Abstract
An experimental study of the optimum maximum plunger speed in the slow phase of a high-pressure die casting machine with horizontal cold chamber is presented. A special apparatus that uses a photoelectric sensor to determine the instant at which the working fluid reaches the runner was developed and installed in the injection chamber. The measured volumes of air remaining in the chamber at this instant for various maximum plunger speeds were compared with those predicted by a three-dimensional numerical model based on a finite element formulation and the volume of fluid method for treating the free surface. Very good agreement was found between experimental and numerical results, except for maximum plunger speeds higher than the optimal, for which very complex fluid flow phenomena (that would require a more detailed numerical analysis of the air entrapment mechanisms) tend to be produced. The optimum maximum plunger speed at which the measured volume of trapped air is minimum was found to be very close to that predicted numerically.
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Abbreviations
- A :
-
Cross-sectional area of the injection chamber
- A l :
-
Cross-sectional area occupied by the liquid
- c :
-
Speed relative to the fluid of a small-amplitude wave corresponding to A l
- f :
-
Initial filling fraction, A l0/ A
- g :
-
Gravitational acceleration
- h :
-
Free-surface height
- H :
-
Height of the injection chamber
- l :
-
Length in the plunger acceleration law of Eq. (2)
- L :
-
Length of the injection chamber
- n :
-
Number of measurements during a shot
- R 2 :
-
Statistical coefficient of determination
- t :
-
Time
- t e :
-
Time delay of the signal emitted by the photoelectric sensor
- t f :
-
Filling time of the injection chamber
- t m :
-
Time at which the control system detects the signal emitted by the photoelectric sensor
- t p :
-
Actual time at which the liquid begins to flow through the runner
- t H :
-
Time at which the plunger acceleration ceases
- T :
-
Width of the free surface
- U max :
-
Maximum plunger speed in the slow phase
- V :
-
Volume of air remained in the chamber at the instant t p
- x,y,z :
-
Coordinates (Fig. 7)
- X :
-
Location of the plunger face
- Subscripts :
-
- 0:
-
Quantity corresponding to the initial depth
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Acknowledgement
The authors gratefully acknowledge the support of the Spanish Ministerio de Educación y Ciencia under Grants DPI2001-1390-C02 and DPI2004-08198.
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Zamora, R., Faura, F., López, J. et al. Experimental verification of numerical predictions for the optimum plunger speed in the slow phase of a high-pressure die casting machine. Int J Adv Manuf Technol 33, 266–276 (2007). https://doi.org/10.1007/s00170-006-0456-z
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DOI: https://doi.org/10.1007/s00170-006-0456-z