scholarly journals The Influence of Sheet Tilting on Forming Quality in Single Point Incremental Forming

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3907
Author(s):  
Hu Zhu ◽  
Yang Wang ◽  
Yibo Liu ◽  
Dongwon Jung

In the CNC incremental forming process, the sheet tilting method can be used to realize the non-fracture forming of a surface with large forming angles. However, the forming effect of the formed part will have big differences when the inclined angle of the sheet is different. Therefore, four different tilted sheets with inclined angles of 15°, 20°, 25°, and 30° were used to study the influence of sheet tilting on forming quality by using 1060 Aluminum sheet as the forming sheet in single point CNC incremental forming. First, the influence of four different inclined angles of the sheet on the overall thickness distribution, plastic strain, and material flow of the formed part was studied by using numerical simulation. Then, the influence of four different inclined angles of sheets on the profile accuracy and thickness thinning rate of the formed part was studied through single point incremental forming experiments. The research results show that sheet tilting has little effect on the profile accuracy of the formed part, but has a great influence on the material flow, plastic strain, and thickness distribution.

Author(s):  
Chetan P. Nikhare

Abstract A substantial increase in demand on the sheet metal part usage in aerospace and automotive industries is due to the increase in the sale of these products to ease the transportation. However, due to the increase in fuel prices and further environmental regulation had left no choice but to manufacture more fuel efficient and inexpensive vehicles. These heavy demands force researchers to think outside the box. Many innovative research projects came to replace the conventional sheet metal forming of which single point incremental forming is one of them. SPIF is the emerging die-less sheet metal forming process in which the single point tool incrementally forces any single point of sheet metal at any processing time to undergo plastic deformation. It has several advantages over the conventional process like high process flexibility, elimination of die, complex shape and better formability. Previous literature provides enormous research on formability of metal during this process, process with various metals and hybrid metals, the influence of various process parameter, but residual formability after this process is untouched. Thus, the aim of this paper is to investigate the residual formability of the formed parts using single point incremental forming and then restrike with a conventional tool. The common process parameters of single point incremental forming were varied, and residual formability was studied through the conventional process. The strain and thickness distribution were measured and analyzed. In addition, the forming limit of the part was plotted and compared.


2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Mingshun Yang ◽  
Lang Bai ◽  
Yan Li ◽  
Qilong Yuan

With increasing design complexities of thin-walled parts, the requirement of enhanced formability has impeded the development of the single point incremental forming (SPIF) process. In the present research, the ultrasonic vibration-assisted single point incremental forming (UV-SPIF) method was introduced to increase the formability of sheet metals. AL1060 aluminum alloy was adopted as the experimental material, and a truncated cone part was considered as the research object. The simulation model of UV-SPIF was established to analyze the distribution of plastic strains in the formed part. A forming angle was selected as the measuring index of formability of the aluminum sheet, and the influences of different vibration parameters on formability were evaluated. An experimental platform was devised to verify the accuracy of the obtained simulation results. It was found that ultrasonic vibration effectively improved the forming limit of the sheet. When the amplitude was 6 µm and the frequency was 25 kHz, the sheet yielded the best formability with the largest forming angle of 67 degrees.


2014 ◽  
Vol 611-612 ◽  
pp. 1031-1038 ◽  
Author(s):  
Henia Arfa ◽  
Riadh Bahloul ◽  
Hedi Belhadjsalah

Single point incremental forming (SPIF) of sheet metal is a promising process to produce small batch production and prototyping. This process consists of a controlled process of displacement performed on a three-axis CNC milling machine. In former work, the most critical factors which affected single point incremental forming process were found to be formed shape, tool size, material type, material thickness and incremental step size. The present work is focused on an optimization strategy of (SPIF) process determined by a numerical study based on finite element analyses (FEA) according to a Box-Behnken Design of Experiments. Two types of hardening behaviour laws of material are used: isotropic and combined isotropic-kinematic hardening behaviour. To do so, a set of numerical simulations are carried out for an aluminum truncated cone as geometry of a benchmark model. The simulation results include some decisions about the mechanical resistance and geometrical quality of the parts such as the thickness distribution and the magnitude of springback. In this paper, the main objective is to present an overview of multiobjective design optimization of process parameters in single point incremental forming operation in order to minimize the sheet thinning rate and the springback simultaneously. In this investigation, the steps of optimization procedure include the using of Box-Behnken experimental design for sample producing, response surface model for coarse fitting and a developed Multiobjective Genetic Algorithm (MOGA) for exact solving of fitness functions. The results show that these methods are able to determine all the best possible compromise with respect several antagonistic objectives as well as generate the approximate Pareto optimal solutions. So these will make it possible to choose the appropriate process parameters according to the objectives functions to be minimized and consequently the improvement of the products formed by the process of incremental forming.


2019 ◽  
Vol 823 ◽  
pp. 1-7
Author(s):  
Ching Lun Li ◽  
Yung Kuan Ni ◽  
Yang Haw ◽  
Yuung Hwa Lu

This study involved planning different tool paths for an axisymmetric cup to explore the forming characteristics of the single point incremental forming (SPIF) process. In addition, this study developed a gradient theory to compute the inclined angle between the tangential and horizontal directions of the cup formed using single point incremental forming. The sheet thickness distribution of the cup was also calculated. To verify the theory, circle arc cups were formed by CNC machining using different tool paths. It was found that the cup formed using the spiral evolutional snail-line tool path produced a better surface than that formed using the equal height evolutional tool path. The sheet thicknesses of circle arc cups obtained by the experiment and using the cosine law were compared. A larger deviation was noted in the initial portion of the cup, whereas a smaller deviation was found in the other portion. This study also adopted a dual-conical cup to investigate the relationship between thickness and the initial inclined angle at the initial portion. It was found that a larger initial inclined angle led to good coincidence between the experimental and theoretical sheet thicknesses.


2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Abdulmajeed Dabwan ◽  
Adham E. Ragab ◽  
Mohamed A. Saleh ◽  
Saqib Anwar ◽  
Atef M. Ghaleb ◽  
...  

Single-point incremental forming is an innovative flexible and inexpensive technique to form sheet products when prototypes or small batches are required. The process allows complex geometries to be produced using a computer numerical control machine, eliminating the need for a special die. This study reports on the effects of four important single-point incremental forming process parameters on produced surface profile accuracies. The profile accuracy was estimated by measuring the side angle errors and surface roughness and also waviness and circularity of the product inner surface. Full factorial design of experiments was used to plan the study, and the analysis of variance was used to analyze and interpret the results. The results indicate that the tool diameter (d), step depth (s), 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.


2019 ◽  
Vol 14 (4) ◽  
Author(s):  
Shalin Marathe ◽  
Harit Raval

Single Point Incremental Forming (SPIF) process is one of the advanced forming techniques that industry has nowadays. Improved formability is one of the major advantages of the process. However, it is associated with limitation such as thinning of blank and poor geometrical accuracy of the formed part. In this study, forming behaviour of homogeneous blanks during the SPIF process has been investigated. A simulation study has been carried out using ABAQUS/Explicit. Effect of change in thickness, yield strength, strain index and strength coefficient of blank on responses like Plastic Equivalent Strain (PEEQ), percentage of thinning and geometrical accuracy of formed component has been evaluated. It has been found that change in the thickness has major effect on PEEQ and geometrical accuracy. Regarding percentage of thinning, change in the yield strength of blank is found to be majorly affecting.


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