Tool path strategies and deformation analysis in multi-pass incremental sheet forming process

2014 ◽  
Vol 75 (1-4) ◽  
pp. 395-409 ◽  
Author(s):  
Zhaobing Liu ◽  
Yanle Li ◽  
Paul A. Meehan
2014 ◽  
Vol 622-623 ◽  
pp. 382-389 ◽  
Author(s):  
Antonio Fiorentino ◽  
G.C. Feriti ◽  
Elisabetta Ceretti ◽  
C . Giardini ◽  
C.M.G. Bort ◽  
...  

The problem of obtaining sound parts by Incremental Sheet Forming is still a relevant issue, despite the numerous efforts spent in improving the toolpath planning of the deforming punch in order to compensate for the dimensional and geometrical part errors related to springback and punch movement. Usually, the toolpath generation strategy takes into account the variation of the toolpath itself for obtaining the desired final part with reduced geometrical errors. In the present paper, a correction algorithm is used to iteratively correct the part geometry on the basis of the measured parts and on the calculation of the error defined as the difference between the actual and the nominal part geometries. In practice, the part geometry is used to generate a first trial toolpath, and the form error distribution of the resulting part is used for modifying the nominal part geometry and, then, generating a new, improved toolpath. This procedure gets iterated until the error distribution becomes less than a specified value, corresponding to the desired part tolerance. The correction algorithm was implemented in software and used with the results of FEM simulations. In particular, with few iterations it was possible to reduce the geometrical error to less than 0.4 mm in the Incremental Sheet Forming process of an Al asymmetric part, with a resulting accuracy good enough for both prototyping and production processes.


Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 661
Author(s):  
Roman Ulrich Christopher Schmitz ◽  
Thomas Bremen ◽  
David Benjamin Bailly ◽  
Gerhard Kurt Peter Hirt

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.


Author(s):  
Zhen Cui ◽  
Feng Ren ◽  
Z. Cedric Xia ◽  
Lin Gao

This paper presents an analytical and numerical study of deformation analysis for multistage incremental sheet forming processes, with a truncated conical part is used as an example. Unlike in the single-pass incremental forming where the sheet deformation is dominantly plane strain in the axial direction when forming a conical part, the sheet is also deformed in the circumferential direction when it is incrementally formed subsequently. Ideal deformation kinetics is assumed in the analytical derivations of strain distributions, which should be valid as long as the increment in deformation from one stage to the next is small. Numerical simulations with LS-DYNA are also conducted in an effort to understand the fundamental deformation mechanics of multistage incremental forming. The simulation result for a five-stage incremental forming process is presented. It is also used to correlate the analytical solution. An improved analytical equation for strain distributions is derived, which compares favorably with simulation results.


2014 ◽  
Vol 939 ◽  
pp. 274-280 ◽  
Author(s):  
Hai Bo Lu ◽  
Yan Le Li ◽  
Zhao Bing Liu ◽  
Sheng Liu ◽  
Paul A. Meehan

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.


Author(s):  
Rui Xu ◽  
Huaqing Ren ◽  
Zixuan Zhang ◽  
Rajiv Malhotra ◽  
Jian Cao

Incremental sheet forming has attracted considerable attention in the recent past due to advantages that include high process flexibility and higher formability as compared to conventional forming processes. However, attaining required geometric accuracy of the formed part is one of the major issues plaguing this process. The Double-Sided Incremental Forming process has emerged as a potential process variant which can preserve the process flexibility while maintaining required geometric accuracy. This paper investigates a mixed toolpath for Double-Sided Incremental Forming which is able to simultaneously achieve good geometric accuracy and higher throughput than is currently possible. The geometries of parts formed using the mixed toolpath strategy are compared to the desired geometry. Furthermore, an examination of the forming forces is used to uncover the reasons for experimentally observed trends. Future work in this area is also discussed.


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