The Basics Of Cnc Machining And Programming

By Author: John sena
Total Articles: 50
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CNC machining and programming have revolutionized the creation of precision machined parts. Developed from older, conventional machine tools CNC machines offer unmatched precision and quality of work pieces. This allows machine shops with very small numbers of employees to carry on in the precision machining industry.

CNC Machining is the process that turns blank billets of material, usually metal alloys, into precision machined components used in industries such as aerospace, oil and natural gas, nuclear energy, paper products production, medical devices, and ship building. The full, complete terminology is 'CNC Precision Machining' where CNC stands for computer numerical control. Items fabricated by CNC machining might be small items like gears, oil jets, valve stems, fuel system couplings, collars, and pump fittings or big components like bulkheads, support stringers, and web assemblies as might be found in helicopters, jet fighters and vertical take-off and landing aircraft.

These machines are generally similar to, but much larger than routers and drill presses that might be found in a small garage. All cutting ...
... edge CNC equipment now in use by machine shops were developed from earlier machine tools which were known as numerically controlled (NC) machine tools. Those early machines from the 1940s and 1950s used punched tape to feed control points into the system that defined the motion of the cutting heads or drill bits. The addition of computers to the machines and the use of computer software to create the programs that are fed into the machines is the key development that defines CNC machining.

Currently the first step in creating a part of some kind by the CNC machining process is to model the part with 3D computer aided design (CAD) software. Then the model is passed over to computer aided manufacturing (CAM) software which analyzes the model and generates all of the numerical data necessary to control and direct the cutting paths the machine will use to make the part. This data is saved as a program which will be fed to the CNC machines. Once the program is approved it is usually tested on inexpensive materials, such as wood or plastic, to check for any flaws in the process. If any are found they are documented and the program goes back to the programmer who adjusts its parameters to fix whatever them problem may be.

The next major step is to create a blank piece of material, sometimes called a billet, that will be used to create the part. With metal parts for the aerospace industry the usual practice is to cast the part to the rough shape of the final part. This cast piece will be slightly larger in all dimensions than the desired final part. Once the billet is loaded into the machine the program is activated and the CNC machine starts systematically cutting away the excess material. An operator is required to load the billets and unload the finished parts and also to monitor the machine while it executes the program. CNC machines are expensive but one operator can load and monitor two or three machines and the parts they produce are very precise and accurate and this is repeatable whether 2, 5, 10, or 25000 finished pieces are needed.

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