Casting – a method of shaping material, usually metal, into desired shapes by melting it, pouring it into a mold of the correct shape and letting it cool – is the cornerstone of manufacturing. Historically, metal parts have had a place in just about every important machine since the beginning of the industrial age. There are two major types of casting, each with its own advantages and disadvantages that make them appropriate for different types of casting jobs and products. The two types of casting are called die casting and investment casting.
What Is Investment Casting?
Investment casting may also be called precision casting, or in some cases, lost wax casting. It starts by the caster creating a wax pattern in the shape of the desired part. The wax shape is attached to a tool called a sprue and then repeatedly dipped into liquid ceramic until the ceramic hardens around the wax shape, taking the shape of the casting. The caster then heats the mold so the wax melts away, leaving a cavity within the ceramic, which the caster can then fill with molted metal. Once the metal cools and hardens within the ceramic mold, the mold is shattered, leaving the cast metal part complete.
Investment casting is good for very complex casting designs, since it’s easier to make intricate and precise shapes out of the wax. Investment casting is used if you need zero draft angles on the part, something die casting cannot offer. Investment is more suited to lower volume quantities since the tooling is less but the part prices is higher than die casting.
What Is Die Casting?
Die casting works by forcing molten metal into a die cavity with high pressure. The caster machines a die cavity tree with hardened tool steel in the shape of the desired parts. A release agent is applied to the die, and then a sleeve is filled with molten metal that is then pushed into the die cavities with a piston. The piston keeps applying pressure to the metal as it fills the die. When the metal cools enough, the caster removes the casting tree from the die and trims the individual parts off the casting tree. Then each part is machined as necessary to finish it off.
There are a number of advantages to die casting. For one, die casting is well-suited to large production runs and high volumes because you get consistent repeatability. For another, you have fewer size restrictions with die casting, since you don’t need to worry about keeping molds for larger parts gated to a sprue for repeated dipping, as you do with the wax forms with investment casting. Also, having something investment casted tends to cost more due to the higher amount of manual labor and precision involved.
Die Casting or Investment Casting?
Whether you opt for die casting or investment casting will depend on your specific casting needs, as neither method is inherently superior. If you’re looking for a way to manufacture a lot of the same part quickly and with good consistency among parts at a good price, die casting is the way to go. If you have a smaller product, with fewer but more complex and intricate parts, and you don’t mind paying a little more for a higher level of precision, investment casting may be your preferred method. Depending upon your manufacturing requirements, you may opt for die casting for the majority of your big jobs, and investment casting for specialized work.
Premier Engineered Products for Your Die Casting Needs
Premier Engineered Products has been providing high-quality die-casting and tooling, CNC machining and metal finishing for more than 70 years. Premier prides itself on state-of-the-art machines and a combination of automation and expert technicians to give you the most efficient, effective machine parts for your business. To learn more about how Premier Engineered Products uses cutting-edge technology to provide you with the best machine parts, get in touch today.
Visit our website and get a copy of our General Design Data Sheet which provides a quick comparison on seven different casting processes.