Numerical Prognosis for the Dimensioning of Injection Heads

The dimensioning of injection heads during extrusion of rubber profiles is exclusively based on empiric knowledge of the non-linear flow behaviour and the shear thinning properties of elastomers boosted with carbon black. Thus, the design of injection heads is carried out with subject to the used rubber blends, where the geometry of the corresponding profile is achieved by empiric adaption of the extrusion die. This so-called truing process is a result of the swelling after extrusion of rubber and is carried out up to three steps of adaption of the production machine. The disadvantages of the current production process are the process technology which is non-reproducible over a long timeframe and the design of dies which is connected with long development time and affects the capacity of the running production.

These weak points will be eliminated by a numerical prediction model for the design of injection heads and dies for the extrusion process of rubber. The numerical model is based on the development of new and the adaption of already developed measuring methods which describe the viscosity properties of rubber. Thus, suitable material models for the description of the properties of the rubber blends will be adopted. These material laws will be used in line with finite element analyses. The availability of such calculation models allows the identification of arrangements which increase the production and leads to the reduction of a scrap-adjusted quantity of the production of rubber profiles, respectively.

The development of such computer-assisted calculation methods opens immense potential for the profile processing which leads to an important reduction of the development time for new extrusion profiles and to a fundamental cost-efficient attainment of the maturity phase of new production lines.

Project team:

H. W. Müllner, J. Eberhardsteiner

Project partner:

Semperit Technische Produkte Ges.m.b.H. & Co KG

References:

[1] Müllner, H.W., Eberhardsteiner, J., Wieczorek, A.: Konstitutive Charakterisierung von Kautschukmischungen mit dem Hochdruckkapillarviskosimeter. PAMM - Proceedings in Applied Mathematics and Mechanics, 5 (2005), 1, 507-508.

[2] Müllner, H.W., Eberhardsteiner, J., Wieczorek, A.: Experimental Investigation and Identification of Material Parameters for Rubber Blends. In: Proceedings of the 22nd Danubia-Adria Symposium on Experimental Methods in Solid Mechanics, G. Nicoletto (ed.); AIAS, Parma, 2005, ISBN: 3-950-1554-3-0, 188-189.

[3] Müllner, H.W., Eberhardsteiner, J., Wieczorek, A.: Constitutive Characterisation of Rubber Blends by means of Genetic Algorithms. In: Constitutive Models for Rubber IV, P.-E. Austrell, L. Kari (ed.); KTH, Stockholm, 2005, ISBN: 0-415-38346-3, 361-368.