A study of workability criteria in bulk forming processes

Author(s):  
A.S. Wifi ◽  
N. El-Abbasi ◽  
A. Abdel-Hamid
Keyword(s):  
2021 ◽  
Vol 64 ◽  
pp. 1273-1286
Author(s):  
Keyang Wang ◽  
Huixia Liu ◽  
Youjuan Ma ◽  
Jinzhong Lu ◽  
Xiao Wang ◽  
...  

1981 ◽  
Vol 9 (5) ◽  
pp. 387-389
Author(s):  
S W Roche ◽  
Margaret Tobin ◽  
J F Fielding

Normacol Special Granules were significantly more palatable than Celevac tablets. This applied overall, in those over 60 years of age, in those under 40 years of age and in both males and females. Order taken had no effect on palatability. Normacol Special Granules are the most palatable of the currently commonly used colloidal bulk-forming agents.


2012 ◽  
Vol 504-506 ◽  
pp. 587-592 ◽  
Author(s):  
Marion Merklein ◽  
Tommaso Stellin ◽  
Ulf Engel

A high rate of production of complex microparts is increasingly required by fields like electronics and micromechanics. Handling is one of the main problems, limiting those forming processes of small metal components consisting of multiple forming stages. A forming chain in which a metal strip acts both as raw material and support of the workpiece through the different stages of the process, is seen as a solution that radically simplifies the positioning of microparts. Each workpiece stays connected to the strip through all the forming steps, being separated just at the end of the process chain. In this work, a tooling system for the bulk forming from copper strips has been set up and employed in a full forward extrusion process of a micro-billet. The same die, with a diameter of 1 mm, has been used with three different strip thicknesses (1, 2 and 3 mm) and three different material conditions. The use of thinner and hard-as-rolled strips has resulted in achieving a higher ratio of the billet length to strip thickness.


Author(s):  
João PM Pragana ◽  
Tomás RM Contreiras ◽  
Ivo MF Bragança ◽  
Carlos MA Silva ◽  
Luis M Alves ◽  
...  

This article presents new joining-by-forming processes to assemble longitudinally two metal–polymer sandwich composite panels perpendicular to one another. Process design draws from an earlier development of the authors for metal sheets to new concepts based on the combination of sheet-bulk forming with mortise-and-tenon joints. Selected examples obtained from experimentation and finite element modelling give support to the presentation. A new three-stage joining by the forming process is capable of producing mechanically locked joints with larger and stiffer flat-shaped heads than those fabricated by alternative single- or two-stage solutions. Failure in the new three-stage joining by the forming process is found to take place by cracking instead of disassembling after unbending the flat-shaped head of the joint back to its original shape. The required forming forces to produce the new metal–polymer joints are below 15 kN, allowing them to be an effective, easy-to-implement alternative to existing solutions based on adhesive bonding, welding and mechanical fastening.


2018 ◽  
Vol 261 ◽  
pp. 140-148 ◽  
Author(s):  
Christoph Hartmann ◽  
Matthias Eder ◽  
Daniel Opritescu ◽  
Daniel Maier ◽  
Mauricio Santaella ◽  
...  
Keyword(s):  

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
M. Kraus ◽  
T. Hufnagel ◽  
M. Merklein

The ongoing miniaturization trend in combination with increasing production and functional volume leads to a rising demand for metallic microparts. Bulk forming of microparts from sheet metal provides the potential for mass production of those components by an extensive simplification of the handling. The advantage of a high production rate contrasts with the disadvantage of a low utilization of material. In this context, it is necessary to investigate suitable measures to increase the material utilization. To save cost intensive trial and error tests, numerical analysis could be an appropriate method for a basic process investigation. In this work, a validation with experimental results in the macro- and microscale was used to investigate the eligibility of the finite element method (FEM) for a basic process analysis. For a high transferability, the finite element (FE) models were validated for various tribological conditions and material states. The results reveal that there is a high agreement of the experimental and numerical results in the macroscale. In microscale, conventional FEM shows inaccuracies due to the negligence of size effects in the discretization of the process. This fact limits the application of conventional FE-programs. Furthermore, the results show that lubricated and dry formed blanks lead to the same friction force and process result in the microscale. In addition, the basic formability of the prestrengthened pins in further forming stages was experimentally demonstrated.


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