For the average person on the street, die casting is how most toys from the 1980’s were made. Very few realize just how many components, tools and objects in our everyday lives are made from some form of casting process. Cast your eye over your home and you’ll see taps, door handles, light fittings, computer components, car components, furniture components. Even components in sewing machines and cameras are all produced using die casting. Casting is one of the most popular effective processes for making metal parts, the other one is milling. But how do you know when to cast and when milling is called for? Here are some of the basic reasons why you might choose casting or milling and how the two processes can work together.
1. How casting and CNC milling works?
2. Why choose CNC milling?
3. Why choose casting?
In casting, your metal material (usually a metal alloy such as aluminum, copper or zinc) melts and injects into a steel mold or mold to form the part you want to manufacture. Once the metal fills the mold, it is cooled, the metal is hardened to the desired shape, and then removed. You can then complete the part and make any necessary assembly.
The CNC in CNC milling represents computer numerical control, which is a way to maximize machining efficiency by automating most of the process. It is placed in a fairly standard machine with a position sensor and motor mounted on the control knob. This is basically just a robotic mechanic. You can use a rotary cutting tool to remove all metal that is not crank. 3D metal etching - sketches, with computer interpolation, making the circles look very smooth.
· Good at making small amounts of complex shapes. In fact, they are just the reason for making molds (called tools and molds) for casting. Therefore, CNC technology actually reduces the "mold" cost associated with casting. A press, while big and heavy is a very simple "low tech" machine, that has very low maintenance requirements. For the most part, they are too stupid to break. The most complicated part of a press are the sensors that make sure that the operator's body is out of the way before it starts moving. No fancy measuring gear. No computer, unless they have a robot next to it to load and unload the finished parts.
· You can't use an acute angle inside the casting, you can never take the part out of the mold. Therefore, all interior angles must be wider than 90 degrees and have rounded edges. The CNC does not impose such restrictions, but in order to get a good rounded corner, you may need to change the tool to make the last pass. Eliminating the stress rise therefore means more expensive machining time.
· It is better for small batch parts because no tooling costs are required.
· With casting, you can use almost any metal involved in the part and there is almost no waste left. While, many scrap metal is left behind after machining the part.
· Reduce unit cost. If complex geometries are processed from solid billets of aluminum, a large amount of material must be removed, which takes time and produces a lot of wasted material. Casting is a near-net-shaped process, so if you are casting instead of milling, you only need to use the required materials, the process is fast and repeatable, and any post-casting process will only add tight tolerance features or other finishing details. A small portion of the time will be processed from the solid.
· Faster cycle times significantly reduce the lead time for high volume production.
· If you are looking for a large number of consistent, reliable parts, casting is preferred.
· If your part has a lot of surface detail, you might prefer to use casting. Surface details can be placed directly into the mold so that your part can complete the surface details it contains without having to machine it during the finishing process.
· High quality advantage. Because modern casting processes are so controllable and repeatable, they have a high quality advantage. Even the most demanding industries, such as medical equipment, aerospace and precision instruments, now trust the key components of casting. Casting can be found inside life support machines, motion capture equipment, armored combat vehicles and airlines.
With the growing trend of light products in all industries, casting is even more important today.
All in all, in this short essay, we have compared the differences between casting and CNC milling. Hoping you can make the right decisions when decide which approach you need to use to obtain your products. For more information, please contact us.