The differences between desktop CNC and 3D printing...
Posted on: 11/15/2017 02:11 AM
CNC:
Computer Numerical Control (CNC) machining is a common Subtractive Manufacturing technology. As the name implies, Subtractive Manufacturing starts with a lot of something (like aluminum) and removes material until what is left, is a shape you designed. This is accomplished by using a variety of sharp rotating tools or cutters. Typical materials for CNC machines include everything from Polymers (plastic) to metals of all types and hardness.
CNC is one of the most popular methods of manufacturing for both small one-off jobs and medium to high volume production. It offers precise, easy to replicate results and has the added benefit of being able to use a wide range of materials. Unlike 3D printing, CNC machines produce finished, user ready, industrial strength products. CNC generally requires a level of training to setup, various machine "heads" or tools for cutting the selected material, some type of lubrication and cooling.
3D Printing:
3D Printing takes the exact opposite approach from CNC. 3D printing is an Additive Manufacturing (AM) process. In Additive Manufacturing (AM) one predictably starts with raw material (usually a polymer) and builds parts by adding material one layer at a time. AM processes require no special tooling or fixtures so initial setup costs are kept to a minimum.
Not all 3D printers work the same. There are different processes depending on what you are trying to print and what material you want to print in. Printing a cool looking sculpture that sits on a shelf or on your desk is one thing, printing a rugged, custom cellphone case is another.
Most desktop 3D printers will use some form of layered extrusion using a polymer. Some industrial grade 3D printers use a technique called Binder Jetting for metals. It is important to have a realistic expectation when purchasing a 3D printer. As with any new venture, it will take some time to learn the full capabilities of the technology.
In the emerging micro manufacturing (maker) movement, desktop milling machines and 3D printers are constantly evolving and growing in sophistication and ease of use. Each platform has a learning curve. Doing your homework in advance and seeking others already involved in the process is always a wise thing to do before investing in a system. Local "Maker Spaces" can be a great way to experiment with each technology without a large financial commitment.
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