What is CNC Machining?

Machining is an important part of many manufacturing operations; when performed manually, it takes a high degree of skill and a lot of time. Since skilled labor and time are a scarce resource, new machining processes have been developed that have been augmented by technology and automation. One of the most widely used forms of technology-driven machining is computer numerical controlled (CNC) machining.

What is CNC Machining?

CNC machining is a subtractive machining process that uses computers to control the motion of the tool being used. While computer numerical control can be used for a variety of manufacturing processes, CNC machining is specific to the subtractive process that is performed when a tool is used to remove material from a blank or other type of unfinished part. Computers set parameters such as tool travel velocity, tool revolutions per minute, working velocity, and position, in addition to many other variables that can be adjusted.

In its early stages, the numbers for a CNC machine were manually entered into a computer to create a CNC machining “program” using a computer language known as G-code. The program could then be repeated over and over as new workpieces were loaded into the machine. The CNC machining could be used to produce repetitive parts much faster than manual methods.

Today, CNC machining typically does not use much G-code. Instead, parts are drawn using a computer-aided design software, and from that the numbers that the computer needs for positional data in the CNC program can be extracted. Other parameters such as travel speed and tool revolutions still need to be entered in by a CNC programmer. It is also common for a teach pendant to be used to guide the tool to a certain spot and save the positional data, which are a combination of numbers sent to the computer and saved in a CNC machining program. Sometimes, the program may be created by having a human physically moving the arm of a tool to a position and saving the location data to the CNC program.

Why is CNC Machining Used?

CNC machining is used for a host of reasons. One of the primary drivers of the proliferation of CNC machining today is speed. CNC machining can perform repetitive machining operations much faster than a manual machining operation. When there is a high-volume project that can be automated, CNC machining is typically a great way to improve productivity and output.

Accuracy and repeatability are other key areas where CNC machining excels. The numerical data used by the computer during CNC machining moves the tool to the virtually exact desired location. CNC machining not only goes to the exact location, but it can do it thousands, hundreds of thousands, and even millions of times repeatedly.

Another reason why CNC machining is used is because of the lack of skilled labor that is required for manual machining operations. Skilled machining labor can be difficult to come by, and if there is machining labor available, then it typically comes at a high price. Since manual machining is slower, it also comes at a high price/volume of product.

Safety is one other major reason why CNC machining is frequently used. Machining can be an extremely dangerous manufacturing process. There are sharp tools, heavy objects, high velocities, and large amounts of high voltage electricity being used. When a human can be taken out of that environment, it can greatly reduce the risk of injury to personnel.

Where is CNC Machining Used?

CNC machining can be used for many different applications. Popular applications of CNC machining include:

  • Automotive components such as pistons and shafts
  • Aerospace parts such as jet engine equipment and body parts
  • Structures such as building supports and lifts
  • Ornaments and metal artwork
  • Polymers
  • Ceramics
  • Many others…

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