Vacuum-Assisted Die Casting (VADC) for T6 Parts

Standard HPDC injects metal at 20-60 m/s gate velocity into a cavity containing air at atmospheric pressure. Turbulent flow entrains and compresses this air into distributed gas porosity. For most applications, this porosity is inconsequential. For T6-treatable structural castings, pressure-tight hydraulic components, and helium-leak-tested sealed systems, it is the fundamental barrier to performance.

Vacuum-assisted die casting removes the air before it can be entrapped.

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How VADC Works

1. Die closes and clamps -same as standard HPDC
2. Vacuum pump evacuates die cavity to <30 mbar -air drawn out through vent valves
3. At vacuum trigger, injection fires -metal enters a near-vacuum environment
4. Turbulence still occurs, but there is no air to compress and entrap
5. Solidification, ejection, and secondary operations proceed normally

The vacuum system adds 3- seconds to cycle time. The die, alloy, and injection parameters are unchanged.

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VADC Performance

Metric	Standard HPDC	VADC
Cavity pressure at injection	1 bar (atmospheric)	<30 mbar
X-ray classification (ASTM E505)	Class 3- typical	Class 1- achievable
T6 heat treatment	No (surface blistering)	Yes
Helium leak rate (manifold)	10^-4-10^-5 mbar·L/s	<10^-6-10^-7 mbar·L/s
Tensile strength (A380 + T6)	317 MPa (as-cast)	~370 MPa
Yield strength (A380 + T6)	159 MPa (as-cast)	~300 MPa

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Why T6 Requires VADC

Standard HPDC contains gas porosity. During T6 solution treatment at 480-540°C, gas in pores expands. In thin wall sections or near the surface, this expansion creates visible blisters -destroying the part. T6 on standard HPDC fails due to blistering.

VADC physically removes the gas before casting. Parts with Class 1- porosity pass T6 solution treatment without blistering. This is the only reliable path to die cast T6 aluminum.

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When to Specify VADC

• T6 heat treatment required (EV structural, suspension, crash safety)
• Rated working pressure >150 bar without impregnation
• Helium leak rate <10^-6 mbar·L/s required
• ASTM E505 Class 1 internal soundness required

Standard HPDC with A413 alloy or VPI impregnation addresses <100 bar applications adequately without VADC investment.

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KastMfg VADC Programs

EV motor housings (T6 + cooling jacket), hydraulic manifold blocks (350 bar), chassis structural nodes (T6), pressure-tight power electronics enclosures (IP67 + T6), EV battery thermal management manifolds.

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VADC inquiry: casting@kastdiecast.com | +86 138 1403 4409 | No.6, Rungu Road, Nanjing, China

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• types of die casting