Cnc manufacturing can be broken down into many categories with the two main types being: additive and subtractive. Additive manufacturing is the process of constructing a component from a 3D model data by adding layer upon layer of material and either fusing, binding or solidifying those layers together create the finished product (also known as 3D printing). Subtractive manufacturing, on the other hand, is the process of removing layers of material from a solid block, pipe or rod to produce an object either from 3-D model data, 2-D CAD data or G-Code.
How do you decipher which type of manufacturing is right for your component?
The answer depends on the requirements of the component and your industry. Both additive manufacturing and subtractive manufacturing techniques have their own advantages, making them suitable for different circumstances. By examining your components end use, you should be able to choose the appropriate method for production.
The type of material your component requires will be the largest deciding factor when it comes to the type of manufacturing you choose. Additive manufacturing processes are used for manufacturing parts out of plastics although some of the newer machines can print parts in materials such as metal and concrete. However, for the majority of metal manufacturing, as well as wood, foam, or other materials, CNC routing and cnc milling is likely the only option.
For metal components, nothing beats CNC cutting or subtractive manufacturing in terms of the ability to adhere to a parts tight tolerance requirement. However, because the parts must be cut from a solid source, subtractive manufacturing cannot create components with hollow sections the way that additive manufacturing can. Regardless, with the most advanced CNC machines on the market, you can only create extremely complex parts out of difficult to machine materials using subtractive cnc manufacturing.
For some clients, they only need a single prototype or a very short run of finished parts. In general, if you need fewer parts and want to keep costs as low as possible, you’ll want to use additive manufacturing practices. On the other hand, for projects that require higher volume of product, subtractive manufacturing becomes much more cost-effective.
While you must decide on your own which manufacturing type to pursue based on your components needs, the following remains true: additive manufacturing is best suited for single prototypes or very small batches, while subtractive manufacturing is more applicable for large parts runs, parts made from difficult to machine materials and parts that can be manufactured exactly the same way many times without changes.