Understanding CNC Machining 101


With any endeavour, a profound understanding of the nuances involved is always helpful in avoiding the accompanying pitfalls as well as extracting optimum utility from that skill or method. This rings true with CNC machining as well. In this article, we are going to wholly examine CNC machining and gain a robust understanding about the field: what it means, its methods, its advantages, and its disadvantages.

Modern CNC services are automated and employ the use of computer-aided design (CAD) and computer-aided manufacturing (CAM) software. Usually, an engineer will input the design instructions by hand for the more simple design specifications and will employ the use of CAD and/or CAM software with more complex design work. Coordinate Measuring Machines (CMM’s) are also used to physically map objects to the system. Once the part is designed in the system, the software automatically formulates a series of steps that are followed systematically until the end goal is reached. During production, the machines follow these steps and the resulting end product are parts that are completely identical in every measurable metric.

In order to fully understand CNC machining, it is important to understand the implements used and they include:

  • Lathes are machines that cut cylindrical workpieces by rotating them at fast speeds against a stationary cutting tool. Because the cutting action on a lathe is uniform, they can only make symmetrical cuts. Lathes are used in making parts such as shafts and bushings.
  • Electricaldischargemachines (EDMs) remove and form material using an electrical discharge. These machines typically work with hard metals which are much more difficult to machine via other methods.
  • Grinders/grinding machines are tools used to grind down parts using abrasive wheels as cutting tools. Commonly used for high accuracy surface finishing, they can also grind larger volumes of metal depending on the application. They are typically the easiest type of CNC machine to work with.
  • Mills, or milling machines are cutting machines which solid shape (typically stationary) workpieces using a movable and rotatable cutting tool. They can perform anything from simple keyway cutting to complex contouring tasks, and come in either vertical or horizontal orientations.
  • Water/abrasive jet machines: These use abrasives added to water and propelled in a high velocity to cut workpieces. They are designed to cut and shape heat-sensitive, thin, brittle, or hard materials as they can form intricate shapes.

The applications for CNC machines are vast. CNC methods can be applied to drilling, milling, turning, broaching, deep drilling, etching, honing, jig boring, laser machining, screw machining, swiss machining, jet machining, and super abrasive machining to mention a few.

With regards to the materials that CNC services can work, there are actually a limited number and they depend on the capabilities of the equipment. Most equipment struggle to handle metals with high hardness without causing wear on the cutting tools. Some equipment also struggle with temperature sensitive materials.

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