FINITE ELEMENT SIMULATION OF BACKWARD EXTRUSION DIES USING SHRINK FITTED RINGS |
|---|
| M. E. Yurci, V. Taskin, N. Urkmez |
- Abstract:
- It is necessary to make constructional changes on the dies for manufacturing of tubular mechanical elements by forward and backward cold extrusion in order to maintain high dimensional precision. The radial elastic deformations are controlled by inserting single or double shrink fit within the die. This arrangement decreases and homogenizes tangential stresses in the die and shrink rings and improve die fatigue life. A conventional way of calculating stress and deformation for this kind problem is Lame Equations. In this study, the effect of dimensional changes of die and shrink rings on the radial deformations occur in the internal surface of the shrink ring, Urr, is investigated. The diameters of die and shrink rings are investigated in order to maintain preselected diametral tolerances. Under preselected process and design conditions the following results were found; for +0.1 mm. tolerance single die, for the tolerance value of 0.05 - 0.1 mm. single shrink ring and for the tolerance values below 0.05 mm. double shrink rings were necesssary. The theoretical results showed that beyond the radial ratios r2/r1 = 4 for single shrink design and r4/r1 =7 for double shrink ring design the radial deformation curve, Urr, becomes asymptotic and an increase in external diameter does not make any change. The results achieved by Lame Equations are compared with those of the Finite Element Method solved by Ansys Programme it is seen that the difference is generally up to 3 %. Also it is predicted that due to the external pressure introduced by shrink rings the radial deformations within the die towards the outer surface is zero. Hence, this results no crack on the outer surface of die and longer fatigue life.
- Keywords:
- backward extrusion, radial displacement, Finite Element Simulation
- Download:
- IMEKO-WC-2000-TC15-P433.pdf
- DOI:
- -
- Event details
- Event name:
- XVI IMEKO World Congress
- Title:
Measurement - Supports Science - Improves Technology - Protects Environment ... and Provides Employment - Now and in the Future
- Place:
- Vienna, AUSTRIA
- Time:
- 25 September 2000 - 28 September 2000