engleski

Finite element approach to combined forward-backward extrusion the body of automatic valve

Abstract: Computer - aided techniques are being applied increasingly in designing the tools for metal forming operations. In precision forming these applications are becoming even more useful since, in these cases, dies are more stressed than in conventional forming operations. The practical and proven use of computers in forming technology include: CAD/CAM for die making ; transfer of geometric data from the customer*s CAD/CAM system to that of supplier, and vice versa ; application of artificial intelligence and expert systems for part and process design ; simulation of metal flow, prediction and optimisation of process variables as well as analysis of stress in dies and prevention of premature die failure. A great variety of modelling techniques is available today to engineers where especially the use of Finite Element Method offers the opportunity of getting important process information by simulation. This technique becomes even more important in the cases where analytical approach is practically impossible, such as combined forward - backward extrusion process where no useful information can be obtained without experiment, and in many cases based on experience, trial and error methodology. In presented paper the general principles in the development of metal forming processes are briefly discussed. The results showed here, demonstrate the finite element approach and simulation as a very useful technique in studding the process of forward - backward extrusion, where there is a generally close correlation in the load results obtained with FEM and the experimental one. The possibility of analysis the local stress - strain rate and stress distribution enhance an improved tool design, prevention of premature die failure and elastic displacement of the tool might assist in the process layout phase, where corrected tool geometry can be developed.

extrusion; simulation

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