Design of calibrators for extruded profiles. Part I: Modeling the thermal interchanges

The parameters influencing the calibration/cooling stage of profile extrusion are discussed, and a numerical finite-volume method code to model the heat transfer is described and validated. For this purpose, the numerical predictions are compared with the analytical solution of a simple problem, with results available in the literature and with those produced by a commercial software. The routines developed are then used to identify the main process parameters and boundary conditions and to estimate their relative importance. The investigation clearly shows the advantages of using several calibrators separated by annealing zones, relative to a single calibrator of the same total length, and the large impact of the contact resistance between extrudate and cooling unit while showing negligible impact of other boundary conditions. A decrease of the extrudate velocity is seen to be also an effective control parameter, but it decreases the production rates. Polym. Eng. Sci. 44:2216–2228, 2004. © 2004 Society of Plastics Engineers.

[1]  I. A. Farah,et al.  Wall thickness uniformity in plastic pipes : computer simulations of the effectiveness of die mandrel offsetting and pipe rotation in combatting sag , 1995 .

[2]  F. Pinho,et al.  Numerical simulation of non-linear elastic flows with a general collocated finite-volume method , 1998 .

[3]  Philippe A. Tanguy,et al.  Optimal Design in Profile Extrusion Calibration , 1995 .

[4]  G. R. Langecker,et al.  Temperature Measuring in Plastics Processing with Infrared Radiation Thermometers , 1998 .

[5]  Edmund Haberstroh,et al.  Systematic lay-out of cooling lines for film, sheet and pipe extrusion plant , 1982 .

[6]  Walter Michaeli,et al.  Extrusion Dies for Plastics and Rubber: Design and Engineering Computations , 1992 .

[7]  António Gaspar-Cunha,et al.  The Design of Extrusion Screws: An Optimization Approach , 2001 .

[8]  W. Dietz.  A cooling time model for plastics processing operations , 1978 .

[9]  Philippe A. Tanguy,et al.  A finite element model for complex profile calibration , 1994 .

[10]  J. F. T. Pittman,et al.  Comprehensive simulation of cooling process in plastic pipe manufacture , 1996 .

[11]  J. Pittman,et al.  Cooling and Wall Thickness Uniformity in Plastic Pipe Manufacture , 1994 .

[12]  Philippe A. Tanguy,et al.  On the determination of heat transfer coefficient between pvc and steel in vacuum extrusion calibrators , 1996 .

[13]  F. Pinho,et al.  NUMERICAL PROCEDURE FOR THE COMPUTATION OF FLUID FLOW WITH ARBITRARY STRESS-STRAIN RELATIONSHIPS , 1999 .

[14]  Walter Michaeli,et al.  Extrusion Dies for Plastics and Rubber , 2003 .

[15]  J. M. Nóbrega,et al.  Accounting for temperature-dependent properties in viscoelastic duct flows , 2004 .