIF technology still faces several challenges so in this study, with the simulation process, we have to determine the suitable values of influential factors to enhance the formability of SUS3043 sheet material. In the paper, with Abaqus software, we construct a model of simulation of SUS304 steel sheet by MSPIF technology to collect data for design of experiment (DOE). The results of the research provide valuable information on the forming process of SUS304 steel by MSPIF technology in order to improve the formability of the products.

Abstract: Although the Incremental Sheet Forming (ISF) technology has been studied and applied from the last decade of the previous century with more than 30 years of experiences and ameliorations of the researchers of this field, but the ability of deformation of the formed material sheet still has remained in a restrictive modest value. This sheet forming technology could be divided into 2 mains branches: Single Point Incremental Forming (SPIF) and Two Point Incremental Forming (TPIF) wherein the first one is usually applying in research and the second branch is used in production. The ISF is suitable for forming sheet for a single product or for small batch production with a great advantage of a no-need pestle and mold manufacture in advance, but the formability of formed sheet material cannot bigger than a limited formed angle of about 80^o that depends on the material and the forming parameters. There are some ameliorations for increasing the formability of the formed sheet such as heating the formed sheet in Hot SPIF or Multistage SPIF (MSPIF)… All the effort and amelioration measures are confronted with different difficulties. In this paper, we concentrate to study on the MSPIF technology on stainless steel SUS304 by simulation method with the proof of experimental method. The results were also compared to the simple SPIF to show its own pros and cons on the related field such as the technology, the productivity and the lubrication.

Abstract: The Forming Limit Curve (FLC) shows the limit combinations of principal strains on the sheet surface that can be successfully achieved before necking appears. Above the FLC, Atkins in 1996 proposed the existence of an unstable region where localized necking develops before reaching at the Fracture Forming Limit (FFL). Only the methodology for the evaluation of the FLC is covered in an international standard ISO 12004-2, where the basis of the tests consists of stretching of a previously clamped sheet blank over a Marciniak or Nakazima punch, providing an almost linear strain path in the sheet surface of the specimen. On the contrary, in single-point incremental forming (SPIF) processes, the hemispherical-shaped tools usually employed are relatively small compared to the general dimension of the specimen, producing a highly nonlinear strain path derived from both the incremental nature of the process and the severe curvature imposed by the small radii of the punches used in the forming process.Many authors have observed fracture strains in SPIFed samples well above the FFL obtained with Nakazima tests under the ISO 12004-2 standard. At the macroscopic level, the reason for this behaviour has been explained mainly based on the effect of bending and the difference in the stress triaxiality level, among others. This research analyzes the initiation of ductile fracture in Nakazima and SPIF specimens under a scanning electron microscope to elucidate the reasons of those differences at the microscopic level.

Abstract: Single point incremental forming process, which is also known as SPIF, that forms from one direction. SPIF process was used for milling an aluminum metallic sheet. In this paper, an aluminum (A5052) sheet was formed in a conical shape by the SPIF process. The A5052 sheet was deformed by the computer numerical control (CNC) technology in the T60 series milling machine. The conical shape was deformed by the spiral toolpath in the T60 series milling machine. At the surface of the A5052, lubricant grease was continuously applied manually for reducing the friction generated due to milling. Also, for decreasing the tool rotational force friction on the A5052 sheet there was the use of lubricant. Moreover, 0.1mm step-down is used for the tool path because it takes more time for forming a metallic sheet, however, it deformed the sheet smoothly. The 0.5mm step-down g-code was extracted from fusion 360. Then the metallic sheet A5052 surface was compared before and after deformation. For testing a metallic sheet A5052 the formability parameter was analyzed in the experiment part. The experiment was performed to find the optimal smooth surface from the CNC milling machine. The initial roughness value and the microscopic image were presented in the investigational part. Likewise, the comparison of points for the highest and lowest rough point was further discussed and compared throughout the experiment.

Abstract: Single-Point Incremental Forming (SPIF) is a flexible technology that can form a wide range of sheet metal products without the need for using punch and die sets. As a relatively cheap and dieless process, this technology is preferable for small and medium customised production. However, the SPIF technology has drawbacks, such as the geometrical inaccuracy and the thickness uniformity of the shaped part. For the purpose of determining the optimal value for the technological parameters from the experimental results when evaluating the forming ability through the strain angle α during the processing of SUS 304 sheet material by SPIF technology. The article has conducted experiments to collect parameters; and experimental planning to establish a mathematical model, determine the optimal value for the parameters of the machining process such as tool diameter, tool feed and tool running speed.

Abstract: Incremental Sheet Forming (ISF) is emerging as one of the popular dieless forming processes for the small-sized batch production of sheet metal components. However, the parts formed by the ISF process suffer from poor surface finish, geometric inaccuracy, and non-uniform thinning, which leads to poor part characteristics. This paper deals with the influence of single point continuous local forming process parameters on the surface roughness of the product. Design of trials used for research planning and analysis and interpretation of results. The results indicate that the tool diameter (D), vertical step-down size (Δz), and sheet thickness (t) have significant effects on the produced profile accuracy, while the feed rate (f) is not significant. As a general rule, thin sheets with greater tool diameters yielded the best surface quality. The results also show that controlling all surface quality features is complex because of the contradicting effects of, and interactions between, a number of the process parameters.

Abstract: The single point incremental forming (SPIF) process is a high-trend method for forming a metal in a desirable shape. Forming parameters is an important part of deforming metal sheets. So, while reshaping a metal sheet parameters like tools, toolpath, material properties, sheet thickness, and lubricant were considered. Since the Aluminum sheet is used world widely for the body parts of machines for manufacturing parts. So, an A5052 metallic sheet was formed for the improvement of the depth deforming through the SPIF process. While forming an A5052 sheet lubricant was used constantly. After deforming through the SPIF process, further evaluations of the formed part were examined with the nanoprofiling machine to evaluate the deformed areas. Moreover, the deformed part was analyzed for the nana profiling for the deformation occurs on the surface. Likewise, before forming a part, the A5052 design was computer analysis. The simulation part was studied for fixing the maximum depth.

Abstract: Forming a metallic sheet along with the consideration of computer simulation and experiment had benefited the milling industry for a long time. The ideal forming, without an error, is a concerning topic. So, the computer simulation had the advantage then direct forming. To observe the results before doing the real experiments simulation comes handy. Which helped to set the parameters for the milling process for the single point incremental forming (SPIF) process. For milling, a CAD design was converted into a 3D model. For this, a conical shape of 3D modeling was made in fusion 360. After onwards, it was simulated for finding the maximum depth for the cracking point. Next for the experimental part, the maximum forming depth was considered, and used lubricant grease for reducing friction. While forming with the grease, the impact of parameters was also changed. Throughout the process, an optimization approach was set to reduce the cracking areas for the G-code. Along with the lubricant use, smooth milling finished surface was observed. To reducing the depth forming errors, an optimization approach was introduced in this research.