scholarly journals Common defects of parts manufactured through single point incremental forming

2021 ◽  
Vol 343 ◽  
pp. 04007
Author(s):  
Mihai Popp ◽  
Gabriela Rusu ◽  
Sever-Gabriel Racz ◽  
Valentin Oleksik

Single point incremental forming is one of the most intensely researched die-less manufacturing process. This process implies the usage of a CNC equipment or a serial robot which deforms a sheet metal with the help of a relatively simple tool that follows an imposed toolpath. As every cold metal forming process, besides the many given advantages it has also some drawbacks. One big drawback in comparison with other cold metal forming processes is the low accuracy of the deformed parts. The aim of this research is to investigate the sheet metal bending mechanism through finite element method analysis. The results shows that the shape of the retaining rings has a big influence over the final geometrical accuracy of the parts manufactured through single point incremental forming.

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.


2010 ◽  
Vol 129-131 ◽  
pp. 1222-1227 ◽  
Author(s):  
Ghulam Hussain ◽  
Gao Lin ◽  
Nasir Hayat ◽  
Asif Iqbal

Single Point Incremental Forming (SPIF) is a novel sheet metal forming process. The formability (i.e. spif-ability) in this process is determined through Varying Wall Angle Conical Frustum (VWACF) test. In this paper, the effect of variation in the curvature radius, a geometrical parameter of test, on the test results is investigated. A series of VWACF tests with a variety of curvature radii is performed to quantify the said effect. It is found that the spif-ability increases with increasing of curvature radius. However, any variation in the curvature radius does not affect the spif-ability when the normalized curvature radius (i.e. curvature radius/tool radius) becomes higher than 9.


2011 ◽  
Vol 12 (3) ◽  
Author(s):  
Meftah Hrairi ◽  
Salah B. M. Echrif

Single Point Incremental Forming (SPIF) is a promising sheet-metal-forming process that permits the manufacturing of small to medium-sized batches of complex parts at low cost. It allows metal forming to work in the critical ‘necking-to-tearing' zone which results in a strong thinning before failure if the process is well designed. Moreover, the process is complex due to the number of variables involved. Thus, it is not possible to consider that the process has been well assessed; several remaining aspects need to be clarified. The objective of the present paper is to study some of these aspects, namely, the phenomenon of the wall thickness overstretch along depth and the effect of the tool path on the distribution of the wall thickness using finite element simulations.Abstrak: Pembentukan Tokokan Mata Tunggal (Single Point Incremental Forming (SPIF)) merupakan satu proses pembentukan kepingan logam yang membolehkan pembuatan dalam jumlah yang kecil hingga sederhana, bahagian-bahagian yang kompleks pada kos yang rendah. Jika proses ini direka dengan baik, kaedah ini membolehkan pembentukan logam yang baik terhasil. Jika tidak, semasa peringkat zon kritikal ‘perleheran-ke-pengoyakan' menyebabkan penipisan keterlaluan yang boleh menyebabkan logam tersebut rosak. Tambahan pula, proses ini agak kompleks, kerana ia melibatkan beberapa pemboleh ubah. Maka, walaupun proses ini telah dinilaikan seeloknya; masih terdapat beberapa aspek lain yang perlu diperjelaskan. Objektif kertas ini dibentangkan adalah untuk mengkaji beberapa aspek tertentu, seperti, ketebalan dinding regangan berlebihan di sepanjang kedalaman dan kesan tool path (beberapa siri posisi koordinat untuk menentukan pergerakan alatan memotong ketika operasi memesin) terhadap pengagihan ketebalan dinding menggunakan simulasi unsur terhingga.


2007 ◽  
Vol 344 ◽  
pp. 931-938 ◽  
Author(s):  
Aleš Petek ◽  
Gašper Gantar ◽  
Tomaz Pepelnjak ◽  
Karl Kuzman

In contemporary industrial production the ecological aspects have increasingly important role in selection of sheet metal forming process. To produce sheet metal parts with minimal environmental burdening the shortening of forming processes including the procedures for production of appurtenant forming tools as well as decrease use of lubricant is prerequisite. The ecological aspects have to be considered also already in developmental phase where the forming technology is evaluated in digital environment with FEM simulations. In addition, particularly in small and medium batch production the geometrically complex parts are difficult to form economically with conventional forming processes like deep drawing or stretching. Therefore, new concepts like hydro-mechanical forming or incremental sheet metal forming were developed. In order to select the optimal forming process the production costs as well as the environmental aspects like lubrication, noise, pollution and energy per produced part have to be considered. The paper is focused towards the comparison of conventional deep drawing (DD) process aimed for forming the pyramid-shaped part with single point incremental forming technology (SPIF). The economical and ecological aspects affecting the successful forming by both concepts are determined. Comparative evaluation was established in order to present advantages and drawbacks of each analysed technology.


Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1287
Author(s):  
Fernando Bautista-Monsalve ◽  
Francisco García-Sevilla ◽  
Valentín Miguel ◽  
Jesús Naranjo ◽  
María Carmen Manjabacas

Single point incremental forming (SPIF) is a cheap and flexible sheet metal forming process for rapid manufacturing of complex geometries. Additionally, it is important for engineers to measure the surface finish of work pieces to assess their quality and performance. In this paper, a predictive model based on machine learning and computer vision was developed to estimate arithmetic mean surface roughness (Ra) and maximum peak to valley height (Rz) of Ti6Al4V parts obtained by SPIF. An image database was prepared to train different classification algorithms in accordance with a supervised learning approach. A speeded up robust feature (SURF) detector was used to obtain visual vocabulary so that the classifiers are able to group the photographs into classes. The experimental results indicated that the proposed predictive method shows great potential to determine the surface quality, as classifiers based on a support vector machine with a polynomial kernel are suitable for this purpose.


2015 ◽  
Vol 658 ◽  
pp. 177-181
Author(s):  
Kittiphat Rattanachan

To produce the forming limited diagram for predicting and studying material behavior in sheet metal forming, grid etching or grid marking on blank surface are applied before forming. But in single point incremental forming process, sheet metal blanks are subjected to highly strain or highly deformation which the conventional gridding is no longer to be occurred on the surface of formed part. And some material such as titanium, nickel based alloy etc are difficulty to etch the grid marks on its surface. So this paper is proposed the drilling hole technique to substitute with the grid etching technique in single point incremental forming process. The holes 2 mm. diameter were drilled on the SUS 304 stainless steel blank before forming. The deformed holes are calculated as true major strain and true minor strain and plot into a forming limited diagram. The results are compared with the conventional etching techniques which show an according trend. The drilling hole technique could be used in study the material behavior in single point incremental forming, it a low cost convenient and easy than grid etching technique.


Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4719
Author(s):  
Kyu-Seok Jung ◽  
Jae-Hyeong Yu ◽  
Wan-Jin Chung ◽  
Chang-Whan Lee

Incremental sheet metal forming can manufacture various sheet metal products without a dedicated punch and die set. In this study, we developed a two-stage incremental forming process to decrease shape errors in the conventional incremental forming process. The forming process was classified into the first single point incremental forming (1st SPIF) process for forming a product and the counter single point incremental forming (counter SPIF) process to decrease shape error. The counter SPIF gives bending deformation in the opposite direction. Furthermore, the counter SPIF compensates for shape errors, such as section deflection, skirt spring-back, final forming height, and round. The tool path of the counter SPIF has been optimized through a relatively simple optimization method by modifying the tool path of the previous step. The tool path of the 1st SPIF depends on the geometry of the product. An experiment was performed to form a circular cup shape to verify the proposed tool path of the 1st and counter SPIF. The result confirmed that the shape error decreased when compared to the conventional SPIF. For the application, the ship-hull geometry was adopted. Experimental results demonstrated the feasibility of the two-stage incremental forming process.


Author(s):  
Rakesh Lingam ◽  
Anirban Bhattacharya ◽  
Javed Asghar ◽  
N. Venkata Reddy

Incremental Sheet Metal Forming (ISMF) is a flexible sheet metal forming process that enables forming of complex three dimensional components by successive local deformations without using component specific tooling. ISMF is also regarded as die-less manufacturing process and in the absence of part-specific dies, geometric accuracy of formed components is inferior to that of their conventional counterparts. In Single Point Incremental Forming (SPIF), the simplest variant of ISMF, bending near component opening region is unavoidable due to lack of support. The bending in the component opening region can be reduced to a larger extent by another variant of ISMF namely Double Sided Incremental Forming (DSIF) in which a moving tool is used to support the sheet locally at the deformation zone. However the overall geometry of formed components still has unacceptable deviation from the desired geometry. Experimental observation and literature indicates that the supporting tool loses contact with the sheet after forming certain depth. Present work demonstrates a methodology to enhance geometric accuracy of formed components by compensating for tool and sheet deflection due to forming forces. Forming forces necessary to predict compensations are obtained using force equilibrium method along with thickness calculation methodology developed using overlap that occurs during forming (instead of using sine law). Results indicate that there is significant improvement in accuracy of the components produced using compensated tool paths.


2014 ◽  
Vol 979 ◽  
pp. 351-354
Author(s):  
Nuttaphong Sornsuwit ◽  
Sunthorn Sittisakuljaroen

The single point incremental forming (SPIF) is a sheet metal forming process with high flexibility on manufacture of each individual workpiece. However, it usually requires more processing time than a conventional forming method and is important to process with appropriate parameters. This study is to investigate the influence of different temperatures on continuing secondary forming of Ti Gr2 sheet, employed the stress relieving and annealing temperature after primary forming. The deformed parts were examined on the following criteria; internal contact surface roughness, microhardness and sectional microstructure. Stress relieving and annealing temperatures of 580°C and 780°C were applied to the formed parts prior to their secondary forming. It is found that the surface roughness increased from Ra 2.104 μm and 2.498 μm to Ra 2.55 μm and 3.18 μm respectively after secondary forming. The formability of 25 mm radius test specimens remained at 12 mm depth with limited obvious change.


2014 ◽  
Vol 979 ◽  
pp. 335-338
Author(s):  
Kittiphat Rattanachan ◽  
Chatchapol Chungchoo

The single point incremental forming process (SPIF) are suited for sheet metal prototyping, because it is a low cost production process that produces sheet metal part without any used of die, and easy to adjust the part’s geometry by change toolpath. But the quality of forming parts is still in doubt. In some applications, such as mould cavity for rapid mould and the medical parts, in this case the inside surface roughness plays an importance role. In this paper, the SPIF process parameters that affected to the inner surface roughness were experimental studied. The investigated parameters are composing of tool feed rate, side overlap, depth step and tool radius. The 2k-p factorial experimental design was used to analyze the interaction between each parameter. The results showed that increasing feed rate and depth step decreased inner surface roughness. Reducing tool rotational speed and feed rate reduced inner surface roughness. So increasing depth step with decreasing side overlap reduced inner surface roughness. The large tool radius and lower side overlap improved inner surface roughness. The large tool radius and higher depth step improved inner surface roughness. And last, reducing tool rotational speed with larger tool radius, the inner surface roughness is decreased.


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