Theoretical and Numerical Analysis of Incremental Sheet Forming by Using High Pressure Water Jet

2011 ◽  
Author(s):  
B. Lu ◽  
J. Cao ◽  
H. Ou
Keyword(s):  
Sheet Thickness ◽  
Dimensional Accuracy ◽  
Sheet Forming ◽  
Water Jet ◽  
Incremental Sheet Forming ◽  
Forming Process ◽  
Back Plate ◽  
Metal Forming Process ◽  
Plastic Forming ◽  
Part Dimension

Incremental sheet forming using water jet (ISF-WJ) is a new sheet metal forming process proposed in recent years. Few reports can be found on this process and some basic questions are unanswered, i.e., the water jet pressure required for plastic forming and the accuracy of this forming process. In this paper, an analytical model was developed to evaluate the size effect in the ISF-WJ process with respect to some key parameters, such as sheet thickness, part dimension, jet size and jet pressure. Three commonly used engineering sheet materials (aluminum, stainless steel and titanium) are studied in the analysis and the formability of water jet on these materials was evaluated. In addition, comparisons are made between the ISF-WJ and conventional ISF process with rigid tool based on finite element simulations. The result suggests that the dimensional accuracy of ISF-WJ may be controlled by a supporting back plate and ISF-WJ shows a better distribution of strain and thickness reduction than ISF process. It also provides a good reference for future ISF-WJ equipment design and development.

scholarly journals On the Influence of the Tool Path and Intrusion Depth on the Geometrical Accuracy in Incremental Sheet Forming

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 661
Author(s):  
Roman Ulrich Christopher Schmitz ◽  
Thomas Bremen ◽  
David Benjamin Bailly ◽  
Gerhard Kurt Peter Hirt
Keyword(s):  
Sheet Metal ◽  
Tool Path ◽  
Sheet Material ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Forming Process ◽  
Geometrical Accuracy ◽  
Metal Forming Process ◽  
Short Time ◽  
Intrusion Depth

Incremental sheet forming (ISF) is a flexible sheet metal forming process to realize products within short time from design to the first produced part. Although fundamental research on ISF has been carried out around the world, ISF still misses commonly required tolerances for industrial application. In this study, the influences of tool path as well as intrusion depth of the forming tool into the sheet material on the geometrical accuracy were investigated. In the conducted experiments, both flat and stretch-formed sheet metal blanks with different tool paths and intrusion depths were examined. Experimental and numerical investigations showed that changes in the range of a tenth millimeter of the intrusion depth with a consistent tool path lead to different resulting part geometries. A better understanding of the sensitive influence of the tool path and the intrusion depth on the resulting geometry might lead to more accurate parts in the future.

scholarly journals Thickness control in a new flexible hybrid incremental sheet forming process

2017 ◽  
Vol 231 (5) ◽  
pp. 779-791 ◽  
Author(s):  
Huan Zhang ◽  
Bin Lu ◽  
Jun Chen ◽  
Sule Feng ◽  
Zongquan Li ◽  
...  
Keyword(s):  
Production Efficiency ◽  
Thickness Distribution ◽  
Sheet Thickness ◽  
Cost Effective ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Optimization Approach ◽  
Forming Process ◽  
Thickness Prediction ◽  
Flexible Forming Process

Incremental sheet forming is a cost-effective process for rapid manufacturing of sheet metal products. However, incremental sheet forming also has some limitations such as severe sheet thinning and long processing time. These limitations hamper the forming part quality and production efficiency, thus restricting the incremental sheet forming application in industrial practice. To overcome the problem of sheet thinning, a variety of processes, such as multi-step incremental sheet forming, have been proposed to improve the material flow and thickness distribution. In this work, a new process has been developed by introducing multi-point forming as preforming step before conducting incremental sheet forming processing. Employing an established hybrid sheet forming system and the corresponding thickness prediction model, the preform shape can be optimized by employing a two-step optimization approach to improve the sheet thickness distribution. In total, two case study examples, including a hemisphere part and an aerospace cowling part, are fabricated using the developed hybrid flexible process in this study. The experimental results show that the hybrid flexible forming process with the optimal preform design could achieve sheet parts with more uniform thickness distribution and reduced forming time.

Study on Step Depth for Part Accuracy Improvement in Incremental Sheet Forming Process

2014 ◽  
Vol 939 ◽  
pp. 274-280 ◽  
Author(s):  
Hai Bo Lu ◽  
Yan Le Li ◽  
Zhao Bing Liu ◽  
Sheng Liu ◽  
Paul A. Meehan
Keyword(s):  
Tool Path ◽  
Dimensional Accuracy ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Geometric Accuracy ◽  
Forming Process ◽  
Sheet Metal Parts ◽  
Fundamental Information ◽  
Path Control ◽  
Material Fracture

Incremental Sheet Forming (ISF) is a new-emerging sheet forming process well suited for small batch production or prototyping because it does not need any dedicated dies or punches. In this forming process, sheet metal parts are formed by a smooth-end tool in a stepwise way, during which plastic deformation is highly localized around the tool end. The part geometric accuracy obtained in the current ISF process, however, has not met the industry specification for precise part fabrication. This paper deals with a study on step depth, a critical parameter in ISF, for improving the geometric accuracy, surface quality and formability. Two sets of experiments were conducted to investigate the influence of step depth on part quality. Dimensional accuracy, surface morphology and material fracture of deformed parts were compared and analysed. An optimum value of step depth was suggested for forming a truncated cone. The present work provided significant fundamental information for the development of an advanced ISF control system on tool path control and optimization.

Comparison of some Final Part Geometrical Characteristics of Cylindrical Cups Manufactured by Deep-Drawing and Two-Point Incremental Sheet Forming

2009 ◽  
Vol 410-411 ◽  
pp. 355-363 ◽  
Author(s):  
Babak Taleb Araghi ◽  
Markus Bambach ◽  
Gerhard Hirt
Keyword(s):  
Sheet Metal ◽  
Deep Drawing ◽  
Thickness Distribution ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Surface Strain ◽  
Forming Process ◽  
Sheet Metal Parts ◽  
Part Surface ◽  
Metal Forming Process

Asymmetric incremental sheet forming (AISF) is a new sheet metal forming process in which sheet metal parts are produced by CNC-controlled movements of a simple ball-headed forming tool. Despite its flexibility and successful application in many cases, AISF has not yet been established in an industrial context due to some still existing process limits such as severe thinning, which strongly depends on the inclination of the part surface, as well as a limited geometric accuracy due to springback. Furthermore, there is little knowledge available about the properties of parts produced by AISF, especially in comparison to deep-drawn parts. The aim of the present paper is to compare cylindrical cups manufactured by deep-drawing and AISF regarding the resulting strain and thickness distribution. For AISF, different forming strategies were applied. Comparisons of the wall thickness and surface strain distributions show similar results for the cup produced by deep-drawing and the best cup produced by AISF, but the surface strains and the sheet thinning in the parts formed by AISF were larger than in the deep-drawn part.

Studies on the Springback Mechanism of Incremental Sheet Forming Based on FEM Simulation

2010 ◽  
Vol 102-104 ◽  
pp. 242-246 ◽  
Author(s):  
Fei Han ◽  
Jian Hua Mo ◽  
Xiao Hui Cui ◽  
Zai Lin Wang
Keyword(s):  
Metal Forming ◽  
Three Dimensional ◽  
Fem Simulation ◽  
Element Model ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Strain History ◽  
Forming Process ◽  
Metal Forming Process

Incremental sheet forming (ISF) is an innovative and highly flexible sheet metal forming process for small batch production and prototyping, but springback is a very important factor to influence the quality of incremental sheet forming. This paper investigates the springback mechanism of incremental sheet forming using numerical method. A three-dimensional elasto-plastic finite element model was established for the simulation of the incremental sheet forming process. In this model, the combination of dynamic explicit algorithm and the static implicit algorithm was proposed to calculate the whole forming process including springback. The results of numerical simulation, such as, the strain history and distribution, the stress state and distribution, etc., are discussed in details. Moreover, the results confirm that residual stress has been releasing during forming process, which reveal the peculiar springback characteristic of incremental sheet forming process.

Investigation of tool wear in single point incremental sheet forming

2019 ◽  
Vol 234 (1-2) ◽  
pp. 170-188 ◽  
Author(s):  
Pablo Josue da Silva ◽  
Alberto J Alvares
Keyword(s):  
Tool Wear ◽  
Single Point ◽  
Dimensional Accuracy ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Numerical Control ◽  
Galvanized Steel ◽  
Forming Process ◽  
Control Machine Tool ◽  
Dimensional Errors

This article presents a proposal for a new method to evaluate tool wear incremental sheet forming process. Incremental sheet forming is an innovative forming process with a high interest in fields of the industry due to its low preparation cost and high flexibility, allowing the production of small batches at a reduced cost. Among the various types of incremental sheet forming processes, the single point incremental sheet forming is the most cost-effective, and unfortunately, the single point incremental sheet forming process has high dimensional errors. In order to understand the process and its dimensional errors better, this article shows the study of tool wear and the quality of surface finish with the generated data can correlate with the tool life. The study is carried out by means of a sequence of experimental tests of galvanized steel sheet conformation by altering the stamping parameters (vertical step in, feed and rotation) and capturing the values of the surface roughness of the parts, the forming tool wear and processing time. After the completion of the tests, the classical formulation of the Taylor equation was utilized to obtain a mathematical model capable of estimating the lifetime of the single point incremental sheet forming tool associated with a tool wear value and the desired dimensional accuracy in relation to the processing parameters for the part or tool pair analyzed in a computer numerical control machine tool. The results of the study present an original model of prediction of tool wear in relation to the input parameters for the single point incremental sheet forming process; the overall error rate is 33.44% for the wear model of prediction and 35.94% for the lifetime model of prediction.

Dieless Water Jet Incremental Micro-Forming

2018 ◽  
Author(s):  
Yi Shi ◽  
Jian Cao ◽  
Kornel F. Ehmann
Keyword(s):  
Process Parameters ◽  
Thin Shell ◽  
High Speed ◽  
Single Point ◽  
Sheet Thickness ◽  
Water Jet ◽  
Micro Forming ◽  
Forming Process ◽  
Thin Foils ◽  
High Pressure Water Jet

Compared to the conventional single-point incremental forming (SPIF) processes, water jet incremental micro-forming (WJIMF) utilizes a high-speed and high-pressure water jet as a tool instead of a rigid round-tipped tool to fabricate thin shell micro objects. Thin foils were incrementally formed with micro-scale water jets on a specially designed testbed. In this paper, the effects on the water jet incremental micro-forming process with respect to several key process parameters, including water jet pressure, relative water jet diameter, sheet thickness, and feed rate, were experimentally studied using stainless steel foils. Experimental results indicate that feature geometry, especially depth, can be controlled by adjusting the processes parameters. The presented results and conclusions provide a foundation for future modeling work and the selection of process parameters to achieve high quality thin shell micro products.

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