George Ure Says: CNC milling finds application making a wide range of custom parts. CNC milling is a cutting process in which material is removed from a block metal or plastic by a rotating tool. In CNC milling the cutting tool (called a “mill”) is moved in all three dimensions to cut a desired shape from stock.In this process, the material is usually removed by both the end and the side of the cutting tool. Unlike a drill which removes material only from the end, in CNC milling the cutting tool rotates about an axis that is perpendicular to the table that holds the work. Cutting tools of various profile shapes are available including square, rounded, and angled. A wide variety of part shapes and geometries are possible. The most common are the “end mill” which finishes to a flat bottom surface while a “ball mill” has a rounded end.A wide variety of 2D and 3D shapes are possible in the process. Some of the examples of CNC milling are engine components, custom jigs and mold tooling, complex mechanisms, enclosures, etc.The thing CNC Milling does especially well is create complex shapes block material. While CNC milling can be used on 2D projects, there are lots of other choices for thin stock. Waterjet cutting and plasma cutting, for example, come to mind. But thick stock, needing metal removed? That’s where CNC milling shines. The CNC Milling process proves to be cost effective for short runs.In the event you run into large production quantities, then you might wish to consider cast or forged parts.When you set about designing a new custom part, keep a wide range of cutting machines in mind. Depending upon the production quantity you can model the cost of Laser Cutting, Turret Punch or Fixed punches, and the cast or forge decision.The easy way to get started making custom CNC parts is to design them in free 3D CAD software available from www.emachineshop.com, the world’s first online machine shop. Once a part is draw, it can be assigned to different machines and prices and deliveries compared. If you like your design, eMachineShop is only too happy to build it for you.