Manufacturing – Die Casting

Fourté focuses on small and miniature precision zinc and aluminum die castings. Fourté utilizes state-of-the-art four slide technology to produce net shape, flash free, multi-cavity, thin wall, precision zinc die castings. while holding close tolerances that are among the best in the industry. Whether you need prototypes, or production quantities for oem applications, Fourté offers dependable zinc and aluminum die castings while adhering to ISO 9001 quality standards.

The method of gating that we use is called Edge Gating. The gating is done on the edges of the product. Thus eliminating gate marks and brings the parting line to the edge of the product where is is almost non visible. We also have no need for ejector marks and tapers. We perform in house Electrolytic and Electroless Nickel plating. All plating is backed up with all industry standard reliability testing.

Process
The following are the four steps in traditional die casting, also known as high-pressure die casting, these are also the basis for any of the die casting variations: die preparation, filling, ejection, and shakeout. The dies are prepared by spraying the mold cavity with lubricant. The lubricant both helps control the temperature of the die and it also assists in the removal of the casting. The dies are then closed and molten metal is injected into the dies under high pressure; between 10 and 175 megapascals (1,500 and 25,400 psi).

Once the mold cavity is filled, the pressure is maintained until the casting solidifies. The dies are then opened and the shot (shots are different from castings because there can be multiple cavities in a die, yielding multiple castings per shot) is ejected by the ejector pins. Finally, the shakeout involves separating the scrap, which includes the gate, runners, sprues and flash, from the shot. This is often done using a special trim die in a power press or hydraulic press. Other methods of shaking out include sawing and grinding. A less labor-intensive method is to tumble shots if gates are thin and easily broken; separation of gates from finished parts must follow. This scrap is recycled by remelting it. The yield is approximately 67%.

The high-pressure injection leads to a quick fill of the die, which is required so the entire cavity fills before any part of the casting solidifies. In this way, discontinuities are avoided, even if the shape requires difficult-to-fill thin sections. This creates the problem of air entrapment, because when the mold is filled quickly there is little time for the air to escape. This problem is minimized by including vents along the parting lines, however, even in a highly refined process there will still be some porosity in the center of the casting.