What are the differences between die casting and cnc machining?

According to DieCasting.com:

“There are a number of effective processes for making metal parts, but two of the most popular for industrial purposes are die casting and machining. But how do you know when to die cast and when machining is called for? Here are some of the basic reasons why you might choose die casting or machining and how the two processes can work together.

How Die Casting Works
“In die casting, your metal material, often an alloy of metals such aluminum, copper or zinc, is melted and injected into a steel die, or mold, in the shape of the part you wish to make. Once the metal fills the die, you cool it down so that the metal hardens in the desired shape, after which you remove it. You can then finish the part and do any necessary assembly.

How CNC Machining Works
“The CNC in CNC machining stands for computer numerical control, and it is a way to maximize the efficiency of machining through automating much of the process. Think of machining like sculpting with metal. We program the CNC robot which then cuts away at the metal until what is left is the desired part.

Die Casting or Machining?
“So, which should you use? It’s important to note that die casting and machining can often work together to optimize the effectiveness of your product line.

“You can use machining on a die casting part to create tighter tolerances or create features on the part that cannot be die cast, and you can even use machining to make the die itself that will be used for the die casting process.

“One advantage of using CNC machining is that it is better for low volume parts since no tooling cost is required. Die casting is the preferred option if you’re looking for a high volume of consistent, reliable parts.

“On the other hand, if your part has a lot of surface detail, you may prefer to use die casting. Surface details can be made right into the die so that your part comes complete with the surface details included, rather than having to machine them later during the finishing process.

“Another consideration when it comes to CNC machining vs. die casting is waste. With die casting, you use almost all the metal involved for the part, with little leftover scrap. On the other hand, there is a lot of scrap metal left lying around after you machine a part. Now, you can recycle that metal of course, but if you are machining parts or working with a company that is machining parts, you want to be sure that there is a recycling mechanism in place.

“If you’re looking to mass produce a high volume of durable, consistent parts affordably, die casting in aluminum or a related alloy is probably the way to go. If you have a smaller run of more complex parts, or you have particularly large or oddly shaped parts, CNC machining may be more effective…”

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