A pattern lined with vent holes is placed on a hollow plate carrier
The V-Process Advantage
The Vacuum Process, or V-Process, is a unique metal casting method the comes with capabilities not seen in other forms of casting. Unlike traditional sand molding that relies on bonded sand, the V-Process uses a vacuum system to hold the shape of the pattern during the pouring stage. When the metal solidifies, the vacuum is released, and a casting is pulled.
This brings many benefits, including:
- Zero-Degree Drafty
- 150 RMS Surface Finish
- Thin Casting Walls
- Faster Speed to Market
- Strong Casting Integrity
- Quick Pattern Revisions
The V-Process Sequence
A heater softens a thin plastic film. Plastic has good elasticity and a high deformation ratio.
The softened film drapes over the pattern with a vacuum acting through the pattern vents to draw the film tightly around the pattern.
The flask is placed on the film-coated pattern. Flask walls are also a vacuum chamber with the outlet shown at right.
The flask is filled with dry, unbonded sand. A slight vibration compacts sand to maximum bulk density.
A sprue cup is formed and the mold surface leveled. The back of the mold is covered with unheated plastic film.
Vacuum is applied to the flask. Atmospheric pressure then hardens the sand. The vacuum is released, pressurized air is introduced into the carrier and the mold is stripped.
The cope and drag assembly forms a plastic-lined cavity. During pouring, molds are kept under vacuum.
After cooling, the vacuum is released and free-flowing sand drops away leaving a clean casting with no sand lumps. The sand is cooled for reuse.
The Casting Capabilities of the V-Process
Because the V-Process does not need to rely on unbonded sand,we are able to manufacture castings with zero draft. This can save the time and money that would usually be needed for machining. If you would like to see how we are able to achieve zero draft, watch this video here.
Aluminum Casting Process Comparisons
The Vacuum Process is our unique service that combines the best features of other casting processes.
Aluminum Castings: Process Comparisons
| Process | Typical Size Range | Tolerances | Surface Finish | Min. Draft Required | Min. Section Thickness | Typical Order Quantities | Typical Tooling Costs | Nominal Lead Times |
|---|---|---|---|---|---|---|---|---|
| V-Process Castings | Up to 150 lbs | ± .010" for the first inch, then add ± .002"per inch. Add a max .020 across parting line | 125-150 RMS | None | .125" | All | $3,000 to $14,000 | Samples: 2 to 3 weeks Production: 4 weeks after approval |
| Sand Castings | Ounces to tons | ± 1/32" to 6", then add ± .003" per inch. Add a ± .020" to .090" across parting line. | 200-550 RMS | 1 to 5 degrees | .25" | All | $800 to $4,000 | Samples: 2 to 6 weeks Production: 2 to 6 weeks after approval |
| Investment (Lost Wax) Castings | Ounces to 20 lbs | ± .003" to 1/4", ± .004" to 1/2", ± .005" to 3",then add ± .003" per inch. | 63-125 RMS | None | .060" | Under 1000 | $3,000 to $20,000 | Samples: 8 to 10 weeks Production: 5 to 12 weeks after approval |
| Permanent Mold Castings | Ounces to 100 lbs | ± 0.15" to 1", then add ± .002" per inch. Add ± .010" to .030" across parting line. | 150-300 RMS | 2 to 5 degrees | .1875" | 500+ | $5,000 to $25,000 | Samples: 8 to 20 weeks Production: 10 to 12 weeks after approval |
| Plaster Mold Castings | Ounces to 50 lbs | ± .005" to 2", then add ± .002" per inch. Add ± .010" across the parting line. | 63-125 RMS | 1/2 to 2 degrees | .070" | Prototypes up to 250 | $3,000 to $15,000 | Samples: 2 to 10 weeks Production: 4 to 8 weeks after approval |
| Die Castings | Ounces to 15 lbs | ± .002" per inch. Add ± .015" across parting line. | 32-63 RMS | 1 to 3 degrees | .030" to .060" | 2500+ | $10,000 to $100,000 | Samples: 12 to 22 weeks Production: 8 to 14 weeks after approval |