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NADCA - Delphi - Alternator housing

This is a benchmark project done by NADCA (North American Die Casting Association.) in cooperation with Delphi Automotive Systems in December 1996. The casting was given to several simulation software companies to compare their results with the actual problems Delphi was experiencing.

SIMTEC detected the problems, then explained the reasons behind the problem and demonstrated countermeasures and their effect. Using SIMTEC software the casting was improved, by eliminating a weak spot.

Project Statement
Construction: STL-Data
Casting technique:High Pressure Die Casting

Casting material: Aluminum 383
Mold material: H13
Cooling material: Water and Oil

Pouring temperature: 1150 F = 620° C
Mold temperature: 150 F = 65° C
Environment temp: 77 F = 25° C

High pressure die casting mold fill
Filling analysis revealed a problem which caused a weak spot in the casting. Animation of the filling process (QuickTime required)
Solidification shows how long the pressure can feed the casting. Images show that the gating is already freezing off.
Porosity areas are marked in color
Temperature (solidification) picture confirms the problem spot.
Heat Balance in the die.
Cut-section through the die; the round shape is the casting; black spots in the middle are cooling lines.
Points indicate spots where the temperature is measured for the curves shown on the right.
The main problems was filling-related. The metal fronts met in-between two overflows and caused a weak spot. Our solution was to increase the size of one overflow. The pictures show already the increased overflow (in the top of the picture) and show that the metalfront of the two meeting streams is pushed into the overflow. This eliminated the weak spot, Delphi was experiencing in a high percentage of their castings.