In traditional machining, a skilled machinist uses a machine to cut or shape metal. This is done according to instructions given by designers and engineers, usually in the form of a drawing or plan. The machinist uses turning wheels, dial gauges, clutches, screws, bolts and various cutting tools made of steel, carbide and industrial diamonds, and then uses measuring equipment to ensure that all dimensions are correct.
CNC machining performs the same operations as traditional machining – cutting, drilling, milling, boring, grinding and other metal forming and removal operations – but uses computer numerical control instead of manual control by the machinist. It is automated, driven by code and developed by programmers. It’s about as accurate on the first cut as it is on the 500th. It is widely used in digital manufacturing (and sometimes in small batches), and can be revised and modified for changes and different materials.
This type of machining is much more accurate, and has largely (though not completely) replaced traditional machining in manufacturing, fabrication and industrial production. It uses mathematical coordinates and the power of computing to achieve the same end with the highest possible accuracy. In particular, numerical computer control uses cartesian coordinates. These are spatial coordinates – in several dimensions – using coordinates and axes. Cutting machine automation controls its cutting, drilling, boring or other operation using the numerical control of a computer that reads the coordinates. Engineers have designated these coordinates in the digital drawing and design of the product.
What is the CNC machining process?
CNC machining uses subtractive processes, which means that the raw material is machined to its final shape by reducing and removing material. Holes are drilled, batches and spacers are drilled, and the metal material is shaped into new materials with varying tapers, diameters and shapes.
In subtractive manufacturing, shapes are created by reducing material. This differs from other types of manufacturing, such as additive manufacturing, where materials are added, layered and shaped to a specific form. It also differs from injection moulding, where the material is injected in a different form using a mould and shaped to a specific shape.
CNC machining is versatile – it can be used for a variety of materials such as metals, plastics, wood, glass, foam and other composite materials. This versatility has helped make CNC machining a popular choice across a range of industries, allowing designers and engineers to manufacture products efficiently and accurately.
Advantages Timeliness, Reliability, Accuracy, Robustness
CNC milling and turning is a highly accurate and repeatable process. Tight tolerances of +/-0.001″ to 0.005″ can be achieved, depending on specifications. CNC milling is a good way to produce parts on demand because the machine can be programmed to run reliably 24 hours a day, 7 days a week, if needed.
CNC machining, which uses standard tooling, is especially valuable for custom, one-off parts, i.e., replacing traditional components or providing special upgrades to customers. It is also possible to produce more than 10,000 units of a single part. Depending on the number of units, size and complexity, delivery time for components can be as short as one day. For shipping and delivery, it is possible to deliver within a week.
Another key advantage of CNC technology is the mechanical properties that can be achieved. By cutting from bulk material, rather than thermally converting it as in injection molding or additive manufacturing, all the desirable mechanical properties of the selected metal or plastic can be retained. 50+ industrial metals, alloys, and plastics can be CNC milled and turned. More than 50 industrial metals, alloys and plastics can be processed by CNC milling and turning. These include aluminum, brass, bronze, titanium, stainless steel, PEEK, ABS, and zinc. the only material required for CNC machining is to be hard enough for the part to be fixed and cut.